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Federal Registers - Table of Contents
• Publication Date: 08/24/2006
• Publication Type: Final Rules
• Fed Register #: 71:50121-50192
• Standard Number: 1910; 1915; 1926
• Title: Assigned Protection Factors; Final Rule


[Federal Register: August 24, 2006 (Volume 71, Number 164)]
[Rules and Regulations]               
[Page 50121-50192]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24au06-14]                         

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Part II


Department of Labor


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Occupational Safety and Health Administration


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29 CFR Parts 1910, 1915, and 1926

Assigned Protection Factors; Final Rule

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DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910, 1915, and 1926

[Docket No. H049C]
RIN 1218-AA05

 
Assigned Protection Factors

AGENCY: Occupational Safety and Health Administration (OSHA), 
Department of Labor.

ACTION: Final rule.

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SUMMARY: In this final rule, OSHA is revising its existing Respiratory 
Protection Standard to add definitions and requirements for Assigned 
Protection Factors (APFs) and Maximum Use Concentrations (MUCs). The 
revisions also supersede the respirator selection provisions of 
existing substance-specific standards with these new APFs (except for 
the respirator selection provisions of the 1,3-Butadiene Standard).
    The Agency developed the final APFs after thoroughly reviewing the 
available literature, including chamber-simulation studies and 
workplace protection factor studies, comments submitted to the record, 
and hearing testimony. The final APFs provide employers with critical 
information to use when selecting respirators for employees exposed to 
atmospheric contaminants found in general industry, construction, 
shipyards, longshoring, and marine terminal workplaces. Proper 
respirator selection using APFs is an important component of an 
effective respiratory protection program. Accordingly, OSHA concludes 
that the final APFs are necessary to protect employees who must use 
respirators to protect them from airborne contaminants.

DATES: The final rule becomes effective November 22, 2006.

ADDRESSES: In compliance with 28 U.S.C. 2212(a), the Agency designates 
Joseph M. Woodward, the Associate Solicitor for Occupational Safety and 
Health, Office of the Solicitor, Room S-4004, U.S. Department of Labor, 
200 Constitution Avenue, NW., Washington, DC 20210, as the recipient of 
petitions for review of this rulemaking.

FOR FURTHER INFORMATION CONTACT: For technical inquiries regarding this 
final rule, contact Mr. John E. Steelnack, Directorate of Standards and 
Guidance, Room N-3718, OSHA, U.S. Department of Labor, 200 Constitution 
Ave., NW., Washington, DC 20210; telephone (202) 693-2289 or fax (202) 
693-1678. For general inquiries regarding this final standard contact 
Kevin Ropp, OSHA Office of Public Affairs, Room N-3647, U.S. Department 
of Labor, 200 Constitution Ave., NW., Washington, DC 20210 (telephone 
(202) 693-1999). Copies of this Federal Register notice are available 
from the OSHA Office of Publications, Room N-3101, U.S. Department of 
Labor, 200 Constitution Ave., NW., Washington, DC 20210 (telephone 
(202) 693-1888). For an electronic copy of this notice, as well as news 
releases and other relevant documents, go to OSHA's Web site (http://www.osha.gov),
and select "Federal Register," "Date of Publication," and then "2006".

SUPPLEMENTARY INFORMATION:

I. General

A. Table of Contents

    The following Table of Contents identifies the major preamble 
sections of this final rule and the order in which they are presented:

I. General
    A. Table of Contents
    B. Glossary
II. Events Leading to the Final Standard
    A. Regulatory History of APFs
    B. Non-Regulatory History of APFs
    C. Need for APFs
III. Methodology for Developing APFs for Respirators
    A. Introduction
    B. Background
    C. Methodology, Data, and Studies on Filtering Facepieces and 
Elastomerics
    D. Alternative Approaches
    E. Updated Analyses
    F. Summary of Studies Submitted During the Rulemaking
IV. Health Effects
V. Summary of the Final Economic Analysis and Initial Regulatory 
Flexibility Analysis
    A. Introduction
    B. The Rule and Affected Respirator Users
    C. Compliance Costs
    D. Benefits
    E. Economic Feasibility
    F. Economic Impacts to Small Entities
VI. Summary and Explanation of the Final Standard
    A. Definition of Assigned Protection Factor
    B. APF Provisions
    C. Assigned Protection Factors for Specific Respirator Types
    1. APF for Quarter Mask Air-Purifying Respirators
    2. APF for Half Mask Air-Purifying Respirators
    3. APF for Full Facepiece Air-Purifying Respirators
    4. APF for Powered Air-Purifying Respirators (PAPRs)
    5. APF for Supplied-Air Respirators (SARs)
    6. APF for Self-Contained Breathing Apparatuses (SCBAs)
    D. Definition of Maximum Use Concentration
    E. MUCs for Mixtures and Hazard Ratios
    F. MUC Provisions
    G. Superseding the Respirator Selection Provisions of Substance-
Specific Standards in Parts 1910, 1925, and 1926
VII. Procedural Determinations
    A. Legal Considerations
    B. Paperwork Reduction Act
    C. Federalism
    D. State Plans
    E. Unfunded Mandates
    F. Applicability of Existing Consensus Standards
List of Subjects in 29 CFR Parts 1910, 1915, and 1926
Authority and Signature
Amendments to Standards

B. Glossary
    This glossary specifies the terms represented by acronyms, and 
provides definitions of other terms, used frequently in the preamble to 
the final rule. This glossary does not change the legal requirements in 
this final rule, nor is it intended to impose new regulatory 
requirements on the regulated community.
1. Acronyms
ACGIH: American Conference of Governmental Industrial Hygienists
AIHA: American Industrial Hygiene Association
ANSI: American National Standards Institute
APF: Assigned Protection Factor
APR: Air-purifying respirator
Ci: Concentration measured inside the respirator facepiece
Co: Concentration measured outside the respirator
DOP: Dioctylphthalate (see definition below)
DFM: Dust, fume, and mist filter
EPF: Effective Protection Factor (see definition below under 
"Protection factor study")
HEPA: High efficiency particulate air filter (see definition below)
IDLH: Immediately dangerous to life or health (see definition below)
LANL: Los Alamos National Laboratory
LASL: Los Alamos Scientific Laboratory
LLNL: Lawrence Livermore National Laboratory
MSHA: Mine Safety and Health Administration
MUC: Maximum Use Concentration
NFPA: National Fire Protection Association
NIOSH: National Institute for Occupational Safety and Health
NRC: Nuclear Regulatory Commission
OSHA: Occupational Health and Safety Administration
OSH Act: The Occupational Safety and Health Act of 1970 (29 U.S.C. 655, 
657, 665).
PAPR: Powered air-purifying respirator (see definition below)
PEL: Permissible Exposure Limit
PPF: Program Protection Factor (see definition below under "Protection 
factor study")
QLFT: Qualitative fit test (see definition below)
QNFT: Quantitative fit test (see definition below)
RDL: Respirator Decision Logic (see definition below)
REL: Recommended Exposure Limit (see definition below)
SAR: Supplied-air (or airline) respirator (see definition below)
SCBA: Self-contained breathing apparatus (see definition below)
WPF: Workplace Protection Factor (see definition below under 
"Protection factor study")
TLV: Threshold Limit Value (see definition below)
SWPF: Simulated Workplace Protection Factor (see definition below under 
"Protection factor study")
2. Definitions
    Terms followed by an asterisk (*) refer to definitions that can be 
found in paragraph (b) ("Definitions") of OSHA's Respiratory 
Protection Standard (29 CFR 1910.134).
    Air-purifying respirator*: A respirator with an air-purifying 
filter, cartridge, or canister that removes specific air contaminants 
by passing ambient air through the air-purifying element.
    Atmosphere-supplying respirator*: A respirator that supplies the 
respirator user with breathing air from a source independent of the 
ambient atmosphere, and includes SARs and SCBA units.
    Canister or cartridge*: A container with a filter, sorbent, or 
catalyst, or combination of these items, which removes specific 
contaminants from the air passed through the container.
    Continuous flow respirator: An atmosphere-supplying respirator that 
provides a continuous flow of breathable air to the respirator 
facepiece.
    Demand respirator*: An atmosphere-supplying respirator that admits 
breathing air to the facepiece only when a negative pressure is created 
inside the facepiece by inhalation.
    Dioctylphthalate (DOP): An aerosolized agent used for quantitative 
fit testing.
    Elastomeric: A respirator facepiece made of a natural or synthetic 
elastic material such as natural rubber, silicone, or EPDM rubber.
    Filter or air-purifying element*: A component used in respirators 
to remove solid or liquid aerosols from the inspired air.
    Filtering facepiece (or dust mask)*: A negative pressure 
particulate respirator with a filter as an integral part of the 
facepiece or with the entire facepiece composed of the filtering 
medium.
    Fit factor*: A quantitative estimate of the fit of a particular 
respirator to a specific individual and typically estimates the ratio 
of the concentration of a substance in ambient air to its concentration 
inside the respirator when worn.
    Fit test*: The use of a protocol to qualitatively or quantitatively 
evaluate the fit of a respirator on an individual.
    Helmet*: A rigid respiratory inlet covering that also provides head 
protection against impact and penetration.
    High-efficiency particulate air filter (HEPA)*: A filter that is at 
least 99.97% efficient in removing monodisperse particles of 0.3 
micrometers in diameter. The equivalent NIOSH 42 CFR part 84 
particulate filters are the N100, R100, and P100 filters.
    Hood*: A respiratory inlet covering that completely covers the head 
and neck and may also cover portions of the shoulders and torso.
    Immediately dangerous to life or health (IDLH)*: An atmosphere that 
poses an immediate threat to life, would cause irreversible adverse 
health effects, or would impair an individual's ability to escape from 
a dangerous atmosphere.
    Loose-fitting facepiece*: A respiratory inlet covering that is 
designed to form a partial seal with the face.
    Negative pressure respirator (tight-fitting)*: A respirator in 
which the air pressure inside the facepiece is negative during 
inhalation with respect to the ambient air pressure outside the 
respirator.
    Permissible Exposure Limit (PEL): An occupational exposure limit 
specified by OSHA.
    Positive pressure respirator*: A respirator in which the pressure 
inside the respiratory inlet covering exceeds the ambient air pressure 
outside the respirator.
    Powered air-purifying respirator (PAPR)*: An air-purifying 
respirator that uses a blower to force the ambient air through air-
purifying elements to the inlet covering.
    Pressure demand respirator*: A positive pressure atmosphere-
supplying respirator that admits breathing air to the facepiece when 
the positive pressure is reduced inside the facepiece by inhalation.
    Protection factor study: A study that determines the protection 
provided by a respirator during use. This determination generally is 
accomplished by measuring the ratio of the concentration of an airborne 
contaminant (e.g., hazardous substance) outside the respirator (Co) to 
the concentration inside the respirator (Ci) (i.e., Co/Ci). Therefore, 
as the ratio between Co and Ci increases, the protection factor 
increases, indicating an increase in the level of protection provided 
to employees by the respirator. Four types of protection factor studies 
are:
    Effective Protection Factor (EPF) study: A study, conducted in the 
workplace, that measures the protection provided by a properly 
selected, fit-tested, and functioning respirator when used 
intermittently for only some fraction of the total workplace exposure 
time (i.e., sampling is conducted during periods when respirators are 
worn and not worn). EPFs are not directly comparable to WPF values 
because the determinations include both the time spent in contaminated 
atmospheres with and without respiratory protection; therefore, EPFs 
usually underestimate the protection afforded by a respirator that is 
used continuously in the workplace.
    Program Protection Factor (PPF) study: A study that estimates the 
protection provided by a respirator within a specific respirator 
program. Like the EPF, it is focused not only on the respirator's 
performance, but also the effectiveness of the complete respirator 
program. PPFs are affected by all factors of the program, including 
respirator selection and maintenance, user training and motivation, 
work activities, and program administration.
    Workplace Protection Factor (WPF) study: A study, conducted under 
actual conditions of use in the workplace, that measures the protection 
provided by a properly selected, fit-tested, and functioning 
respirator, when the respirator is worn correctly and used as part of a 
comprehensive respirator program that is in compliance with OSHA's 
Respiratory Protection Standard at 29 CFR 1910.134. Measurements of Co 
and Ci are obtained only while the respirator is being worn during 
performance of normal work tasks (i.e., samples are not collected when 
the respirator is not being worn). As the degree of protection afforded 
by the respirator increases, the WPF increases.
    Simulated Workplace Protection Factor (SWPF) study: A study, 
conducted in a controlled laboratory setting and in which Co and Ci 
sampling is performed while the respirator user performs a series of 
set exercises. The laboratory setting is used to control many of the 
variables found in workplace studies, while the exercises simulate the 
work activities of respirator users. This type of study is designed to 
determine the optimum performance of respirators by reducing the impact 
of sources of variability through maintenance of tightly controlled study 
conditions.
    Qualitative fit test (QLFT)*: A pass/fail fit test to assess the 
adequacy of respirator fit that relies on the individual's response to 
the test agent.
    Quantitative fit test (QNFT)*: An assessment of the adequacy of 
respirator fit by numerically measuring the amount of leakage into the 
respirator.
    Recommended Exposure Limit (REL): An occupational exposure level 
recommended by NIOSH.
    Respirator Decision Logic (RDL): Respirator selection guidance 
developed by NIOSH that contains a set of respirator protection 
factors.
    Self-contained breathing apparatus (SCBA)*: An atmosphere-supplying 
respirator for which the breathing air source is designed to be carried 
by the user.
    Supplied-air respirator (or airline) respirator (SAR)*: An 
atmosphere-supplying respirator for which the source of breathing air 
is not designed to be carried by the user.
    Threshold Limit Value (TLV): An occupational exposure level 
recommended by ACGIH.
    Tight-fitting facepiece*: A respiratory inlet covering that forms a 
complete seal with the face.

II. Events Leading to the Final Standard

A. Regulatory History of APFs

    Congress established the Occupational Safety and Health 
Administration (OSHA) in 1970, and gave it the responsibility for 
promulgating standards to protect the health and safety of American 
workers. As directed by the OSH Act, the Agency adopted existing 
Federal standards and national consensus standards developed by various 
organizations such as the NFPA and ANSI. The ANSI standard Z88.2-1969, 
"Practices for Respiratory Protection," was the basis of the first 
six sections (permissible practice, minimal respirator program, 
selection of respirators, air quality, use, maintenance and care) of 
OSHA's Respiratory Protection Standard (29 CFR 1910.134) adopted in 
1971. The seventh section was a direct, complete incorporation of ANSI 
Standard K13.1-1969, "Identification of Gas Mask Canisters."
    The Agency promulgated an initial respiratory protection standard 
for the construction industry (29 CFR 1926.103) in April 1971. On 
February 9, 1979, OSHA formally applied 29 CFR 1910.134 to the 
construction industry (44 FR 8577). Federal agencies that preceded OSHA 
developed the original maritime respiratory protection standards in the 
1960s (e.g., Section 41 of the Longshore and Harbor Worker Compensation 
Act). The section designations adopted by OSHA for these standards, and 
their original promulgation dates, are: Shipyards--29 CFR 1915.82, 
February 20, 1960 (25 FR 1543); Marine Terminals--29 CFR 1917.82, March 
27, 1964 (29 FR 4052); and Longshoring--29 CFR 1918.102, February 20, 
1960 (25 FR 1565). OSHA incorporated 29 CFR 1910.134 by reference into 
its Marine Terminal standards (Part 1917) on July 5, 1983 (48 FR 
30909). The Agency updated and strengthened its Longshoring and Marine 
Terminal standards in 1996 and 2000, and these standards now 
incorporate 29 CFR 1910.134 by reference.
    Under the Respiratory Protection Standard that OSHA initially 
adopted, employers were required to follow the guidance of the Z88.2-
1969 ANSI standard to ensure proper selection of respirators. 
Subsequently, OSHA published an Advance Notice of Proposed Rulemaking 
("ANPR") to revise the Respiratory Protection Standard on May 14, 
1982 (47 FR 20803). Part of the impetus for this notice was the 
Agency's inclusion of new respirator requirements in the comprehensive 
substance-specific standards promulgated under section (6)(b) of the 
OSH Act, e.g., fit testing protocols, respirator selection tables with 
assigned protection factors, use of PAPRs, changing filter elements 
whenever an employee detected an increase in breathing resistance, and 
referring employees with breathing difficulties, either at fit testing 
or during routine respirator use, to a physician trained in pulmonary 
medicine (see, e.g., 29 CFR 1910.1025 (OSHA's Lead Standard)). The 
respirator provisions in these substance-specific standards reflected 
advances in respirator technology and changes in related guidance 
documents that were state-of-the-art information at the time when OSHA 
published these substance-specific standards. These standards 
recognized that effective respirator use depends on a comprehensive 
respiratory protection program that includes the use of APFs.
    In the 1982 ANPR, OSHA sought information on the effectiveness of 
its current Respiratory Protection Standard, the need to revise the 
standard, and recommendations regarding what revisions should be made. 
The 1982 ANPR referenced the ANSI Z88.2-1980 standard on respiratory 
protection with its table of protection factors, the 1976 report by Ed 
Hyatt from LASL titled "Respiratory Protection Factors" (Ex. 2), and 
the RDL developed jointly by OSHA and NIOSH, as revised in 1978 (Ex. 9, 
Docket No. H049). The 1982 ANPR asked for comments on how OSHA should 
use protection factors. The Agency received 81 responses to this 
inquiry. The commenters generally supported revising OSHA's Respiratory 
Protection Standard, and provided recommendations regarding approaches 
for including a table of protection factors (Ex. 15).
    On September 17, 1985, OSHA announced the availability of a 
preliminary draft of the proposed Respiratory Protection Standard. This 
preproposal draft standard included a discussion of the public comments 
received in response to the 1982 ANPR, and OSHA's analysis of revisions 
needed in the Respiratory Protection Standard to address up-to-date 
respiratory protection. The Agency received 56 responses from 
interested parties (Ex. 36), which OSHA carefully reviewed in 
developing the proposed rule.
    On November 15, 1994, OSHA published the proposed rule to revise 29 
CFR 1910.134, and provided notice of an informal public hearing on the 
proposal (59 FR 58884). The Agency convened the informal public hearing 
on June 6, 1995. In response to the comments OSHA received on the 
proposal, the Agency proceeded to develop APFs. On June 15, 1995, as 
part of the public hearing, OSHA held a one-day panel discussion by 
respirator experts on APFs. The discussion included measuring 
respirator performance in WPF and SWPF studies, the variability of data 
from these studies, and setting APFs for various types of respirators 
that protect employees across a wide variety of workplaces and exposure 
conditions.
    OSHA also reopened the rulemaking record for the revised 
Respiratory Protection Standard on November 7, 1995 (60 FR 56127), 
requesting comments on a study performed for OSHA by Dr. Mark Nicas 
titled "The Analysis of Workplace Protection Factor Data and 
Derivation of Assigned Protection Factors" (Ex. 1-156). This study, 
which the Agency placed in the rulemaking docket on September 20, 1995, 
addressed the use of statistical modeling for determining respirator 
APFs. OSHA received 12 comments on the Nicas report. This report, and 
the comments received in response to it, convinced OSHA that more 
information would be necessary before the Agency could resolve the 
complex issues regarding how to establish APFs, including what methodology
to use in analyzing existing protection factor studies. (See Section IV. 
Methodology for Developing Assigned Protection Factors in the June 6, 2003 
NPRM, 68 FR 34044, for a detailed discussion of the Nicas report and the 
comments OSHA received.)
    OSHA published the final, revised Respiratory Protection Standard, 
29 CFR 1910.134, on January 8, 1998 (63 FR 1152). The standard contains 
worksite-specific requirements for program administration, procedures 
for respirator selection, employee training, fit testing, medical 
evaluation, respirator use, and other provisions. However, OSHA 
reserved the sections of the final standard related to APFs and MUCs 
pending further rulemaking (see 63 FR 1182 and 1203). The Agency stated 
that, until a future rulemaking on APFs is completed:

    [Employers must] take the best available information into 
account in selecting respirators. As it did under the previous 
[Respiratory Protection] standard, OSHA itself will continue to 
refer to the [APFs in the 1987 NIOSH RDL] in cases where it has not 
made a different determination in a substance specific standard. (63 
FR 1163)

The Agency subsequently established a separate docket (i.e., H049C) for 
the APF rulemaking. This docket includes copies of material related to 
APFs that previously were placed in the docket (H049) for the revised 
Respiratory Protection Standard. The APF rulemaking docket also 
contains other APF-related materials, studies, and data that OSHA 
obtained after it promulgated the final Respiratory Protection Standard 
in 1998.
    On June 6, 2003, the Agency published in the Federal Register an 
NPRM titled "Assigned Protection Factors; Proposed Rule" (68 FR 
34036) that contained proposed definitions for APFs and MUCs, a 
proposed Table 1 with APFs for the various respirator classes, and 
proposed revisions to the APF provisions and tables in OSHA's 
substance-specific standards. The NPRM announced that OSHA would be 
holding an informal public hearing in Washington, DC on the proposal. 
The public hearings were held over three days, from January 28-30, 
2004. OSHA received extensive pre-hearing comments (Exs. 9-1 through 9-
43 and 10-1 through 10-60), written hearing testimony (Exs. 16-1 
through 16-25), post-hearing comments (Exs. 17-1 through 17-12), and 
post-hearing briefs (Exs. 18-1 through 18-9 and 19-1 through 19-8). 
Transcripts of the public hearings also were made and added to the APF 
Docket (Exs. 16-23-1, 16-23-2, and 16-23-3). It is from these public 
comments, exhibits, hearing transcript, and post-hearing submissions 
that OSHA has prepared these final APF and MUC provisions and revisions 
to substance-specific standards.

B. Non-Regulatory History of APFs

    In 1965, the Bureau of Mines published "Respirator Approval 
Schedule 21B," which contained the term "protection factor" as part 
of its approval process for half mask respirators (for protection up to 
10 times the TLV) and full facepiece respirators (for protection up to 
100 times the TLV). The Bureau of Mines based these protection factors 
on quantitative fit tests, using DOP, that were conducted on six male 
test subjects performing simulated work exercises.
    The Atomic Energy Commission (AEC) published proposed protection 
factors for respirators in 1967, but later withdrew them because 
quantitative fit testing studies, which the AEC used to determine APFs, 
were available for some, but not all, types of respirators. To address 
this shortcoming, the AEC sponsored respirator performance studies at 
LASL, starting in 1969.
    ANSI standard Z88.2-1969, which OSHA adopted by reference in 1971, 
did not contain APFs for respirator selection. Nevertheless, this ANSI 
standard recommended that "due consideration be given to potential 
inward leakage in selecting devices," and contained a list of the 
various respirators grouped according to the expected quantity of 
leakage into the facepiece during routine use.
    In 1972, NIOSH and the Bureau of Mines published new approval 
schedules for respiratory protection under 30 CFR 11. However, these 
new approval schedules did not include provisions for determining 
facepiece leakage as part of the respirator certification process.
    NIOSH sponsored additional respirator studies at LASL, beginning in 
1971, that used quantitative test systems to measure the overall 
performance of respirators. In a 1976 report titled "Respirator 
Protection Factors", Edwin C. Hyatt of LASL included a table of 
protection factors for: single-use dust respirators; quarter mask, half 
mask, and full facepiece air-purifying respirators; and SCBAs (Ex. 2). 
Hyatt based these protection factors on data from DOP and sodium 
chloride quantitative fit test studies performed at LASL on these 
respirators between 1970 and 1973. The table also contained recommended 
protection factors for respirators that had no performance test data. 
Hyatt based these recommended protection factors on the judgment and 
experience of LASL researchers, as well as extrapolations from 
available facepiece leakage data for similar respirators. For example, 
Hyatt assumed that performance data for SCBAs operated in the pressure-
demand mode could be used to represent other (non-tested) respirators 
that maintain positive pressure in the facepiece, hood, helmet, or suit 
during inhalation. In addition, Hyatt recommended in his report that 
NIOSH continue testing the performance of respirators that lacked 
adequate fit test data. To increase the database, Hyatt used a 
representative 35-person test panel to conduct quantitative fit tests 
from 1974 to 1978 on all air-purifying particulate respirators approved 
by the Bureau of Mines and NIOSH.
    In August 1975, the Joint NIOSH-OSHA Standards Completion Program 
published the RDL (Ex. 25-4, Appendix F, Docket No. H049). The RDL 
contained a table of protection factors that were based on quantitative 
fit testing performed at LASL and elsewhere, as well as the expert 
judgment of the RDL authors. In 1978, NIOSH updated the RDL specifying 
the following protection factors:

5 for single-use respirators;
10 for half mask respirators with DFM or HEPA filters;
50 for full facepiece air-purifying respirators with HEPA filters or 
chemical cartridges;
1,000 for PAPRs with HEPA filters;
1,000 for half mask SARs operated in the pressure-demand mode;
2,000 for full facepiece SARs operated in the pressure-demand mode; and
10,000 for full facepiece SCBAs operated in the pressure-demand mode.

    ANSI's Respiratory Protection Subcommittee ("Subcommittee") 
decided to revise Z88.2-1969 in the late 1970s. During its 
deliberations, the Subcommittee conducted an extensive discussion 
regarding the role of respirator protection factors in an effective 
respiratory protection program. As a result, the Subcommittee decided 
to add an APF table to the revised standard. In May 1980, ANSI 
published the revision as Z88.2-1980 which contained the first ANSI 
Z88.2 respirator protection factor table (Ex. 10, Docket H049). The 
ANSI Subcommittee based the table on Hyatt's protection factors, which 
it updated using results from fit testing studies performed at LANL and 
elsewhere since 1973. For example, the protection factor for full 
facepiece air-purifying particulate respirators was 100 when 
qualitatively fit tested, or 1,000 when equipped with HEPA filters and 
quantitatively fit tested. The table consistently gave higher protection 
factors to tight-fitting facepiece respirators when employers performed 
quantitative fit testing rather than qualitative fit testing. The ANSI 
Subcommittee concluded that PAPRs (with any respiratory inlet covering), 
atmosphere-supplied respirators (in either a continuous flow or pressure-demand
mode), and pressure-demand SCBAs required no fit testing because they operated 
in a positive-pressure mode. ANSI assigned high protection factors to these
respirators, but limited their use to concentrations below the IDLH values. 
Pressure-demand SCBAs and combination continuous flow or pressure-demand airline 
respirators with escape provisions for use in IDLH atmospheres were 
assigned protection factors of 10,000 plus.
    In response to a complaint to NIOSH that the PAPRs used in a 
workplace did not appear to provide the expected protection factor of 
1,000, Myers and Peach of NIOSH conducted a WPF study during silica-
bagging operations. Myers and Peach tested half mask and full facepiece 
PAPRs under these conditions, and found protection factors that ranged 
from 16 to 215. They published the results of their study in 1983 
(Ex.1-64-46). The results of this study led NIOSH and other 
researchers, as well as respirator manufacturers, to perform additional 
WPF studies on PAPRs and other respirators.
    NIOSH revised its RDL in 1987 (Ex. 1-54-437Q) to address advances 
in respirator technology and testing. The revision retained many of the 
provisions of the 1978 RDL, but also lowered the APFs for other 
respirators based on NIOSH's WPF studies. For example, the APFs were 
lowered for the following respirator classes: PAPRs with a loose-
fitting hood or helmet (reduced to 25); PAPRs with a tight-fitting 
facepiece and a HEPA filter (lowered to 50); supplied-air continuous 
flow hoods or helmets (decreased to 25); and supplied-air continuous 
flow tight-fitting facepiece respirators (reduced to 50).
    In August 1992, ANSI again revised its Z88.2 Respiratory Protection 
Standard (Ex. 1-50). The ANSI Z88.2-1992 standard contained a revised 
APF table, based on the Z88.2 Subcommittee's review of available 
protection factor studies. In a report describing the revised standard 
(Ex. 1-64-423), Nelson, Wilmes, and daRoza described the rationale used 
by the ANSI Subcommittee in setting APFs:

    If WPF studies were available, they formed the basis for the 
[APF] number assigned. If no such studies were available, then 
laboratory studies, design analogies, and other information [were] 
used to decide what value to place in the table. In all cases where 
the assigned protection factor changed when compared to the 1980 
standard, the assigned number is lower in the 1992 standard.

In addition, the 1992 ANSI Z.88.2 standard abandoned ANSI's 1980 
practice of giving increased protection factors to some respirators 
when quantitative fit testing was performed.
    Thomas Nelson, the co-chair of the ANSI Z88.2-1992 Subcommittee, 
published a second report entitled "The Assigned Protection Factor 
According to ANSI" (Ex. 135) four years after the Z88.2 Subcommittee 
completed the revised 1992 standard. In the report, Nelson reviewed the 
reasoning used by the ANSI Subcommittee in setting the 1992 ANSI APFs. 
Nelson noted that the Z88.2 Subcommittee gave an APF of 10 to all half 
mask air-purifying respirators, including quarter mask, elastomeric, 
and disposable respirators. The Subcommittee also recommended that full 
facepiece air-purifying respirators retain an APF of 100 (from the 1980 
ANSI standard) because no new data were available to justify another 
value. Nelson noted that the Z88.2 Subcommittee approved the RDL's 
reduction to an APF of 25 for loose-fitting facepieces and PAPRs with 
helmets or hoods based on their performance in WPF studies. For half 
mask PAPRs, the ANSI Subcommittee set an APF of 50 based on a WPF study 
by Lenhart (Ex. 1-64-42). The ANSI Subcommittee had no WPF data 
available for full facepiece PAPRs, so Nelson indicated that the 
Subcommittee selected an APF of 1,000 to be consistent with the APF for 
PAPRs with helmets or hoods. The Subcommittee, in turn, based its APF 
of 1,000 for PAPRs with helmets or hoods on design similarities (i.e., 
same facepiece designs, operation at the same airflow rates) between 
these respirators and airline respirators. Nelson noted that the 
results from a subsequent WPF report by Keys (Ex. 1-64-40) on PAPRs 
with helmets or hoods were consistent with an APF of 1,000. According 
to Nelson, the Subcommittee used WPF studies by Myers (Exs. 1-64-47 and 
1-64-48), Gosselink (Ex. 1-64-23), and Que Hee and Lawrence (Ex. 1-64-
60) to set an APF of 25 for PAPRs with loose-fitting facepieces. Nelson 
stated that two WPF studies, conducted by Gaboury and Burd (Ex. 1-64-
24) and Stokes (Ex. 1-64-66) subsequent to publication of ANSI Z88.2-
1992, supported the APF of 25 selected by the Subcommittee for PAPRs 
with loose-fitting facepieces.
    Nelson also stated in his report that the ANSI Subcommittee had no 
new information on atmosphere-supplying respirators. Therefore, the 
APFs for these respirators were based on analogies with other similarly 
designed respirators (Ex. 135). The ANSI Subcommittee based the APF of 
50 for half mask continuous flow atmosphere-supplying respirators, and 
the APF of 25 for loose-fitting continuous flow atmosphere-supplying 
respirators, on the similarities between these respirators and PAPRs 
with the same airflow rates. Nelson noted that the ANSI Subcommittee 
set the APF of 1,000 for full facepiece continuous flow atmosphere-
supplying respirators consistent with the APF for SARs with helmets or 
hoods using the results of two earlier studies: a WPF study by Johnson 
(Ex. 1-64-36) and a SWPF study by Skaggs (Ex. 1-38-3). The Subcommittee 
used the design analogy between PAPRs and continuous flow supplied-air 
respirators to select the APF of 50 for half mask pressure-demand SARs 
and an APF of 1,000 for full facepiece pressure-demand SARs. Nelson 
stated, "The committee believed that setting a higher APF because of 
the pressure-demand feature was not warranted, but rather that the 
total airflow was critical" (Ex. 135).
    Nelson noted in the report that the Subcommittee selected no APF 
for SCBAs. In explaining the committee's decision, he stated that "the 
performance of this type of respirator may not be as good as previously 
measured in quantitative fit test chambers." Nelson also observed that 
the ANSI Z88.2-1992 standard justified this approach in a footnote to 
the APF table. The footnote states:

    A limited number of recent simulated workplace studies concluded 
that all users may not achieve protection factors of 10,000. Based 
on [these] limited data, a definitive assigned protection factor 
could not be listed for positive pressure SCBAs. For emergency 
planning purposes where hazardous concentrations can be estimated, 
an assigned protection factor of no higher than 10,000 should be 
used.

    A new ANSI Z88.2 Subcommittee recently finished revising the ANSI 
Z88.2-1992 standard, in accordance with the ANSI policy specifying that 
each standard receive a periodic review. This revised ANSI Z88.2 
standard is currently under appeal to the ANSI Board.

C. Need for APFs

    When OSHA published the final Respiratory Protection Standard in 
January 1998, it noted that the revised standard was to "serve as a 
`building block' standard with respect to future standards that may 
contain respiratory protection requirements" (63 FR 1265).
OSHA's final Respiratory Protection Standard established the minimum 
elements of a comprehensive program that are necessary to ensure 
effective performance of a respirator. The only parts missing from this 
building block standard are the APF and MUC provisions that are being 
finalized in this rulemaking. In the standard the Agency recommended 
that employers in the interim "take the best information into account 
in selecting respirators. As it did under the previous standard, OSHA 
itself will continue to refer to the NIOSH APFs in cases where it has 
not made specific compliance interpretations" (63 FR 1203).
    In October 2004, NIOSH published its Respirator Selection Logic 
(RSL), an update of the 1987 RDL. The APF tables in the new RSL have 
not changed from those in the 1987 RDL. However, NIOSH stated in the 
forward to the 2004 RSL: "[w]hen the OSHA standard on APFs is 
finalized NIOSH intends to consider revisions to this RSL." (Ex. 20-
4.)
    The ANSI Z88.2-1992 APF table also has been a source for interim 
APFs while OSHA completed its APF rulemaking. However, the ANSI Z88.2-
1992 respiratory protection standard was withdrawn by ANSI in 2003. 
While a revised ANSI Z88.2 standard has been written, the final ANSI 
standard has yet to be published since it is currently under appeal. 
Therefore, no ANSI respiratory protection standard with recommended 
APFs is available at this time. The draft APF table from the ANSI Z88.2 
revision was submitted to the OSHA rulemaking docket (Ex.13-7-2), and 
was the subject of discussion during the public hearings on APFs. OSHA 
considered the draft ANSI table during its deliberations in this 
rulemaking.
    Throughout the Respiratory Protection Standard rulemaking, OSHA has 
emphasized that the APF and MUC definitions and the APF table are an 
integral part of the overall standard. A careful review of the 
submitted comments and information supports the Agency's conclusion 
that this final standard is necessary to guide employers in selecting 
the appropriate class of respirator needed to reduce hazardous 
exposures to acceptable levels. The final APF for a class of 
respirators specifies the workplace level of protection that a class of 
respirator should provide under an effective respiratory protection 
program. In addition, the APFs can be utilized by employers to 
determine a respirator's MUC for a particular chemical exposure 
situation.
    The final APFs must be used in conjunction with the existing 
provisions of the Respiratory Protection Standard. Integration of the 
final APF and MUC provisions into the reserved provisions of paragraph 
(d) completes that standard. With the addition of these provisions, 
appropriate implementation of the Respiratory Protection Standard by 
employers in their workplaces should afford each affected employee the 
maximum level of respiratory protection.

III. Methodology for Developing APFs for Respirators

A. Introduction

    In the proposed rule for Assigned Protection Factors (APFs), OSHA 
raised a number of issues or questions about its proposed methodology 
for deriving APFs (68 FR 34112-34113). OSHA asked for information on: 
(1) The evidence-based method used by OSHA in developing the proposed 
APFs; (2) any additional studies that may be useful in determining APFs 
that were not already identified by OSHA in the proposal; and, (3) 
statistical analyses, treatments, or approaches, other than those 
described in the proposal, available for differentiating between, or 
comparing, the respirator performance data. The vast majority of the 
comments in response to the NPRM addressed the use of WPF studies for 
establishing the APF for filtering facepiece half mask respirators. 
OSHA also received comments on the methodology and data it used for 
determining the filtering facepiece APF, and was provided with new 
studies on these respirators for consideration. OSHA's quantitative 
analyses for establishing the APFs for other classes of higher 
performing respirators drew little comment, and no new studies on these 
respirators were submitted. This section, therefore, focuses on 
methodology and new information relative to the APF for half mask air-
purifying respirators.
    More specifically, Part C of this section contains a discussion of 
the comments about OSHA's proposed methodology for determining APFs for 
filtering facepiece half mask respirators, including comments on data 
analysis and study selection. In addition, OSHA is providing an 
overview of Dr. Kenny Crump's statistical analyses (Ex. 20-1) of the 
updated half mask database (Ex. 20-2). Comments about alternative 
approaches are discussed in Part D ("Methodology, Data, and Studies on 
Filtering Facepieces and Elastomerics"). The Agency's overall 
conclusions on methodology, and summaries of new studies submitted 
during the public comment process, are presented under Part E. 
Discussion of the comments and opinions regarding the APF for half mask 
respirators and the establishment of the APFs for higher performing 
respirators is included in Section VI, Summary and Explanation of the 
Final Standard.

B. Background

    The Occupational Safety and Health Act of 1970 ("OSH Act"), 29 
U.S.C. 651-678, enacted to ensure safe and healthy working conditions 
for employees, empowers OSHA to promulgate standards and provides 
overall guidance on how these standards are to be developed. It states:

    (5) The Secretary, in promulgating standards dealing with toxic 
materials or harmful physical agents under this subsection, shall 
set the standard which most adequately assures, to the extent 
feasible, on the basis of the best available evidence, that no 
employee will suffer material impairment of health or functional 
capacity even if such employee has regular exposure to the hazard 
dealt with by such standard for the period of his working life. 
Development of standards under this subsection shall be based upon 
research, demonstrations, experiments, and such other information as 
may be appropriate. In addition to the attainment of the highest 
degree of health and safety protection for the employee, other 
considerations shall be the latest available scientific data in the 
field, the feasibility of the standards, and experience gained under 
this and other health and safety laws. Whenever practicable, the 
standard promulgated shall be expressed in terms of objective 
criteria and of the performance desired. 29 U.S.C. 655(b)(5) 
[emphasis added].

A reviewing court will uphold standards set under this section when 
they are supported by substantial evidence in the record considered as 
a whole (29 U.S.C. 655(f)). In searching for the "best available 
evidence" upon which to base its rulemaking, OSHA is required to 
"identify the relevant factual evidence, * * * to state candidly any 
assumptions on which it relies, and to present its reasons for 
rejecting any significant contrary evidence or argument." Public 
Citizen Health Research Group v. Tyson, 796 F.2d 1479, 1495 (D.C. Cir. 
1986).

    OSHA has retained the multifaceted approach it used in the proposal 
to determine the APFs for classes of respirators. That is, the Agency 
reviewed all of the available literature, including the various 
analyses by respirator authorities, as well as quantitative analyses of 
data from WPF and SWPF studies. During revision of the overall 
Respiratory Protection Standard, the Agency used a similar approach 
when reviewing protection factor studies related to the effectiveness 
and necessity of a comprehensive respiratory protection program.

    The Agency did not use Effective Protection Factor (EPF) and 
Program Protection Factor (PPF) studies in its APF analyses since these 
measure deficiencies in respirator program practices. More 
specifically, EPFs are not directly comparable to WPF values because 
the determinations include the time spent in contaminated atmospheres 
both with and without respiratory protection. PPFs are affected by any 
deficient elements of a respirator program, including inadequate 
respirator selection and maintenance, poor user training and 
motivation, work activities, and inadequate program administration. 
Therefore, OSHA relied on WPF and SWPF studies, since they focus on the 
performance characteristics of the respirator only.
    During the APF rulemaking, OSHA reviewed the extensive literature 
on APFs and developed selection criteria for including studies and data 
in its quantitative analysis of respirator performance. This procedure 
ensured that only carefully designed and executed WPF and SWPF studies 
were included in the analysis. The Agency then used these studies to 
compile the NPRM's original database. The database was comprised of 917 
data points from 16 WPF studies for half mask respirators (Matrix 1) 
and 443 data points from 13 studies for PAPRs and SARs (Matrix 2), 
conducted in a variety of American workplaces. OSHA made the studies, 
its selection criteria, the data, and its analyses available to the 
public electronically and through the rulemaking docket. In addition, 
the Agency encouraged the public to access this information and to 
reanalyze the data using methods of their choice. The Agency also 
sought submissions from the public of any additional studies for 
inclusion in its database. Four additional WPF studies of half masks 
were submitted during the public comment period following publication 
of the NPRM. Dr. Kenny Crump updated the Matrix 1 half mask database 
with these additional studies (Ex. 20-2) and reanalyzed the resulting 
1,339 data points for half mask respirators (Ex. 20-1).
    Dr. Crump also performed a second quantitative analysis in which 
the 1,339 accepted data points (original NPRM database updated with 
data from the four new studies) for half mask respirators were combined 
with 403 data points from 12 studies that the Agency originally 
excluded from the analysis. This second analysis corroborated the 
original findings to the extent practicable. The results of both of 
these analyses provide compelling support of OSHA's conclusions 
regarding the appropriate APF for half mask respirators. The Agency 
believes that the database it constructed represents the best available 
data on APFs, and that its conclusions are based on substantial 
evidence. See Texas Independent Ginners' Association v. Marshall, 630 
F.2d 398, 413 n. 48 (5th Cir. 1980), citing Industrial Union Dept., 
AFL-CIO-CIC v. American petroleum Institute, 448 U.S. 607, 661 (1980).
    In past rulemakings, OSHA's conclusions as to the best available 
evidence have been upheld as based on substantial evidence when it has 
relied on a body of reputable scientific evidence. See ASARCO v. 
Occupational Safety and Health Administration, 746 F.2d 483, 494 (9th 
Cir. 1984). OSHA need not accept all data presented to it as long it 
considers the data and rejects it on reasonable grounds. See id. 
Furthermore, each study relied upon by the Agency need not be a model 
of textbook scientific inquiry, and OSHA need not find one definitive 
study supporting its decision. Public Citizen Health Research Group, 
796 F.2d at 1489, 1495. Rather, the Agency is justified in adopting a 
conclusion when the cumulative evidence is compelling. Id. at 1489, 
1491, 1495. OSHA's conclusions are strongest when it has relied on 
multiple data sources that support each other, as it has in this 
rulemaking.

C. Methodology, Data, and Studies on Filtering Facepieces and 
Elastomerics

1. Comments on the Methodology
    OSHA developed the proposed APFs through a multi-faceted approach. 
As it stated in the preamble to the proposal, "The Agency reviewed the 
various analyses of respirator authorities, available WPF and SWPF 
studies, and other APF literature." It later concluded that "the APFs 
proposed by OSHA in this rulemaking represent the Agency's evaluation 
of all available data and research literature i.e., a composite 
evaluation of all relevant quantitative and qualitative information" 
(68 FR 34050). OSHA then asked the public if this method was 
appropriate to determine APFs. The methodology was supported by a 
number of commenters, including NIOSH (Ex. 9-13), the Department of the 
Army (Ex. 9-42), ALCOA (Ex. 10-31), and others (e.g., Exs. 9-1, 9-4, 9-
14, 9-16, 9-22, 10-2, 10-17, 10-18, and 10-59). NIOSH stated:

    NIOSH agrees that the APF values resulting from this multi-
faceted approach are reasonable indications of the level of 
protection that should be expected for each class of respirators. * 
* *
    The available data are not ideal because there can be 
considerable model-to-model variation and only a few models in each 
class have been evaluated. Given that lack of complete data, the 
approach taken by OSHA is the most appropriate currently possible. 
(Ex. 9-13.)

    The United States Army Center for Health Promotion and Preventive 
Medicine commented:

    The method of APF development used by OSHA is appropriate. OSHA 
reviewed available data, both published and unpublished; utilized 
technical reviews and summaries from subject matter experts outside-
OSHA; weighed study findings and conclusions based on study 
shortfalls, as then state-of-the-art technical bias and procedural 
omissions; and used a conservative approach to maintain confidence 
that minimal risk of respirator selection and use errors will exist 
in worker protection from proposed APF use. (Ex. 9-42-1.)

    Nevertheless, some commenters did not agree with OSHA's approach. 
These participants included several labor organizations (Exs. 9-27, 9-
29, 9-34, 9-40, and 10-37), trade associations (Exs. 9-24 and 10-27), 
and individuals (e.g., Exs. 9-17, 9-25, 9-33, 9-41, 10-33, and 10-42). 
Criticisms of OSHA's approach focused on the Agency's selection of WPF 
studies for its determination of the proposed APFs. Reasons given to 
support these criticisms included: The differences between the studies 
do not permit comparison of the studies; the study conditions are not 
representative of typical workplaces; the study data are too old; the 
data do not cover all configurations of filtering facepieces available; 
and, the analytical method employed by some studies was too sensitive.
    A few commenters (Exs. 10-34 and 10-47) recommended that certain 
criteria should be met before a WPF study is deemed acceptable for 
analysis. These criteria include: Exposures to small particle sizes; 
work time of at least four hours; moderate to heavy work rate; and, 
high temperature and humidity. Still others believed that OSHA should 
develop and perform SWPFs on a representative subset of all filtering 
facepieces or all configurations of filtering facepiece respirators and 
all respirator models, and establish APFs for all classes of 
respirators based on the SWPF study results (Exs. 9-41 and 10-27). A 
more detailed discussion of data issues is presented below.
2. Comments on Data and Study Problems
    Selection bias in WPF studies. Several commenters stated that the 
authors of WPF studies "cherry-picked" either the workplaces in which 
the studies were conducted or the individual tasks that were performed 
by workers chosen for monitoring (Pascarella, Tr. at 464; Faulkner, 
Tr. at 549 and 564-565). "Cherry-picking" is a common term for 
"selection bias." Selection bias is a matter of concern when either 
workplace study participants or job tasks are selected for inclusion in 
the study in a manner that skews the results of the study away from the 
true value.
    Selection bias is a matter of concern for all scientific studies, 
not just WPF studies, and peer reviewers typically evaluate its effects 
before a study is accepted for publication in a peer-reviewed journal. 
Most of the studies included in OSHA's analysis of WPF studies were 
either published in peer-reviewed journals or were presented at the 
AIHCE, and met the criteria for respirator research studies accepted by 
the industrial hygiene community. The half mask database consists of 16 
studies performed in a variety of workplaces over a range of years 
(from 1976 to 2004) by many different researchers. Therefore, it is 
highly improbable that these studies were subject to selection bias. 
OSHA could find no instance of selection bias either in its review of 
the scientific studies or its analysis of the data. Finally, OSHA 
repeatedly asked commenters who raised concerns about "cherry-
picking" for specific studies in which selection bias occurred. In no 
case did the commenters provide any details to support their 
allegations.
    Observer effect in WPF studies. Several commenters (Shine, Tr. at 
644 and Macaluso, Tr. at 652) stated that data from the WPF studies 
considered by OSHA were the result of a condition known as the 
"observer effect." The observer effect occurs when the act of 
observing or monitoring test subjects causes their responses to differ 
from their usual (nonobserved) responses. In some of the WPF studies 
used by OSHA, the researchers stated that during the study, they were 
present to monitor the test equipment to ensure that the sampling 
equipment functioned properly, thereby increasing the usefulness of the 
results. In other WPF studies, the researchers did not indicate their 
presence during the study.
    The mere presence of an observer does not, in and of itself, 
presume that there will be an observer effect. For example, if the 
observer is a researcher who is monitoring the test equipment instead 
of a supervisor who is monitoring the workers' practices, the workers 
are unlikely to change their practices.
    Although the Agency repeatedly asked the commenters who raised this 
concern to identify specific studies in which the observer effect may 
have been involved, they could not do so (i.e., in no case did the 
commenters provide any example to support their allegations). In its 
own analysis of the WPF studies, the Agency was also unable to find any 
evidence of an observer bias.
    Representativeness of the data. A number of commenters expressed 
concern that the study data analyzed by OSHA were not representative of 
conditions found in the construction industry (Ex. 9-29, Building 
Construction Trades Department), or of workplace conditions in general 
(e.g., Exs. 9-34, International Union Operating Engineers; 9-35, 
Melissa Rich; 9-40, United Steel Workers of America; and 10-60, Paul 
Hewett). The bulk of these concerns are represented in the comments of 
Melissa Rich, a Department of Energy respirator program manager, who 
stated:

    The selection of the test sites for the cited APF proposed 
rulemaking WPF studies are not representative of the worksite for 
American workers. Many test sites chosen for these studies were 
selected on availability only. Moreover, key study attributes such 
as hot humid conditions, long work hours, and heavy workload were 
the exception, not the norm for most of the cited studies. Most test 
sites had ambient concentrations less than the OSHA half mask 
respirator maximum use limit (i.e., ten times the PEL).
* * * * *
    The various particle sizes, a critical issue in a WPF, cited in 
many of the APF proposed rule Workplace Protection Factor studies 
are so large that they do not penetrate the faceseal. Many 
respiratory protection studies have indicated that particles larger 
than two microns are less likely to penetrate the most important 
attribute of a respirator, the faceseal. Most of the APF proposed 
rule Workplace Protection Factor studies have a particle size 
greater than two microns. (Ex. 9-35.)

    The studies analyzed by OSHA consisted of a varied cross-section of 
workplaces and conditions. For example, workplaces included ship 
breaking, asbestos removal, aluminum and lead smelters, brass 
foundries, and aircraft painting and manufacturing. Two of the four new 
studies analyzed by OSHA involved concrete-block manufacturing. The 
authors of an aluminum smelter study (Ex. 1-64-24) noted that employees 
were required to rest in a cool area for 50% of each hour due to high 
heat, and a steel mill study (Ex. 1-64-50) and a primary lead smelter 
study (Ex. 1-64-42) both were conducted in the sinter plant and blast 
furnace areas. The asbestos study (Ex. 1-64-54) was conducted under 
high humidity conditions. Tasks performed by test subjects included 
welding and grinding, torch cutting, pouring molten metal, handling 
concrete blocks, and spray painting. Work rates for these studies, when 
provided, ranged from low to heavy.
    The purpose of a WPF study is to evaluate a respirator's 
effectiveness under actual workplace use conditions. Consequently, the 
contaminant concentrations and particle sizes contained in the analyzed 
studies were generated while the workers performed their normal job 
duties. With regard to concerns about particle size, Myers et al. 
(Ex.1-64-51) found particles larger than 10 microns inside the 
respirator facepiece. The Agency believes that accepting only WPF 
studies that are conducted at exposure levels close to 10 times the 
PEL, with particulates of two microns in size or less, would not be 
representative of the conditions found in the workplace. Studies based 
on such selective criteria would be more akin to a SWPF, rather than a 
WPF, study. OSHA has concluded that the data used in its analyses are 
applicable to other American work settings because a range of work 
rates and environmental conditions were represented, and many of the 
tasks performed by the test subjects are performed in a variety of 
workplaces, including construction. Accordingly, the Agency is not 
persuaded by comments suggesting that the studies were so narrowly 
focused that the data cannot be applied to other work settings.
    Sensitive analytical method. Several commenters questioned the use 
of sensitive analytical methods for the analyses of workplace 
exposures, sometimes accompanied by a recommendation to test 
respirators under controlled laboratory settings, and at sufficiently 
high concentrations to obtain inside-the-facepiece measurements (Ci) 
that can be assessed by less sensitive methods (e.g., Exs. 9-32, 9-35, 
10-6, 10-37, and 10-49). The commenters believed that sensitive 
analytical methods (particularly PIXEA, proton-induced x-ray emission 
analysis) permit the determination of low Ci concentrations, resulting 
in high protection factors.
    In response to these comments, OSHA reviewed the seven half mask 
studies that used the PIXEA analytical method (Exs. 1-64-19, 1-64-51, 
1-64-52, 1-64-15, 1-64-16, and 1-64-34) and found that six of the 
studies used the method to measure both the Ci and Co concentrations. 
The seventh study (Ex. 3-12) used PIXEA to measure the Ci concentration 
but used atomic absorption (AA) to assess Co concentrations because the 
respirator filters were overloaded. However, the Agency does not believe 
that this study provided inaccurate results. Under conditions of high Co 
concentrations, the AA method must be used because the PIXEA method would 
exceed its maximum measurement limits. Therefore, the PIXEA method would 
be unable to provide accurate Co data. Based on its review of these seven 
studies, the Agency found that the sensitive analytical method (i.e., PIXEA) 
allowed the investigators to quantify small amounts of contaminant that 
penetrate a respirator. This method permitted accurate assessment of Ci 
concentrations under conditions of low ambient concentrations, thereby 
permitting the use of actual Ci values in determining WPFs. Less sensitive 
methods would result in penetration values that are nondetectable or less 
than the limit of detection (LOD) for the analytic method, thereby requiring 
the study to discard these data or to correct for nondetected values using 
unvalidated statistical techniques. On the other hand, the sensitive 
analytical method was able to quantify low Ci concentrations, thereby 
enhancing the validity of the subsequent analysis by retaining the 
actual data and avoiding unvalidated statistical corrections.
    Craig Colton of 3M provided the following testimony in support of 
OSHA's conclusions:

    Some commenters also asserted that the use of analytical methods 
with low detection limits are a reason to invalidate some of the WPF 
studies. The claim is erroneously made that the analytical 
sensitivity affects the results from WPF studies. However, the 
actual amount of contaminant on the Ci sample is not changed by the 
analytical method.
    * * * Because the [Ci levels are] typically very small in a WPF 
study, the higher sensitivity of [the PIXEA method] is necessary to 
get the best data.
    * * * The WPF protocol from the AIHA Respirator Committee 
recommended the use of analytical methods with sensitive detection 
limits. * * * Use of less sensitive analytical methods for * * * 
[Ci] sample[s] that result in nondetect values are not meaningful 
for determining true exposure. (Tr. at 413-414.)

    In its post-hearing comments, 3M illustrated the value of sensitive 
analytical methods using the following example:

    [C]onsider three filters "spiked with 1 [mu]g of silicon each 
and analyzed by three different methods [gravimetric, atomic 
absorption (AA), and PIXEA]. In the case of gravimetric and AA 
analyses, it is certain only that the silicon mass on the filter is 
between 0 [mu]g and 10 [[mu]g] or 0 [mu]g and 5 [mu]g respectively. 
However, PIXE[A] has sufficient analytical sensitivity to "find" 
the true value of 1 [mu]g. Because the mass of contaminants on a Ci 
filter is typically very small in a WPF study, the higher 
sensitivity of PIXE[A] is necessary to get the best data. (Ex. 19-3-
1.)

    Tom Nelson commented that "[t]he analytical method must be 
sensitive for a WPF study. For a half facepiece respirator[,] the 
detection limit should be at least \1/100\ of the ambient 
concentration" (Ex. 18-9). Later in these comments, Nelson stated, 
"The [low-concentration Ci] samples are part of the distribution of 
WPF samples collected during a study. These represent true measures of 
performance."
    Based on the evidence in the record, OSHA concludes that using 
sensitive analytic methods for assessing Ci samples is both necessary 
and appropriate. Specifically, the Agency sees no scientific basis for 
excluding WPF studies that used PIXEA, particularly when using the 
method to determine both Ci and Co. The Agency's review of the record 
evidence shows that a leading national organization representing 
industrial hygienists (i.e., the AIHA) recommends using sensitive 
analytic methods for assessing Ci samples. Furthermore, using sensitive 
analytic methods improves significantly the validity of data analyses 
by allowing studies to retain low Ci values, and by reducing 
substantially the need to use unvalidated techniques to correct low Ci 
values. Therefore, OSHA concludes that the data from the WPF studies 
used in its analyses are accurate, and that the availability of data 
with low Ci values improved the validity of the APFs derived from these 
analyses.
    Large particles. Several commenters (e.g., Exs. 9-33, 9-35, 10-6, 
10-37, and 10-41) postulated that larger particles (greater than one or 
two microns) do not penetrate a respirator's faceseal. They believed 
that WPF studies having large particles in the Co concentration should 
be excluded from OSHA's analyses. They reasoned that these large 
particles were being measured as part of the Co but had no chance of 
being measured in the Ci, and consequently were inflating the WPF 
values.
    These commenters appear to be ignoring the possibility that half 
masks (both elastomerics and filtering facepieces) with faceseals that 
selectively filter large particles still are capable of providing an 
adequate level of protection. Nevertheless, OSHA notes that in one of 
the WPF studies used in OSHA's data analyses, Myers et al. found large 
particles (i.e., 10 microns in diameter) inside the facepiece, 
indicating that large particles are capable of penetrating a respirator 
faceseal (Ex. 1-64-51). Consistent with these results, Tom Nelson 
stated in his comments that "[t]he particle size of contaminants in 
the various WPF studies in the docket range from [about] 0.5 [microns] 
to 14 [microns] MMAD," and that "particles much larger than those 
that would be predicted from laboratory studies have been found inside 
the facepiece in WPF studies" (Ex. 18-9). At the hearing, Nelson 
presented data showing that large particles enter half mask 
respirators, probably through breaks in the faceseal; moreover, these 
data demonstrate that no relationship exists between particle size and 
the WPF obtained for the respirator (Tr. at 146-148). The 3M Company 
addressed this point further, stating in its comments:

    Laboratory studies have shown that particle losses occur through 
fixed leaks. A faceseal leak is not accurately represented by a 
fixed leak, however. To perform these studies[,] assumptions were 
made regarding leak size, shape, and the particle size penetrating 
those leaks. These assumptions have been shown to be wrong. Myers 
has shown that large particles can be found inside the facepiece[,] 
much larger than could have occurred with the fixed leaks used by 
several researchers.[] As shown in Figure 1 [of the Myers et al. 
study], an analysis of particle size and the geometric mean WPF from 
a number of studies does not show any relationship between particle 
size and WPF. If the size of the particle played a role in faceseal 
leaks, a relationship would be evident. (Ex. 9-16.)

    Based on the evidence in the record, OSHA concludes that the data 
in its APF analyses for half masks were the same as particle sizes 
found in the workplaces represented in the WPF studies. Therefore, 
eliminating the study data from the Agency's analyses would be 
unnecessary and inappropriate.
    Probe bias. Probe bias refers to the misplacement of the sampling 
probe when taking measurements inside the respirator facepiece. Some 
commenters expressed concern that probe bias may have underestimated Ci 
in the half mask WPF studies analyzed by Dr. Brown (e.g., Exs. 9-17, 9-
30, 9-35, and 10-42). These commenters suggested that OSHA reanalyze 
its database after applying a correction factor to account for probe 
bias. Tim Roberts provided a specific description of this concern when 
he testified:

    Respirator probe error is an issue. It's been better 
characterized for elastomeric type respirators than it has for 
filtering facepiece respirators, and we think that this needs some 
additional work as well, to characterize what that means when we put 
probes in different locations in elastomeric facepieces (Tr. at 
208).

    Later in the hearings, Ching-tsen Bien questioned Craig Colton of 
3M on Colton's experiences with probe location while conducting 
filtering facepiece WPF studies. Colton responded:

    [S]treamlining that you see is similar to that in the 
elastomeric half-facepieces. You see it streamlining from the leak 
up to the mouth and nose. And so what Dr. Myers indicated in his 
sampling bias--not really probe bias, but the sampling bias--was 
that location becomes important because if your probe is flushed 
with the facepiece, you can miss the streamlines. So his 
recommendation was that the probe needs to be ideally on the 
midline, between the mouth and the nose, and as close to the face as 
possible. And so that's what we attempt to do as best as you can 
with the products you end up testing to meet his recommendations. 
(Tr. at 455-456.)

    Colton also noted that, although some of his studies may show 
probes entering the side of the filtering facepiece, a probe extension 
was used to place the sampling inlet in the nose-mouth area (Tr. at 
455-456). Tom Nelson explained the purpose of the probe location when 
he commented, "The sampling probe is placed so that it is close to the 
nose and mouth. This minimizes sampling bias" (Ex. 18-9). Warren Myers 
testified that, in unusual circumstances, the configuration of a half 
mask (including some elastomerics) requires placing the sampling probe 
on the side of the mask instead of the centerline between the nose and 
the mouth; in these cases, a study can control for sampling bias by 
randomly alternating the location of the probe on the right and left 
side of the mask (Tr. at 77).
    OSHA also reviewed the 13 half mask studies analyzed by Dr. Brown. 
The authors of nine of these studies specifically state that the probe 
was located in the area of the nose and mouth. While the remaining four 
studies do not specify the probe's location, no evidence from this 
rulemaking indicates that the sampling probes were inappropriately 
placed. Therefore, the majority of the WPF studies, along with the new 
studies included in the updated database, located the sampling probe in 
the nose-mouth area. Of the 1,339 data points in the updated database, 
approximately 220 of these points (about 16%) are from the four studies 
in which no information on probe placement was available. OSHA believes 
the sampling methodology that was used in these studies was consistent 
with comments indicating that the optimum location for a probe is at 
the centerline between the nose and the mouth. At this location, the 
probe will sample any streamlining that occurs between a faceseal leak 
and the nose-mouth area, thereby detecting the maximum Ci exposure 
level. In addition, no analysis was submitted indicating that the data 
from these studies, whether corrected for probe bias or excluded 
altogether, would have resulted in APFs that differed from the final 
APFs derived from this rulemaking.
3. Summary and Conclusion
    OSHA considered the comments addressing the data and study problems 
identified by commenters, but does not find that these comments merit 
rejection of the data or analyses. The studies OSHA analyzed were 
conducted on employees in actual workplaces who were performing their 
normal job duties. Consequently, the particle sizes, work rates, work 
times, and environmental conditions varied among these studies. The 
Agency has concluded that using data collected under these various 
conditions presents a more accurate picture of workplace use of these 
respirators and is a better measure of the protection provided by half 
mask respirators than data collected only from SWPF or other highly 
controlled studies.

D. Alternative Approaches

1. Alternatives Based on Non-Compliant Respirator Programs
    Several commenters suggested alternative means for ascertaining 
APFs. While not completely disagreeing with OSHA's approach, Paul 
Hewett of Exposure Assessment Solutions Incorporated (Ex. 10-60) stated 
that OSHA should include EPF studies in its APF deliberations. He 
commented that EPF studies account for actual use conditions in that 
they factor in the time that the employee does not wear the respirator 
but is still exposed to atmospheric contaminants. He also believed that 
determination of an appropriate APF should represent respirator use in 
hot, strenuous jobs. Therefore, he recommended that "OSHA should 
factor in real world conditions and not rely exclusively on WPF and 
particularly SWPF studies" (Ex. 10-60.)
    OSHA noted in the proposal that the Agency would analyze only WPF 
and SWPF studies since they address respirator performance exclusively 
(68 FR 34045). This alternative approach already has been addressed 
above by the Agency in its discussion of the usefulness of WPF data. 
The Agency has no data in the record showing that EPF studies would 
improve, or even complement, its analyses. Therefore, OSHA is not 
convinced that EPF data would increase the validity of the APFs derived 
in this final rule. The discussion of an EPF study by Harris et al. 
(Ex. 27-11; 63 FR 1167) substantiates these conclusions.
    Ching-tsen Bien of LAO Consulting, Inc. (Ex. 18-5) wanted OSHA to 
enter into the record any available independent assessment reports (and 
applicable check lists) for the year prior to, and for the year of, 
each WPF study. Bien noted that the reports would have covered 
applicable program elements, and ensure that OSHA selected studies for 
its analyses that were in compliance with appropriate respiratory 
protection standards. He also requested that OSHA enter the "selection 
criteria, decision matrix for each study, and the review report for 
these studies to the H-049C Docket" (Ex. 18-5.)
    As stated in the NPRM at 68 FR 34046, the Agency evaluated all 
studies used in its analyses for compliance with the requirements of 
OSHA's Respiratory Protection Standard (29 CFR 1910.134), as well as 
for completeness of the data. The Agency also compiled a list of 
criteria (Ex. 5-5) for evaluating each study. Accordingly, OSHA 
evaluated each published article or each written study report to 
determine whether the test subjects were trained properly, fit tested, 
medically evaluated, and in compliance with the requirements of the 
OSHA Respiratory Protection Standard. The researchers performing these 
WPF studies ensured that fit testing was performed on the test 
subjects, trained them on doffing and donning the respirator, as well 
as the performance of user seal checks, on the selection of proper-
sized respirators, and on the other elements of a complete OSHA-
compliant respirator program. These researchers did not rely on the 
existing workplace respirator program, but instead performed the 
necessary actions to ensure that the test subjects in their WPF studies 
met the respirator program requirements.
    The WPF studies the Agency evaluated were either WPF studies that 
had been published previously, or were newly performed studies that 
were submitted during the rulemaking for inclusion in the OSHA 
database. OSHA did not perform these studies, and was not involved in 
the selection of the worksites being tested. Therefore, the Agency 
could not gather additional information on a worksite's respirator 
program that was in effect when a WPF study was performed, as Bien 
requested. Additionally, such information is irrelevant to the results 
of a WPF study since the researchers had to demonstrate compliance with 
the required respirator program before OSHA included the study in its 
database.

2. Alternatives Based on SWPF Studies
    The American Chemistry Council (Ex. 10-25) stated that OSHA's APFs 
should be based on SWPF studies, and that the APFs derived from this 
rulemaking should be used only as interim values until SWPF studies 
could be performed. OSHA notes that basing APFs on SWPF studies, rather 
than on WPF studies, was recommended by a number of commenters 
including Organizational Resource Counselors Worldwide (ORC) (Ex. 10-
27), Paper, Allied-Industrial, Chemical & Energy Workers International 
Union (PACE) (Ex. 10-37), and others (e.g., Exs. 9-32, 9-41, 10-6, 10-
49, 9-33, 9-35, and 18-5). These commenters expressed various concerns 
about the WPF studies, and stated that SWPF studies permit 
investigators to control a number of variables (e.g., particle size, 
contaminant concentration, environmental conditions) that cannot be 
controlled in WPF studies.
    SWPF studies use sensitive analytical methods, such as PIXEA, to 
obtain measurable Ci information. SWPF studies safely test a respirator 
in a high-concentration atmosphere (i.e., at the respirator's limit of 
protection) to generate enough penetration for the analytical method to 
quantify Ci results. OSHA agrees that SWPF testing permits an 
investigator to control factors such as particle size, contaminant 
concentration, temperature, and humidity. Accordingly, the Agency used 
data generated from all available SWPF studies in determining APFs. 
However, OSHA concluded that controlled SWPF studies alone are not 
representative of, nor can they be extrapolated readily to, typical 
workplaces. Standardized protocols for conducting such testing, or a 
methodology for extrapolating SWPF results to protection levels 
expected in the workplace, are not available. ORC stated, "We advocate 
development of a protocol based on a combination of laboratory testing 
and field trials for determining expected respirator performance" (Ex. 
10-27). NIOSH also supported the use of both SWPF and WPF studies, 
noting, "NIOSH agrees that the APF values resulting from OSHA's 
multifaceted approach to analysis of existing data provide reasonable 
values for the level of protection that should be expected for each 
class of respirators" (Tr. at 102). NIOSH continued, "Given this lack 
of complete data, the noted model-to-model variation and the 
imperfection in protection level measurements, the approach taken by 
OSHA is the best currently possible based upon available data" (Tr. at 
103). The Agency has concluded that its approach in using both WPF and 
SWPF studies is well supported by the rulemaking record and is 
appropriate for determining APFs specified in this final rule.
3. Model-Specific APFs
    The Organization Resources Counselors Worldwide (Ex. 10-27), the 
American Chemistry Council (Ex. 10-25), and the Pharmaceutical Research 
and Manufacturers of America (Ex. 9-24) urged OSHA to develop model-
specific APFs. Under this recommendation, each respirator model would 
undergo testing and be assigned a unique APF. NIOSH did not support 
this approach. In response to questioning by OSHA, NIOSH stated:

    This morning's expert witnesses and the questions I think 
clearly identified that there is variability, and because of this 
variability, we believe that class APFs are more appropriate and 
consistent with the state of the art today. In order to achieve more 
precise data, much, much larger data sets, including the numbers of 
test subjects that would have to be involved to eliminate this 
variability, seems impractical based upon the state of the art 
today. So we are for these reasons supporting class APFs, not model-
specific APFs. (Tr. at 120.)

    OSHA considered the use of SWPF studies in developing model-
specific APFs. The Agency's review of the ORC SWPF study of PAPRs and 
SARs in the proposal (68 FR 34069) stated that ORC had recommended that 
"the [ORC SWPF] study methodology should be the basis for determining 
APFs for all respiratory protective equipment regulated by OSHA" (68 
FR 34070). However, only a few SWPF studies are available that measured 
the performance of a few PAPRs and SARs. Model-specific SWPF studies 
for the remaining respirator classes have not been performed. In 
addition, the respirator protection community has not agreed on a 
standard protocol for conducting SWPF studies, or how the results 
relate to APFs. These issues would have to be addressed before it would 
be possible to use model-specific APFs. Also, insufficient data are 
available to set model-specific APFs, and developing the methodology 
and conducting the testing could take years. OSHA believes that 
completing the APF rulemaking with the information available now is 
necessary. Delaying this rulemaking to develop model-specific APFs will 
result in employers not knowing what respirators to select and, 
consequently, employees will not receive adequate protection. Based on 
the rulemaking record, the Agency has concluded it will determine an 
APF for each respirator class using information from existing WPF and 
SWPF studies.
4. Nicas-Neuhaus Model
    Several commenters (Paul Hewett, Ex. 10-60; Bill Kojola, AFL-CIO, 
Ex. 17-2; and NIOSH, Ex. 17-7-1) asked OSHA to consider a February 2004 
article by Nicas and Neuhaus (Ex. 17-7-2) that applies a model for 
analyzing WPF data to establish APFs. The Nicas-Neuhaus article is 
based on the variability of WPFs (i.e., the variability between 
different test subjects, as well as the variability within a test 
subject resulting from repeated donnings of the respirator). APFs based 
on this Nicas-Neuhaus model require that WPFs for 95% of all workers be 
above the APF 95% of the time. However, the established method for 
deriving APFs used by OSHA, NIOSH, and ANSI sets the APFs at the 95% 
percentile of the between-subject WPFs. By controlling for within-
subject variability, APFs based on the Nicas-Neuhaus model will always 
be smaller than APFs derived using the established method.
    To account for within-subject variability, the Nicas-Neuhaus model 
requires repeated measurements on each test subject which is not 
required by the established method. Consequently, most available WPF 
studies did not include multiple measures on individual test subjects, 
resulting in an extremely limited database for applying the Nicas-
Neuhaus model. Nicas and Neuhaus were able to analyze only seven half 
mask respirator studies, comprising a total of 310 data pairs. In 
comparison, the database established and analyzed by OSHA for 
determining the final APFs contains 1,339 data pairs from 16 half mask 
respirator studies. Also, OSHA had rejected for its analyses several of 
the WPF studies used by Nicas and Neuhaus in developing their model 
because these studies did not meet the Agency's selection criteria.
    The Nicas-Neuhaus model is a significant departure from established 
and accepted practices used by the respirator research community, The 
Agency has concluded that there are insufficient data to fully evaluate 
the proposed model, and to incorporate it in setting APFs.
5. Other Alternative Approaches
    Sheldon Coleman recommended that OSHA select a panel from AIHA 
members to review the APF data and OSHA's APF determinations (Ex.10-
40). OSHA believes this rulemaking has provided ample opportunity for 
comment from the public and professional associations. Further analysis 
would delay the development of the final APFs, and is unnecessary as 
the rulemaking record is sufficient to determine APFs.
6. Summary and Conclusion
    OSHA is relying on science, data, and established quantitative 
analyses to establish the final APFs for filtering facepiece and 
elastomeric half mask respirators, and is limiting its statistical 
analyses to those procedures that use the selected data to the fullest 
extent possible. Reliance on alternative approaches is not supported by 
the evidence in the record. The data to use such approaches are not 
currently available, and require either a different set of data or a 
standardized testing protocol that requires testing every respirator 
model. OSHA concludes that the available data and analytic methods used 
in determining the final APFs are appropriate.

E. Updated Analyses

1. Review of the Original WPF and SWPF Databases
    In developing its proposed rule regarding APFs for respirators, 
OSHA contracted with Dr. Kenneth Brown to investigate possible 
approaches for evaluating respirator performance data from WPF and SWPF 
studies. To assist Dr. Brown in this evaluation, the Agency reviewed 
the available studies and created a database from these studies. In 
deciding which WPF studies to include in this database, OSHA evaluated 
studies with respect to compliance with the requirements of its 
Respiratory Protection Standard (29 CFR 1910.134) and the completeness 
of the data. In doing so, the Agency excluded WPF studies of gas or 
vapor contaminants due to the limited number of these studies and the 
difficulties in conducting and interpreting data from such studies (68 
FR 34046). During the rulemaking, OSHA received new WPF data on half 
mask respirators. No new SWPF data were submitted for half masks, and 
no new WPF data were submitted for higher-performing respirators.
    In the NPRM, Dr. Brown initially divided negative pressure half 
mask air-purifying respirators (APRs) into five classes. Four classes 
of filtering facepiece half masks were derived based on whether a 
respirator had adjustable head straps, an exhalation valve, a double-
shell construction, or a foam-ring faceseal. Elastomeric half masks 
were grouped together in a single fifth class. (See Ex. 5-1 for details 
on respirator class definitions.) In his analyses, Dr. Brown found no 
clear evidence of a difference in WPFs across these different classes. 
In particular, he found that elastomeric half masks performed 
substantially the same as filtering facepieces. From the original 
database of 917 WPF measurements for negative pressure half mask APRs, 
36 WPF measurements (3.9%) were found to have an APF less than 10, and 
96.1% at 10 and above.
2. Updated OSHA Database on APRs
    In the NPRM, OSHA asked if any more WPF or SWPF studies should be 
considered in setting APFs. Data from four additional studies were 
submitted for OSHA's evaluation during the comment period, and an 
updated half mask database was compiled using these studies (Ex. 20-2). 
During the post-hearing comment period, the 3M Company provided OSHA 
with data from two additional WPF studies of filtering facepiece 
respirators. One study (Colton and Bidwell, Ex. 9-16-1-1) measured the 
performance of three different types of filtering facepiece respirators 
used by 21 workers at a lead-battery manufacturing plant. One 
respirator (3M 8710) was approved under 30 CFR part 11, and two 
respirators were N95 particulate respirators (3M 8210 and 3M 8510) 
approved under 42 CFR part 84. Up to three WPF measurements were made 
with each worker on each respirator type, for a total of 143 WPF 
measurements. The data submitted to OSHA from this study are provided 
in Appendix A of Dr. Crump's report on the reanalysis of the half mask 
database (Ex. 20-1).
    The second set of WPF data provided by 3M Company was from a study 
by Bidwell and Janssen (Ex. 9-16) on the performance of a "flat-fold" 
filtering facepiece respirator conducted at a concrete-block 
manufacturing facility. Repeated measurements of WPFs were made on 19 
workers, and each sample was analyzed for both silicon and calcium. A 
total of 73 Co and 73 Ci air samples were collected, for a total of 146 
WPF measurements. Eleven of the 146 Ci measurements were non-detectable 
(all coming from silicon exposures).
    The third study added to the database was a WPF study by Colton 
(Ex. 4-10-4) on the performance of an elastomeric half mask respirator. 
This study had been submitted earlier to OSHA, but was not included in 
the NPRM database since it was received too late for inclusion in Dr. 
Brown's original analysis. The data from this study, conducted in the 
battery-pasting and assembly areas of a battery manufacturing plant, 
have now been added to OSHA's updated database. Also, three additional 
data points from a study by Myers and Zhuang (Exs. 1-64-50 and 3-14) 
were added to the updated database. These data were collected in a 
concrete-block facility while elastomeric half mask respirators were 
worn as protection against calcium and silicon particulates.
    The updated OSHA half mask database (Ex. 20-2), summarized in Table 
III-1, contains 1,339 WPF measurements--760 collected from filtering 
facepiece respirators, and 579 from elastomeric respirators. The 
database originally analyzed by Dr. Brown contained 917 WPF 
measurements--471 from filtering facepieces, and 446 from elastomerics.

                                                   Table III-1.--Summary of OSHA WPF Database for APRs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                   Number       Number
            Respirator  class               Figure 1       Constituent sampled                Author              Exhibit No.   samples per  samples per
                                              No.                                                                                  study        class
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Filtering Facepiece Respirators
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.......................................            1  Asbestos...................  Dixon.....................         1-64-54           26          474
1.......................................            2  Fe.........................  Myers.....................   1-64-50, 3-14           21  ...........
1.......................................            3  Mn.........................  Wallis....................         1-64-70           69  ...........
1.......................................            4  Al.........................  Colton....................         1-64-15           23  ...........
1.......................................            5  Al.........................  Johnston..................         1-64-34           13  ...........
1.......................................            6  Si.........................  Johnston..................         1-64-34           15  ...........
1.......................................            7  Ti.........................  Johnston..................         1-64-34           18  ...........
1.......................................            8  Pb.........................  Colton & Bidwell..........        9-16-1-1          143  ...........
1.......................................            9  Si.........................  Bidwell & Janssen.........            9-16           73  ...........
1.......................................           10  Ca.........................  Bidwell & Janssen.........            9-16           73  ...........
3.......................................           11  Pb.........................  Myers.....................   1-64-51, 3-12           19          162
3.......................................           12  Zn.........................  Myers.....................   1-64-51, 3-12           20  ...........
3.......................................           13  Fe.........................  Colton....................           1-146           31  ...........
3.......................................           14  Mn.........................  Colton....................           1-146           32  ...........
3.......................................           15  Ti.........................  Colton....................           1-146           28  ...........
3.......................................           16  Zn.........................  Colton....................           1-146           32  ...........
4.......................................           17  Pb.........................  Colton....................         1-64-16           62          124
4.......................................           18  Zn.........................  Colton....................         1-64-16           62  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Elastomeric Respirators
--------------------------------------------------------------------------------------------------------------------------------------------------------
5.......................................           19  Asbestos...................  Dixon.....................         1-64-54           46          579
5.......................................           20  B(a)Pyrene.................  Gaboury...................         1-64-24           18  ...........
5.......................................           21  Pb.........................  Lenhart...................         1-64-42           25  ...........
5.......................................           22  Pb.........................  Myers.....................   1-64-51, 3-12           46  ...........
5.......................................           23  Zn.........................  Myers.....................   1-64-51, 3-12           46  ...........
5.......................................           24  Fe.........................  Myers.....................   1-64-50, 3-14           30  ...........
5.......................................           25  Cr.........................  Myers.....................    1-64-52, 4-5           35  ...........
5.......................................           26  Ti.........................  Myers.....................    1-64-52, 4-5           33  ...........
5.......................................           27  Cd.........................  Colton....................         1-64-13           68  ...........
5.......................................           28  Pb.........................  Colton....................         1-64-13           57  ...........
5.......................................           29  Pb.........................  Dixon & Nelson............         1-64-19           42  ...........
5.......................................           30  Pb.........................  Colton....................          4-10-4          130  ...........
5.......................................           31  Calcium....................  Myers.....................   1-64-50, 3-14            3  ...........
                                         ---------------------------------------------------------------------------------------------------------------
    Grand Total.........................  ...........  ...........................  ..........................  ..............  ...........         1339
--------------------------------------------------------------------------------------------------------------------------------------------------------

3. Variability of the APF Data
    Several commenters (Faulkner, Ex. 9-40 and Kojola, Ex. 9-27) 
criticized WPF studies because the studies demonstrated what they 
considered to be a high degree of variability of the data. However, it 
is inappropriate to describe the variability of the data with terms 
such as "high" or "low" because no recognized standard exists by 
which to characterize variability. The variability of the data should 
reflect the true variability in respirator fit and performance 
experienced by workers who wear respirators. It is reasonable to expect 
variability because respirator performance is determined by many 
factors, including: Respirator type, the workers' face shapes, work 
practices and effort levels, and workplace conditions such as 
temperature and humidity. Thus, the key issue is not whether the data 
have too much or too little variability, but whether the variability in 
the data reflects the true variability in respirator performance under 
actual workplace conditions.
    A logarithmic transformation was applied to the WPF data set to 
adjust for a skewed distribution and extreme outliers, both of which 
are common with ratio-based data. As Figure III-1 shows, when a 
logarithmic transformation is applied to OSHA's WPF database, the data 
closely follow a standard normal distribution. Therefore, OSHA's 
analysis of the data, which assumes that WPFs are log-normally 
distributed with a geometric mean of 307 and a geometric standard 
deviation of 7.1, appropriately accounts for the variability in the WPF 
data.

Figure III-1

4. Analysis of Updated Database on APRs
    OSHA proposed an APF of 10 for negative pressure half mask APRs, 
including both filtering facepieces and elastomerics (68 FR 34096). 
Accordingly, the present analysis focuses on estimating this APF, 
particularly the percent of WPFs that are less than 10.
    Figure III-2 displays the 1,339 WPF values, grouped by respirator 
class,\1\ study, and contaminant. Each column of data points in the 
figure corresponds to a row number listed in column 2 of Table III-1. 
This figure shows that more WPFs for elastomerics are less than 10 than 
was the case for filtering facepieces, even though a much larger 
proportion of these WPFs are from filtering facepieces.
---------------------------------------------------------------------------

    \1\ Includes four of the five classes originally determined in 
the analysis conducted for OSHA by Dr. Ken Brown; no data were 
available for Class 2. Dr. Brown characterized disposable half marks 
according to combinations of the following four design 
characteristics: (1) Adjustable head straps, (2) presence of an 
exhalation valve, (3) double shell construction, and (4) foam ring 
liner. Class 1 has none of the four design characteristics. Class 2 
has design characteristics (1) and (3). Class 3 has design 
characteristics (1) through (3). Class 4 has all four of the design 
characteristics. Class 5 consists of all elastomeric half masks.

---------------------------------------------------------------------------

Figure III-2

    Figure III-2 also shows that differences exist between WPFs 
measured in different studies, even among respirators of the same type. 
For example, both the Colton (Ex. 1-64-15, 4 in Figure 2) and 
the Colton and Bidwell (Ex. 9-16-1-1, 8 in Figure 2) studies 
were conducted by some of the same investigators, and both studies used 
Class 1 filtering facepieces. Nevertheless, all but one of the 23 WPFs 
in the Colton study (Ex. 1-64-15) are less than 40, while all 143 of 
the WPFs from the Colton and Bidwell study (Ex. 9-16-1-1) are at least 
58 or higher. However, the Colton study evaluated respirators approved 
under 30 CFR part 11, whereas the Colton and Bidwell study evaluated 
respirators approved under 42 CFR part 84.
    Table III-2 shows the percentages of WPFs less than 10 by 
respirator class, along with the 90% statistical confidence intervals 
on these percentages. The exact confidence intervals are based on a 
binomial distribution for counts. The percentage of WPFs less than 10 
is less than 5% for all four classes, and the 90% statistical 
confidence interval on this percentage excludes 5% for every class 
except elastomerics. Also, elastomerics had the highest percentage of 
WPFs less than 10 (4.5%). Over all classes, 38/1339, or 2.8%, of WPFs 
were less than 10 (90% confidence interval: 2.1%, 3.7%). The upper 
bound of this two-sided 90% confidence interval, 3.7%, is equivalent to 
a one-sided 95% upper statistical confidence bound on the true 
proportion of WPFs less than 10. This bound may be interpreted as 
follows: assuming the database is representative of workplace WPFs in 
general (more specifically, that the data approximate a random sample 
of WPFs from all workers who use respirators), when the true proportion 
of WPFs less than 10 is 3.7%, the probability of observing 2.8% or less 
(the observed percentage) would be 1 - 0.95 = 0.05. Thus, under these 
assumptions, it is unlikely that the true proportion of WPFs less than 
10 is as high as 3.7% (and extremely unlikely to be as high as 5%).

                         Table III-2.--Percent of WPFs Less Than 10 by Respirator Class
----------------------------------------------------------------------------------------------------------------
                                                           Total n       n <  10      Percent        (90% Cl)
----------------------------------------------------------------------------------------------------------------
Class 1................................................          474           11          2.3      (1.3%, 3.8%)
Class 3................................................          162            0          0.0      (0.0%, 1.8%)
Class 4................................................          124            1          0.8      (0.0%, 3.8%)
Class 1-4 (Filtering Facepieces).......................          760           12          1.6      (0.9%, 2.5%)
Class 5 (Elastomerics).................................          579           26          4.5      (3.2%, 6.2%)
                                                        --------------------------------------------------------
    Total..............................................         1339           38          2.8      (2.1%, 3.7%)
----------------------------------------------------------------------------------------------------------------

    In the earlier database analyzed by Dr. Brown, 3.9% of the WPFs 
were less than 10. By comparison, among the 422 WPFs added to the 
database, only \2/422\ (0.5%) were less than 10. Thus, the new data 
indicate a higher level of protection by APRs.
    In addition to the 1,339 WPFs in the updated OSHA database, an 
additional 403 WPFs from 12 studies were coded by OSHA but were not 
included in either the present database or the one analyzed by Dr. 
Brown. These data were omitted for various reasons, including too few 
WPF measurements in a study and problems with the quality of the 
studies (i.e., study did not meet requirements of OSHA's Respiratory 
Protection Standard). In addition, as noted earlier, OSHA did not 
include data from studies in which exposures were predominantly to a 
gas or vapor. To determine the effect that excluding these data had on 
the results in Table III-2, the 403 WPFs were added to the updated data 
base of 1,339 WPFs (for a total of 1,742 WPFs), and the overall 
fraction of WPFs less than 10 was computed (Table III-3). The percent 
of WPFs less than 10 was 4.0% (90% confidence interval: 3.2%, 4.8%). 
Thus, even with no data exclusions, the overall percent of WPFs smaller 
than 10 is less than 5%, and the 95% statistical upper confidence bound 
is also less than 5% (i.e., 4.8%).

          Table III-3.--Comparison of Percent of WPFs Less Than 10 in Studies Used and Not Used by OSHA
----------------------------------------------------------------------------------------------------------------
                                                           Total n       n <  10      Percent        (90% Cl)
----------------------------------------------------------------------------------------------------------------
Used...................................................         1339           38          2.8      (2.1%, 3.7%)
Unused.................................................          403           31          7.7     (5.6%, 10.2%)
Both Used and Unused...................................         1742           69          4.0      (3.2%, 4.8%)
----------------------------------------------------------------------------------------------------------------

    Consistent with the WPF studies used in its analysis, OSHA adopted 
the point estimate of the lower 5th percentile of WPF or SWPF data to 
establish APFs. Table III-4 shows the point estimate of the 5th 
percentiles of WPFs for different categories of respirators using the 
updated database. The 5th percentile of WPFs for filtering facepieces 
as a whole was 18.1, and for elastomerics it was 12.0. In both cases, 
the point estimate was above the APF of 10 proposed by OSHA. Since 
several commenters expressed concern about whether sufficient evidence 
is available to support an APF of 10 for filtering facepieces, OSHA 
also calculated 90% confidence intervals for each point estimate. (As 
noted earlier, the lower limit estimate of a two-sided 90% confidence 
interval is equivalent to a one-sided 95% lower confidence bound.) The 
lower 95% confidence bounds for the 5th percentile of WPFs exceeded 10 
for all classes combined, and, with the exception of elastomerics, for 
each individual class. The confidence limits for the 5th percentiles 
were computed using the method for distribution-free confidence 
intervals of Hahn and Meeker (1991), as implemented in SAS (2001). 
Therefore, OSHA concludes that sufficient statistical evidence is 
available to justify an APF of at least 10 for filtering facepieces.

       Table III-4.--Fifth Percentiles of WPFs by Respirator Class
------------------------------------------------------------------------
                                                    5th
                                                 percentile    (90% Cl)
------------------------------------------------------------------------
Class 1.......................................         14.8     (12, 18)
Class 3.......................................         19.7     (15, 24)
Class 4.......................................         27.0     (22, 49)
Class 1-4 (Filtering Facepieces)..............         18.1     (15, 22)
Class 5 (Elastomerics)........................         12.0      (7, 14)
                                               -------------------------
    Total.....................................         14.7     (13, 18)
------------------------------------------------------------------------

5. Comparison of Respirators Approved Under 30 CFR Part 11 Versus 42 
CFR Part 84
    Several commenters expressed concern that the majority of WPF and 
SWPF studies were conducted on respirators certified by NIOSH under 
requirements in 30 CFR 11, instead of the newer NIOSH certification 
procedure described in 42 CFR 84. While these commenters did not 
explain the basis of their concern, two major studies were submitted 
that examined the performance of 42 CFR 84-approved respirators. The 3M 
study by Colton and Bidwell (Ex. 9-16-1-1) evaluated one respirator 
approved under 30 CFR 11, and two respirators approved under 42 CFR 84. 
In this study, WPFs were measured on up to nine different occasions for 
21 workers (143 total measurements), 17 of whom used each type of 
respirator on at least one occasion, with none of them using the same 
type respirator on more than three occasions. Thus, this study provides 
an opportunity for comparing the performance of respirators approved 
under the two standards. Table III-5 shows the performance of these 
three respirators using three methods: the proportion of samples with 
Ci non-detects, the distribution of the 30 smallest WPF values among 
the three respirators, and the geometric mean of WPFs. The two 42 CFR 
84-approved respirators performed similarly with each of these methods, 
and they both performed better than the 30 CFR 11-approved respirator 
(see Table III-5).

Table III-5.--Performance of the 30 CFR Part 11 Respirator (3M 8710) and
          the 42 CFR Part 84 Respirators (3M 8511 and 3M 8210)
------------------------------------------------------------------------
                                   Inside-the-  Dist. of 30      WPF
                                    mask non-     smallest    geometric
                                     detects        WPF       means \1\
------------------------------------------------------------------------
3M 8710..........................         5/49           15          792
3M 8511..........................        23/47            7         2506
3M 8210..........................        19/47            8         2405
------------------------------------------------------------------------
\1\ Modeled assuming log-normal distribution with non-detects set at
  detectin limit.

    The geometric means of WPFs of the 42 CFR 84 respirators were 
similar (2506 and 2405), and were significantly (p <  0.0001) higher 
than the geometric mean of the 30 CFR 11 respirator (792). This 
comparison was made using a repeated measures analysis that accounted 
for dependence among different samples collected from the same worker, 
assumed log-normally distributed WPFs, and set non-detects at the 
detection limit (which should minimize differences between the two 
respirator types). All three respirators performed well in this study, 
with the smallest of the 143 WPFs being 52, well above the APF of 10 
proposed by OSHA.
    When the 146 WPF measurements from the Bidwell and Janssen study 
(Ex. 9-16) (that assessed the 3M 9211 respirator approved under 42 CFR 
84) are added to the 94 WPFs from the Colton and Bidwell study (Ex. 9-
16-1-1), 240 WPFs in the OSHA database are from 42 CFR 84 respirators. 
None of these WPFs was less than 10 (0/240). This finding, along with 
the evidence that 42 CFR 84 respirators performed better than 30 CFR 11 
respirators in the same study, suggests that the new filtering 
facepiece respirators certified under 42 CFR 84 may perform better than 
the respirators relied on by OSHA for its analyses, which consisted 
mainly of respirators approved under 30 CFR 11. Because the respirators 
approved under 42 CFR 84 outperformed those respirators approved under 
30 CFR 11, which were adequately protective, OSHA is confident current 
workers will be well protected by the respirators approved under 42 CFR 
84.
6. Methodology of Evaluating Overexposure
    Another method to assess the appropriateness of an APF is to 
determine whether an overexposure occurs (Ex. 10-17). The Agency 
reviewed relevant studies on this subject cited by several commenters 
(Exs. 9-16, 9-22, and 10-17-1) to determine if such an analysis would 
provide useful information on filtering facepiece and elastomeric half 
mask respirators.
    Two major studies (Exs. 9-16-1-9 and 4-21) address the likelihood 
that half mask respirators will not sufficiently reduce occupational 
exposures to airborne contaminants. In the first of these two studies 
(Nelson et al., Ex. 9-16-1-9), the authors evaluated the risk of 
overexposure for selected APFs using Monte Carlo simulation modeling. 
For a half mask respirator with an APF of 10, the calculations 
indicated a low risk of being exposed above an occupational exposure 
limit (OEL), with mean exposures being controlled well below an OEL. In 
the second article by Drs. Myers and Zhuang (Ex. 4-21), ambient (Co) 
and in-facepiece exposure monitoring data (Ci) from studies of worker 
exposures in foundry, aircraft-painting, and steel-manufacturing 
industries were compared with the OSHA PEL for single-substance 
exposures. The 5th percentiles of the protection factor (Co/Ci) data 
from each study were calculated. The authors used a new binomial 
analysis of likelihood of successes (no overexposure) and failures 
(overexposures). Their calculations indicate, for both half mask 
elastomeric and filtering facepiece respirators, that the < 5% of 
workers who fail to achieve an APF of 10 are still being protected.
    OSHA considered Nelson's analysis along with the findings of Myers 
and Zhuang when it conducted its own analysis. Accordingly, the Agency 
was persuaded to quantify the probability of overexposure by applying 
the Myers and Zhuang binomial analysis to OSHA's updated database. 
OSHA's expert, Dr. Gerry Wood, performed the analysis and presented his 
results in a report (Ex. 20-3) described below. The updated OSHA half 
mask database (Ex. 20-2) used in this analysis contains 1,339 WPFs from 
studies with both filtering facepiece half mask respirators (760 WPFs) 
and elastomeric half mask respirators with cartridge filters (579 
WPFs). This database also contains Co and Ci measurements (expressed in 
[mu]g/m\3\), with asbestos fiber counts converted as follows: 1 fiber/
cm\3\ = 30 [mu]g/m\3\); these measurements permit binomial analysis of 
overexposure through calculation of hazard ratios (HR).
    The following 8-hour TWA PELs were used to calculate HR = Co/PEL 
for this study (see Table III-6).

    Table III-6.--8-Hour TWA PELs Used to Calculate the Hazard Ratios
------------------------------------------------------------------------
                  Analyte                            PEL (mg/m3)
------------------------------------------------------------------------
Benzo(a)pyrene............................  0.2
Lead......................................  0.05
Zinc......................................  15
Iron......................................  10
Chromium..................................  0.5
Titanium..................................  15
Manganese.................................  5
Aluminum..................................  15
Asbestos..................................  0.003 (0.1 fiber/cm3)
Silica....................................  10
Cadmium...................................  0.005
Calcium...................................  15
------------------------------------------------------------------------

    Values for individual WPFs then were plotted against HR as 
illustrated in the figures of the Myers and Zhuang reference (Ex. 4-21, 
Figure 1, page 798, and Figure 2, page 799). The same reference lines 
and labels were used, but the scales were expanded to include all data 
in the OSHA database.
    Figure 1 below shows the plot of all data for both filtering 
facepieces and elastomerics. The line labeled CD represents WPF = 10; 
38 (2.8%) of the 1,339 data points fell below this line and five data 
points (0.37%) fell within the triangle defined by the letters ABK; 
Myers and Zhuang (Ex. 4-21) label this triangle as "Inadequate 
Protection, Overexposure," which corresponds to the region in which Ci 
exceeds the PEL.

Figure 1

    Figure 2 shows the same plot for studies using filtering facepieces 
only. Twelve data points (1.6%) are below the WPF = 10 line. Two of 
these twelve data points equal WPF = 10 when rounded off to the nearest 
whole number. Only 2 (0.26%) of the points are within the ABK 
overexposure region. The data point in the A corner (from a study by 
Colton (Ex. 1-64-16, CL4.15.Pb)) represents a Co just above the lead 
PEL (HR = 1.20) that, with a WPF = 1.15 (almost no protection), gave a 
Ci = 1.04 * PEL; this value represents an inside-the-mask exposure just 
barely higher than the PEL. The only other data point in the over-
exposure region is from the asbestos (PEL-0.1 fiber/cm3) 
study by Dixon (Ex. 1-64-54, CL1.2.Asb) which corresponds to HR = 77, 
WPF = 47, and a Ci = 1.6 * PEL, (or 0.16 fiber/cm3).

Figure 2

    If the MUC is defined as MUC = APF x PEL, and an APF = 10 is 
assumed, then data points in the triangle labeled AHE represent 
overexposures. With one data point in this triangle, filtering 
facepieces are 99.4% effective in protecting employees at an APF = 10 
and an MUC = 10 x PEL (i.e., 160 of 161 data points in the AGFE area, 
with an HR ranging from 1 to 10, are outside the triangle (AHE) that 
represents diminished protection).
    Figure 3 shows the same plot for the elastomerics. Of these 579 
data points, 26 (4.5%) fall below WPF = 10. Three data points (0.5%) in 
the ABK overexposure triangle are from an asbestos study by Dixon (Ex. 
1-64-54, CL5.2.Abs). However, no data points of 265 in the AGFE area 
fall within the AHE triangle, indicating that all of these respirators 
provided protection at APF = 10 x PEL.

Figure 3

    Figures 4 and 5 demonstrate that both filtering facepiece and 
elastomeric respirators maintain the level of employee protection found 
in Figures 2 and 3, even when the data are plotted using the higher 
PELs specified by the older OSHA asbestos standard (pre-August 1994) 
and cadmium standard (pre-April 1993). The combined data for both 
Figures 4 and 5 show that filtering facepieces had only one data point 
of 160 (with an HR ratio of 1 to 10) in the overexposure area (i.e., 
the AHE triangle), while none of the 241 data points for elastomeric 
respirators fell into this area. Therefore, Figures 4 and 5 and Figures 
2 and 3 demonstrate that both filtering facepiece and elastomeric 
respirators afford employees effective protection against two different 
exposure levels of asbestos and cadmium.
BILLING CODE 4510-26-P

Figure 4

Figure 5

BILLING CODE 4510-26-C
7. Summary of Quantitative Analyses of the Updated Database
    First, OSHA's database includes the best available data. As part of 
the APF rulemaking process, the Agency conducted a metaanalysis of data 
collected from numerous scientific studies related to APFs. OSHA 
established criteria that were used to evaluate each study's design and 
data quality to assure that the database included only the most valid 
data. The Agency, at each step in the rulemaking process, called on 
participants to identify additional studies to augment the dataset or 
to discuss alternative methods of analysis. In response, a number of 
commenters expressed these concerns about the data analysis: The 
statistical treatment minimized the true differences between elastomeric
and filtering facepieces, and there was too much variability in the data. 
In all cases, concerns raised by commenters about the composition of the 
dataset used in the metaanalysis, or the statistical methods used to 
conduct the analyses, were unsubstantiated by evidence submitted to the 
record despite repeated requests by OSHA for either specific examples or 
additional evidence.
    Second, the best available data support an APF of 10 for half mask 
elastomerics and filtering facepieces. The final APF half mask database 
consists of 1,339 data points from 16 different studies, which 
represents a data increase of 46% over the 917 data points initially 
available for analysis in the proposal. The full data set indicates: 
(a) The precise APF for filtering facepieces is 18.1, with a 90% 
confidence interval between 15 and 22; (b) the precise APF for 
elastomerics is 12.0, with a 90% confidence interval between 7 and 14; 
and (c) that a greater percentage of elastomerics failed to achieve an 
APF of 10 (4.5%) than filtering facepieces (1.6%). In both cases, fewer 
than 5% of the respirators failed to achieve an APF of 10, which is the 
maximum failure rate historically allowed by both OSHA and other 
standards-setting bodies.
    Third, OSHA substantiated its previous analysis by adding to its 
updated database 403 data points that were excluded originally because 
they did not meet OSHA's selection criteria and reanalyzing the 
database. This additional analysis also supports an APF of 10 for both 
types of respirators, with the results being highly similar to the 
analysis based on the best-available data.
    Fourth, new studies submitted during the rulemaking allowed OSHA to 
compare the performance of similar respirators that were certified 
under both NIOSH's old (30 CFR 11) and new (42 CFR 84) certification 
standards. The 42 CFR 84 respirators achieved a WPF that was better 
than the 30 CFR 11 respirators. This finding is significant because the 
majority of the WPF studies, and the only studies in OSHA's original 
data set, were conducted on respirators certified under 30 CFR 11. 
Thus, the improved performance of 42 CFR 84 respirators indicates that 
these respirators are likely to be even more protective of worker 
health than an APF of 10 as provided for in the final rule.
    OSHA also addressed the issue of overexposure among workers. In 
doing so, it reviewed the respirator literature and performed an 
analysis of overexposure risk using filtering facepiece or elastomeric 
respirators. Based on this risk analysis, OSHA concluded that workers 
participating in effective respirator programs had an extremely low 
risk of overexposure.
    In conclusion, the extensive quantitative analyses of the databases 
clearly indicate that both filtering facepieces and elastomeric 
respirators are capable of achieving an APF of 10. The results 
demonstrate that no statistical justification exists for assigning an 
APF of less than 10 to either of these two types of respirators. 
Finally, the results show that an APF of 10 is an underestimate of the 
true protection provided by both types of respirators. Therefore, the 
final APF of 10 determined by this rulemaking provides employees who 
use respirators with an extra margin of safety against airborne 
contaminants.

F. Summary of Studies Submitted During the Rulemaking

1. Additional Studies Used in the Updated Analyses
    OSHA found the studies discussed in this section to be of 
sufficient quality for inclusion in its APF analyses.
    Bidwell and Janssen study (Exs. 9-16-1-1 and 9-16). J. O. Bidwell 
and L. Janssen of 3M gave a presentation at the May 2003 American 
Industrial Hygiene Conference and Exposition (AIHCE) on a workplace 
protection factor study they performed in a concrete-block 
manufacturing plant with workers using a NIOSH-approved N95 flatfold 
filtering facepiece respirator. The filtering facepiece respirator 
tested was the 3M Particulate Respirator 9211, approved by NIOSH under 
the 42 CFR 84 respirator certification standards. The authors measured 
silicon and calcium exposures to 19 workers in the bagging and block-
handling areas of the plant. In the bagging area, workers placed bags 
over cement-dust chutes for filling, and then transferred the bags to 
pallets. In the other areas of the plant sampled by the authors, 
workers handled concrete blocks, swept and shoveled dust and block 
pieces into containers, and cleaned out mullers with chipping tools. 
The workers were informed of the purpose and procedures of, and their 
role in, the study, and were provided with instructions on proper 
donning, fitting, and user seal check procedures, as well as respirator 
operation. In addition, the workers had to pass a Bitrex[supreg] 
qualitative fit test that followed the fit test protocol described in 
OSHA's Respiratory Protection Standard prior to study participation. 
They also had to be clean shaven. They were observed by the authors in 
the workplace on a one-on-one basis throughout the sampling periods.
    The inside-the-facepiece sampling train consisted of a 25-mm three-
piece cassette with a 0.8-micron pore-size polycarbonate filter with 
porous plastic back-up pads for collecting the inside samples. For 
sampling purposes, a Liu probe was inserted opposite the mouth near the 
midline of the respirator. It projected one centimeter into the 
facepiece. The sampling cassette was attached directly to the probe, 
and a cassette heater was used to prevent condensation of moisture from 
exhaled breath. Outside-the-facepiece samples used a 25-mm three-piece 
cassette with a 0.8-micron pore-size mixed cellulose-ester filter. The 
outside sample cassette also was connected to a Liu probe, and this 
combination was attached in the worker's breathing zone. Inside samples 
and outside samples were collected at a flow rate of two liters per 
minute. Respirators were donned and doffed, and sampling trains started 
and stopped, in a clean area. Field blanks were used to evaluate for 
sample-handling contamination, and manufacturer blanks were collected 
to determine background contamination on the filters.
    The inside samples were analyzed using proton-induced X-ray 
emission analysis (PIXEA), and the outside samples were analyzed by 
inductively coupled plasma (ICP) spectroscopy. For both calcium and 
silicon, the authors presented the range of Co, Ci, and the associated 
geometric means and standard deviations. Three sets of WPF results were 
determined: One for calcium, a second for silicon, and a harmonic mean 
for the combined calcium and silicon samples. Silicon was not detected 
on eleven of the Ci samples. However, by using 70% of the limit of 
detection as the inside mass, the authors were able to include these 
samples in the statistical analysis. No field-blank adjustments were 
made (i.e., no calcium or silicon detected), and no mention is made of 
adjusting the data for pulmonary retention of particles. In addition, 
three sample sets were invalidated as a result of equipment and 
procedural problems. The authors reported a mean WPF of 152, with a 5th 
percentile of 13, for the calcium samples; a mean WPF of 394, with a 
5th percentile of 34, for the silicon samples; and a harmonic mean of 
the calcium and silicon samples of 206, with a 5th percentile of 20. 
The authors noted a difference in the WPFs measured for calcium and 
silicon (using the same respirator), and discussed a number of possible 
reasons for the difference (e.g., random sampling and analytical 
errors, possible non-uniformity of the challenge aerosol over time). The 
authors concluded, "The estimated WPF for this respirator model based 
on this study exceeds the APF of 10 assigned to this respirator class 
by ANSI Z88.2-1992 and proposed by OSHA." They also stated, "The 
respirator provided an adequate level of protection and reliably 
provided workplace protection factors of at least 10 when properly 
fitted, worn, and used" (Ex. 9-16, page 40).
    Colton and Bidwell study (Ex. 4-10-4). C. Colton and J. Bidwell of 
3M made a presentation on May 25, 1995 at the AIHCE comparing the 
workplace performance of two different types of HEPA filters on an 
elastomeric half mask respirator in a battery manufacturing plant. The 
HEPA filters and the respirator model tested were approved under the 30 
CFR 11 respirator certification standards. The half facepiece 
respirator tested was the 3M 7000, available in three sizes. The HEPA 
filters tested were the 3M 7255 high-efficiency (mechanical) filter and 
the 3M 2040 high efficiency (electret) filter. The authors measured 
lead exposures for 19 workers in the battery-pasting and assembly areas 
of the plant because these areas had the highest lead exposures. The 
workers were informed of the purpose and procedures of, and their role 
in, the study, and were provided with instructions on proper donning 
and fitting procedures, as well as respirator operation. In addition, 
the workers had to pass a saccharin qualitative fit test performed 
using the fit test protocol described in OSHA's Lead Standard. Workers 
had to be clean shaven. They were observed in the workplace by the 
authors on a one-on-one basis throughout the sampling periods.
    For sampling purposes, a Liu probe was inserted opposite the mouth 
near the midline of the respirator. It projected one centimeter into 
the facepiece. The sampling cassette was attached directly to the 
probe, and a cassette heater was used to prevent condensation of 
moisture from exhaled breath. A Liu probe was also attached to the 
outside sample to ensure that particle loss for the outside samples 
would be similar to that with the inside samples. Inside samples and 
outside samples were collected at a flow rate of two liters per minute, 
and sampling times ranged from 56 to 200 minutes. Up to four samples 
were collected per day on each worker, each worker was sampled for two 
days, field blanks were used, and care was taken to avoid handling 
contamination. The filter for the first day was assigned randomly, with 
a worker using one filter type on the first day and the second filter 
type on the second day.
    The inside- and outside-the-facepiece samples were analyzed for 
lead by ICP spectroscopy. The authors presented the range of outside 
and inside lead concentrations, and the associated geometric means and 
standard deviations. Two sets of WPF results were determined: One for 
the 3M 2040 filter and a second for the 3M 7255. A total of 140 samples 
were collected--one sample was eliminated due to low mass loading, 10 
samples were lost due to equipment problems, and 85 samples had inside-
sample mass values that were non-detectable. Of the remaining 44 
samples, one outlier was identified in the electret filter data set, 
leaving 22 sets for the 3M 2040 filter and 21 sets for the 3M 7255 
filter. No field blank adjustments were reported (i.e., no lead was 
detected on the field blanks). The authors reported a mean WPF of 562 
and a 5th percentile of 71 for the 3M 2040 filter-respirator 
combination, and a mean WPF of 1006 and a 5th percentile of 80 for the 
3M 7255 filter-respirator combination.
    When no lead was detected for the inside samples, the WPF results 
were recalculated using the detection limit to represent the mass for 
these samples. From these recalculations, the authors identified one 
outlier in the electret filter data set and two outliers in the 
mechanical filter data set. They then calculated geometric means, 
geometric standard deviations, and 5th percentile WPFs for the 67 
samples for the 3M 2040 filter and for the 59 samples for the 3M 7255 
filter. The authors reported a mean WPF of 420 and a 5th percentile of 
101 for the 3M 2040 filter-respirator combination, and a mean WPF of 
549 and a 5th percentile of 138 for the 3M 7255 filter-respirator 
combination.
    The authors concluded that the performance differences between the 
two filter types were not statistically significant. Both filters 
provided 5th percentile protection factors above 10. No WPFs were less 
than 30. Under these workplace conditions, no difference was found in 
the level of protection provided by the electrostatic HEPA filter 
compared to a mechanical HEPA filter.
    Colton and Bidwell study (Ex. 9-16). C. Colton and J. Bidwell of 3M 
presented a research paper at the May 1999 AIHCE on a WPF study they 
performed in a battery manufacturing plant with workers using three 
NIOSH-approved filtering facepiece respirators. The filtering facepiece 
respirators tested were the 3M 8210 and 3M 8511, approved by NIOSH 
under the 42 CFR 84 respirator certification standards, and the 3M 8710 
filtering facepiece, approved by NIOSH under the 30 CFR 11 respirator 
certification standards. The authors measured lead exposures for 21 
workers in the battery-manufacturing and assembly areas of the plant. 
The worker job classifications tested were stackers, heat sealers, 
burners, and assemblers. The workers were informed of the purpose and 
procedures of, and their role in, the study, and were provided with 
instructions on proper donning, fitting, and user seal check 
procedures, as well as respirator operation. In addition, the workers 
had to pass a Bitrex[supreg] qualitative fit test with all three 
respirators, and they had to be clean shaven. They were observed in the 
workplace by the authors on a one-on-one basis throughout the sampling 
periods.
    The sampling probe was a Liu probe that was inserted opposite the 
mouth near the midline of the respirator. It projected one centimeter 
into the facepiece. The sampling cassette was attached directly to the 
probe, and a cassette heater was used to prevent condensation of 
moisture from exhaled breath. Inside and outside samples were collected 
at a flow rate of two liters per minute for 79 to 159 minutes. Three 
samples were collected per day for each worker. Field blanks were used, 
and care was taken to avoid handling contamination.
    The inside samples were analyzed for lead using PIXEA. Outside 
samples were analyzed by ICP spectroscopy. The authors presented the 
range of outside and inside sample lead concentrations, and the 
associated geometric means and standard deviations for each respirator 
model tested. Three sets of WPF results were determined: One for the 3M 
8710, a second for the 3M 8210, and a third for the 3M 8511. Lead was 
not detected on five of the inside samples for the 3M 8710, 19 for the 
3M 8210, and 23 for the 3M 8511. No field blank adjustments were 
reported (i.e., no lead was detected on the field blanks). The authors 
reported a mean WPF of 730, with a 5th percentile of 105, for the 3M 
8710 respirator; a mean WPF of 955, with a 5th percentile of 73, for 
the 3M 8210; and a mean WPF of 673, with a 5th percentile WPF of 169, 
for the 3M 8511 using test samples with detectable lead levels. When no 
lead was detected on the inside samples, the WPF results were 
calculated by using 70% of the limit of detection as the mass for 
inside samples. The authors reported a mean WPF of 804, with a 5th 
percentile of 111, for the 3M 8710 respirator; a mean WPF of 2210, with 
a 5th percentile of 133, for the 3M 8210; and a mean WPF of 1970, with a 
5th percentile WPF of 223, for the 3M 8511.
    The authors stated, "All respirator models provided an equivalent 
level of protection," and that "[a]ll the respirators tested reliably 
provided workplace protection factors of 10 when properly fitted, worn, 
and used." No reported WPFs were less than 51, and no difference in 
workplace protection was found between workers using 30 CFR part 11-
approved respirators and workers using 42 CFR 84-approved respirators. 
The authors concluded that, using the 5th percentile WPFs as an 
indicator of performance, the APFs should not differ between these 
respirators.
2. Additional Studies Not Used in the Updated Analyses
    The Agency received a number of comments on the relationship 
between fit testing and APFs. OSHA regulations require that when a 
respirator user cannot pass a fit test with a particular respirator 
model, it cannot be used. OSHA does not believe that it is appropriate 
to assign a lower protection factor to a respirator (e.g., half the 
APF) when the respirator doesn't fit. However, a number of fit test 
studies, and one study on farm worker exposures to bioaerosols, were 
submitted to the record for the Agency to evaluate in terms of APFs. 
OSHA has evaluated these studies and determined that they do not meet 
the criteria that data must meet to be included in the database. These 
criteria have been described above.
    NIOSH agreed (Tr. at 102) that the APF values resulting from OSHA's 
multifaceted approach provide reasonable values for the level of 
protection expected for each respirator class. Proposed Table 1 
("Assigned Protection Factors") represents the state of the art for 
each class or respirator. However, NIOSH stated that designating a 
specific APF for a respirator class will not ensure that a respirator 
will perform as expected. The protection afforded by a respirator is 
contingent on: The respirator user adhering to the respirator program 
requirements of OSHA's Respiratory Protection Standard; the use of 
NIOSH-certified respirators in their approved configuration; and fit 
testing for each employee that ensures selection of a properly fitting 
respirator. The following studies, which OSHA did not include in its 
updated analyses, typically violated one or more of these three 
conditions.
    Don-Hee Han study (Ex. 9-13-2). NIOSH (Ex. 9-13) submitted a study 
by Don-Hee Han (Ex. 9-13-2) of the 3M 8511 cup-shaped filtering 
facepiece, the MSA Affinity foldable FR 200, and the Willson N95 10FL 
produced by Dalloz Safety in response to OSHA's request in the NPRM for 
additional studies that may be useful in determining APFs. The author 
of the study permitted workers who did not pass a fit test with a 
minimum fit factor of 100, as required by OSHA's Respiratory Protection 
Standard, to participate in the study. OSHA reviewed this study and did 
not add the data set to its quantitative analyses because it was a PPF 
study that is not directly comparable with WFP studies used by OSHA in 
its APF determinations. However, the study results confirmed that when 
a worker's filtering facepiece respirator is fit tested properly, it is 
capable of achieving a protection factor of at least 10.
    Peacock study (Ex. 9-13-4). This fit test research report was 
submitted to the record by NIOSH. In this study, a liquid-aerosol QNFT 
(Large Particle QNFT (LPQNFT)) was developed and used to evaluate 
filter penetration of a regular N95 respirator. Protection factors 
determined by the LPQNFT were compared to fit factors obtained using 
the saccharin QLFT. The sensitivity and specificity of the saccharin 
QLFT were evaluated. The results for the specifity of the LPQNFT 
indicated that workers who failed the saccharin QLFT also failed the 
LPQNFT when using a protection factor >= 100. The sensitivity was low. 
Twelve (12) subjects passed both the LPQNFT and the saccharin QLFT (out 
of 28 subjects), but another 16 subjects failed the saccharin test 
while passing the LPQNFT. Peacock concluded that the LPQNFT may be 
subject to particle deposition at leakage sites, as well as conditions 
inside the facepiece that would lead to sampling bias. OSHA did not 
rely on these fit test data for setting APFs because, as Peacock noted, 
further studies should be conducted to identify the cause of these 
problems.
    Lee and Nicas study (Ex. 17-7-3). NIOSH submitted this study of N95 
respirators used against Mycobacterium tuberculosis (TB). In this 
study, Lee and Nicas (Ex. 17-7-3) computed risks of TB infection using 
five medium- or regular-size N95 filtering facepiece respirators. Five 
NIOSH-approved respirators were selected for evaluation after reviewing 
manufacturer-provided fit test, comfort, and cost data. After extensive 
evaluation, the original five brands were rank ordered from highest to 
lowest fit test pass rates, and the authors calculated the risk of TB 
transmission. The authors concluded that fit testing is necessary to 
ensure that respirators perform as expected. However, OSHA did not 
accept this study for its APF analyses because it is not a WPF or SWPF 
study, and addresses only fit testing issues.
    Coffey, et al. study (Ex. 17-7-4). NIOSH submitted to the record a 
publication by Coffey et al. (Ex. 17-7-4). In this study, 18 N95 
filtering facepiece respirators were evaluated. The authors determined 
the following measurements from the results: 5th percentile SWPF value; 
the average SWPF per shift; the h-value; and the assignment error. A 
SWPF test was used to determine respirator performance, which was 
assessed using a Portacount Plus with test subjects performing six 
standard fit test exercises. However, the generally accepted format for 
a SWPF study involves test subjects performing simulated workplace 
exercises (e.g., shoveling pebbles, moving blocks, pounding nails).
    Using this procedure, the authors found that when properly fit 
tested, over 80% of the poorly performing respirators achieved a 
protection factor of more than 10. However, OSHA did not use this study 
in its APF determinations since this was not a WPF or SWPF study. 
Nevertheless, the study supports the requirement that APFs apply only 
when used within the context of a comprehensive respirator program.
    Reponen et al. study (Exs. 19-8-3 and 19-8-4). The purpose of this 
study was to further develop a prototype personal-sampling system for 
use with N95 filtering facepiece respirators. The study results were 
calculated from 30-60 minute Co and Ci measurements taken across 
multiple agricultural settings, tasks, and simulated exposures. The 
data were combined to calculate dust, microorganism, and cultured 
microorganism exposures. Descriptions of tasks in several workplaces 
were provided.
    The N95 respirators in this study performed at or above a WPF of 10 
when evaluated using dust measurements. However, the dust-exposure 
measurements counted both dust particles and microorganisms because the 
optical-particle counter used for this purpose does not differentiate 
between organic and nonorganic particles. When they calculated WPFs for 
the microorganism samples alone, the WPFs decreased somewhat. The 
authors concluded that the geometric mean WPF increased with increasing 
particle size, and that the WPFs were smaller for biological particles 
than for dust. The authors speculated that differences in WPFs may 
result from the measurement effects of particle size or density. They 
also said that even a small variation in the density of particles can 
have a pronounced effect on the loss of dust particles through faceseal 
leaks due to impaction. The authors concluded that their findings deserve 
further research.
    OSHA agrees with the authors that further research is needed to 
substantiate and explore these findings. Also, the Agency has 
significant concern regarding the measurement methodology used in this 
prototype study. For example, it is not clear whether the WPF 
differences are valid or are simply the result of using different 
measurement methods. Therefore, the Agency decided not to use this 
study for developing APFs.
    Summary and conclusions for studies not used in the updated 
database. OSHA reviewed the studies submitted to the APF rulemaking 
docket and determined that five of them were unsuitable for the 
database used to develop APFs. OSHA established a set of criteria in 
the proposal for evaluating new studies for inclusion in the APF 
database. The studies by Han (Ex. 9-13-4), Peacock (Ex. 9-13-4), Lee 
and Nicas (Ex. 17-7-3), Coffey et al. (Ex 17-7-4), and Reponen et al. 
(Exs. 19-8-3 and 19-8-4) were not used by OSHA in setting the final 
APFs because these studies did not follow established WPF or SWPF 
protocols, or required further research to substantiate or explore the 
results.

IV. Health Effects

    American workers use respirators as a means of protection against a 
multitude of respiratory hazards that include chemical, biological, and 
radiological agents. Respirators provide protection from hazards that 
are immediately life-threatening, as well as hazards associated with 
routine operations for which engineering controls and work practices do 
not protect employees sufficiently. When respirators fail, or do not 
provide the degree of protection expected by the user, the user is 
placed at an increased risk of adverse health effects that result from 
exposure to the respiratory hazards present. Therefore, it is critical 
that respirators perform properly to ensure that users are not at an 
increased risk of experiencing adverse effects caused by exposure to 
respiratory hazards.
    In this final rulemaking, OSHA defined the minimal level of 
protection a respirator is expected to achieve (i.e., the APFs in Table 
1), as well as the MUCs for the respirators. The Agency also is 
superseding most of the existing APF table requirements in its 
substance-specific standards. By superceding the APF tables, the Agency 
estimates that the benefits for the final APFs under the Respiratory 
Protection Standard will be available as well to employers who must 
select respirators for employee use under the substance-specific 
standards. In addition, the Agency believes that harmonizing the APFs 
of the substance-specific standards with the APFs in the Respiratory 
Protection Standard will reduce confusion among the regulated community 
and aids in uniform application of APFs, while maintaining employee 
protection at levels at least as protective as the existing APF 
requirements.

V. Summary of the Final Economic Analysis and Regulatory Flexibility 
Analysis

A. Introduction

    OSHA's Final Economic and Regulatory Flexibility Screening Analysis 
(FEA) addresses issues related to the costs, benefits, technological 
and economic feasibility, and economic impacts (including small 
business impacts) of the Agency's Assigned Protection Factors (APF) 
rule. The Agency has determined that this rule is not an economically 
significant rule under Executive Order 12866. The economic analysis 
meets the requirements of both Executive Order 12866 and the Regulatory 
Flexibility Act (RFA; as amended in 1996). The FEA presents OSHA's full 
economic analysis and methodology. The Agency entered the complete FEA 
into the docket as Exhibit 11. The remainder of this section summarizes 
the results of that analysis.
    The purpose of this FEA is to:
     Evaluate the costs employers would incur to meet the 
requirements of the APF rule;
     Estimate the benefits of the rule;
     Assess the economic feasibility of the rule for affected 
industries; and
     Determine the impacts of the rule on small entities and 
the need for a Regulatory Flexibility Analysis.

B. The Rule and Affected Respirator Users

    OSHA's APF rule would amend 29 CFR 1910.134(d)(3)(i)(A) of the 
Respiratory Protection Standard by specifying a set of APFs for each 
class of respirators. These APFs specify the highest multiple of a 
contaminant's permissible exposure limit (PEL) at which an employee can 
use a respirator safely. The APFs would apply to respirator use for 
protection against overexposure to any substance regulated under 29 CFR 
1910.1000. In addition, OSHA rules for specific substances under 
subpart Z (regulated under the authority of section 6(b)(5) of the OSH 
Act of 1970, 29 U.S.C. 655) specify APFs for respirators used for 
protection against these chemicals (hereafter referred to as Sec.  
6(b)(5) substances). The rule would supercede most of these protection 
factors, and harmonize APFs for these substances with those for general 
respirator use.
    OSHA based estimates of the number of employees using respirators 
and the corresponding number of respirator-using establishments on the 
NIOSH-BLS survey of respirator use and practices \2\ (Ex. 6-3). The 
NIOSH-BLS survey provides up-to-date use estimates by two-digit 
industry sector and respirator type for establishments in which 
employees used respirators during the previous 12 months.\3\ As shown 
in Table V-1, an estimated 291,085 establishments reported respirator 
use in industries covered by OSHA's regulation. Most of these 
establishments (208,528 or 71.6 percent) reported use of filtering 
facepieces. Substantial percentages of establishments also reported the 
use of half-mask and full facepiece non-powered air-purifying 
respirators (49.0 and 21.4 percent, respectively). A smaller number of 
establishments reported use of powered air-purifying respirators 
(PAPRs) and supplied-air respirators (SARs). Fifteen percent of 
establishments with respirators (43,154) reported using PAPRs and 19 
percent (56,022) reported using SARs. Table V-2 presents estimates of 
the number of respirator users by two-digit industry sector. An 
estimated 2.3 million employees used filtering facepiece respirators in 
the last 12 months, while 1.5 million used half masks, and 0.7 million 
used full facepiece non-powered air-purifying respirators. Fewer 
employees reported using PAPRs (0.3 million) and SARs (0.4 million). 
The industry-specific estimates show substantial respirator use in 
several industries, including the construction sector, several 
manufacturing industries (SICs 28, 33, 34, and 37), and Health services 
(SIC 80).
BILLING CODE 4510-26-P
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    \2\ Preliminary results from the 2001 NIOSH-BLS "Survey of 
Respirator Use and Practices" in press. NIOSH commissioned the 
survey to be conducted by BLS, who also tabulated the data after 
completing the survey.
    \3\ The survey was conducted between August 2001 and January 
2002. It asked: "During the past 12 months, how many of your 
current employees used respirators at your establishment?" It 
excluded voluntary use of respirators from detailed followup 
respirator use questions (Ex. 6-3).

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Table V-1


Table V-2

BILLING CODE 4510-26-C

    The standard would have different impacts on employers using 
respirators to comply with OSHA substance-specific standards than for 
employers using respirators for other purposes. Therefore, OSHA used 
findings from the NIOSH-BLS survey of establishments that reported 
respirator use, by general respirator class, for protection against 
specific substances (see Table V-3). OSHA applied these numbers to all 
respirator users and establishments within the industries that make up 
each sector to derive substance-specific estimates of respirator use. 
For those Sec.  6(b)(5) substances not reported by NIOSH, OSHA used 
expert judgments of a consultant with experience in the respirator 
industry to estimate the percentage of establishments and employees 
that use respirators for protection against these chemicals (Ex. 6-2) 
(see Table V-3).

C. Compliance Costs

    The standard does not raise issues of technological feasibility 
because it requires only that employers use respirators already on the 
market. Further, these respirators are already in use and have proven 
feasible in a wide variety of industrial settings. However, costs for 
the APF standard result from requiring some users to switch to more 
protective respirators than they currently use. When the APF is lower 
than the baseline (current) APF, respirator users must upgrade to a 
more protective model. Both the 1992 ANSI Z88.2 Respiratory Protection 
Standard and the 1987 NIOSH RDL specify APFs for certain classes of 
respirators. The Agency assumed that employers currently use the ANSI 
or NIOSH APFs, or the APFs in the OSHA substance-specific standards, as 
applicable, to select respirators. While the Agency currently refers to 
the NIOSH RDL as its primary reference for APFs, in the absence of an 
applicable OSHA standard, this analysis assumes that, in most cases, 
adhering to the existing ANSI APFs fulfills employers' legal obligation 
for proper respirator selection under the existing Respiratory 
Protection Standard. However, in the case of full facepiece negative 
pressure respirators, the Agency has established that an APF of 50, as 
opposed to ANSI's APF of 100, is currently acceptable. In this regard, 
all but one of the substance-specific standards with APFs for full 
facepiece negative pressure respirators set an APF of 50. In addition, 
the existing respirator rule and its supporting preamble require that 
quantitative fit testing of full facepiece negative pressure 
respirators must achieve a fit factor of 500 when employees use them in 
atmospheres in excess of 10 times the PEL; this requirement assumes a 
safety factor of 10. Therefore, based on a fit factor of 500, such 
respirators are safe to wear in atmospheres up to 50 times the PEL, 
consistent with similar requirements regarding respirator use found in 
existing standards for Sec.  6(b)(5) chemicals.
BILLING CODE 4510-26-P

Table V-3A


Table V-3B

BILLING CODE 4510-26-C
    For each respirator type, OSHA compared the new and existing 
standards and, where these new APFs were lower, identified an 
incrementally more protective respirator model. To be adequate, the 
more protective respirator must have an APF greater than the current 
APF.
1. Number of Users Required To Upgrade Respirator Models
    For a given respirator type, the number of users required to shift 
to a more protective respirator depends on two factors: the total 
number of users of that type, and the percentage of those users for 
whom the ambient exposure level is greater than the APF. While survey 
data are available to estimate the number of users, virtually no 
information is available in the literature that provides a basis for 
estimating the percentage of users required to upgrade respirators. The 
percentage of workers switching respirators would depend on the profile 
or frequency distribution of users' exposure to contaminants relative 
to the PEL. For example, the Agency is lowering the APFs for full 
facepiece respirators used to protect against cotton dust from 100 to 
50; accordingly, when workers have ambient exposures that are greater 
than 50 times the PEL, employers must upgrade the respirator from a 
full facepiece negative pressure respirator to a more protective 
respirator (e.g., a PAPR).
    Because of the absence of data on this issue, OSHA made several 
assumptions regarding the requirement to upgrade respirators. First, 
OSHA assumed that employers use respirators only when their employees 
have exposures above the PEL. Second, OSHA assumed employers use the 
most inexpensive respirator permitted, taking into consideration the 
employees' safety and compliance with regulatory requirements. These 
assumptions most likely overestimate the cost of compliance because 
many employers require their employees to use respirators when OSHA 
does not require such use, or they require respirators with higher APFs 
than OSHA currently requires. As a result, this analysis assumes shifts 
in respirators that employers may have implemented already. Two 
commenters on this issue agreed that these assumptions overestimate the 
number of employers that would need to change respirators as a result 
of this rule (see Exs. 9-16 and 13-8). One commenter (Ex. 9-16) noted 
that "For about twenty years, 3M has looked for worksites where 
employers were using respirators at concentrations at the upper end of 
the APF range. We have not been able to find these worksites." This 
commenter went on to note, as a result "we believe that the overall 
compliance costs associated with the proposal, as currently written, 
will likely be even lower than OSHA has estimated."
    The Agency estimated distributions of exposures above the PELs 
based on reports from its Integrated Management Information System 
describing workplace monitoring of Sec.  6(b)(5) toxic substances 
performed during OSHA health inspections. Of the 9,095 samples reported 
above the PELs, 68.0 percent reported exposures between one and five 
times the PEL, 13.1 percent found exposures between five and 10 times 
the PEL, and 9.5 percent documented exposures between 10 and 25 times 
the PEL. Exposures for the remaining 9.4 percent of the samples were 
greater than 25 times the PEL. Based on these data, OSHA modeled the 
current exposure distribution for each respirator type.
2. Incremental Costs of Upgrading Respirator Models
    OSHA also analyzed the costs of upgrading from the current 
respirator to a more protective alternative. In doing so, OSHA 
estimated the annualized unit costs for each respirator type, including 
equipment and accessory costs, and the costs for training and fit 
testing. One commenter (Ex. 17-9) noted the importance of not just 
considering the initial costs of a respirator, but all associated 
costs. OSHA has considered all of these costs, including training, fit 
testing, program development, and medical evaluation, as this commenter 
suggested. OSHA then calculated the incremental cost for each combination 
of upgrades from an existing model to a more protective one, taking into 
account the effect of replacement before the end of the respirator's useful 
life. These annualized costs range from $49.98 (for upgrading from a 
supplied-air, demand mode, full facepiece respirator to a supplied-air, 
continuous flow, half-mask respirator) to $963.73 (for upgrading from a 
non-powered, air-purifying full facepiece respirator to a full 
facepiece PAPR).
    In certain instances, workers who use respirators under the 
substance-specific standards may have to upgrade to a SAR with an 
auxiliary escape SCBA. Several substance-specific standards currently 
specify SARs for exposures that exceed 1,000 times the PEL.\4\ OSHA 
believes that workers are unlikely to regularly use respirators at such 
extreme exposure levels, i.e., they are most likely to use them only in 
exceptional, possibly emergency-related situations. Furthermore, 
exposures at levels more than 1,000 times the PEL would generally be at 
or above levels deemed immediately dangerous to life or health (IDLH), 
so employers already are required by the Respiratory Protection 
Standard to provide each worker with a respirator that has SCBA 
capability. For these reasons, this PERFSA estimated no impacts for 
these situations.\5\
---------------------------------------------------------------------------

    \4\ These standards regulate cotton dust, coke oven emissions, 
acrylonitrile, arsenic, DBCP, ethylene oxide, and lead.
    \5\ Paragraph (d)(2) of the Respiratory Protection Standard 
requires employers to provide either a pressure demand SCBA or a 
pressure demand SAR with auxiliary SCBA to any employee who works in 
IDLH atmospheres.
---------------------------------------------------------------------------

3. Aggregate Compliance Costs
    For each respirator type affected by the regulation, OSHA combined 
the incremental costs of upgrading to a more protective respirator, the 
estimated share of users forecast to upgrade, and the number of users 
involved to estimate the compliance costs associated with each 
respirator type. Table V-4 shows estimated compliance costs for OSHA's 
APF rule. The rule would require 1,918 users of non-powered air-
purifying respirators to upgrade to some respirator more expensive than 
they are now using at a cost of $1.8 million. The Agency estimates that 
22,848 PAPR users would upgrade their respirators at a cost of $2.3 
million. A relatively small number of SAR users (5,110) would upgrade 
to more expensive respirators at a cost of $0.4 million. Industry-
specific compliance costs vary according to the number of respirator 
users and the proportion of these users affected by the rule. 
Industries with relatively large compliance costs include SIC 17, 
Special trade contractors ($0.8 million), and SIC 80, Health services 
($0.8 million).
    As discussed previously, the Agency believes the actual costs of 
the standard almost certainly are overestimated. The cost analysis 
assumes all respirator wearers have levels of exposures that require 
the particular respirator they are using. Under this assumption, 15,000 
employees would be allowed to safely shift to a less expensive 
respirator, which could lead to cost savings for the employer. Such 
potential cost savings are not accounted for in this cost analysis.
    In many cases, employers use respirators when respirators are not 
required by OSHA, or use respirators more protective than required by 
OSHA. As a result, OSHA's cost analysis overestimates the number of 
employees who are affected by the standard, and therefore overestimates 
costs associated with the standard.

D. Benefits

    The benefits that would accrue to respirator users and their 
employers take several forms. The standard would benefit workers by 
reducing their exposures to respiratory hazards. Improved respirator 
selection would augment previous improvements to the Respiratory 
Protection Standard, such as better fit-test procedures and improved 
training, contributing substantially to greater worker protection. 
Estimates of benefits are difficult to calculate because of 
uncertainties regarding the existing state of employer respirator-
selection practices and the number of covered work-related illnesses. 
At the time of the 1998 revisions to the Respiratory Protection 
Standard, the Agency estimated that the standard would avert between 
843 and 9,282 work-related injuries and illnesses annually, with a best 
estimate (expected value) of 4,046 averted illnesses and injuries 
annually (63 FR 1173). In addition, OSHA estimated that the standard 
would prevent between 351 and 1,626 deaths annually from cancer and 
many other chronic diseases, including cardiovascular disease, with a 
best estimate (expected value) of 932 averted deaths from these causes. 
The APFs in this rulemaking will help ensure that these benefits are 
achieved, as well as provide an additional degree of protection. These 
APFs also will reduce employee exposures to several Sec.  6(b)(5) 
chemicals covered by standards with outdated APF criteria, thereby 
reducing exposures to chemicals such as asbestos, lead, cotton dust, 
and arsenic.\6\ While the Agency did not quantify these benefits, it 
estimates that 29,655 employees would have a higher degree of 
respiratory protection under this APF standard. Of these employees, an 
estimated 8,384 have exposure to lead, 7,287 to asbestos, and 3,747 to 
cotton dust, all substances with substantial health risks.
---------------------------------------------------------------------------

    \6\ In the 1998 rulemaking revising the Respiratory Protection 
Standard, the Final Economic Analysis noted that the standard would 
not directly affect the benefits for the estimated 5% of employees 
who use respirators under OSHA's substance-specific health standards 
(except to the extent that uniformity of provisions improve 
compliance). Therefore, the Agency likely over-estimated the 
benefits of that rulemaking since the standard did not affect 
directly the type of respirator used by those employees (63 FR 
1173). Conversely, this rule directly addresses the APF provisions 
of the substance-specific standards; therefore, this rule would 
affect directly the respirators used by employees covered by these 
standards.
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BILLING CODE 4510-26-P

Table V-4

BILLING CODE 4510-26-C

    In addition to health benefits, OSHA believes other benefits result 
from the harmonization of APF specifications, thereby making compliance 
with the respirator rule easier for employers. Employers also benefit 
from greater administrative ease in proper respirator selection. 
Employers would no longer have to consult several sources and several 
OSHA standards to determine the best choice of respirator, but could 
make their choices based on a single, easily found regulation. Some 
employers who now hire consultants to aid in choosing the proper 
respirator should be able to make this choice on their own with the aid 
of this rule. In addition to having only one set of numbers (i.e., 
APFs) to assist them with respirator selection for nearly all 
substances, some employers may be able to streamline their respirator 
stock by using one respirator class to meet their respirator needs 
instead of several respirator classes. The increased ease of compliance 
would also yield additional health benefits to employees using 
respirators.
    Alternatively, these APFs would clarify when employers can safely 
place employees in respirators that impose less stress on the 
cardiovascular system (e.g., filtering facepiece respirators). Many of 
these alternative respirators may have the additional benefit of being 
less expensive to purchase and operate. As previously discussed, OSHA 
estimates that over 15,000 employees currently use respirators that 
fall in this group (i.e., shift to a less expensive respirator).
    One commenter (Ex. 9-16) agreed that the standard would have 
significant benefits, saying:

    3M concurs with OSHA's conclusion that significant health 
benefits will accrue to workers as a result of this rulemaking. 3M 
believes that the majority of these benefits will be the result of 
simplification of the respirator selection process for employers. 
This will in turn lead to greater compliance with OSHA's various 
standards regarding exposure to toxic and harmful substances. * * *
    In addition to these benefits from increased compliance, 3M also 
concurs with OSHA's determination that the simplification and 
clarification of the APF tables will result in lessening of 
cardiovascular stress, as well as other potential stresses, because 
of the ability to select a filtering facepiece respirator.

E. Economic Feasibility

    OSHA is required to set standards that are feasible. To demonstrate 
that a standard is feasible, the courts have held that OSHA must 
"construct a reasonable estimate of compliance costs and demonstrate a 
reasonable likelihood that these costs will not threaten the existence 
or competitive structure of an industry" (United Steelworkers of 
America, AFL-CIO-CLC v. Marshall (the "Lead" decision), 647 F.2d 1189 
(DC Cir. 1980)).
    OSHA conducted its analysis of economic feasibility on an 
establishment basis. Accordingly, for each affected industry, the 
Agency compared estimates of per-establishment annualized compliance 
costs with per-establishment estimates of revenues and per-
establishment estimates of profits. It used two worst-case assumptions 
regarding the ability of employers to pass the costs of compliance 
through to their customers: The no-cost-pass-through assumption, and 
the full-cost-pass-through assumption. Based on the results of these 
comparisons, which define the universe of potential impacts of the 
APFs, OSHA then assessed the economic feasibility for all affected 
establishments, i.e., those covered by this rule.
    The Agency assumed that establishments falling within the scope of 
the standard would have the same average sales and profits as other 
establishments in their industries. OSHA believes this assumption is 
reasonable because no evidence is available showing that the financial 
characteristics of those firms with employees who use respirators are 
different from firms that do not use respirators. In the absence of 
such evidence, OSHA relied on the best available financial data (those 
from the Bureau of the Census (Ex. 6-4) and Robert Morris Associates 
(Ex. 6-5)), used a commonly accepted methodology to calculate industry 
averages, and based its analysis of the significance of the projected 
economic impacts and the feasibility of compliance on these data.
    The analysis of the potential impacts of this standard on before-
tax profits and sales shown in Table V-5 is a "screening analysis," 
so called because it simply measures costs as a percentage of pre-tax 
profits and sales under the worst-case assumptions discussed above, but 
does not predict impacts on these before-tax profits or sales. OSHA 
used the screening analysis to determine whether the compliance costs 
potentially associated with the standard could lead to significant 
impacts on all affected establishments. The actual impact of the 
standard on the profit and sales of establishments in a specific 
industry would depend on the price elasticity of demand for the 
products or services of these establishments.
    Table V-5 shows the economic impacts of these costs. For each 
industry, OSHA constructed the average compliance cost per affected 
establishment and compared it to average revenues and average 
profits.\7\ These costs are quite small, i.e., less than 0.005 percent 
of revenues; the one major exception is SIC 44 (Water transportation), 
for which OSHA estimated the costs impacts to be 0.16 percent of 
revenues. When the Agency compared average compliance costs with 
profits, the costs also are small, i.e., less than 0.17 percent; again, 
the major exception was SIC 44, which had an estimated impact of 2.12 
percent of profits.\8\ Based on the very small impacts for 
establishments in all industries shown in Table V-5, OSHA concludes 
that the APF standard is economically feasible, in the sense of being 
unlikely to close or alter the competitive structure of the affected 
industries, for the affected establishments.
---------------------------------------------------------------------------

    \7\ OSHA defines "affected establishment" as any facility that 
uses respirators, as represented in the NIOSH-BLS survey data.
    \8\ For some industries, such as SIC 44, data from the NIOSH-BLS 
survey were suppressed due to low response rates. In these cases, 
the Agency, for the purposes of assessing economic feasibility, 
imputed broader sector-level data from the survey to form an 
estimate of respirator use. This procedure may result in 
overestimating the impact of the standard (proposal) in some 
industries. See the full FEA (Ex. 11) for further details.
---------------------------------------------------------------------------

BILLING CODE 4510-26-P

Table V-5

BILLING CODE 4510-26-C

F. Economic Impacts to Small Entities

    OSHA also estimated the economic impacts of the rule on affected 
entities with fewer than 20 employees, and for affected small entities 
as defined by the Small Business Administration (SBA). Table V-6 shows 
the estimated economic impacts for small entities with fewer than 20 
employees: average compliance costs by industry are less than 0.005 
percent of average revenues, and less than 0.19 percent of profits, in 
all industries. Table V-7 presents the economic impacts for small 
entities as a whole, as defined by SBA. For these firms, average 
compliance costs are less than 0.005 percent of average revenues and 
less than 0.03 percent of average profits. Thus, the Agency projects no 
significant impacts from the rule on small entities.
BILLING CODE 4510-26-P

Table V-6

Table V-7

BILLING CODE 4510-26-C

    When costs exceed one percent of revenues or five percent of 
profits, OSHA considers the impact on small entities significant for 
the purposes of complying with the RFA. For all classes of affected 
small entities, the Agency found that the costs were less than one 
percent of revenues and five percent of profits. Therefore, OSHA 
certifies that this regulation would not have a significant impact on a 
substantial number of small entities.

VI. Summary and Explanation of the Final Standard

    This section of the preamble provides a summary and explanation of 
each revision made to OSHA's Respiratory Protection Standard involving 
APFs.

A. Definition of Assigned Protection Factor

    As part of its 1994 proposed rulemaking for the Respiratory 
Protection Standard, OSHA proposed a definition for APFs that read as 
follows: "[T]he number assigned by NIOSH [the National Institute for 
Occupational Safety and Health] to indicate the capability of a 
respirator to afford a certain degree of protection in terms of fit and 
filter/cartridge penetration" (59 FR 58938). OSHA proposed this 
definition on the assumption that NIOSH would develop APFs for the 
various respirator classes, building on the APFs in the 1987 NIOSH RDL 
(59 FR 58901-58903). However, NIOSH subsequently decided not to publish 
a list of APFs as part of its 42 CFR 84 Respirator Certification 
Standards (60 FR 30338), and reserved APFs for a future NIOSH 
rulemaking.
    During his opening statement on June 15, 1995, at an OSHA-sponsored 
expert-panel discussion on APFs, Adam Finkel, then Director of the 
Agency's Directorate of Health Standards Programs, noted that OSHA 
would explore developing its own list of APFs (H-049, Ex. 707-X). The 
Agency then announced in the preamble to the final Respiratory 
Protection Standard (63 FR 1182) that it would propose an APF table 
"based on a thorough review and analysis of all relevant evidence" in 
a subsequent rulemaking. In the final Respiratory Protection Standard, 
OSHA reserved space for a table for APFs, a paragraph ((d)(3)(i)(A)) 
for APF requirements, and a definition of APF under paragraph (b).
    In its 1987 RDL, NIOSH defined an APF as "[t]he minimum 
anticipated protection provided by a properly functioning respirator or 
class of respirators to a given percentage of properly fitted and 
trained users" (Ex. 1-54-437Q). ANSI subsequently developed a 
definition for an APF in its Z88.2-1992 Respiratory Protection Standard 
that reads, "The expected workplace level of respiratory protection 
that would be provided by a properly functioning respirator or class of 
respirators to properly fitted and trained users" (Ex. 1-50). The ANSI 
Z88.2 subcommittee that developed the 1992 standard used the NIOSH 
definition of an APF as a template for its APF definition. However, the 
Z88.2 subcommittee revised the phrase "minimum anticipated 
protection" in the NIOSH definition to "expected workplace level of 
respiratory protection." It also removed the NIOSH phrase "to a given 
percentage" from its definition.
    The phrase "a given percentage" implies that some respirator 
users will not achieve the full APF under workplace conditions. The 
"given percentage" usually is about five percent, which is a 
percentage derived from statistical analyses of results from WPF 
studies. In this regard, five percent represents the 5th percentile of 
the geometric distribution of individual protection factors in a WPF 
study. Therefore, the 5th percentile is the threshold for specifying 
the APF for the respirator tested under those workplace conditions. 
Using the 5th percentile means that about five percent of the employees 
who use the respirator under these workplace conditions may not achieve 
the level of protection assigned to the respirator (or class of 
respirators), even after they receive proper fit testing and use the 
respirator correctly under a comprehensive respiratory protection 
program. However, ANSI dropped the phrase "to a given percentage" to 
reduce confusion (i.e., the phrase did not specify a percentage), and 
to emphasize the level of protection needed by the vast majority of 
employees who use respirators in the workplace. See also subsection E.4 
("Analysis of Updated Database on APRs") of Section III 
("Methodology for Developing APFs for Respirators") of this preamble.
    The Agency's review of the available data on respirator 
performance, as well as findings from surveys of personal protective 
equipment (Exs. 6-1 and 6-2), indicate that existing APF definitions 
are confusing to the respirator-using public. Accordingly, OSHA has 
developed its own definition in this final rule that will reduce 
confusion among employers and employees regarding APFs, thereby 
assisting employers in providing their employees with effective 
respirator protection, consistent with its Respiratory Protection 
Standard.
    The major revision the Agency made to the ANSI APF definition in 
developing the proposed APF definition included adding the phrase 
"when the employer implements a continuing, effective respiratory 
protection program as specified by 29 CFR 1910.134." The Agency added 
this phrase to emphasize the already existing requirement that 
employers must select a respirator in the context of a comprehensive 
respiratory protection program. Also, the Agency revised the phrase 
"as specified by 29 CFR 1910.134" at the end of the proposed APF 
definition to read "as specified by this section" to conform to style 
conventions for referencing an entire standard. Therefore, the Agency 
is adopting the APF definition that was proposed in the NPRM except for 
this minor revision. OSHA's final definition for APF reads as follows:

    Assigned protection factor (APF) means the workplace level of 
respiratory protection that a respirator or class of respirators is 
expected to provide to employees when the employer implements a 
continuing, effective respiratory protection program as specified by 
this section.

B. APF Provisions

1. Paragraph (d)(3)(i)(A)--APF Provisions
    Paragraph (d)(3)(i)(A) is the provision in OSHA's Respiratory 
Protection Standard that requires employers to use the APFs in Table 1 
of this final standard to select respirators. The language of the final 
provision is the same as the language in the proposal. Therefore, 
paragraph (d)(3)(i)(A) in the final rule reads as follows:

    (A) Assigned Protection Factors (APFs). Employers must use the 
assigned protection factors listed in Table 1 to select a respirator 
that meets or exceeds the required level of employee protection. 
When using a combination respirator (e.g., airline respirators with 
an air-purifying filter), employers must ensure that the assigned 
protection factor is appropriate to the mode of operation in which 
the respirator is being used.

    The proposed language in paragraph (d)(3)(i)(A) also contained the 
following note that addressed two issues related to APFs:

    Note to paragraph (d)(3)(i)(A): The assigned protection factors 
listed in Table 1 are effective only when the employer has a 
continuing, effective respiratory protection program as specified by 
29 CFR 1910.134, including training, fit testing, maintenance and 
use requirements. These assigned protection factors do not apply to 
respirators used solely for escape.


    The first sentence of the note was proposed to remind employers 
that the APFs in Table 1 are effective only when they have a complete 
respirator program that meets the requirements of OSHA's Respiratory 
Protection Standard. Table 1 of the final rule already contains a note 
(footnote 2) that essentially repeats this language. Therefore, to avoid 
unnecessary duplication, the Agency decided to remove this language for
the final rule. However, the Agency is retaining the last part of the
note as a footnote in Table 1 of the final rule (see discussion of 
footnote 5 in the following subsection). 
2. Table 1--APF Table
    The NPRM contained Table 1 ("Assigned Protection Factors"), which 
listed the APFs for the various respirator classes. The final APFs for 
these respirators are discussed in detail in subsection C ("Assigned 
Protection Factors for Specific Respirator Types") of this section.
    The proposed APF Table also contained a set of footnotes that 
informed users regarding the application of APFs in the table. In the 
final rule, footnote 1 remains essentially unchanged from the proposal. 
Footnote 2 has been clarified to explain when APFs are effective, 
rather than when APFs apply. All employers who use respirators need to 
comply with the Respiratory Protection Standard. The language in 
footnote 3 of the proposed table was revised from the proposal. 
Proposed footnote 3 stated "This APF category includes quarter masks, 
filtering facepieces, and half-masks." The reference to quarter masks 
has been removed from this footnote since quarter mask respirators have 
been assigned a separate APF in Table 1. Also, the phrase "with 
elastomeric facepieces" has been added to the description of half 
masks to clarify that elastomeric facepieces are included in the half 
mask respirator class. Final footnote 3 reads as follows in the final 
rule: "This APF category includes filtering facepieces, and half masks 
with elastomeric facepieces."
    Footnote 4 relates to the testing of PAPRs with helmets or hoods to 
demonstrate that these respirators can perform at the required APF of 
1,000 or greater for this class. The proposed footnote and the changes 
made to it in the final standard are discussed in subsection C 
("Assigned Protection Factors for Specific Respirator Types") in item 
4 ("APF for Powered Air-Purifying Respirators (PAPRs)") of this 
section.
    Footnote 5 in the proposal described limitations for the APF of 
10,000 (maximum) for pressure-demand SCBAs. The proposed footnote 5 
described an SWPF study demonstrating that, when test subjects used 
pressure-demand SCBAs under high work rates, a few of the study results 
indicated that the respirators may not achieve an APF of 10,000. 
Consequently, the proposed footnote cautioned employers not to use 
these respirators under conditions that would require protection above 
this level. In discussing this footnote in the proposal, OSHA stated 
that, "the employer must restrict [pressure-demand SCBA] use to 
conditions in which the required level of employee protection is at or 
below an APF of 10,000" (68 FR 34105). While the Agency received no 
comments on the proposed footnote, it believes that, when employers use 
these respirators, they must assess the exposure conditions prior to 
such use as required by paragraph (d)(1)(iii) of OSHA's Respiratory 
Protection Standard. In view of the already existing requirement, the 
Agency decided that the information in proposed footnote 5 was 
unnecessary, and, therefore, removed it from the final rule.
    As noted previously under subsection B ("Paragraph (d)(3)(i)(A)--
APF Provisions") of this section, OSHA is adding a new footnote 5 to 
Table 1 in the final rule. The new footnote will remind employers that 
they cannot apply the APFs specified in Table 1 to emergency-escape 
conditions. OSHA believes this footnote is important because precise 
exposures levels, which serve as the basis for determining APFs, cannot 
be assessed accurately for emergency-escape conditions. Under these 
conditions, the only appropriate respirators for employee use are 
respirators designated for escape (i.e., escape respirators), 
consistent with the requirements specified by OSHA's Respiratory 
Protection Standard at 29 CFR 1910.134(d)(2)(ii). New footnote 5 is 
similar to the APF provisions of the Agency's substance-specific 
standards that designate appropriate respirators for use under 
emergency-escape conditions. Because both the substance-specific 
standards and 29 CFR 1910.134(d)(2)(ii) contain requirements for 
selecting escape respirators, the Agency is revising the note slightly 
to ensure that employers refer to the appropriate provisions. 
Therefore, footnote 5 to Table 1 in the final rule will read as 
follows:

    These APFs do not apply to respirators used solely for escape. 
For escape respirators used in association with specific substances 
covered by 29 CFR part 1910 subpart Z, employers must refer to the 
appropriate substance-specific standard in that subpart. Escape 
respirators for other IDLH atmospheres are specified by 29 CFR 
1910.134(d)(2)(ii).

C. Assigned Protection Factors for Specific Respirator Types

    OSHA received comments on APFs during the public comment period 
following publication of the NPRM, and at the public hearing. These 
comments and hearing testimony are addressed in the following sections.
1. APF for Quarter Mask Air-Purifying Respirators
    Introduction. OSHA proposed an APF of 10 for quarter mask air-
purifying respirators (i.e., quarter masks/quarter mask respirators), 
including them in the same category as filtering facepieces and half 
mask air-purifying respirators (68 FR 43115). However, the Agency 
specifically requested comment on whether this action was appropriate 
(see 68 FR 34112).
    The following recommendations include all of the issues raised by 
commenters regarding quarter mask respirators: assign them an APF of 
10; assign them an APF of 5; prohibit their use altogether; or refrain 
from assigning an APF to them until more studies become available. In 
general, those commenters who recommended an APF of 10 for quarter mask 
respirators based their recommendations on the analogous structural 
characteristics (i.e., similarities in design) of quarter mask and half 
mask respirators. Commenters who recommended an APF of 5 pointed out 
that the only available APF data for quarter mask respirators were in 
the 1976 study by Edwin C. Hyatt entitled "Respiratory Protection 
Factors" (i.e., the "Hyatt Study" (Ex. 2)). Based on this study, 
Hyatt assigned quarter masks an APF of 5.
    Comments regarding quarter mask respirators. The commenters who 
advised OSHA to give quarter mask respirators an APF of 10 believed 
that when these respirators are used in a workplace where the employer 
has implemented a complete respirator program as required by 29 CFR 
1910.134, their performance should be the same as that of half mask 
respirators. For example, Thomas Nelson of Nelson Industrial Hygiene 
Systems, Inc. testified,

    There is no unique property of a quarter mask respirator that 
makes it[s] use different from half facepiece respirators provided 
the person using the respirator is trained, fitted and maintains the 
respirator. OSHA should include quarter masks in the half facepiece 
category. (Ex. 10-17.)

    Michael Runge of 3M Corporation recommended that both half mask and 
quarter mask respirators should receive an APF of 10 because of their 
similarity in performance, which he described as follows:

    [L]eakage into a respirator can occur through three pathways[:] 
defects, filter penetration or faceseal leakage. Leakage through 
defects is controlled by the respirator maintenance program. Quarter 
facepiece respirators are no harder to maintain than half facepiece 
respirators; they have many of the same parts * * * Filter leakage 
is controlled by the NIOSH certification process * * * Faceseal 
leakage is controlled through fit testing. The same fit tests can be 
used with either type of respirator, hence the same maximum face 
seal leakage would be expected for the quarter and half facepiece 
respirator. (See Ex. 9-16.)

    Daniel Shipp and Janice Bradley of the International Safety 
Equipment Association and Kenneth V. Bobetich of MSA made similar 
statements (Exs. 9-22, 9-37, and 16-14).
    Thomas Nelson asserted that the Hyatt Study may have underestimated 
the APF for quarter mask respirators because the study did not control 
adequately for respirator leakage. His comment was based on the fact 
that the authors of the study: (1) Did not administer a proper fit test 
to the test subjects prior to measuring particle contamination inside 
the respirator, and (2) used a fine particle (sodium chloride) as a 
test aerosol, that may have penetrated both the faceseal and filter, 
thereby artificially increasing concentrations inside the respirator 
(Tr. at 163 and Ex. 18-9).
    The commenters who recommended that OSHA assign quarter mask 
respirators an APF of 5 stressed that no studies, including WPF and 
SWPF studies, on quarter mask respirators have been performed since the 
Hyatt Study. Few quantitative data are thus available on which OSHA can 
rely to set an APF for quarter mask respirators. These commenters, who 
include NIOSH, pointed out that NIOSH used the Hyatt Study to set the 
APF for quarter mask respirators at 5 in its 1987 RDL. NIOSH commented 
further that, "quarter mask respirators should be separated from half 
mask respirators into a class of their own with an APF of 5. The data 
from Hyatt's study [1976] do not support an APF of 10" (Ex. 17-7-1). 
Similarly, James S. Johnson stated, "We object to the agency's 
proposed APF of 10 for quarter mask respirators. There is no evidence 
in the record, from either WPF or simulated workplace protection factor 
(SWPF) studies that support this conclusion" (Ex. 16-9-1). Johnson's 
comments were echoed by the AFL-CIO (Exs. 9-27 and 19-1-1). These 
comments indicate that the Hyatt Study was not a valid WPF or SWPF 
study because it was a fit test protocol, not an experimental study.
    The International Brotherhood of Teamsters and the AFL-CIO Building 
and Construction Trades Department supported an APF of 5 for quarter 
mask respirators because they believed that quarter mask respirators 
were more likely than half mask respirators to move around on workers' 
faces when the workers communicate, or because of movement, exertion, 
or perspiration. These commenters stated:

    Since the lower seal of the facepiece in quarter mask 
respirators is on the chin, rather than below the chin, the seal is 
much more likely to be compromised than the seal on a half face 
respirator. Additionally, in use factors such as movement, exertion, 
and perspiration add to the likelihood that the seal of these masks 
will be compromised in the work place. (Exs. 9-12 and 9-29.)

    The Nuclear Regulatory Commission commented that its regulations 
prohibit the use of quarter masks because of "the potential lack of 
stability of fit and the availability of acceptable alternatives (half-
face respirators)" (Ex. 10-7). Tracy Fletcher of Parsons-Oderbrecht JV 
recommended that OSHA prohibit the use of both quarter and half masks, 
stating, "Employees are required to wear eye protection with the 
respirator, and use of the two together is difficult as the wearer will 
find that the glasses rest on the nose piece of the respirator creating 
an entry point for an overspray, splash or whatever." (Ex. 10-1.)
    A small number of commenters expressed the opinion that, because 
the Hyatt Study provides the only data on the protection afforded by 
quarter mask respirators, OSHA should reserve its decision on the APF 
for these respirators until more studies can be completed. ORC 
Worldwide commented that "[q]uarter masks should be evaluated as 
individual respirator models. In the absence of comprehensive testing 
data over the last 27 years, there is no valid basis for giving them an 
APF of any kind" (Ex. 10-27). David Spence, an industrial hygienist, 
stated:

    We recommend that SWPF studies be performed on quarter masks 
respirators in a manner analogous to the ORC SWPF studies performed 
on powered air-purifying respirators and supplied-air respirators. 
To not delay publishing APFs for the other classes of respirators, 
the section on APF of quarter masks could be reserved pending 
completion of SWPF studies. (Ex. 10-6.)

    Summary and conclusions. In light of these comments, the Agency has 
reconsidered the proposed APF of 10 for quarter masks. The comments 
recommending an APF of 10 for quarter mask respirators are based solely 
on structural analogies between quarter masks and half masks, and not 
on the functional characteristics of these respirators. Accordingly, 
the rulemaking record contains no quantitative or qualitative data or 
other convincing evidence confirming that quarter mask and half mask 
respirators function in a similar fashion to provide employees with 
equal levels of respiratory protection. No WPF or SWPF studies 
conducted on quarter mask respirators were submitted to the record. The 
Hyatt Study, which consisted of testing quarter masks using a fit 
testing protocol, provides the only data available for quarter mask 
respirators, and it supports an APF of 5. Therefore, OSHA has decided 
to separate quarter mask respirators into their own category and assign 
them an APF of 5.
    It is possible that the facepieces of quarter masks and half masks 
are not functionally analogous. Some commenters noted that half masks 
rest under the chin while quarter masks rest on the chin. Consequently, 
quarter masks are more prone than half masks to slip and compromise the 
face seal when a worker talks or performs heavy work. While the record 
contains no quantitative evidence supporting such assertions, there is 
ample qualitative evidence, and OSHA is entitled under these 
circumstances to take a conservative approach in weighing the available 
evidence (see, e.g., 29 U.S.C. 655(b)(5) and United Steelworkers of 
America, AFL-CIO-CLC v. Marshall, 647 F.2d 1189, 1248 (D.C. Cir. 
1980)). Moreover, OSHA believes that these respirators can be used 
safely at an APF of 5 because properly administered fit testing 
protocols (including administering the fit test with glasses and other 
protective equipment worn during respirator use),\9\ as well as 
appropriate respirator training, will inform employees of this problem 
and the procedures they can use to prevent it.
---------------------------------------------------------------------------

    \9\ As required under Appendix A (Part IA, paragraph 13) of 29 
CFR 1910.134.
---------------------------------------------------------------------------

    In further response to those commenters who advised OSHA to 
prohibit quarter masks, OSHA does not believe that this approach is 
reasonable. As discussed at the public hearing, quarter mask 
respirators are not widely used, but they do have some popularity in 
particular industries (Tr. at 558). All existing quarter mask 
respirators have received an N95 rating under NIOSH's certification 
program, indicating that the respirators are designed to prevent at 
least 95% of the challenge agent from penetrating the filter. 
Therefore, these certification results, along with the other evidence 
in the rulemaking record, have convinced OSHA that employees can use 
these quarter mask respirators safely at an APF of 5 in workplaces that 
implement a respirator program that complies with 29 CFR 1910.134.
    Regarding those commenters who advised OSHA to delay the APF 
decision for quarter mask respirators until WPF or SWPF studies are 
available, OSHA notes that in the intervening 29 years following the 
Hyatt Study, no WPF or SWPF studies have been conducted on quarter mask 
respirators. If OSHA was to delay setting an APF for quarter mask 
respirators pending further study, it could in effect be deciding to 
delay setting an APF for these respirators indefinitely. OSHA has not 
been persuaded by the record to delay setting an APF for quarter mask 
respirators. Moreover, as noted in the previous paragraph, OSHA has 
concluded that the record evidence supports an APF of 5 for quarter 
mask respirators.
2. APF for Half Mask Air-Purifying Respirators
    Introduction. OSHA proposed an APF of 10 for both elastomeric and 
filtering facepiece half mask respirators. During the public comment 
period, interested parties expressed two divergent views on this 
proposed APF. The healthcare industry (Ex. 9-18 to 9-21), NIOSH (Tr. 
107 and 112) and other commenters (e.g., Exs. 9-11, 9-22, 9-26, 9-42, 
and 10-18) agreed to an APF of 10 for both types of respirators, while 
a number of commenters stated that filtering facepieces should be 
assigned a protection factor of 5 (e.g., Exs. 9-8, 9-12, 9-29, and 10-
6; AFL-CIO Tr. at 122-126). The following sections discuss this issue 
in detail.
    A number of reasons were presented for limiting filtering facepiece 
half masks to an APF of 5. These reasons can be categorized generally 
into concerns related to: (1) WPF studies and associated data; (2) 
design of filtering facepiece respirators; (3) respirator use in the 
workplace; and (4) ANSI standards. As discussed in Section III above, 
some commenters believed that the WPF studies evaluated by OSHA 
suffered from multiple problems (e.g., old data, studies not 
representative of typical workplaces). While these points are addressed 
in detail in Section III of this preamble, some of these concerns 
warrant further discussion here.
    Some filtering facepieces do not achieve an APF of 10. Comment was 
made that the data presented in the studies analyzed by OSHA indicate 
that not all filtering facepieces achieved an APF of 10. Consequently, 
these commenters argued that the entire class of respirators should 
receive an APF of 5 (Exs. 9-29, 9-27, and 10-54). The AFL-CIO stated:

    An examination of the summary table of WPF studies for filtering 
facepieces and half-mask elastomeric respirators at 68 FR 30495 of 
OSHA's preamble to this proposed rule justifies our position. Of the 
seven respirators that had a 5th percentile WPF less than 9, five of 
[the] respirators that failed consisted of the filtering facepiece 
style of respirator. Thus [of] the overwhelming majority of the half 
mask respirators that failed, five of the seven or 71%, were 
filtering facepieces. At the qualitative level then, this data 
clearly indicates that most of the problem with failing to provide 
adequate protection rests with filtering facepieces and not with 
half-mask elastomerics. (Ex. 9-27.)

    The summary table in the proposal at 68 FR 34095 contains several 
studies that were reviewed by OSHA, but did not meet the selection 
criteria and were excluded from the quantitative analyses. The two 
filtering facepiece respirators (one model in each study) evaluated in 
these excluded studies had WPFs less than 9 (Cohen, Ex. 1-64-11; and 
Reed, Ex. 1-64-61), while five of the respirators included in OSHA's 
analyses failed to achieve a WPF of 9. Three of these five respirators 
were filtering facepiece respirators and the remaining two respirators 
were elastomeric half masks. As noted at the hearing, OSHA conducted a 
Chi-square analysis to determine if the proportion of filtering 
facepieces having a WPF less than 9 differed from the proportion of 
elastomerics with a WPF less than 9 (Trans. at 135-136). This 
statistical comparison showed that these proportions did not differ 
significantly from each other, indicating that similar proportions of 
filtering facepiece and elastomeric respirators performed at this 
level--i.e., that the filtering facepiece respirators did not perform 
more poorly than the elastomeric respirators.
    After updating the proposal's half mask WPF database (Ex. 20-2) 
with new and additional data, Dr. Crump reanalyzed the database (Ex. 
20-1). Plotting the observed protection factors for both the 
elastomeric and the filtering facepiece half masks shows that over 95% 
of each type of half mask attained an APF of at least 10. Moreover, a 
review of these updated analyses reveals that more elastomeric than 
filtering facepiece respirators failed to achieve an APF of 10 (see 
Table 2 in Ex. 20-1). Even when the data from studies excluded from 
these analyses were added to the database, over 95% of the WPFs for 
both types of half mask (separately and combined) are still equal to or 
greater than 10. (A detailed discussion of Dr. Crump's analyses can be 
found in section III (Methodology) of this preamble.) Therefore, OSHA 
does not agree that the evidence in the record supports an APF for 
filtering facepieces of 5 as suggested by these commenters.
    Respirator configuration and certification issues. Commenters also 
stated that not all configurations (e.g., cups, duckbills, fold flats) 
of filtering facepiece respirators have been studied (e.g., Exs. 9-17, 
9-34, 9-40, 10-33, and 10-34; Tr. at 204-205). In addition, some 
commenters mentioned that none of the respirators in the studies 
evaluated by the Agency for the proposal were certified under NIOSH's 
new 42 CFR 84 requirements (Exs. 9-33, 9-34, 10-22, and 10-38). The 
focus of these comments was that OSHA should not assume that all 
filtering facepieces perform the same as those filtering facepieces 
that were tested. These commenters believed that filtering facepiece 
half masks should be given an APF of 5 because, in their view, there is 
a lack of information on 42 CFR 84 filtering facepieces.
    OSHA recognizes that its analyses do not encompass all 
configurations or models of filtering facepiece half masks. However, 
this is true for all types of respirators, not just filtering facepiece 
half masks. Since filter efficiency is certified by NIOSH, the filter 
media of all filtering facepiece (and elastomeric) half mask 
configurations are equivalent. Therefore, any differences in 
performance would arise from variations in faceseal leakage among the 
different configurations. OSHA's Respiratory Protection Standard 
requires that all respirator users pass a respirator fit test to ensure 
that a minimum acceptable faceseal performance is achieved. Therefore, 
because all respirators must be used in accordance with the Respiratory 
Protection Standard, the Agency sees no reason to conclude that 
differences in configuration will result in performance variations. In 
addition, Section III of this preamble discusses two studies that 
compare the workplace performance of 42 CFR 84 and 30 CFR 11 filtering 
facepiece half masks. The 42 CFR 84 respirators demonstrated superior 
performance when compared to the 30 CFR 11 respirators. OSHA concludes 
that, based on the more stringent filter efficiency certification 
requirements and these study results, 42 CFR 84 respirators provide 
performance at least equal to 30 CFR 11 respirators. Therefore, the 
record evidence does not support lowering the APF for filtering 
facepieces to 5.

    Determining faceseal leakage. Several commenters mentioned that 
NIOSH had eliminated the fit test portion of its certification 
procedures. They believed that as a result of this NIOSH action, one 
could not be sure if a filtering facepiece respirator achieves an 
adequate faceseal and provides the expected protection (Exs. 9-8, 9-27, 
9-29, 9-34, 9-35, 9-40, 9-41, 10-22, 10-33, 10-38, 10-50, and 10-55). 
During the public hearing, NIOSH indicated that it would establish a 
new respirator certification testing procedure, stating:

    Such changes would result in additional certification tests to 
assure or assess the overall performance of every respirator model, 
and thus assure that every model is capable of providing a level of 
protection consistent with the class APF. (Tr. at 103.)

    Several commenters supported this approach, and indicated that 
implementing such a procedure would be beneficial. For example, Tim 
Roberts (Exs. 17-8 and 18-4) stated that the procedure would help to 
identify respirators that may not have adequate workplace performance. 
The AFL-CIO (Ex. 19-1) believed that while the procedure would help 
assure certified filtering facepieces are capable of fitting an 
employee properly, these respirators should still be given an APF of 5.
    Two respirator manufacturers also addressed this issue. The 3M 
Company commented that no evidence exists showing that employee 
protection would be enhanced by adding a fit test requirement to 
NIOSH's certification procedures, and added that proper respirator fit 
must be determined by fit testing each wearer (Ex. 18-7). When asked by 
OSHA about the proposed NIOSH testing, Jay Parker of Bullard responded 
that he believed such testing would be an improvement over the current 
procedures (Tr. at 497).
    OSHA has reviewed this information and supports NIOSH's plans to 
add performance testing to its respirator certification procedures. The 
Agency agrees with the 3M Company that proper facepiece fit can only be 
assured through individual fit testing. However, OSHA also agrees with 
Tim Roberts that performance testing will assist in identifying 
respirators with poor fitting characteristics that may not provide 
protection consistent with the respirator's APF. Thus, OSHA concludes 
that performance testing will enhance the information needed for 
selecting appropriate respirators, and encourages NIOSH to expedite its 
efforts in this area. However, employers and respirator users should 
note that using a respirator certified by NIOSH through performance 
tests would not preclude individual fit testing as required by OSHA's 
Respiratory Protection Standard.
    Filtering facepiece design problems. Several commenters urged an 
APF of 5 for filtering facepiece half masks based on the design 
characteristics of these respirators. Some commenters expressed concern 
that, in comparison to elastomeric half masks, filtering facepieces are 
poorly constructed (e.g., non-adjustable head straps, prone to crushing 
or denting, facepiece too stiff or too soft) (e.g., Exs. 9-34, 10-37, 
10-38, 10-54, and 12-7-1). For example, T.C. Lefford of Fluor Hanford 
stated:

    Elastomeric half-mask respirators provide a better face seal 
that filtering facepieces (Disposable respirators or maintenance-
free masks). Most elastomeric half-mask respirators are made of more 
pliable silicone rubber that provides a much better seal on the 
face. Elastomeric half-mask respirators have three sizes with 
adjustable head straps and a head cradle to improve stability while 
the majority of filtering facepieces have one or two sizes and the 
head straps are non-adjustable. (Ex. 9-32.)

    OSHA believes that concerns about loose, dented, or crushed 
filtering facepieces are addressed adequately by compliance with 
existing program requirements under 29 CFR 1910.134(d) and (g).
    In addition, comment was received alleging that the 42 CFR 84 
requirements for increased filter efficiency result in respirators with 
stiff facepieces, poor face seals, and high breathing resistance, 
thereby producing filtering facepieces with increased faceseal leakage 
(e.g., Exs. 9-34, 9-41-1, 10-46, and 10-50). Mark Haskew, Tim Roberts, 
and Ching-tsen Bien (Exs. 12-7-1, 16-12, 16-20-3, and 17-5) also 
expressed concern about the increased filter efficiency requirements of 
the new 42 CFR 84 certification standards and their effect on the 
performance of filtering facepiece respirators. In their written 
comments, Mark Haskew and Tim Roberts stated that the 42 CFR 84 filter 
efficiency requirements "would increase the breathing resistance and 
in turn cause an increase in faceseal leakage when compared to 30 CFR 
part 11 filtering facepieces" (Ex. 12-7-1). Haskew, Roberts and Bien 
also questioned the ability of 42 CFR 84 filtering facepieces to fit 
the user's face, and the applicability of 30 CFR part 11 study data to 
42 CFR 84 respirators. For example, Mark Haskew testified:

    The other problem with the old data is that the 30 CFR 11 
respirators are significantly different in performance, or at least 
we would anticipate that they may be different in the performance 
that they provide. Based on the newer filter media with the 95, 99 
and 100 series, there's an allowance for increased breathing 
resistance. And because the efficiency has to be greater, the filter 
media itself tends to be stiffer. And the concern we have, of 
course, which is untested in the research as far as we know, is that 
it may not conform as well to a wearer's face. (Tr. at 203.)

    Based on their opinion that manufacturers would have to produce 
thicker, stiffer filter media to meet the new filter efficiency 
requirements, these commenters concluded that the data for 42 CFR 84 
filtering facepieces would show a decrease in performance compared to 
the older 30 CFR 11 respirators. These commenters, based on this 
assumption, concluded that it would be inappropriate to set the APF for 
filtering facepieces based on WPF studies of the older 30 CFR 11 
respirators. However, they presented no data to substantiate this 
claim.
    When NIOSH published the 42 CFR 84 respiratory protective devices 
final rule (60 FR 30336), Section 84.180 of this rule increased the 
maximum allowable breathing resistance levels during inhalation to 35 
mm (of water pressure), and during exhalation, to 25 mm. NIOSH 
explained this increase as follows:

    [It will] enable manufacturers to produce respirators meeting 
the new requirements more expeditiously and at lower cost. * * * 
This small increase in maximum allowable breathing resistance for 
particulate respirators does not add substantially to physiologic 
burden for respirator users, and will be compensated for by 
increased worker protection provided by the new filter efficiency 
tests and classification system. (60 FR 30346.)

    However, when respirator manufacturers developed new particulate 
filters to meet the 42 CFR 84 performance requirements, they were able 
to meet them without increasing the breathing resistance levels. For 
example, the 3M Company submitted the following table of breathing 
resistance values for several classes of 42 CFR 84 filters made by 
different manufacturers (Ex. 17-9-1, page 6; derived from a paper 
submitted by 3M to the OSHA docket (Ex. 9-16-1-3)).


------------------------------------------------------------------------
                                    Manufacturer A      Manufacturer B
          Filter Class             ([Delta]P mmH2O)    ([Delta]P mmH2O)
------------------------------------------------------------------------
N95.............................  11.5..............  9.7
R95.............................  No Product........  13.6
P95.............................  14.9..............  No Product
P100............................  23.9..............  17.3
------------------------------------------------------------------------

    No measurement in this table exceeds the 30 CFR 11 limit of 30 mm 
of water pressure. As the 3M Company stated, "Breathing resistance of 
42 CFR 84 respirators are contained within the range of breathing 
resistances allowed for 30 CFR 11 respirators, rather than being 
significantly higher" (Ex. 16-25-2, page 17).
    OSHA also received comments that higher breathing resistance leads 
to increased faceseal leakage (Exs. 9-34, 9-35, 9-41, 10-38, and 10-
50). During the public hearings, 3M submitted two new studies of 
filtering facepiece respirators certified under 42 CFR 84 (Ex. 16-25-
3). The 42 CFR 84 certified filtering facepieces used in these studies 
performed better, overall, than comparable filtering facepieces 
certified under 30 CFR 11 (see discussion above under Section III 
("Methodology, etc.")). These results indicate that faceseal leakage, 
if it existed, did not impair the performance of these filtering 
facepieces.
    At the 2004 AIHCE in Atlanta, Georgia, Larry Janssen of the 3M 
Company presented the results of a recently completed study (Ex. 17-9-
1) using the OHD FitTester 3000 controlled negative pressure (CNP) fit 
testing instrument to measure faceseal leak rate (i.e., a drop in 
pressure inside the mask). Leak-rate measurements first were made using 
the negative pressure and flow-rate settings listed for the CNP fit 
test in Appendix A of 29 CFR 1910.134. Without disturbing the fit of 
the respirator, four additional leak-rate measurements then were made 
at four different negative pressures and flow rates ranging from 5.6 
through 20.1 mm of water pressure, followed by a final measurement at 
the CNP fit test rates. Janssen found that test subjects with a fit 
equal to or greater than a fit factor of 100:

    [D]id not show any increase in leak rate as pressure drop 
increased. Subjects with a fit factor below 100 * * * showed 
significant variability in leakage as the settings were changed, but 
the amount of leakage did not correlate with increasing pressure 
drop, i.e., sometimes the leakage was higher and sometimes lower. 
(Ex. 18-7, page 49.)

    The 3M Company concluded that the study "demonstrates the value of 
fit testing: respirators that fit well enough to be assigned to a 
worker do not exhibit increased leakage as pressure drop increases" 
(Ex. 18-7, page 49). Janssen, in a summary of this study that he 
presented at the May 2004 AIHCE stated, "Results of this study do not 
support the concept of increased faceseal leakage with increased 
pressure drop."
    While concern was expressed by some commenters about increased 
filter efficiency requirements resulting in increased breathing 
resistance and faceseal leakage, no data were submitted to support this 
viewpoint. However, studies were submitted that demonstrated that 42 
CFR 84 filtering facepiece respirators perform at least as well as 30 
CFR 11 filtering facepieces, and that increased filter efficiency does 
not result in increased faceseal leakage. After reviewing this 
information, OSHA is persuaded that 42 CFR 84 half masks are as 
protective as 30 CFR 11 half masks and that increased face seal leakage 
in such respirators has not been demonstrated by evidence in the 
record. Therefore, these arguments do not support an APF for filtering 
facepieces of 5.
    The efficacy of user seal checks provided by respirator 
manufacturers also was questioned by several commenters. These 
commenters stated that user seal checks for filtering facepieces either 
could not be performed or were more difficult than user seal checks 
with elastomeric facepieces (e.g., Exs. 9-27, 9-31, 9-34, 9-35, 9-40-1, 
9-41-1, and 10-54). In general, their opinion was that the inability to 
perform an adequate user seal check on filtering facepiece respirators 
would lead to decreased protection, thereby warranting a reduced APF 
for this type of respirator.
    Bill Kojola of the AFL-CIO (Exs. 9-27 and 19-1) stated that "user 
seal checks are rarely performed on filtering facepieces in the field 
and * * * it is extremely difficult, if not impossible, to perform 
effective user seal checks on filtering facepieces." He stated that it 
was "easy for wearers to perform effective user seal checks on 
elastomerics." Kojola cited this difficulty in performing user seal 
checks as a reason for separating filtering facepieces from 
elastomerics, and giving filtering facepieces an APF of 5. However, he 
did not provide any data to support his experience that filtering 
facepieces demonstrate a difference in user seal check performance 
compared to elastomerics.
    Similar concerns were voiced by Mark Haskew (Exs. 17-5 and 18-3), 
Tim Roberts (Exs. 9-8, 10-55, and 17-8), and Ching-tsen Bien (Exs. 9-
43-2 and 18-5). In addition, Mark Haskew stated that filtering 
facepieces with adjustable nose pieces cannot normally obtain 
repeatable fit factors. However, these commenters did not submit any 
supporting data for this contention. In his post-hearing submission, 
Tim Roberts (Ex. 18-4) stated that data demonstrating this difference 
in performance are not available.
    James Johnson (Exs. 10-33, 16-9-1, and 17-10) also stated that 
filtering facepieces cannot be fit checked effectively, and presented 
results from a series of fit tests he performed on himself with 
filtering facepieces and elastomeric half masks. Three of the four 
elastomeric half masks that he tested passed a positive or negative 
user seal check, and consistently achieved a fit factor of 1500 or more 
using the Portacount fit test instrument. One elastomeric half mask did 
poorly (fit factor of less than 100), and it was identified clearly as 
a failure by a user seal check and a subsequent fit test. He found that 
it was difficult to achieve a minimum fit factor of 100 or greater with 
filtering facepieces using the Portacount Companion fit test 
instrument. However, two of the eight filtering facepiece models he 
tested achieved fit factors of 100 or greater. He stated that he was 
able to identify obvious leaks with the filtering facepieces he tested 
by exhaling heavily and sensing the airflow, but that cupping his hands 
over the facepiece was not an effective user seal check for him. He 
stated further that these preliminary fit test results demonstrated a 
significant difference in performance between elastomeric and filtering 
facepiece half masks, and that OSHA should give filtering facepieces an 
APF of 5 based on these results.
    The numerical differences in fit factors between filtering 
facepieces and elastomeric half masks reported by Johnson may not be 
significant. Achieving a fit factor of 170, as Johnson did with the 3M 
9211 foldable filtering facepiece using the Portacount Companion, is not 
necessarily worse than achieving a fit factor of 2200 with a MSA Comfo 
elastomeric half mask using the Portacount alone. In this regard, the 
fit test instruments identified the elastomeric half masks and filtering
facepieces that provided adequate fits on Johnson (i.e., they met their 
required fit factor of 100), and he was able to perform user seal checks 
with both respirators. Therefore, OSHA finds that these fit test measurement 
differences are not a convincing argument for an APF for filtering 
facepiece respirators of 5. The Agency believes that Johnson's pilot 
study proves only that some makes and models of filtering facepieces 
are not suitable for his face size and shape. When he wore a filtering 
facepiece or elastomeric respirator that fit him, an APF of at least 10 
was achieved.
    In response to these concerns, the 3M Company (Ex. 17-9-2) and the 
Aearo Company (Ex. 17-3-1) submitted to the record instructions for 
conducting user seal checks on their filtering facepiece respirators. 
The Aearo Company instructs users to cup their hands over the 
respirator to test the seal, stating: "If air flows around your nose, 
tighten the nosepiece; if air leaks around the edges, reposition the 
straps to fit better (Ex. 17-3-1)." User seal check instructions for 
3M filtering facepieces read, "If air leaks between the face and 
faceseal of the respirator, reposition it and readjust the nose clip 
for a more secure seal" (Ex. 17-9-2).
    In their post-hearing comments (Exs. 9-16, 17-9-1, 18-7, and 19-3), 
3M responded to the comments raised at the public hearing regarding the 
difficulty or impossibility of performing user seal checks on filtering 
facepiece respirators. The 3M Company pointed out that no data were 
offered to support this position, nor was recognition given to the 
methods contained in both the 1980 and 1992 editions of the ANSI Z88.2 
respirator standard for performing user seal checks. The 3M Company 
also cited a study in the docket by Myers et al. (Ex. 9-16-1-13), which 
concluded that no difference was found in the effectiveness of 
performing user seal checks on filtering facepiece respirators or 
elastomeric respirators. This study also referenced a comment by Daniel 
K. Shipp of the ISEA (Ex. 9-22) that user seal checks can be performed 
with filtering facepieces. A second evaluation of user seal checks 
submitted by 3M (Ex. 17-9-10) involved the use of a 3M flat-fold 
filtering facepiece by novice respirator users. It showed that novice 
respirator users can be trained to effectively perform user seal 
checks, and that the use of seal checks improved the overall quality of 
respirator fit.
    The 3M Company also stated that the ease or difficulty in 
performing user seal checks is based on many factors. These factors 
include difficulty in performing a user seal check on some elastomeric 
respirators when the exhalation valve cover must be removed without 
disturbing the fit. Also, it can be difficult to perform a user seal 
check on elastomerics by blocking off the filter when a respirator user 
has small hands. In addition, 3M cited an analysis from its report at 
the 2001 AIHCE (Ex. 4-10-7) that showed no significant differences in 
WPF results for filtering facepieces measured in the morning and 
afternoon, with repeated redonnings of the respirators performed during 
each of these periods. These results indicate that the user seal check 
conducted after each redonning was effective in ensuring proper 
respirator fit.
    During the rulemaking, several commenters referred to the use of 
fit check cups to perform user seal checks. These devices are designed 
to assist the respirator user in performing a positive and negative 
pressure seal check by covering the surface of a filtering facepiece 
respirator. For example, Tim Roberts stated:

    One of the manufacturers did recognize that there was difficulty 
in doing these types of fit checks, and they designed, and 
constructed, and sold a fit-check cup that actually fit over the 
facepiece of a respirator, a filtering facepiece respirator, so that 
it would actually check the seal in a more conventional manner. We 
think that that may be another alternative approach to assuring that 
these respirators fit properly if there was a requirement to do 
that. (Tr. at 216.)

    Another commenter who discussed the use of fit check cups was 
Donald Faulkner of the United Steelworkers, who stated during his 
questioning of Warren Myers:

    [W]e don't see a real good fit with the hands-over filtering 
facepiece. That's why the cups were developed by many manufacturers, 
but we don't see them being utilized, bought, or anything else. (Tr. 
at 95.)

    He elaborated in his post-hearing comment: "Filtering facepieces 
do not allow seal checks to be performed without the assistance of 
additional equipment [i.e., fit check cups] that is never provided by 
the employers, as being cost prohibitive." (Ex. 19-2.)
    Bill Kojola of the AFL-CIO (Tr. at 132) and George Macaluso of the 
Building Construction Trades Department of the AFL-CIO (Tr. at 654) 
made similar statements regarding the infrequent use of fit check cups, 
i.e., that they are generally not used in the workplaces their unions 
represent. They asserted that user seal checks that involve cupping the 
hands over the facepiece were not effective, and that the use of fit 
check cups should be required by OSHA. They implied that fit check cups 
are a generic device for doing user seal checks, and that one 
manufacturer's fit check cup can be used with other types of filtering 
facepieces. On the other hand, Ken Wilson of the Ohio Board of Water 
Quality, Division of Safety and Hygiene (Ex. 10-3) stated that he has 
not seen fit check cups used in the field, and doubted that their use 
would allow a respirator user to achieve a successful fit check.
    OSHA has considered carefully the opinions presented about fit 
check cups and user seal checks. The Agency recognizes that the use of 
a fit check cup is one way of performing a user seal check. However, 
these cups can be inconvenient when used in the workplace on a daily 
basis. In this regard, each respirator user would need ready access to 
a fit check cup, not only to perform the required user seal checks when 
initially donning the respirator, but for any repeated respirator 
donnings that occur throughout the workday. The fit check cup would be 
another piece of equipment for respirator users to carry with them, and 
it can be misplaced. However, most respirator manufacturers have not 
adopted the use of fit check cups, and these manufacturers recommend 
cupping the hands over the filtering facepiece to perform a user seal 
check. As the 3M Company stated in describing the use of fit check 
cups, "Based on our experience, user seal checks without cups are 
effective, more convenient, and easier to perform" (Ex. 17-9-1, page 
4).
    Since only a few respirator manufacturers have fit check cups, it 
is not surprising that they are seldom used in the workplace. The fit 
check cups that exist are designed by the respirator manufacturer to 
work with a specific facepiece configuration and respirator model, and 
the cups do not necessarily work with other models of respirators, even 
models made by the same manufacturer. OSHA knows of only one series of 
42 CFR part 84 filtering facepiece respirators that have fit check cups 
available.
    OSHA does not find merit in the comments that fit check cups are 
necessary to perform user seal checks with filtering facepieces. While 
a fit check cup designed to work with a particular model of respirator 
can be used to perform a user seal check, it is not the only way to 
perform this function. Accordingly, the Agency believes that respirator 
users can follow a respirator manufacturer's instructions to perform a 
user seal check, e.g., whether the seal check involves cupping the hands 
over the facepiece or the use of a fit check cup.
    The OSHA Respiratory Protection Standard requires that an employee 
perform a user seal check to use a respirator. The WPF database that 
OSHA developed contains over 1,000 WPF data points for half mask 
respirators collected from workers using respirators in programs that 
included user seal checks. Analyses of these data showed that the 
filtering facepiece respirators achieved an APF of 10. These data are 
derived from WPF studies in which user seal checks were performed on 
filtering facepiece respirators by 100s of workers. In addition, 3M's 
analysis (Ex. 4-10-7) indicates that user seal checks performed on 
filtering facepieces ensure proper redonning of these respirators. When 
a respirator user cannot perform a user seal check with a particular 
respirator model, then that respirator cannot be used by that employee, 
and the employer must find another respirator model on which a user 
seal check can be performed. This requirement applies to all tight-
fitting facepieces, including filtering facepieces and elastomeric half 
masks. How easy or difficult it is for an employee to perform a user 
seal check on a particular type of respirator is not an issue that 
precludes other employees from using that respirator. Therefore, the 
comments on user seal checks do not provide convincing evidence that 
would support decreasing the APF for filtering facepieces to 5.
    OSHA argued previously in National Cottonseed Products Association 
v. Brock, 825 F.2d 482 (D.C. Cir. 1987) that filtering facepieces used 
to protect employees against exposure to cotton dust should have an APF 
of 5 based on the difficulty of fit testing, particularly fit checking 
on a daily basis. However, the Agency now believes that the record 
evidence for this rulemaking shows that the industrial-hygiene research 
community has developed and refined qualitative and quantitative fit 
tests, as well as developed sophisticated techniques for determining 
respirator leakage. Several commenters (Exs. 16-25-3 and 17-9-1) 
provided evidence that filtering facepieces could be fit tested and 
then used effectively. Seal-check techniques and procedures (e.g., fit-
test cups, manual testing) also have been developed to help ensure that 
filtering facepieces maintain their fit while being worn in the 
workplace. These new developments allowed the Agency to reassess 
filtering facepieces and find that these respirators can be reliably 
fit tested and fit checked.
    The WPF studies provide further support for this conclusion. In 
fact, every WPF study of filtering facepieces in the OSHA APF database 
involved fit testing the respirator, using the new and refined methods, 
prior to the worker using the respirator in the study. Researchers used 
the available fit testing and checking technologies and methodologies 
in the studies to be assured that employees would be protected during 
the study by the respirators when exposed to airborne contaminants up 
to 10 times the PEL, and so that they could determine the results of 
the study would be accurate.
    Non-compliance and economic incentive issues. Several commenters 
asserted that filtering facepiece half masks should be given an APF 
less than 10 because employers do not comply with the Respiratory 
Protection Standard (e.g., by not performing fit testing) (e.g., Exs. 
9-40-1, 10-33, and 10-52; Tr. at 663). In this regard, Donald Faulkner 
of the United Steelworkers of America (USWA) stated:

    We observe in many worksites that the employers are issuing 
filtering masks as if they were candies. They don't have respiratory 
protection programs, requirements to be clean shaven, and no medical 
or no idea of the MUC of the contaminant that the worker needs to be 
protected from. (Ex. 9-40-1.)

    However, the 3M Company commented that non-compliance with the 
Respiratory Protection Standard should not be a factor in determining 
APFs, noting:

    OSHA has appropriately made the proposed APFs contingent upon 
the existence of an effective and well-managed respiratory 
protection program. This is the only circumstance under which APFs 
can be used. Setting APFs on assumptions of poor fit and lack of 
training is impossible because of the countless variables that exist 
in the workplace and workforce. APFs can only apply under properly 
managed respiratory protection programs. This is supported by 
following the American Industrial Hygiene Association Respiratory 
Protection Committee definition of APFs: An APF is the level of 
respiratory protection that a properly functioning respirator or 
class of respirators would be expected to provide to properly fitted 
and trained users in the workplace. The APF takes into account all 
expected sources of facepiece penetration (e.g., face seal 
penetration, filter penetration, valve leakage). It is not intended 
to take into account factors that degrade performance such as poor 
maintenance, failure to follow manufacturers' instructions, and 
failure to wear the respirator during the entire exposure period. 
(Ex. 9-16.)

    Several commenters voiced concern that assigning a protection 
factor of 10 to both elastomeric and filtering facepiece half masks 
will result in an economic incentive for employers to provide filtering 
facepiece respirators to employees rather than elastomeric half masks. 
These commenters assumed that the less expensive filtering facepiece 
respirators were less protective than the more expensive elastomerics 
(e.g., Exs. 9-29, 10-38, and 10-54; Tr. at 212-213 and 659-660). The 
USWA expressed this concern, stating, "If OSHA gives the filtering 
face piece type of respirator an APF of 10, employers would interpret 
this as `let's take the cheap way out.' It will be a dis-incentive to 
issue to workers the proven protection of the elastomeric face piece 
respirator" (Ex. 9-40-1). Responding to an OSHA question about this 
issue, Thomas O'Connor of the National Grain and Feed Association 
stated:

    Well, clearly, if [you] had two respirators that provided the 
comfort and fit to the employee that's needed and one was half the 
cost of the other one, obviously anybody would select the lower cost 
respirator. But as I noted, that's not the primary motivation, cost. 
The primary motivation is complying with the standard, making sure 
that the employee[s] wear it and it fits properly and it's 
comfortable. * * * If an employee's wearing a respirator that's not 
comfortable, there's going to be an incentive for them possibly not 
to wear that respirator * * * when they should be wearing it. So 
from our perspective, comfort is one of the primary considerations 
in selecting a respirator for an employee. (Tr. at 684-685.)

    OSHA considered these comments and concludes that neither cost nor 
non-compliance with the Respiratory Protection Standard is an 
appropriate basis for determining the final APF for half masks. 
Employers are required to comply with all the provisions of the 
Respiratory Protection Standard. Non-compliance is not an option for 
employers. Thus, there is no compliance reason to reduce the APF for 
half masks.
    As to whether assigning a protection factor of 10 to filtering 
facepiece half masks will provide an economic incentive to use these 
respirators, OSHA concludes that so long as a respirator achieves an 
APF of 10, it doesn't matter what respirator an employer uses. Once 
again, OSHA's data analyses, as well as consensus standards, show that 
filtering facepieces can attain an APF of 10.
    ANSI's updated APF of 5. Several commenters noted that the recent 
draft of the ANSI Z88.2 respirator standard gave filtering facepieces 
an APF of 5 (e.g., Exs. 9-8, 10-51, and 10-54; Tr. at 124-125 and 197-
201). For example, Bill Kojola of the AFL-CIO testified:

    The AFL-CIO's position that filtering facepieces should be given 
an APF of 5 is also provided by other organizations with considerable 
expertise on respiratory protection. Indeed, the ANSI Z88.2 Committee, 
charged with the responsibility for the American standard for respiratory 
protection, has recently proposed an APF of 5 for filtering 
facepiece respirators. We believe that OSHA should give serious 
consideration to this ANSI position as well when it issues its final 
rule. (Tr. at 124-125.)

    OSHA considered the draft ANSI standard during this APF rulemaking. 
However, this draft standard currently is under appeal, and has not 
been designated by ANSI as a final standard (Ex. 17-9-10-2). Jill 
Snyder, Standards Coordinator for the AIHA secretariat of the ANSI Z88 
committee, addressed the status of the draft ANSI Z88.2 revised 
respiratory protection standard in an e-mail sent to participants in 
Roundtable 228 held at the 2004 AIHCE. This e-mail stated:

    Until a standard is approved by ANSI, it is not an ANSI 
standard. Therefore, we should not say things like `ANSI completed 
drafting * * *' etc. It is actually the Accredited Standards 
Committee (ASC) Z88 or Z88.2 that put together what is still the 
DRAFT standard. We also have to make sure we call it a draft 
standard, not a standard at this point. (Ex. 17-9-10-2.)

    The method used by ANSI to determine the draft APFs also differs 
from OSHA's approach, which used data analyses and expert opinion to 
arrive at the final APF for half masks. James Johnson, representing the 
ANSI Z88.2 subcommittee, stated that the subcommittee did not perform 
an extensive quantitative analyses similar to OSHA's in determining the 
draft APFs (Tr. at 357). In response to questions from Thomas Nelson, 
ANSI subcommittee member George Macaluso confirmed that an overall 
tabulation and review of available WPF data was not conducted by the 
ANSI subcommittee in determining APFs (Tr. at 663-666).
    With regard to the decision of the ANSI subcommittee, James Johnson 
agreed that a subcommittee composed of other members may have reached a 
different conclusion regarding the APF for filtering facepiece half 
masks (Tr. at 354-355). He also stated:

    There's nothing in the consensus process that says every part of 
the standard has to have an absolute defendable, scientific, 
technically traceable base. It doesn't exist. It's not there. We 
have tremendous numbers of standards that are out there that the 
professionals develop with the best knowledge and experience that 
they have, and this is the process. (Tr. at 363.)

    Summary and conclusions. In this section, OSHA considered the issue 
of the appropriate APF for filtering facepieces. OSHA's data analyses 
in the record support an APF of 10 for filtering facepiece respirators. 
Moreover, a number of commenters supported the APF of 10. Some 
commenters recommended a lower APF for filtering facepieces than 
proposed based on the poor structural integrity of the mask, the 
availability of additional models of respirator protection, poor 
compliance with the respirator program requirements, difficulty 
performing user seal checks, increased breathing resistance among 
filtering facepieces approved under 42 CFR part 84, and the recent ANSI 
draft APF for filtering facepieces. As discussed in the previous 
sections, the evidence in the record with regard to these issues 
justifies retaining in this final rulemaking the proposed APF of 10 for 
filtering facepieces.
3. APF for Full Facepiece Air-Purifying Respirators
    Introduction. In a 1976 report, Ed Hyatt of LANL developed an APF 
table that included this respirator class (Ex. 2). In this report, 
Hyatt used the results from quantitative fit testing to assess six 
models of full facepiece negative pressure air-purifying respirators 
equipped with HEPA filters. Five of these respirators achieved a 
protection factor of at least 100 for 95% of the respirator users. The 
sixth respirator attained this level of protection for 70% of the 
users. Based on the results for the sixth respirator, Hyatt recommended 
an APF of 50 for the respirator class as a whole.
    The 1980 ANSI respirator standard listed an APF of 100 for full 
facepiece air-purifying respirators with DFM filters (Ex. 7-3). ANSI 
increased the APF for this respirator class from 50 to 100 because the 
poorly performing respirator in Hyatt's study was no longer in 
production. Using the 1976 LANL quantitative fit testing results, the 
1980 ANSI standard increased this APF to a maximum of 1,000 when the 
respirator used HEPA filters and respirator users received quantitative 
fit testing (Ex. 7-3).
    Based on Hyatt's 1976 data, the 1987 NIOSH RDL recommended that 
this respirator class receive an APF of 50 when equipped with a HEPA 
filter. However, the RDL gave these respirators an APF of 10 when using 
DFM filters. NIOSH gave these respirators an APF of 10 when equipped 
with DFM filters because testing that it conducted showed that the 
filters had relatively low efficiency.
    The 1992 ANSI respirator standard retained the 1980 ANSI standard's 
APF of 100 for full facepiece air-purifying respirators, but required 
that respirator users perform quantitative fit testing and achieve a 
minimum fit factor of 1,000 prior to using the respirators. QNFTs were 
necessary because no QLFTs could achieve a fit factor of 1,000. The 
ANSI standard kept this APF because the ANSI committee found, as it did 
in 1980, that no WPF or SWPF studies had been performed for this 
respirator class.
    The following table summarizes the previous APFs assigned to full 
facepiece air-purifying respirators.

----------------------------------------------------------------------------------------------------------------
                                                                        APFs
  Fully facepiece air-purifying   ------------------------------------------------------------------------------
           respirators                                                                                1992 ANSI
                                        LANL (1976)       1980 ANSI standard     NIOSH RDL (1987)      standard
----------------------------------------------------------------------------------------------------------------
All respirators in the class.....  50 (with HEPA         10 (with QLFT)......  10 (with DFM filter)          100
                                    filter).
                                                         100 maximum (with     50 (with HEPA         ...........
                                                          QNFT).                filter).
----------------------------------------------------------------------------------------------------------------

    In the proposal, OSHA also discussed a WPF study that Colton, 
Johnston, Mullins, and Rhoe (Ex. 1-64-14) conducted in a lead smelter. 
The respirator used in this study was a 3M 7800 full facepiece air-
purifying respirator equipped with HEPA filters. The authors found a 
5th percentile protection factor of 95 for the sample, but concluded 
that the respirator only provided reliable protection at a protection 
factor of 50. In addition, a LANL SWPF study by Skaggs, Loibl, Carter, 
and Hyatt (Ex. 1-38-3) measured the protection afforded by the MSA 
Ultra Twin respirator with HEPA filters. The authors reported fit 
factors with geometric means ranging from 1,000 to 5,300. However, 23 
of the 60 measurements reported were less than 1,000, seven were less 
than 100, and three were less than 50. Based on a careful review of 
these studies, OSHA proposed an APF of 50 for full facepiece air-
purifying respirators.
    OSHA requested comment in question 7 of the proposal on 
whether it should limit full facepiece negative pressure respirators to 
an APF of 20 when N95 filters are used. The NIOSH certification tests 
for 42 CFR part 84 filters are conducted using monodisperse aerosols of 
the most penetrating particle size (0.3 [mu]m) delivered at a high flow 
rate of 85 liters per minute. Also, the 42 CFR part 84 certification 
standards allow up to 5% filter leakage with an N95 filter. If this level 
of leakage were to occur in the workplace, an APF of 20 would be 
appropriate for a full facepiece respirator using N95 filters. However, 
as several commenters noted (Exs. 9-16, 9-22, 9-23, 9-37, 10-6, 10-17, 
10-27, 10-59, and 10-60), workplace filter penetration is always much 
less than filter penetration estimated from certification testing. 
Kenneth Bobetich of MSA (Ex. 9-37) stated that while 5% leakage is the 
worst case, such leakage does not occur in the workplace. Compared to 
the aerosols used in certification testing, workplace aerosols are not 
monodisperse, are many times larger, and are delivered through the 
filters at a lower flow rate. In addition, the 3M Company (Ex. 9-16) 
cited studies performed by Janssen (Exs. 9-16-1-3 and 9-16-1-4) that 
compared the performance of N95 and P100 filters made by two 
manufacturers and used during grinding operations in a steel plant. 
Workplace performance of both filters was equivalent statistically, and 
the study showed that N95 filter performance was adequate under these 
conditions. Lisa Brosseau of the University of Minnesota (Ex. 10-59) 
stated that it was entirely inappropriate for OSHA to consider a 5% 
leakage effect for N95 filters because such leakage would only occur 
when the aerosol is monodisperse and of a small size, conditions that 
she said are unlikely to occur in most workplaces.
    Bill Kojola of the AFL-CIO (Ex. 9-27), Pete Stafford of the 
Building Construction Trades Department of the AFL-CIO (Ex. 9-29), and 
Michael Watson of the International Brotherhood of Teamsters (Ex. 9-7) 
supported limiting the APF for full facepieces to 20 when N95 filters 
are used. Watson stated that if OSHA gave these respirators an APF 
higher than 20, employees would likely be exposed to hazardous levels 
of workplace contaminants. Kojola stated further that OSHA should take 
into account both sources of leakage (filter and faceseal), and lower 
the APF accordingly. However, neither Watson nor Kojola provided any 
evidence to support these misgivings about the performance of these 
respirators.
    NIOSH (Ex. 9-13) recommended that OSHA consider the limitations of 
the filter, but did not have any WPF or SWPF data on the performance of 
full facepiece respirators certified under 42 CFR part 84 using N, R, 
or P95 filters. NIOSH stated that because the filters are tested at the 
most penetrating particle size, filter efficiency in the workplace 
should exceed certification efficiency. However, NIOSH noted that some 
workplace tasks, such as welding and grinding, may result in high 
leakage rates through the N95 filter because the tasks produce fine or 
ultra fine particles.
    Loraine Krupa-Greshman of the American Chemistry Council (Ex. 10-
25) stated that OSHA could not justify using a simplistic, generalized 
treatment of N95 filter efficiency to limit the APF to 20. She noted 
that using N95 or N100 filters is a matter of professional judgment, 
based on the type and concentration of the contaminant. Frank White of 
ORC Worldwide (Ex. 10-27) stated that reducing the APF to 20 was 
unnecessary because protection factors and filter performance need to 
be considered separately as part of the respirator selection process. 
Ted Steichen of the American Petroleum Institute (API) (Ex. 9-23) 
mentioned that API believes that OSHA should further evaluate the data 
before assigning, based on worst-case assumptions, an APF of 20 to 
these respirators. Thomas O'Connor of the National Grain & Feed 
Association (Ex. 10-13) commented that he was not aware of any 
scientific information that refuted assigning an APF of 50 to full 
facepiece respirators or justified lowering the APF for N95 filters to 
20. He supported retaining the proposed APF of 50 for this class of 
respirators. Sheldon Coleman of the Hanford Site Respiratory Protection 
Committee (Ex. 10-40) stated that, based on fit testing data, an APF of 
50 for these respirators already is conservative.
    OSHA agrees with these commenters that full facepiece respirators 
with N95 filters provide sufficient protection to maintain an APF of 
50, and Table 1 of the final standard reflects this decision. Any 
effect of filter penetration on respiratory protection is best 
addressed during respirator selection, which also is the case for half 
masks and other respirator classes using particulate filters. In rare 
cases, when workplace exposures consist of a large percentage of 
particles of the most penetrating size, this information must be taken 
into account by the employer when selecting the appropriate class of 
particulate filter for any respirator, not just for full facepieces.
    Summary and conclusions. In the proposal, OSHA asked for any 
additional studies of full facepiece air-purifying respirators, but 
none was submitted. After carefully evaluating the original studies 
reviewed in the proposal, the Agency is setting an APF of 50 for full 
facepiece air-purifying respirators. The final APF agrees with the 
conclusion of Colton, Johnston, Mullins, and Rhoe (Ex. 1-64-14) cited 
earlier in this discussion that this class of respirators provides 
reliable protection at an APF of 50. Importantly, an APF of 50 
corresponds with the APF previously assigned to full facepiece air-
purifying respirators by OSHA in its substance-specific standards, and 
by NIOSH in its 1987 RDL. Therefore, OSHA is assigning an APF of 50 to 
full facepiece air-purifying respirators based on: the results of WPF 
and SWPF studies (which used N95 filters at moderate to high 
contaminant levels); The APFs given previously to this respirator class 
by NIOSH and ANSI; comments in the record indicating that N95 filters 
function effectively under the workplace exposure conditions in which 
they are used; and years of experience showing that these respirators, 
when equipped with an N95 filter, are safe when used in the manner 
prescribed by OSHA's respiratory protection standards. However, as with 
any respirator, if a full facepiece air-purifying respirator is 
unsuitable for the exposure conditions, paragraph (d)(1) of OSHA's 
Respiratory Protection Standard requires that employers select a 
respirator that will protect employees from the exposure hazards.
4. APF for Powered Air-Purifying Respirators (PAPRs)
    Half mask tight-fitting PAPRs. In the proposal, OSHA assigned an 
APF of 50 to tight-fitting half mask PAPRs (68 FR 34098 and 34115) 
based on the 1987 NIOSH RDL and the Z88.2-1992 ANSI respirator 
standard. In arriving at a proposed APF of 50 for these respirators, 
the Agency relied heavily on the WPF study conducted by Lenhart and 
Campbell (Ex. 1-64-42), instead of the WPF study performed by Myers and 
Peach (Ex. 1-64-46) and the SWPF studies of Skaggs et al. (Ex. 1-38-3) 
and da Roza et al. (Ex. 1-64-94). In explaining its position, OSHA 
stated:

    [The Lenhart and Campbell] study was well controlled and 
collected data under actual workplace conditions; these conditions 
ensure that the results are reliable and represent the protection 
employees likely would receive under conditions of normal respirator 
use. The Agency did not consider the Myers and Peach WPF study * * * 
for this purpose because of problems involving filter assembly 
leakage and poor facepiece fit reported by the authors; 
consequently, the abnormally high levels of silica measured inside 
the mask would most likely underestimate the true protection
afforded by the respirator. The two SWPF studies * * * reported much 
higher geometric mean protection factors than did the WPF study 
performed by Lenhart and Campbell. However, OSHA believes that the 
higher protection factors reported for these SWPF studies are 
consistent with the proposed APF of 50 based on data obtained for 
this respirator class in the Lenhart and Campbell WPF study because 
SWPF studies typically report significantly higher protection 
factors than WPF studies of the same respirator. (68 FR 34098.)

    During this rulemaking, OSHA received no substantive comments or 
other information regarding the proposed APF of 50 for these 
respirators. Nevertheless, OSHA believes that the existing WPF and SWPF 
studies on this class proved adequate support for OSHA's conclusion 
that an APF of 50 is an appropriate level to predict the protection 
capabilities of this class of respirators.
    Full facepiece PAPRs and PAPRs with hoods or helmets. In the 
proposal, OSHA assigned an APF of 1,000 to tight-fitting full facepiece 
PAPRs (68 FR 34099). In support of the proposed APF, OSHA cited a WPF 
study by Colton and Mullins that found a corrected 5th percentile 
protection factor of 1,335 for these respirators. OSHA received no 
substantive comments or other information regarding the proposed APF of 
1,000 for these respirators. However, the ANSI Z88.2-1992 respirator 
standard and the 2004 draft revision to the ANSI standard both assign 
an APF of 1,000 to this respirator class. Based on its review of these 
consensus standards and the existing WPF research literature (see Exs. 
1-64-12 and 1-64-40), and SWPF research studies (Ex. 3-4), OSHA 
concludes that this respirator class warrants an APF of 1,000.
    In proposing an APF of 1,000 for PAPRs with helmets or hoods, the 
Agency stated in footnote 4 of proposed Table 1 that "only helmet/hood 
respirators that ensure the maintenance of a positive pressure inside 
the facepiece during use, consistent with performance at a level of 
protection of 1,000 or greater, receive an APF of 1,000" and that 
"[a]ll other helmet/hood respirators are treated as loose-fitting 
facepiece respirators and receive an APF of 25." (See 68 FR 34115.) 
OSHA proposed this condition because available WPF and SWPF studies 
found that some of these hood/helmet respirators achieved protection 
factors well below 1,000 (Exs. 3-4 and 3-5). Under the proposed 
condition, the burden of conducting any testing likely would fall on 
respirator manufacturers, but the employer would be responsible for 
selecting a properly tested respirator.
    According to James Johnson of LLNL, simple and effective equipment 
and procedures are available for detecting leaks in these respirators. 
In this regard, Johnson noted that LLNL developed equipment that 
monitors and records positive pressure in these respirators using a 
commercially available device. As he stated at the hearing:

    [T]his is the one we chose, a data logging micro manometer, the 
TSI-DP Calc, with a range of -5 to +15 inches of water gauge, and 
data recording intervals of one second and longer were chosen. * * * 
We plan on using this technique periodically to monitor actual high-
contamination work activities to assure this PAPR maintains a 
positive pressure. (Ex. 16-9-1.)

    A number of commenters provided additional support for using 
positive pressure inside the facepiece as the criterion for protection. 
For example, Rick Givens of the Atlanta, GA Utilities Department stated 
that "the maintenance of positive pressure is an appropriate method 
for distinguishing high-performing hood/helmet respirators from 
others" (Ex. 10-2), while Sheldon Coleman of the Hanford, Washington 
DOE site asserted:

    In the last three years, our program has used approximately 
10,000 PAPR hoods. We have conducted some limited fit testing using 
particulate fit testers (although the hood manufacturer does not 
recommend using a particulate tester due to the extensive dead space 
in the hood). All of our information suggests that an APF of 1,000 
is appropriate for a PAPR hood that maintains positive pressure 
inside of the hood. (Ex. 10-40.)

    Several commenters took exception to the positive pressure 
criterion. Craig Colton of 3M stated that "3M disagrees with OSHA's 
proposed requirement that hoods and helmets demonstrate that they 
maintain positive pressure at all times of use to receive an APF of 
1,000" (Tr. at 390). In this regard, Colton argued that the recent 
study conducted on PAPRs with hoods/helmets by ORC and LLNL showed that 
every respirator tested in the study "had two or more brief negative 
pressure spikes within the respiratory inlet covering. Under the 
current proposal, all of these respirators, except the poorest 
performing supplied-air respirator would have received an APF of 25, 
even though the 5th percentile SWPFs found in the study ranged from 
86,000 to 250,000" (Tr. at 391). Colton then added, "This study 
indicates that pressure within the respiratory inlet covering is only 
one of a complex set of factors that determine the protection provided 
by PAPRs and supplied-air respirators, and should not be considered by 
itself" (Tr. at 391). John P. Farris of Safe Bridge Consultants echoed 
this concern (Exs. 9-11 and 10-32).
    Other comments focused either on the need for a protocol to 
determine if the respirators could perform at an APF level of 1,000, or 
on design characteristics that would permit respirator users to select 
appropriate respirators. In advocating the testing approach, Stephan 
Graham of the U.S. Army Center for Health Promotion and Preventative 
Medicine noted that respirators that have high APFs should receive 
credit for their design and performance. Graham recommended that 
manufacturers test their hooded and helmeted respirators, and set the 
maximum APF (to a maximum of 1,000) based on the results (Ex. 9-42-1). 
The 3M Company stated that if OSHA retains a testing requirement in the 
final rule, it must specify the testing conditions. The 3M Company 
recommended testing at a work rate of 40 liters per minute, ensuring 
that pressure inside the hood or helmet is maintained at a minimum 
level of one atmosphere at this work rate, measuring this pressure at 
the flow rate recommended by the manufacturer, and maintaining the 
maximum static pressure inside the hood or helmet at 38 mm of water 
pressure (Ex. 18-7). Similarly, Jay Parker of the Bullard Co. stated 
that "without oversight and guidance, testing performed may not 
achieve such goals. This may lead to the use of respirators and an APF 
of 1,000 that actually should not be used at that level because the 
testing performed was not really capable of ensuring that level of 
performance" (Tr. at 492).
    ORC Worldwide stated that "the approach proposed by OSHA would 
hold hood/helmet or loose-fitting facepiece PAPRs and SARs to a higher 
standard than that required of other respirator classes, based simply 
on the results of one model" (Ex. 10-27), a point made as well by 
Alice E. Till of the Pharmaceutical Research and Manufacturers 
Association (PhRMA) (Ex. 9-24). Nevertheless, ORC concluded that, 
"[s]hould OSHA retain this requirement, the final rule should clearly 
specify acceptable testing criteria to which respirator manufacturers 
must conform" (Ex. 10-27). PhRMA believed that OSHA should consider 
the proposed APF table to be an interim step in a transition toward the 
development of a certification protocol by NIOSH that provides APFs for 
each respirator model (Ex. 9-24). Thomas Nelson of NIHS, Inc. agreed, 
stating, "Specific test conditions and performance criteria must be 
identified" (Ex. 10-17).

    Respirator models should not be assigned to the higher APF level 
following promulgation of the proposed APF rule unless the 
respirator manufacturer provides evidence that testing of that model 
demonstrates performance at the higher APF level. A standard test 
protocol is needed to assure reliable and reproducible results when 
determining if a hood/helmet PAPR * * * can consistently achieve a 
protection factor of 1000. NIOSH will assist in developing this 
protocol. With implementation of new NIOSH certification criteria, 
every respirator model could be evaluated using this protocol as a 
condition of certification to assure overall performance consistent 
with the established APF. Thus, NIOSH will assure that approved 
respirators are capable of providing this assigned level of 
protection so that employers have appropriate guidance and APF 
values when selecting respirators for their workers. (Ex. 16-4.)

    Proponents of using design criteria, instead of testing, to assess 
the protection afforded by these respirators recommended that poorer 
performing respirators should be identifiable by either their 
appearance or technical specifications. For example, John Ferris of 
Safe Bridge Consultants, stated:

    In my experience, the most important factor in achieving 
workplace protection factors of 1,000 or greater with these devices 
is the ability to tuck the inner bib (or shroud) into the outer work 
garment with the outer shroud placed over the shoulders on the 
outside of the garment. I support the use of a 1000-fold APF for 
helmet hood PAPRs without the footnote. (Ex. 9-11.)

    Robert Barr of Alcoa noted that design flaws need to be identified, 
stating, "For example, flip-front types could be designated 25; and 
helmets with shrouds at 1000" (Exs. 9-26 and 10-31). PhRMA, ORC, and 
the American Chemistry Council argued that OSHA should base the APFs 
for these respirators on design and construction characteristics that 
would "enable a more exacting selection process, and * * * would be 
conducive to eventually assigning protection factors based on 
individual model performance" (Exs. 9-24 and 10-27). However, Jay 
Parker of the Bullard Co. noted that the latest ANSI Z88.2 subcommittee 
"was unable to agree on the design characteristics of a hood or helmet 
that would lead to a performance level equivalent to an APF of 25" 
(Tr. at 480). Continuing, Jay Parker stated:

    I don't see that we will ever be able to define the performance 
of a respirator by its design. We don't want to stifle innovation. 
We want to be able to allow respirator manufacturers to develop new 
hoods and helmets. If OSHA comes up with a definition that limits a 
hood or helmet to a certain design, then that would limit the 
manufacturer's ability to innovate with new designs. (Tr. at 480.)

    After reviewing the comments on proposed footnote 4, OSHA concludes 
that: no single parameter (e.g., positive pressure inside the 
facepiece) will identify respirators that consistently perform at a 
high APF level; no agreement exists on how to determine APFs for these 
respirators based on design characteristics alone; no uniform testing 
criteria are available to use in determining APFs for these 
respirators; and ample evidence demonstrates that WPF or SWPF studies 
conducted under a variety of conditions reliably determine reliable and 
safe protection factors for these respirators. Therefore, OSHA is 
revising footnote 4 to Table 1 in the final standard to read as 
follows:

    The employer must have evidence provided by the respirator 
manufacturer that testing of these respirators demonstrates 
performance at a level of protection of 1,000 or greater to receive 
an APF of 1,000. This level of performance can best be demonstrated 
by performing a WPF or SWPF study or equivalent testing. Absent such 
testing, all other PAPRs and SARs with helmets/hoods are to be 
treated as loose-fitting facepiece respirators, and receive an APF 
of 25.

    The Agency is setting an APF of 1,000 for tight-fitting facepiece 
PAPRs with hoods and helmets when the manufacturers of these 
respirators conduct testing that demonstrates that the respirators 
provide a level of protection of at least 1,000(e.g., demonstrating 
WPFs of at least 10,000 or greater divided by a safety factor of 10, or 
lower fifth percentile SWPFs of at least 25,000 divided by a safety 
factor of 25). Based on its review of the record regarding these 
respirators, the Agency believes that tight-fitting facepiece PAPRs 
with hoods and helmets tested in a manner that is consistent with the 
SWPF testing performed previously under the ORC-LLNL study of 
respirators in this class (Ex. 3-4-1) will provide the required level 
of protection for employees who use these respirators.
    While proposed footnote 4 emphasized that respirator manufacturers 
have responsibility for testing these respirators, it did not address 
who is responsible for selecting properly tested respirators. 
Consistent with Section 5 of the OSH Act (29 U.S.C. 654), which places 
the responsibility for employee protection on employers, footnote 4 in 
the final rule now clearly places the responsibility for proper 
respirator selection on employers. Accordingly, employers may use a 
respirator at an APF of 1,000 only when they have appropriate test 
results provided by the respirator manufacturer demonstrating that the 
respirator performs at a protection level of 1,000 or greater.
    Evidence in the rulemaking record indicates that the technology 
exists to measure any leakage into the facepiece from the ambient 
atmosphere that could lessen the protection afforded by a PAPR or SAR 
with a helmet or hood (Ex. 16-9-1). This evidence also shows that small 
amounts of leakage measured by this technology during testing did not 
reduce the performance of the respirator below a level that was 
consistent with an APF of at least 1,000 (Exs. 3-4-1, 1-38-3, 1-64-12, 
and 1-64-40) Based on this evidence, OSHA believes that it is important 
for respirator manufacturers to determine, using available technology, 
that leakage into a respirator does not compromise the respirator's 
capability to maintain a level of performance throughout testing that 
is consistent with an APF of at least 1,000. Therefore, the Agency 
removed from footnote 4 in the final rule the language in proposed 
footnote 4 stating that "only helmet/hood respirators that ensure the 
maintenance of positive pressure inside the respirator during use * * * 
receive an APF of 1000."
    Loose-fitting facepiece PAPRs with hoods or helmets. OSHA proposed 
an APF of 25 for loose-fitting PAPRs with hoods or helmets based on WPF 
studies described in the proposal (68 FR 34100), the NIOSH RDL, and the 
Z88.2-1992 ANSI respirator standard. In supporting the proposed APF, 
ISEA commented that "as the reports of many WPF studies have shown, 
the performance of loose-fitting PAPRs with loose-fitting facepieces 
warrants a lower APF than for loose-fitting hoods and helmets" (Ex. 9-
24). Additional support came from Warren Myers, OSHA's expert witness 
at the rulemaking hearing, who stated:

    Our summary conclusion was that PAPRs were incorrectly 
considered as positive pressure devices by the respirator community 
and that a minimum certification air flow of 170 liters a minute, at 
least for the loose-fitting class of devices, does not necessarily 
provide a positive pressure operational characteristic with the 
respirator. And then finally, that the assigned protection factor 
for these devices with those types of air flows would be 25. (Tr. at 
69.)

    The WPF studies previously cited (68 FR 34100) demonstrate that 
OSHA based the proposed APF on valid data that were substantiated by 
the Myers study. OSHA concludes that an APF of 25 is appropriate for 
loose-fitting facepiece PAPRs with hoods or helmets, and therefore is 
retaining this APF for this respirator class in the final rule. No
adverse comments regarding the proposed APF were submitted.
5. APFs for Supplied-Air Respirators (SARs)
    Half mask SARs. The Agency based its proposed APF of 10 for this 
respirator class on the analogous performance between these respirators 
and negative pressure half mask air-purifying respirators tested in WPF 
and SWPF studies (68 FR 34100). Furthermore, the Agency proposed to 
give half mask SARs that function in continuous flow or pressure-demand 
modes an APF of 50, consistent with the analogous performance between 
these respirators and half mask PAPRs operated in a continuous flow 
mode during WPF and SWPF studies. Additional support for the proposed 
APFs came from the Z88.2-1992 ANSI respirator standard that assigned an 
APF of 10 to half mask airline SARs operated in the demand mode, and an 
APF of 50 to these respirators when operated in the continuous flow or 
pressure-demand modes. The 1987 NIOSH RDL also gave half mask demand 
SARs an APF of 10, but recommended an APF of 1,000 for these 
respirators when functioning in the pressure-demand or other positive-
pressure modes.
    OSHA received no comments or other information during this 
rulemaking regarding these proposed APFs. However, the Agency is 
confident that the available WPF and SWPF studies for half mask air-
purifying respirators cited in the proposal provide sufficient data to 
retain an APF of 10 for half mask SARs when operated in the demand 
mode, and an APF of 50 for these respirators when operated in the 
continuous flow or pressure-demand modes. Therefore, OSHA is retaining 
these APFs in Table 1 of the final rule.
    Full facepiece SARs. OSHA stated in the proposal that "[n]o WPF or 
SWPF studies were available involving tight-fitting full facepiece SARs 
operated in the demand mode. Therefore, in the absence of any such 
quantitative data, the Agency assigned this respirator class an APF of 
50" (68 FR 34102). OSHA based the proposed APF on the analogous 
operational characteristics of these respirators and negative pressure 
full facepiece air-purifying respirators tested under WPF conditions in 
the demand mode. Also, the proposed APF is the same as the APF 
recommended for this respirator class by the 1987 NIOSH RDL.
    The Agency proposed an APF of 1,000 for full facepiece SARs 
operated in continuous flow, pressure-demand, or other positive-
pressure mode (68 FR 34102). It based the proposed APF on a SWPF study 
(Ex. 1-38-3) in which the results for these respirators showed 
geometric mean protection factors ranging from 8,500 to 20,000. Further 
justification for the proposed APF came from the similarity in 
operational characteristics between these respirators and tight-fitting 
full facepiece continuous flow PAPRs, which had a proposed APF of 
1,000. The proposed APF for these respirators also was consistent with 
the APFs of 1,000 assigned to them under the Z.88.2-1992 ANSI 
respirator standard, and was substantially lower than the APF of 2,000 
recommended for these respirators by the 1987 NIOSH RDL.
    OSHA received no comments on full facepiece SARs operated in a 
demand, pressure-demand, or other positive-pressure mode. The Agency 
believes that the evidence in the proposal is sufficient to support an 
APF of 50 for these respirators when operated in the demand mode, and 
an APF of 1,000 when the respirators function in a pressure-demand or 
other positive-pressure mode, and has included these APFs in the final 
standard.
    SARs with hoods or helmets. Based on a number of WPF studies, OSHA 
proposed an APF of 1,000 for continuous flow SARs with hoods or 
helmets, contingent on the manufacturers' demonstration that the 
respirators meet the criteria specified in Table 1 of the proposed 
standard (68 FR 34103). In responding to the proposed APF, Paul Schulte 
of NIOSH noted that an APF of 1,000 is appropriate for these 
respirators only when the manufacturer demonstrates that the models 
performed at this level (Ex. 9-13). ORC Worldwide stated that only SWPF 
data would give employers the assurance that the SAR offers the 
necessary protection for their workers (Ex. 10-27). ISEA recommended 
that further testing be performed before assigning an APF of 1,000 for 
continuous flow SARs with hoods and helmets (Ex. 9-22). MSA concluded 
that an APF of 1,000 is appropriate (Ex. 16-10) because, it asserted, 
every credible WPF study demonstrates that continuous flow SARs with 
hoods and helmets perform at an APF of 1,000.
    These commenters generally agree that continuous flow SARs with 
hoods or helmets should be assigned an APF of 1,000 only after 
manufacturers demonstrate through appropriate WPF or SWPF studies that 
the respirators are capable of performing at an APF of 1000. Therefore, 
based on the evidence cited in the proposal, the comments from ORC 
Worldwide, NIOSH, and ISEA, and the absence of any new studies or 
evidence submitted in response to the proposal, OSHA is assigning these 
respirators an APF of 1,000 in the final rule only when the employer 
can provide evidence from the respirator manufacturers that 
demonstrates the respirators perform at that level; absent such 
testing, these respirators must receive an APF of 25.
    Loose-fitting facepiece SARs. OSHA proposed an APF of 25 for this 
class of respirators based on analogous performance between these 
respirators and loose-fitting facepiece PAPRs (68 FR 34104). Additional 
support cited in the proposal included data from NIOSH showing that the 
two types of respirators (i.e., loose-fitting facepiece SARs and PAPRs) 
have the same minimum airflow rates when evaluated under 42 CFR part 
84. The proposed APF also is consistent with the APF specified for 
respirators in the 1987 NIOSH RDL and the Z88.2-1992 ANSI respirator 
standard.
    Commenters agreed with OSHA's proposed APF of 25 (Exs. 9-22 and 10-
39; Tr. at 75 and 546). For example, Warren Myers stated, "I believe 
it is reasonable for OSHA to use analogous operational characteristics 
between PAPRs and SARs equipped with loose-fitting hoods or helmets to 
set the APF for the SARs devices at 25" (Tr. at 75). ISEA noted that 
WPF studies conducted on loose-fitting facepieces justify an APF of 25 
for these respirators (Ex. 9-22). Based on these comments, the 
analogous performance with loose-fitting PAPRS, NIOSH certification 
testing at the same minimum flow rates, and the APFs given these 
respirators in the 1987 NIOSH RDL and the ANSI Z88.2-1992 respirator 
standard, OSHA has concluded that an APF of 25 is appropriate for this 
respirator class. Therefore, the final rule will list an APF of 25 for 
SARs with loose-fitting facepieces.
6. APF for Self-Contained Breathing Apparatuses (SCBAs)
    Ed Hyatt, in 1976, assigned a protection factor of 50 to a full 
facepiece SCBA operated in the demand mode, the same protection factor 
he assigned to full facepiece SARs used in this mode. Based on results 
from a panel of 31 respirator users tested at LANL, he gave full 
facepiece SCBAs used in the pressure demand mode an APF of 10,000+ (Ex. 
2). The 1980 ANSI respirator standard listed half mask and full 
facepiece SCBAs operated in the demand mode with APFs of 10 and 100, 
respectively, when qualitatively fit tested. The APFs for half mask or 
full facepiece SCBAs functioning in the demand mode were the protection 
factors obtained during quantitative fit testing, with this APF limited 
to the sub-IDLH value. Full facepiece SCBAs used in the pressure-demand 
mode received an APF of 10,000+. The 1987 NIOSH RDL recommended that half 
mask and full facepiece SCBAs operated in the demand mode receive APFs of 
10 and 50, respectively, and that the APF for full facepiece SCBAs operated 
in the pressure-demand or other positive pressure mode be 10,000.
    The Z88.2 subcommittee responsible for the 1992 ANSI respirator 
standard could not reach a consensus on an APF for full facepiece 
pressure-demand SCBAs. Available WPF and SWPF studies reported that, in 
some cases, the respirators did not achieve an APF of 10,000 (Ex. 1-
50). Nevertheless, the subcommittee found that a maximum APF of 10,000 
was appropriate when employers use the respirators for emergency-
planning purposes and could estimate levels of hazardous substances in 
the workplace.
    Two respirators equipped with hoods, Draeger's Air Boss Guardian 
and Survivair's Puma, have operational characteristics similar to 
SCBAs. The facepiece of the Draeger respirator consists of a hood with 
an inner nose cup and a tight-fitting seal at the neck, and an air 
cylinder that supplies breathing air to the facepiece. NIOSH reviewed 
this respirator in accordance with its 42 CFR part 84 certification 
requirements, and in January 2001 certified the respirator as a tight-
fitting full facepiece demand SCBA when equipped with a cylinder having 
a 30-minute service life. NIOSH also approved the respirator for use in 
entering and escaping from hazardous atmospheres. In a May 16, 2001 
letter to OSHA's Directorate of Enforcement Programs (Ex. 7-1), Richard 
Metzler of NIOSH justified the classification of the Draeger respirator 
as an SCBA on the basis that the neck seal, which is integral to the 
facepiece, forms a gas-tight or dust-tight fit with the face consistent 
with the definition of a tight-fitting facepiece specified by 42 CFR 
84.2(k). This letter also noted that the fit testing procedures used 
for full facepiece demand SCBAs apply to the Draeger SCBA, and that, as 
a full facepiece demand SCBA, NIOSH recommended that the respirator 
receive an APF of 50 in accordance with its 1987 RDL.
    NIOSH subsequently certified the Survivair Puma respirator, which 
has a tight-fitting hood supplied by an air cylinder, as a pressure-
demand SCBA with a tight-fitting facepiece. As part of the 42 CFR part 
84 certification process, NIOSH specified that the fit testing 
requirement for tight-fitting SCBAs would apply to this respirator. 
However, Steve Weinstein of Survivair (Ex. 7-2) stated that the hood 
totally encapsulates the respirator user's hair, making quantitative 
fit testing (e.g., with a Portacount) impossible. In such cases, the 
fit testing instrument treats dander and other material shed by the 
hair as particulates originating from outside the respirator, causing 
the fit factor to be artificially low. Nevertheless, qualitative fit 
testing with the hood is possible because Survivair provides an adapter 
and P100 filters for this purpose. Such fit testing meets the fit-
testing requirements for tight-fitting SCBAs specified in paragraph 
(f)(8) of OSHA's Respiratory Protection Standard.
    The table below provides a summary of APFs given to the half mask 
and full facepiece SCBAs by different groups.

----------------------------------------------------------------------------------------------------------------
                                                             APFs
             SCBAs              --------------------------------------------------------------     1992 ANSI
                                    LANL  (1976)      1980 ANSI  standard   NIOSH RDL  (1987)       standard
----------------------------------------------------------------------------------------------------------------
Tight-fitting half mask........  10 (demand)......  10 (demand; with QLFT)  10 (demand)......
                                                     Same as QNFT factor
                                                     (demand; sub-IDLH
                                                     value max.).
Tight-fitting Full facepiece...  50 (demand)......  100 (demand; with       50 (demand)......
                                                     QLFT) Same as QNFT
                                                     factor (demand; sub-
                                                     IDLH value max.).
Tight-fitting Full facepiece...  10,000 (pressure   10,000+ (pressure       10,000 (pressure   10,000 maximum
                                  demand).           demand).                demand).           (emergency
                                                                                                planning
                                                                                                purposes only).
----------------------------------------------------------------------------------------------------------------

    OSHA received no new WPF or SWPF studies for tight-fitting half 
mask SCBAs and tight-fitting full facepiece SCBAs operated in the 
demand mode in response to the proposal. In the only WPF study 
conducted on full facepiece positive-pressure SCBAs, Campbell, Noonan, 
Merinar, and Stobbe of NIOSH assessed the performance of two different 
models of full facepiece pressure-demand SCBAs that met the NFPA 1981 
air-flow requirements for respirators used by firefighters (Ex. 1-64-
7). While the authors could not determine protection factors for these 
respirators because contaminant levels measured inside the facepiece 
were too low, pressure measurements taken inside the facepiece proved 
more useful. These measurements showed that four of the 57 test 
subjects (i.e., firefighters) experienced one or more negative pressure 
incursions inside the facepiece while performing firefighting tasks. 
After analyzing the data for these firefighters using two different 
methods, the authors estimated that the overall protection factor 
exceeded 10,000.
    In the first of two SWPF studies performed on full facepiece SCBAs 
used in the pressure-demand mode, McGee and Oestenstad determined the 
protection afforded to members of a respirator test panel who used the 
Biopack 60 closed-circuit SCBA (Ex. 1-64-86). Three members of the 
panel had protection factors of 4,889, 7,038, and 18,900, with the 
remaining members having protection factors over 20,000. In the second 
study, Johnson, da Roza, and McCormack of LLNL (Ex. 1-64-98) tested the 
Survivair Mark 2 SCBA that met NFPA 1981 air-flow requirements. During 
testing, a panel of 27 test subjects exercised on a treadmill at 80% of 
their cardiac reserve capacity. Although the authors found negative 
pressure incursions inside the facepiece at high work rates, they 
concluded that the respirator "provided [a minimum] average fit factor 
of 10,000 [for any single subject], with no single subject having a fit 
factor less than 5,000 at a high work rate." The tables below 
summarize the results of the WPF and SWPF studies performed on full 
facepiece pressure-demand SCBAs.

----------------------------------------------------------------------------------------------------------------
    WPF studies for tight-fitting full                                 Geometric
 facepiece pressure demand SCBAs (by name   Sample size   Geometric     standard         5th percentile WPF
of authors and model of respirator tested)                   mean      deviation
----------------------------------------------------------------------------------------------------------------
Campbell et al. (Ex. 1-64-7) Unspecified             57  ...........  ...........  >10,000 (estimated).
 model (with NFPA-compliant airflow).
----------------------------------------------------------------------------------------------------------------


----------------------------------------------------------------------------------------------------------------
                                                                                         Geometric       5th
SWPF studies for ight-fitting full facepiece pressure demand  Sample size   Geometric     standard    percentile
   SCBAs (by name of  authors & mode of respirator tested)                     mean      deviation       WPF
----------------------------------------------------------------------------------------------------------------
McGee and Oestenstad (Ex. 1-64-86) Biopack 60 (closed                  23      >20,000  ...........  ...........
 circuit)...................................................
Johnson et al. (Ex. 1-64-98) Survivair mark 2 with NFPA-               27       29,000         1.63  ...........
 compliant airflow).........................................
----------------------------------------------------------------------------------------------------------------

    Janice Bradley (Ex. 9-22) of the International Safety Equipment 
Association and Kenneth Bobetich of the MSA Company (Ex. 9-37) both 
stated that footnote 5 in the proposed OSHA APF Table 1 was not 
necessary because most SCBA models now meet the increased air-flow 
requirements in the NFPA 1981 standard. They further noted that the 
study that served as the basis of the footnote was more than 15 years 
old, and that OSHA should remove the footnote. They recommended that 
the APF should be 10,000 for pressure-demand SCBAs that meet the air-
flow requirements of NFPA 1981. Janice Bradley (Tr. at 531) cited the 
WPF study NIOSH performed with firefighters (Ex. 1-64-7) as supporting 
the conclusion that SCBAs meeting the NFPR 1981 requirements would 
provide APFs of 10,000.
    Summary and conclusions. OSHA is setting APFs of 10 and 50, 
respectively, for tight-fitting half mask SCBAs and tight-fitting full 
facepiece SCBAs operated in the demand mode. In the absence of any new 
WPF and SWPF studies on these respirators, the Agency is basing the 
final APFs on analogous operational characteristics between these 
respirators and half mask facepiece and full facepiece air-purifying 
respirators, that have APF values of 10 and 50, respectively. In 
addition, the final APFs are consistent with the APFs recommended by 
the 1987 NIOSH RDL for these respirators. (Note that the 1992 ANSI 
standard did not assign APFs for these respirator classes.)
    For tight-fitting full facepiece SCBAs used in the pressure-demand 
or other positive pressure modes, OSHA is setting an APF of 10,000 in 
the final standard, which is consistent with the 1987 NIOSH RDL and the 
1992 ANSI respirator standard. Empirical support for the final APF 
comes from the WPF study conducted by Campbell, Noonan, Merinar, and 
Stobbe (Ex. 1-64-7). This study showed that protection factors for 
these respirators, when operating at NFPA-compliant air flows, far 
exceed 10,000. While four respirator wearers experienced momentary 
negative-pressure spikes inside their facepieces, which indicates 
possible leakage into the facepiece under some workplace conditions, 
these spikes did not impair overall respirator performance. The Agency 
concludes that these study results justify an unrestricted APF of 
10,000 for tight-fitting full facepiece SCBAs.
    For the class of respirators designated as pressure-demand SCBAs 
with tight-fitting hoods or helmets, including the Survivair Puma, OSHA 
is setting an APF of 10,000. The basis for this final APF is the 
analogous operational characteristics between these respirators and 
tight-fitting full facepiece pressure-demand SCBAs.

D. Definition of Maximum Use Concentration

    Employers use MUCs to select appropriate respirators, especially 
for use against organic vapors and gases. MUCs specify the maximum 
atmospheric concentration that an employee can experience while wearing 
a specific respirator or class of respirators. MUCs are a function of 
the APF determined for a respirator (or class of respirators), and the 
exposure limit of the hazardous substance in the workplace.
1. Introduction
    Ed Hyatt, in the 1976 LASL report on respiratory protection factors 
(Ex. 2, Docket H049), recounted the early history of MUCs, starting 
with the MUC recommendations of the joint AIHA-ACGIH committee in 1961. 
This committee recommended that, for highly toxic compounds, full 
facepiece respirators with HEPA filters use a maximum limit of 100 
times the TLV. Hyatt noted that Dr. Letts in 1961 in the United 
Kingdom, recommended that half mask dust respirators provided effective 
protection against airborne contaminant levels no greater than 10 times 
the TLV.
    In 1974, NIOSH and OSHA started the Standards Completion Program to 
develop standards for substances with existing PELs. As part of this 
process, the initial respirator decision logic was developed and the 
concept of MUCs began to be used. NIOSH Criteria Documents also 
recommended MUCs for different types of respirators. The information 
for these MUCs were obtained from various sources, including NIOSH 
Current Intelligence Bulletins and recognized industrial hygiene 
references. NIOSH later published this information in its Pocket Guide 
to Chemical Hazards. Other source documents for MUC definitions and 
regulations include the 1987 NIOSH RDL, and the ANSI Z88.2-1980 and 
ANSI Z88.2-1992 respiratory protection standards.
    OSHA's 1994 proposed Respiratory Protection Standard contained the 
following definition of MUC:

    Maximum use concentration (MUC) means the maximum concentration 
of an air contaminant in which a particular respirator can be used, 
based on the respirator's assigned protection factor. The MUC cannot 
exceed the use limitations specified on the NIOSH approval label for 
the cartridge, canister, or filter. The MUC can be determined by 
multiplying the assigned protection factor for the respirator by the 
permissible exposure limit for the air contaminant for which the 
respirator will be used. (59 FR 58884.)

    Several commenters to this 1994 proposal recommended alternatives 
to this definition. Reynolds Metal Company recommended defining MUC as 
"the maximum concentration of an air contaminant in which a particular 
respirator can be used, based on the respirator's assigned protection 
factor" (Ex. 1-54-222). The American Petroleum Institute (API) noted 
NIOSH developed the term "MUC," and that, to avoid confusion, OSHA 
should not use the term (Ex. 1-54-330). API proposed using the term 
"assigned use concentration" to replace MUC. API defined "assigned 
use concentration" as "the maximum concentration of an air 
contaminant in which a particular respirator can be used, based on the 
respirator's assigned protection factor" (Ex. 1-54-330). However, when 
the Agency published the final Respiratory Protection Standard in 1998, 
it reserved the definition of MUC in paragraph (b), and the MUC requirements 
in paragraph (d)(3)(i)(B), for future rulemaking because it reserved the APF 
provisions of the respirator selection section of the standard (i.e., 
MUCs could not be determined without knowing the APF values).
    In the June 6, 2003 proposal, OSHA defined MUC as follows:

    Maximum use concentration (MUC) means the maximum atmospheric 
concentration of a hazardous substance from which an employee can be 
expected to be protected when wearing a respirator, and is 
determined by the assigned protection factor of the respirator or 
class of respirators and the exposure limit of the hazardous 
substance. The MUC usually can be determined mathematically by 
multiplying the assigned protection factor specified for a 
respirator by the permissible exposure limit, short-term exposure 
limit, ceiling limit, peak limit, or any other exposure limit used 
for the hazardous substance. (68 FR 34036.)

    Under this definition, MUC represents the maximum atmospheric 
concentration of a hazardous substance against which a specific 
respirator or class of respirators with a known APF can protect 
employees who use these respirators. Accordingly, MUCs are a function 
of the APF determined for a respirator (or class of respirators) and 
the exposure limit of the hazardous substance in the workplace.
    The last sentence in the definition describes the MUC in terms of a 
mathematical calculation, i.e., that employers can "usually" 
determine the MUC by multiplying the APF for the respirator by the 
exposure limit used for the hazardous substance.\10\ The last sentence 
of the proposed definition also specifies the exposure limits as 
"permissible exposure limit (PEL), short-term exposure limit (STEL), 
ceiling limit (CL), peak limit, or any other exposure limit used for 
the hazardous substance." Although OSHA received no comments on the 
proposed definition, it nevertheless is making several minor revisions 
to the definition in the final rule. First, the Agency is removing the 
term "usually" from the definition because multiplying the assigned 
protection factor by the exposure limit for a hazardous substance is 
the currently accepted method used by safety and health professionals 
for calculating MUCs. Absent any other accepted method, the term 
"usually" is confusing and unnecessary.
---------------------------------------------------------------------------

    \10\ For example, when the hazardous substance is lead (with a 
PEL of 50 [mu]g/m\3\), and the respirator used by employees has an 
APF of 10, then the calculated MUC is 500 [mu]g/m\3\ or 0.5 mg/m\3\ 
(i.e., 50 [mu]g/m\3\ x 10).
---------------------------------------------------------------------------

    The second revision to the proposed MUC definition involves the 
last part of the second sentence, which required employers to consider 
an "exposure limit" when determining an MUC. OSHA is making two 
changes to this proposed language to make clear its intent regarding 
the information employers need to consider when making this 
calculation. First, OSHA is clarifying the language to require 
employers to calculate an MUC using an OSHA exposure limit in those 
instances where one exists. OSHA was concerned that employers could 
have misinterpreted the language in the proposed MUC definition as 
meaning that they could use any available exposure limit for 
calculating an MUC (and, by implication, for protecting employees from 
hazardous airborne contaminants). This revision emphasizes the priority 
that OSHA exposure limits have in regulating hazardous airborne 
contaminants.
    Second, OSHA is changing the language to make clear the information 
employers need to consider to determine an MUC in the absence of an 
OSHA exposure limit. The Agency revised the language to require 
employers to use relevant available information and informed 
professional judgment when determining an MUC when no OSHA exposure 
limit exists. This language more clearly states OSHA's intent that 
employers can utilize a wide range of available information in 
calculating an MUC when OSHA has not yet promulgated an exposure limit 
for a hazardous airborne contaminant. While not required, some 
employers may choose to conduct individualized risk assessments of 
hazards. Others may consult information from manufacturers or other 
published exposure limits (e.g., the NIOSH RELs or the AIHA WEELs) for 
making MUC determinations. However, whatever approach employers choose 
to take, the MUC must provide adequate protection for their employees. 
OSHA believes this approach provides employers with greater flexibility 
than the proposed MUC definition while still maintaining employee 
protection.
    The Agency also broadened the language in this second sentence by 
requiring employers to "take the best available information into 
account" when determining an MUC in the absence of an OSHA exposure 
limit. This language is consistent with the guidance that the Agency 
provided to employers in the preamble to the Respiratory Protection 
Standard for determining APFs in the absence of a final APF standard 
(see, e.g., 63 FR 1203). OSHA believes this language gives employers 
maximum flexibility to develop MUCs that protect their employees from 
hazardous airborne contaminants, including the use of other exposure 
limits when appropriate.
    In the proposal to this final rule, OSHA requested comments on the 
development of the MUC for substances with no OSHA PEL, limiting 
factors such as eye irritation, LELs and IDLHs, and mixtures of 
substances (68 FR 34112). OSHA received numerous comments on these 
issues, as well as on hazard ratios, an issue raised by several 
commenters. These issues are discussed in the following sections.
2. MUCs for Substances With No OSHA PEL or Other Limiting Factors
    OSHA received many comments on this issue. Some commenters believed 
that in the absence of a PEL it is appropriate for the Agency to 
require calculation of MUCs based on other information (Exs. 10-54, 9-
27, and 10-3). Other commenters supported using any occupational 
exposure limit for this purpose, but some of these commenters specified 
that no other limiting factors should be used (Exs. 9-26, 9-42, 10-27). 
Others specified that additional limiting factors were needed (Exs. 9-
13, 9-15, 9-29, 10-6, and 10-60). Several commenters recommended using 
only the OSHA PELs with limiting factors (Ex. 10-17, 10-25, and 9-16) 
or without limiting factors (Exs. 9-22 and 9-23). A few commenters 
addressed limiting factors only, either supporting specific factors 
(Exs. 9-12 and 10-1) or stating that no limiting factors were needed 
when determining MUCs (Ex. 9-37). These comments are discussed in the 
following paragraphs.
    W.M. Parris of Alabama Power (Ex. 9-15) proposed the following 
generic definition of MUC that would include all possible MUCs:

    Maximum use concentration (MUC) means the maximum atmospheric 
concentration of a hazardous substance from which an employee can be 
expected to be protected when wearing a respirator. The MUC will be 
the lowest of the following: (1) IDLH value for the substance, (2) 
the LEL value, (3) limitations set by manufacturer, or (4) 
mathematically determined by multiplying the assigned protection 
factor specified for the respirator by the permissible exposure 
limit, short term exposure limit, ceiling limit, peak, or another 
occupational exposure limit used for the hazardous substance.

    Paul Schulte of NIOSH (Exs. 9-13, 13-11-1, and 16-4) recommended 
that employers use the RELs, or in the absence of a REL, another appropriate 
exposure limit. Schulte also stated that, for both regulated and non-
regulated substances, the MUC for any respirator other than a pressure-
demand SCBA should never exceed the IDLH value. Schulte noted further 
that NIOSH did not agree with the use of the LEL as an appropriate 
respirator-selection factor for MUCs unless the respirator is the 
source of an ignition hazard (e.g., respirators with communication 
systems). Accordingly, Schulte (Ex. 9-13) proposed revising the MUC 
definition to read as follows:

    Maximum use concentration (MUC) means the maximum atmospheric 
concentration of a hazardous substance from which an employee can be 
expected to be protected when wearing a respirator, and is 
determined by the lesser of
     APF times (x) exposure limit
     The respirator manufacturer's maximum use concentration 
for a hazardous substance (if any)
     The IDLH, unless the respirator is a positive-pressure, 
full facepiece SCBA

    Daniel K. Shipp of the International Safety Equipment Association 
(ISEA) (Ex. 9-22) commented that ISEA believed that OSHA should not 
expand the MUC definition to include MUCs for hazardous substances not 
regulated by OSHA, and that the definition should not involve limiting 
factors. He indicated that employers should have the flexibility to 
determine what to do in these situations. Shipp also stated that the 
NIOSH approval labels on chemical cartridges already read "Do not 
exceed maximum use concentrations established by regulatory 
standards." In this regard, he suggested that OSHA rewrite the MUC 
definition to require that MUCs used to select respirators shall not be 
exceeded.
    Michael Sprinker of the International Chemical Workers Union 
Council of the United Food and Commercial Workers Union (Ex. 10-54) 
believed that OSHA's definition of MUC should be revised because it is 
unclear whether the MUC is a concentration never to be exceeded or a 
time weighted average. He also stated that OSHA should require 
employers to determine MUCs for substances for which no OSHA PEL is 
available, and that these MUCs can be derived from occupational 
exposure limits issued by NIOSH, ACGIH, EPA, or the manufacturer.
    Robert W. Barr and Linda M. Maillet of Alcoa, Inc. (Exs. 9-26 and 
10-31) said that OSHA should not expand the definition and application 
of MUCs to hazardous substances it does not regulate because that would 
constitute adoption of these exposure limits as OSHA rules. The Alcoa 
representatives said that employers should be free to select the 
criteria for calculating MUCs based on their own risk assessments. 
Also, they did not want the lower NIOSH RELs to replace OSHA PELs in 
calculating MUCs. They did not believe that OSHA should specify the LEL 
or 10% of the LEL as a limiting factor because LEL is an independent 
indicator of a physical hazard. They asserted that respirator users who 
could be exposed to an explosive level of a substance must not enter 
such an area because of the physical hazard--the characteristics of 
their respirators are irrelevant in such situations. Similarly, Daniel 
P. Adley and William L. Shoup of the Society for Protective Coatings 
(Ex. 9-10) did not agree with the "or any other exposure limit" in 
the definition of MUC, which would give regulatory authority to TLVs, 
RELs, and other industry--established exposure limits.
    Bill Kojola of the AFL-CIO (Exs. 9-27 and 16-5) believed that OSHA 
should expand the definition and application of MUC to include 
substances it does not regulate, and that the exposure limits issued by 
NIOSH, ACGIH, EPA, or the manufacturer should be used when available. 
Pete Stafford of the Building and Construction Trades Department, AFL-
CIO (Ex. 9-29) recommended that OSHA expand the definition of MUC to 
include appropriate exposure values because thousands of harmful and 
potentially harmful chemicals used in the workplace are not regulated 
by OSHA. He indicated that alternative MUCs calculated for chemicals 
using a non-OSHA exposure limit should be used when these MUCs are 
lower than the MUCs determined from using PELs. He also recommended 
that OSHA specify 10% of the LEL as a limiting factor for MUCs.
    Stephan C. Graham of the United States Army Center for Health 
Promotion and Preventive Medicine (Exs. 9-42, 9-42-1, and 9-42-2) 
indicated that OSHA should expand the MUC definition to include 
hazardous substances it does not regulate. However, he did not believe 
that NIOSH MUCs should be used when they are lower than the MUCs 
calculated using OSHA PELs. Rick N. Givens of Augusta Utilities 
Department (Ex. 10-2) also agreed that OSHA should require employers to 
calculate MUCs for substances that do not have OSHA PELs. Ken M. Wilson 
of the Division of Safety & Hygiene, Ohio Board of Water Control (Ex. 
10-3) stated that OSHA should require employers to determine MUCs for 
substances that have no OSHA PEL because many of these substances can 
harm employees.
    David L. Spelce (Ex. 10-6) stated that the PELs in 29 CFR 1910.1000 
were adopted by OSHA in 1971 and came mostly from the 1968 ACGIH TLVs. 
He recommended that OSHA require employers to use the ACGIH TLVs and 
AIHA Workplace Environmental Exposure Levels when no OSHA PEL exists. 
He indicated that these alternative values also should be used when 
they are more stringent than the OSHA PELs. He agreed with OSHA that 
when the IDLH level is lower than the calculated MUC, the IDLH 
concentration must take precedence. In such circumstances, only the 
most protective atmosphere-supplying respirators should be used. He 
also stated that IDLH limits should be established based on 
toxicological data, but, in the absence of toxicological data, 10% of 
the LEL should be used as the limiting factor (i.e., having the same 
weight as the IDLH for flammable substances).
    Thomas C. O'Connor of the National Grain and Feed Association 
(NGFA) (Exs.10-13 and 16-19) recommended a revised MUC definition that 
would read as follows:

    Maximum use concentration (MUC) * * * usually can be determined 
mathematically by multiplying the assigned protection factor 
specified for a respirator by the permissible exposure limit or 
ceiling value as appropriate. In a situation when such regulatory 
limits have not been set by OSHA, the employer may rely on limits 
established by non-regulatory organizations based on professional 
judgment and the working environment.

    However, he (Ex. 10-13) said that NGFA strongly opposes requiring 
employers to determine MUCs for substances for which no OSHA PELs are 
available. The NGFA also opposed any requirement that employers rely on 
MUCs developed by NIOSH, but supported the use of non-OSHA exposure 
limits as aids employers can use in establishing MUCs.
    Thomas Nelson of NIHS, Inc. (Ex. 10-17) indicated that OSHA should 
not require employers to determine MUCs for substances that have no 
OSHA PELs. Nelson said that OSHA first must determine when a need for 
such exposure limits exists, and then issue new PELs. Furthermore, 
Nelson stated that OSHA cannot rely on other groups to establish limits 
for OSHA's use. He also said that the only limiting factors that should 
be used in calculating MUCs are APFs and IDLHs, and that the Agency 
should specify the LEL, or a value close to the LEL (e.g., 90% of the
LEL), when no IDLH exists for a substance.
    Lorraine Krupa-Greshman of the American Chemistry Council (ACC) 
(Ex. 10-25) indicated that NIOSH MUCs should not be adopted as a 
specific requirement, but should remain available for guidance. The ACC 
also does not support requiring compliance with NIOSH MUCs when they 
are lower than OSHA's MUCs. The ACC recommends a requirement for 
employers to determine the appropriate MUCs for substances that do not 
have an OSHA PEL. However, employers should be allowed to designate and 
document the basis for these MUCs using either the OSHA formula or 
other criteria. She stated that the IDLH is a reasonable limit on the 
MUC for some types of respirators, and that an IDLH should be based on 
health effects. She noted that using the LEL or a percentage of the LEL 
to limit MUCs is confusing and inappropriate because an LEL is used to 
determine whether an employee can safely enter an area with a fire 
hazard, not for selecting respirators.
    Frank A. White of ORC Worldwide (Ex. 10-27) stated that OSHA should 
not require employers to calculate MUCs for substances that have no 
OSHA PEL, but that employers should have the freedom to select the 
occupational exposure limits used for calculating MUCs based on their 
own risk assessments. He emphasized that it is important that employers 
be able to show the documented evidence used to support their MUC 
decisions. ORC Worldwide also indicated that OSHA should not expand the 
application of MUCs to hazardous substances it does not regulate 
because these exposure limits (e.g., developed by chemical 
manufacturers, ACGIH, NIOSH, EPA) would become OSHA regulations. He 
also stated that OSHA should not enforce the 1994 NIOSH IDLHs, but 
instead should continue to rely on those IDLHs that NIOSH developed in 
1990. OSHA should not use either the LEL or 10% of the LEL as a 
limiting factor because these factors are not health-based, and are 
used as indicators of a physical hazard.
    Ted Steichen of the American Petroleum Institute (Ex. 9-23) 
believed that the determination of MUCs for substances with no OSHA 
PELs should be left to the good practices of the employer. He stated 
that OSHA would be exceeding its authority if it expanded the 
definition and application of MUC to hazardous substances that it does 
not regulate. Steichen said that the use of the LEL to limit the MUC is 
confusing and inappropriate. He stated that the LEL has no relationship 
to the protection provided by a respirator, but is an essential factor 
to consider when working with flammable or combustible materials.
    Paul Hewett of Exposure Assessment Solutions, Inc. (Ex. 10-60) 
believed that OSHA should require employers to determine MUCs for those 
substances that have no OSHA PEL. He pointed out that employers already 
are required to consider all hazardous substances, including those 
substances without an OSHA PEL, under the "recognized hazards" 
provision of the general-duty clause of the OSH Act. He recommended 
that OSHA indicate, either by regulation or by repeated emphasis in the 
preamble of this final standard and in all respirator guidelines, that 
these requirements also apply to overexposures involving unregulated 
substances. Hewett also stated that OSHA should not require employers 
to comply with MUCs calculated using NIOSH RELs when these MUCs are 
lower than the MUCs calculated using OSHA PELs. He recommended as well 
that OSHA should specify an upper bound on MUCs that is a percentage of 
the IDLH for a substance, e.g., the MUC is no more than 25% of the 
IDLH.
    Michael Watson of the International Brotherhood of Teamsters, AFL-
CIO (Ex. 9-12), Pete Stafford of the Building and Construction Trades 
Department, AFL-CIO (Ex. 9-29), and Rick N. Givens of the Augusta 
Utilities Department (Ex. 10-2) agreed with using the IDLH as a 
limiting factor for MUCs. Givens also recommended that OSHA specify 10% 
of the LEL as an additional limiting factor for MUCs.
    Michael Runge of the 3M Company (Exs. 9-16, 16-25, and 16-25-2) 
said that only APFs and IDLHs should be used to calculate MUCs. The LEL 
and eye irritation, as well as all other limitations, already are 
considered in the respirator selection process, and do not necessarily 
need to be considered when establishing specific MUCs. He did not 
support use of 10% of the LEL as a limiting factor, but stated that 
OSHA should specify the LEL when no IDLH is available for a chemical. 
He also stated that when employers use the REL for an unregulated 
contaminant to select a respirator, the APF and MUC principles 
specified in the proposal should apply.
    Kenneth Bobetich of Mine Safety Appliances (Ex. 9-37) believed that 
OSHA's definition of MUC is sufficient to cover the limitations, and 
that MUCs should not be based on eye irritation. Tracy C. Fletcher of 
Parsons-Odebrecht JV (Ex. 10-1) recommended that OSHA use 10% of the 
LEL as an MUC-limiting factor. Accordingly, when the atmosphere reaches 
10% of the LEL, the employee should be removed and steps taken to make 
the work area safe (e.g., ventilate the area). When the area cannot be 
made safe, the employer should provide the employee with a fire-
retardant suit and supplied air.
3. Summary and Conclusions
    As noted above in the discussion of the MUC definition, the final 
standard will require employers to use an OSHA exposure limit when 
available. However, absent an OSHA exposure limit, employers must use 
relevant available information combined with informed professional 
judgment to determine MUCs. The purpose of this approach is to permit 
employers to rely on existing data sources and professional judgment 
when determining an MUC that will provide adequate protection for their 
employees from hazardous airborne contaminants that have no OSHA 
exposure limit.

E. MUCs for Mixtures and Hazard Ratios

1. MUCs for Mixtures
    Paragraph (d)(3)(i)(B)(1) requires employers to select respirators 
for employee use that maintains the employees exposure to the hazardous 
substance at or below the MUC. However, a question arises regarding how 
to make these calculations for mixtures. Question 12 in Section VIII. 
("Issues") of the proposal addressed this issue by requesting 
comments on the proposed MUC for mixtures., About half of the 
commenters supported the MUC provisions as proposed, but believed that 
insufficient data were available to perform the calculations for 
mixtures (Exs. 9-23, 9-37, 10-17, 10-25, and 10-59). Another group of 
commenters supported performing the calculations based on information 
that each component of a mixture has a non-additive effect on 
independent organ systems. In this case, the commenters suggested 
either a separate MUC for each component, or lowering the MUC according 
to the proportion of each component in the mixture (Exs. 9-12, 9-13, 9-
22, 9-29, and 9-37). Still others recommended lowering the MUC by an 
unspecified proportion when individual components of the mixture have 
synergistic effects on organ systems (Ex. 9-42), or simply requiring 
employers to use supplied-air respirators when employees are exposed to 
mixtures (Ex. 10-1).
    Daniel K. Shipp of the International Safety Equipment Association 
(Ex. 9-22) pointed out that the effect of the mixture on canister/
cartridge service life must be evaluated, and an appropriate change 
schedule established for a mixture of gases or vapors. Shipp indicated 
that no MUC equation is available for mixtures. He suggested that when 
the health effects of a mixture's components are not additive, then each 
component should be evaluated separately, and the respirator must be 
appropriate for the sum of the individual chemical concentrations.
    Kenneth Bobetich of Mine Safety Appliances (Ex. 9-37) noted that no 
evidence exists to indicate that respirator performance is different 
when the exposure is to a mixture of particulates versus a single 
particulate. However, the effect of a mixture of gases or vapors on 
canister/cartridge service life must be evaluated, and an appropriate 
change schedule established. He further mentioned that Dr. Gerry Wood 
of LANL is conducting a study to evaluate the effect of mixtures on 
service life, and is developing a model to predict cartridge service 
life. Bobetich indicated that when the health effects of the mixture 
components are on the same organ system and these effects are additive, 
an additive formula can be used to establish the PEL for the mixture. 
However, when the health effects are not additive, then each component 
should be evaluated individually and the respirator must be appropriate 
for the sum of the individual chemical concentrations.
    Thomas Nelson of NIHS, Inc. (Ex. 10-17) said that, because 
exposures to multiple organic vapors will affect the service life of a 
cartridge, the employer already is required to consider multiple 
contaminants in setting a cartridge change schedule. He recommended 
that, to determine the MUC for a mixture that affects the same organ 
system, employers should assume that the health effects of each 
component are additive.
    Frank A. White of ORC Worldwide (Ex. 10-27) indicated that exposure 
to multiple gas or vapor contaminants may affect the service life of 
respirator filters and cartridges differently than exposure to a single 
contaminant. He, too, mentioned that Dr. Gerry Wood is working on this 
issue with NIOSH, and that a service life calculation model for 
multiple contaminants will soon be available. He emphasized that the 
more important consideration in determining MUCs for mixtures is the 
health effects of multiple contaminants. He stated that the employers 
are in the best position to apply recommendations from chemical 
manufacturers and information on health effects to their specific 
workplaces. He noted that industrial hygienists should determine if the 
contaminants have additive health effects, and they should use the 
additive mixture formula set by ACGIH and OSHA to calculate the MUC.
    Michael Watson of International Brotherhood of Teamsters, AFL-CIO 
(Ex. 9-12) and Pete Stafford of the Building and Construction Trades 
Department, A FL-CIO (Ex. 9-29) stated:

    The presence of multiple contaminants in the workplace should be 
taken into consideration when the employer determines the MUC and 
respirator change schedules for gases and vapors. Mixtures may have 
similar effects on chemical cartridge loading, so the MUC of each 
component of a mixture should be lowered in proportion to its 
percentage of the total concentration of contaminants in air.

    Paul Schulte of NIOSH (Exs. 9-13, 13-11-1, and 16-4) recommended 
that the equation C1/MUC1 + C2/
MUC2 + * * * + Cn/MUCn = 1 should be 
used to determine MUCs for mixtures. He asserted that the MUC would be 
safe only when the result is [gteqt]1. Schulte also stated that the 
rated service life of the cartridge may be shortened during exposure to 
a mixture (i.e., one or more of the mixture's components may break 
through before the rated end-of-service-life).
    Ted Steichen of American Petroleum Institute (Ex. 9-23) indicated 
that no data are available comparing respirator performance during 
exposure to multiple contaminants and exposure to single contaminants, 
and that it is impractical to discuss establishing different MUCs for 
mixtures. Stephan C. Graham of the United States Army Center for Health 
Promotion and Preventive Medicine (Exs. 9-42, 9-42-1, and 9-42-2) 
stated that MUCs for mixtures should differ from MUCs for single 
compounds depending on whether the health effects are additive or 
synergistic.
    Tracy C. Fletcher of Parsons-Odebrecht JV (Ex. 10-1) believed that 
supplied-air respirators should be used to eliminate the risk of filter 
failure caused by chemical reactions that may occur among the 
components of a mixture. Lorraine Krupa-Greshman of the American 
Chemistry Council (ACC) (Ex. 10-25) indicated that by addressing 
contaminants with additive effects, 29 CFR 1910.1000(d)(2)(i) and the 
proposal provide adequate means of achieving suitable protection. Also, 
she said that MUCs can be developed for multiple contaminants that have 
independent health effects by using the change schedule provisions of 
1910.134(d)(3)(iii)(B)(2). The ACC does not believe that adequate 
information and data are available to develop MUCs for mixtures with 
synergistic effects.
    Lisa M. Brosseau of the University of Minnesota (Ex. 10-59) 
believed that the issue of mixtures, as addressed in the proposal, is 
confusing and incorrect. She stated that the only requirements needed 
are to assure that respirators have the required filters and that gases 
and vapors have appropriate cartridges.
2. Use of Hazard Ratios
    Michael Runge of the 3M Company (Ex. 9-16), Daniel K. Shipp of the 
International Safety Equipment Association (Ex. 9-22), and Lisa M. 
Brosseau of the University of Minnesota (Ex. 10'59) supported another 
method for selecting respirators, the hazard ratio (HR). The HR is 
defined as the ratio of the workplace concentration of an airborne 
contaminant divided by the occupational exposure limit (e.g., PEL). Any 
respirator that has an APF equal to or greater than the HR may be 
selected. They stated that the HR is more useful to employers than MUCs 
because employers likely will have information on airborne 
concentrations and occupational exposure limits when selecting 
respirators. Both Runge and Shipp said that the HR is similar to the 
MUC. Brosseau noted that it makes more sense to use the HR rather than 
the MUC to select respirators, and she recommended that OSHA require 
the HR method, and use the MUC as guidance.
    OSHA is not adopting hazard ratios under this final rulemaking 
because it was not addressed in the notice of proposed rulemaking. 
Accordingly, OSHA would have to provide the public with notice and an 
opportunity for comment on this issue before taking such action.
3. Summary and Conclusions
    OSHA agrees with the commenters who stated that the data on 
mixtures are limited, and that no revision is needed for OSHA's 
proposed single-contaminant MUC definition (Exs. 9-23, 9-37, 10-17, 10-
25, and 10-59). The existing requirement for setting change schedules 
for respirator cartridges and canisters specified in 29 CFR 1910.134 
(d)(3)(iii)(B)(2) already requires that employers consider the effects 
of each component in organic vapor mixtures when they develop change 
schedules. The Agency recognizes that reliable methods are not 
available to develop MUCs for mixtures based on whether the components 
of the mixture act additively or synergistically, and whether they 
affect the same organ or different organs. Therefore, OSHA will rely on 
the provisions at 29 CFR 1910.1000(d)(2)(i) to assist employers in 
calculating MUCs.

    While the determination of MUCs and service life are both necessary 
for respirator selection, they should not be confused. MUCs can be used 
to decide if a certain type of respirator even qualifies for 
consideration for use in defined workplace concentrations. Service life 
estimation identifies how long a properly selected respirator can be 
expected to provide worker protection and, therefore, is useful for 
setting change schedules.
    OSHA has established at 29 CFR 1910.1000(d)(2)(i) an equivalent 
exposure requirement for mixtures of air contaminants. Accordingly, 
MUCs for respirators used in a mixture of contaminants must satisfy the 
following equation:

Em = (C1 / L1 + C2 / 
L2) + * * * + (Cn / Ln)

Where:

Em is the equivalent exposure for the mixture
C is the concentration of a particular contaminant
L is the exposure limit for that substance
The value of Em shall not exceed unity (1).

    OSHA is maintaining the MUC as a requirement in the final standard 
for determining the maximum concentration of an airborne contaminant 
from which a respirator will protect an employee. In addition, the 
Agency cannot revise the final rule to mandate the use of hazard ratios 
because the regulated community must have adequate notice of, and an 
opportunity to comment on, any such revision to the standard.

F. MUC Provisions

1. Paragraph (d)(3)(i)(B)--MUC Provisions
    These final requirements consist of three separate paragraphs 
((d)(3)(i)(B)(1) through (d)(3)(i)(B)(3)). Paragraph (d)(3)(i)(B)(1), 
which sets the requirements for the use and application of MUCs, reads, 
"The employer must select a respirator for employee use that maintains 
the employee's exposure to the hazardous substance, when measured 
outside the respirator, at or below the MUC." This paragraph, which 
has the same designation in the proposal, requires employers to select 
respirators for employee protection that are appropriate to the ambient 
levels of the hazardous substance found in the workplace, i.e., that 
the ambient level of the hazardous substance must never exceed the MUC, 
which is the exposure limit specified for the hazardous substance 
multiplied by the respirator's APF. Accordingly, this provision ensures 
that employers maintain employees' direct exposure to hazardous 
substances (i.e., inside the respirator) below levels specified by 
OSHA's Z tables and substance-specific standards, and, when OSHA has no 
standards, below exposure levels determined by the employer. Therefore, 
this provision provides employee protection consistent with existing 
regulatory requirements and prevailing industrial-hygiene practice.
    In the MUC provision following paragraph (d)(3)(i)(B)(1) in the 
proposal, OSHA had incorporated a note that stated: "MUCs are 
effective only when the employer has a continuing, effective 
respiratory protection program as specified by 29 CFR 1910.134, 
including training, fit testing, maintenance and use requirements." 
The Agency is removing this note because the program already is 
required under its Respiratory Protection Standard for all employers 
using respirators, and OSHA believes that duplicating this information 
in a note is unnecessary.
    The second MUC provision in the proposal, paragraph 
(d)(3)(i)(B)(2), required employers to use MUCs determined by 
respirator manufacturers when those MUCs were lower than the MUCs 
determined using the general calculation (i.e., MUC = APF x PEL). 
Several commenters objected to the proposed provision, stating that it 
gave regulatory status to manufacturer's MUCs (e.g., Exs. 9-10, 9-22, 
9-23, 9-24, 9-26, and 10-13). However, the Agency often defers in its 
rules to instructions and other documents published by manufacturers 
(e.g., no fewer than seven provisions of OSHA's Respiratory Protection 
Standard refer to manufacturers' instructions or recommendations). 
Nevertheless, the Agency believes that the proposed provision is 
unnecessary because using the general calculation specified in the MUC 
definition is an accepted safe practice in the industrial-hygiene 
community.
    Paragraph (d)(3)(i)(B)(2) of the final MUC provisions (which was 
designated as paragraph (d)(3)(i)(B)(3) in the proposal) specifies that 
employers must not use MUCs to select respirators for employees who are 
entering an IDLH atmosphere. OSHA previously specified the requirements 
for selecting respirators for use in IDLH atmospheres in paragraph 
(d)(2) of its Respiratory Protection Standard. Paragraph (d)(2) 
requires employers to select for this purpose a full facepiece 
pressure-demand SCBA certified by NIOSH to have a service life of at 
least 30 minutes, or a combination full facepiece pressure-demand 
supplied-air respirator with an auxiliary self-contained air supply. In 
the preamble to the final Respiratory Protection Standard, the Agency 
justified selecting these respirators as follows: "In [IDLH] 
atmospheres there is no tolerance for respirator failure. This record 
supported OSHA's preamble statement that IDLH atmospheres `require the 
most protective types of respirators for workers' " (59 FR 58896). 
Commenters to the APF proposal, including NIOSH, ANSI, and 
representatives of both labor and management, agreed that employees 
should use these respirators, which are the most protective respirators 
available, when exposed to IDLH atmospheres. (See 63 FR 1201 for a more 
complete discussion of these comments.)
    Ted Steichen of the American Petroleum Institute (Ex. 9-23) 
requested that OSHA clarify that a pressure-demand full facepiece SAR 
with auxiliary SCBA can be used at an APF higher than 1,000. He said 
that positive-pressure SARs with auxiliary SCBAs often are used by the 
petroleum industry for non-emergency work in high-hazard operations 
(e.g., cleaning refinery flare systems) that may involve potential 
exposures greater than 1,000 times the PEL. Under proposed Table 1, he 
questioned whether OSHA would consider this use of SARs with auxiliary 
SCBAs to be acceptable. The Agency notes that paragraph (d)(2)(i)(B) of 
its Respiratory Protection Standard already permits employers to use a 
combination full facepiece pressure-demand supplied-air respirator 
(SAR) with auxiliary self-contained air supply in IDLH atmospheres. 
Also, paragraph (d)(3)(i)(A) of this final standard states, "When 
using a combination respirator * * * employers must ensure that the 
assigned protection factor is appropriate to the mode of operation in 
which the respirator is being used." In this case, the combination 
pressure-demand full facepiece SAR with auxiliary SCBA respirator is 
equivalent to an SCBA, and, therefore, the APF for an SCBA applies.
    The last MUC provision, proposed paragraph (d)(3)(i)(B)(4), would 
have required that "[w]hen the calculated MUC exceeds another limiting 
factor such as the IDLH level for a hazardous substance, the lower 
explosive limit (LEL), or the performance limits of the cartridge or 
canister, then employers must set the maximum MUC at that lower 
limit." Accordingly, the IDLH limits for hazardous substances would 
take precedence over the calculated MUC when the IDLH limits result in 
lower employee exposures to the hazardous substances. Consequently,
this provision increases employee protection against these hazardous 
substances. OSHA is retaining a revised version of this proposed 
provision in the final rule (redesignated as paragraph 
(d)(3)(i)(B)(3)). The remaining paragraphs of this subsection discuss 
the revisions.
    The previous discussion of MUCs for substances with no OSHA PEL or 
other limiting factors (see subsection 2 ("MUCs for Substances with No 
OSHA PEL or Other Limiting Factor") of this section) addressed the use 
of the LEL as a limiting factor to be considered when calculating the 
MUC. NIOSH did not agree with the use of the LEL as a limiting factor 
for MUCs in respirator selection unless the respirator is the source of 
an ignition hazard (Ex. 9-13). Alcoa, Inc. did not believe OSHA should 
use the LEL as a limiting factor for MUCs since the LEL "is not 
health-based, rather it is an independent indicator of a physical 
hazard" (Ex. 10-31). The American Chemical Council commented using the 
LEL to set MUCs was confusing and inappropriate, because the LEL is 
used to determine whether an employee can safely enter an area with a 
fire hazard, not for selecting respirators (Ex. 10-25). The American 
Petroleum Institute also questioned the use of the LEL to limit the MUC 
because the LEL has no relationship to the protection provided by a 
respirator, but is a factor to consider when working with flammable or 
combustible substances (Ex. 9-23). The 3M Company stated that the LEL 
already is required under the Respiratory Protection Standard when 
selecting respirators, and does not need to be taken into account when 
establishing specific MUCs (Ex. 9-16).
    The Agency agrees with these commenters that the LEL is not 
appropriate as a limiting factor in setting MUCs. Therefore, OSHA 
removed from paragraph (d)(3)(i)(B)(3) in the final rule the language 
that identified the LEL as a limiting factor in setting MUCs. The 
Agency made this revision to the proposal because the LEL is not 
related to the performance of the respirator, but is an independent 
indicator of a physical hazard (i.e., the flammability or 
combustibility of a substance) that already must be considered when 
determining whether an employee can safely enter a hazardous area.
    The revised and redesignated final paragraph (d)(3)(i)(B)(3) now 
reads as follows:

    (3) When the calculated MUC exceeds the IDLH level for a 
hazardous substance, or the performance limits of the cartridge or 
canister, then employers must set the maximum MUC at that lower 
limit.

G. Superseding the Respirator Selection Provisions of Substance-
Specific Standards in Parts 1910, 1915, and 1926

1. Introduction
    OSHA proposed to revise the provisions in its substance-specific 
standards under 29 CFR parts 1910, 1915, and 1926 that regulate APFs 
(except the APF requirements for the 1,3-Butadiene Standard at 29 CFR 
1910.1051). These substance-specific standards specify numerous 
requirements for regulating employee exposure to toxic substances. The 
proposed revisions would have removed the APF tables from these 
standards, as well as any references to these tables, and would have 
replaced them with a reference to the APF and MUC provisions specified 
by proposed paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of the Respiratory 
Protection Standard at 29 CFR 1910.134. In justifying these proposed 
revisions, the Agency stated that the proposed revisions would simplify 
compliance for employers by removing many APF requirements across its 
substance-specific standards. The proposed revisions would enhance 
consolidation and uniformity of these requirements, and conform them to 
each other and to the general APF and MUC requirements specified by 29 
CFR 1910.134 (68 FR 34107).
    As noted elsewhere in this preamble to the final APF rule, OSHA 
developed the final APFs using the best available evidence. The 
development of these final APFs included a careful review of the 
comments, testimony, data, and other evidence submitted to the 
rulemaking record, a quantitative (i.e., statistical) analysis of the 
results from WPF studies performed among workers wearing air-purifying 
half mask respirators (both filtering facepieces and elastomerics) 
discussed above in this preamble, and a thorough quantitative and 
qualitative review of existing WPF and SWPF studies performed with 
other types of respirators. Using the best data and analytic techniques 
available, as well as the extensive comments and testimony provided to 
the rulemaking record, lends a high degree of reliability and validity 
to the final APF determinations.
    The Agency believes that the final APFs developed under this 
rulemaking will improve the substance-specific standards. The final 
APFs will provide employers with confidence that their employees will 
receive the level of protection from airborne contaminants signified by 
these APFs when they implement a respiratory protection program that 
complies with the requirements of 29 CFR 1910.134. In addition, 
applying the final APFs to the substance-specific standards is 
consistent with OSHA's goal of bringing uniformity to its respiratory 
protection requirements. Moreover, protection for workers likely will 
be increased because the final APFs result in regulatory consistency, 
enhanced employer compliance, and reduced the compliance burden on the 
regulated community, and, consequently, further increases the 
protection afforded to employees who use respirators.
    In its Respiratory Protection Standard, OSHA noted that the revised 
standard was to "serve as a "building block" standard with respect 
to future standards that may contain respiratory protection 
requirements." (See 63 FR 1265, 1998.) However, in the proposed APF 
rulemaking that would provide generic APFs and MUCs as part of the 
Respiratory Protection Standard, the Agency decided to retain former 
respirator selection provisions in the existing substance-specific 
standards that it found supplemented or supplanted the proposed APFs 
and MUCs (e.g., organic vapor cartridge and canister procedures, 
prohibiting use of filtering facepieces or half mask respirators). OSHA 
did so because these provisions enhance the respirator protection 
afforded to employees.
2. Comments Regarding the Respirator Selection Provisions of the 1,3-
Butadiene Standard
    The former respirator selection provisions being retained in this 
final rule include those provisions in the 1,3-Butadiene (BD) Standard. 
In issue 13 of the proposed APF rule (68 FR 34112), OSHA asked if 
exclusion of this standard was warranted. The responses to this 
question addressed only the service life requirement for cartridges 
used to absorb atmospheric BD. Typical of these responses is the 
following comment from the 3M Company:

    A short service life does not affect the ability of a specific 
respirator to reduce a concentration of a contaminant below the PEL. 
* * * [W]ith the cartridge change requirements in 1910.134 there is 
no need to limit the use of organic vapor cartridges or canisters to 
specific levels of BD. The employer is required to determine a 
useful service life. If that service life is very short, the 
employer will need to determine if the replacement schedule is 
realistic. (Ex. 18-7.)

    However, two other commenters made important observations. First, 
the American Chemistry Council representative noted that "[E]xclusion 
of [the BD] standard is reasonable since this standard has a more 
comprehensive respirator section that includes end of service life 
specifications' (Ex. 10-25). Second, ORC Worldwide stated, "Excluding
[BD] is warranted. Additional verbiage relative to service lives developed 
under a negotiated rulemaking process should not be changed" (Ex. 10-
27).
    Commenters who recommended adopting the change-out schedule 
provisions of 29 CFR 1910.134 provided no compelling rationale for 
disturbing the extensive change-out schedules developed for the BD 
Standard on the recommendation of industry and labor representatives . 
Substituting the performance-based provisions that regulate change 
schedules under 29 CFR 1910.134 for the existing BD Standard's change 
schedule provisions for the sake of convenience is insufficient 
justification for revisiting these relatively recently promulgated 
provisions. In this regard, the latter two commenters clearly 
recognized the importance of the process that resulted in the existing 
change schedule requirements.
    In the preamble to the final BD Standard, the Agency reviewed test 
data that demonstrated short breakthrough times for BD concentrations 
above 50 ppm. Accordingly, these short breakthrough times justified 
setting at 50 ppm the upper limit at which employees can use air-
purifying respirators for protection against BD exposures. The Agency 
used these data to develop change schedules for cartridges and 
canisters that are unique for BD exposures (see Table 1 of the BD 
Standard). OSHA reviewed the test data when it published the final 
standard in 1996 and found that these conclusions remain valid. The 
Agency believes that it would impose an unnecessary burden on employers 
who are subject to the BD Standard to require them to repeat the review 
already conducted by OSHA on BD breakthrough times, and then develop 
their own change-out schedules under 29 CFR 1910.134. Moreover, 
employee protection from exposure to BD is unlikely to be increased.
    The Agency acknowledged in the preamble to the final BD Standard 
that it took a conservative approach to employee protection. In this 
regard, OSHA noted that its "decision to rely on the more protective 
NIOSH APFs is based on evidence showing that organic vapor cartridges 
and canisters have limited capacity for adsorbing BD and may have too 
short a service life when used in environments containing greater than 
50 ppm BD." (See 61 FR 56816.) With regard to the change-out 
schedules, the Agency concluded:

    Allowing for a reasonable margin of protection, and given that 
test data were available only for a few makes of cartridges and 
canisters, OSHA believes that air-purifying devices should not be 
used for protection against BD present in concentrations greater 
than 50 ppm, or 50 times the 1 ppm PEL. Thus, OSHA finds that the 
ANSI APFs of 100 for full facepiece, air-purifying respirators and 
1,000 for PAPRs equipped with tight-fitting facepieces are 
inappropriate for selecting respirators for BD.

    Accordingly, OSHA is retaining the respirator selection provisions 
of the BD Standard to avoid imposing on employers the new burden of 
developing their own change-out schedules, and to ensure maximum 
protection for employees exposed to BD.
3. Comments Regarding the Respirator Selection Provisions of Other 
Substance-Specific Standards
    The Agency proposed to retain a number of special respirator 
selection provisions in the existing substance-specific standards. In 
this regard, OSHA noted that the respirator selection requirements 
proposed for retention were developed in rulemakings to provide 
protection against a hazardous characteristic or condition that is 
unique to the regulated substance. Additionally, the Agency stated that 
retaining these requirements would not increase the existing employer 
burden because they already must comply with these requirements. 
Consequently, retaining these provisions would maintain the level of 
respiratory protection currently afforded to employees. These 
provisions were in the substance-specific standards regulating employee 
exposure to vinyl chloride, inorganic arsenic, asbestos, benzene, coke 
oven emissions, cotton dust, ethylene oxide, and formaldehyde.
    Under issue 13 in the proposal, OSHA requested comments on the need 
to standardize the respirator selection provisions being proposed for 
retention. The Agency received numerous comments and hearing testimony 
on this issue. Most of these comments and testimony encouraged OSHA not 
to retain these provisions in their existing form, but instead to 
subsume these provisions under the Respiratory Protection Standard at 
29 CFR 1910.134. An example of such a recommendation was provided by 
the 3M Company (3M) when it stated, in its hearing testimony, "It is 
neither necessary nor justified to retain any of the specific 
requirements in the substance-specific standards. * * * They do not 
reflect the changes in science and technology, respirator design, 
respirator certification, or respirator regulation under 29 CFR 
1910.134" (Tr. at 393). In subsequent testimony, a representative from 
3M stated, "We contend that requiring separate respirator APFs and 
selection requirements in the substance-specific standards as proposed 
would only add confusion to the respirator selection process, and is 
not justified by any scientific or practical evidence" (Tr. at 394). 
Thomas Nelson of NIHS, Inc., provided similar rationale in support of 
standardizing these provisions, stating:

    The proposal would retain information [on] cartridge change 
schedules, filter selection and some specific respirator selection 
requirements in the substance specific standards. None of these 
requirements are necessary in the substance specific standard[s]. 
The current 1910.134 with the addition of an assigned protection 
factor table contains requirements that are protective. (Ex. 18-9.)

    Many of these comments addressed issues involving single substance-
specific standards, including their cartridge, canister, and filter 
requirements. The following paragraphs provide a summary of the 
comments that pertain to individual substance-specific standards, as 
well as OSHA's response to these comments.
     Inorganic Arsenic (29 CFR 1910.1018). A commenter wanted 
OSHA to "[c]larify if filtering facepieces will be acceptable [under 
this standard]," and asserted that requiring "gas masks or SARs for 
exposures above the PEL is unnecessary (Ex. 9-5). Two commenters, the 
Mine Safety Appliances Co., and the 3M Company, questioned the need to 
require a HEPA filter when using a cartridge or canister for exposures 
above a specified limit (Exs. 9-37, 18-7), while one of these 
commenters claimed that any filter approved by NIOSH under 42 CFR part 
84 would provide the required level of filter efficiency (Ex. 18-7).
    The Agency did not address, as part of this rulemaking, the use of 
filtering facepieces during inorganic arsenic exposures. This question 
deals with compliance. The other two commenters provided no basis for 
questioning the requirement for HEPA filters, while the issue of 
filters approved under 42 CFR part 84 is addressed below (see section 
entitled "Substituting N95 Filters for HEPA Filters").
     Asbestos (29 CFR 1910.1001 and 29 CFR 1926.1101). The 3M 
Company (3M) objected to the provision in this standard that prohibits 
the use of disposable half masks, but permits the use of elastomeric 
respirators, at asbestos concentrations that are 10 times the PEL (Ex. 
18-7). In these comments 3M stated that this disparity "is counter to 
OSHA's analysis of WPF data that does not show a difference
between filtering facepieces and elastomeric facepieces." The 3M 
Company continued by noting that NIOSH stated that the aerosol size 
used in its respirator certification test ensures that filter 
performance will be at least as efficient "for essentially all other 
aerosol sizes" (see 60 FR 30344). While this comment implies that 
NIOSH would accept filtering facepieces for protection against 
asbestos, another commenter observed that the 1997 NIOSH Pocket Guide 
to Chemical Hazards expressly prohibits such use (Ex. 18-5).
    The rebuttal made by the last commenter indicates that 3M's 
concerns regarding the use of disposable respirators are controversial. 
Consequently, revision would require a new rulemaking.
     Coke Oven Emissions (29 CFR 1910.1029). A 3M 
representative asserted that OSHA made an error when it proposed to 
revise the term "single-use respirator" to "filtering facepiece 
respirators" in item (b)(1) of Table 1 in paragraph (g)(3) of this 
standard (Ex. 18-7). This commenter supported this assertion by noting 
that "[t]he `single use type' respirator was a term that NIOSH started 
after promulgation of the coke oven emission standard," and that 
"[d]isposable dust/mist respirators are not prohibited from use under 
the * * * standard." In conclusion, this commenter remarked that, by 
revising the term "single-use respirator" to "filtering facepiece 
respirators," the Agency is "prohibiting disposable particulate 
respirators from being used, which was not the intent of the original 
standard." However, another commenter took exception to removing the 
proposed prohibition against all filtering facepiece respirators (Ex. 
18-5), claiming that the particle size of coke oven emissions is 
unknown, and that coke oven fumes may degrade the electrostatic filters 
used in filtering facepieces. This commenter asserted that employers 
should use only HEPA filter cartridges, or P100 filtering facepieces 
that respirator manufacturers demonstrate will not degrade when exposed 
to coke oven fumes.
    The Agency agrees with the first commenter that the term "single-
use respirator" is outdated. It believes that the regulated community 
now designates these respirators as filtering facepiece respirators. 
Accordingly, the definition of filtering facepiece respirators in 
paragraph (b) of 29 CFR 1910.134 consists of three key 
characteristics--they function under negative pressure, are used 
against particulates and vapors, and consist of a filtering medium that 
is an integral part of the facepiece or that constitutes the entire 
facepiece. These characteristics also describe single-use respirators. 
This definition does not specify the functional characteristics of 
filtering facepieces, only their structural features. In this regard, 
both filtering facepiece and single-use respirators generally are 
considered disposable, with the period of effectiveness determined by 
the functional characteristics of either respirator. Therefore, because 
single-use and filtering facepiece respirators are identical with 
regard to their structural characteristics, OSHA is retaining the 
proposed terminology in the final APF standard. However, while 
paragraph (b)(1) of the Table I in the Coke Oven Emissions Standard 
prohibits using a single-use, filtering facepiece respirator, paragraph 
(b)(2) of this table permits its use when it functions as a 
"particulate filter respirator." Accordingly, employers may select 
filtering facepiece respirators when employees are exposed to coke oven 
emissions and those emissions (1) consist solely of particulates, and 
(2) the exposure conditions are no more than 10 times the PEL for coke 
oven emissions. Finally, OSHA simply cannot adopt the recommendation of 
the second commenter to use only P100 filtering facepieces under these 
conditions as this issue was not part of this rulemaking.
     Cotton Dust (29 CFR 1910.1043). The comments concerning 
this standard addressed whether filtering facepieces used to protect 
employees against cotton dust exposure should retain the current APF of 
5 or be upgraded to an APF of 10. In this regard, one commenter 
believed that revising this standard to upgrade the APF of filtering 
facepieces to 10 would be consistent with the results of OSHA's 
statistical analysis of WPF studies for filtering facepiece respirators 
(Ex. 18-7). This commenter stated, "[F]iltering facepieces should have 
the same APF of 10 for cotton dust as they would for all other dusts. 
Filtering facepieces do not show selective performance to cotton dust 
versus other aerosols." Three additional commenters echoed a similar 
concern with regard to filtering facepieces used against cotton dust. 
Two of these commenters noted that no technical reason exists "to 
reduce the APF to 5 for filtering facepieces" (Exs. 9-22 and 9-37), 
while the third commenter stated that "[n]ot allowing filtering 
facepieces for greater than 5 times the PEL is inconsistent with an APF 
of 10 indicated in [proposed] Table 1" (Ex. 9-42).
    Several commenters responded negatively to the recommendations to 
raise the APF from 5 to 10 for filtering facepieces used for protection 
against cotton dust (Exs. 12-7-1 and 18-5; Tr. at 41-43). However, 
these commenters provided no technical or safety-and-health rationale 
for their position. Typical of these comments was the following 
statement made at the rulemaking hearing by one of the participants: 
"If OSHA goes ahead and assigns a 10 * * * for [filtering facepieces] 
for the cotton dust standard * * *, you're going against what was 
established way back when and settled by the court [at] an APF of 5." 
(Tr. at 43.)
    The first set of commenters recommended revising this standard to 
raise the APF for filtering facepieces from 5 to 10, consistent with 
the APF for filtering facepieces proposed for 29 CFR 1910.134. However, 
the Agency did not propose to raise the APF for filtering facepieces 
used against cotton dust, and the record is inadequate to make that 
decision at this time. The second set of comments noted that revising 
the APF from 5 to 10 for filtering facepieces used during exposures to 
cotton dust would be foreclosed by the court's decision in Minnesota 
Mining and Manufacturing Co. v. OSHA, 825 F.2d 482 (D.C. Cir. 1987); 
this decision upheld the Cotton Dust Standard's assignment of an APF of 
5 for disposable respirators. While OSHA is not revising the APF for 
filtering facepieces used against cotton dust at this time, the Agency 
notes that the court's decision in this case does not preclude it from 
revising the Cotton Dust Standard in the future based on an appropriate 
rulemaking record.
4. Change-Out Schedules for Vinyl Chloride (29 CFR 1910.1017), Benzene 
(29 CFR 1910.1028), Formaldehyde (29 CFR 1910.1048), and Ethylene Oxide 
(29 CFR 1910.1047)
    The International Safety Equipment Association (ISEA), the Mine 
Safety Appliances Co., and the 3M Company (3M) requested OSHA to remove 
the existing cartridge change-out schedules under the Vinyl Chloride 
Standard and replace them with the change-out schedule provisions of 29 
CFR 1910.134 (Exs. 9-22, 9-37, and 18-7). In its comments on this 
issue, 3M stated that "the nature of toxicity of any analyte does not 
affect the service life of a chemical cartridge" (Ex. 18-7). ISEA and 
3M submitted similar comments regarding the existing cartridge change-
out schedules in the Benzene Standard (Exs. 9-22 and 18-7). 
Accordingly, 3M noted that the Agency should not limit cartridge 
selection to only organic vapor
cartridges specified for benzene absorption, but should expand the 
permitted cartridges to organic vapor cartridges for acid gas or 
formaldehyde absorption, as well as multi-gas cartridges (Ex. 18-7). 
The three commenters also recommended that OSHA remove the requirements 
for cartridges, filters, and the cartridge change-out schedules in the 
Ethylene Oxide Standard, as well as the specifications for cartridges/
canisters and change-out schedules in the Formaldehyde Standard, 
asserting that employers could refer to 29 CFR 1910.134 to obtain the 
necessary information (Exs. 9-22, 9-37, and 18-7).
    In response to these commenters, the Agency notes that it believes 
that the minimum change-out schedules specified by these standards 
ensure that employers use the designated respirators at appropriate 
concentration levels of the regulated substance. OSHA also recognizes 
that retaining these specifications may limit employers' flexibility in 
adopting change-out schedules. However, it considers this limitation 
justified because the specified change-out schedules provide a high 
level of protection for employees against the dangerous properties of 
these substances. In addition, adopting the change-out schedule 
provisions of 29 CFR 1910.134 for current OSHA health standards is 
beyond the scope of this APF rulemaking. The Agency cannot make 
revisions to this final rule based on these comments because the 
regulated community must have adequate notice of, and an opportunity to 
comment on, any proposed revisions.
5. Miscellaneous Comments Regarding Superseding Other Substance-
Specific Standards
    A number of comments were general, and did not address a single 
substance-specific standard. These comments centered on respirator 
selection issues that involved two or more of the substance-specific 
standards, such as HEPA filters and training. The following paragraphs 
identify the issues addressed in these comments, and provide a summary 
of the comments that address these general issues, including OSHA s 
response to them.
     Skin absorption and eye irritation. Three commenters 
argued that it was unnecessary to preclude the use of half masks 
against eye irritants in the Ethylene Oxide, Methylene Chloride, and 
Formaldehyde standards when employees wear appropriate eye protection 
with half masks (Exs. 9-22, 9-37, and 9-42). A fourth commenter made a 
similar statement regarding protection against eye irritants, but did 
not identify any specific substances (Ex. 9-59). One of these 
commenters asked, "Why make it a requirement to wear eye protection 
unless the concentrations are at irritant levels?" (See Ex. 9-42.) 
This commenter also noted that OSHA does not permit the use of half 
mask respirators during exposure to arsenic trichloride, but did not 
apply this prohibition to other chemicals that employees may absorb 
rapidly through the skin. This commenter recommended that the Agency 
"[p]rovide consistent recommendations that involve chemicals that can 
be absorbed through the skin in significant amounts (e.g., chemicals 
with PEL or TLV with `skin' notations)." Another commenter took a 
different approach to this issue, proposing that OSHA should "[r]emove 
all references to [the] use of respirators for protection from 
substances that can be absorbed through the skin or irritate the skin 
or eyes. There are other ways that the skin can be protected" (Ex. 10-
59).
    The purpose of this rulemaking was to provide the regulated 
community with notice of, and an opportunity to comment on, specific 
respirator selection provisions that the Agency proposed for revision. 
In this regard, OSHA proposed no revisions to any requirements in the 
substance-specific standards that addressed protection against eye or 
skin irritants. Accordingly, these provisions will remain intact. The 
Agency believes that the requirements of existing substance-specific 
standards that specify the use of protective clothing and the other 
personal protective equipment requirements of 29 CFR 1910 subpart D 
will prevent serious skin absorption of toxic substances. Moreover, 
provisions in the substance-specific standards that require the use of 
full facepiece respirators and other high-end respirators for eye 
protection will provide employees with an integrated protection system 
that assures maximum respiratory and eye protection.
     HEPA Filters. Several commenters took exception to 
requirements in many substance-specific standards that some respirators 
use HEPA filters. For example, one commenter stated that NIOSH's 
updated respirator testing protocol in 42 CFR 84 eliminated the need 
for HEPA filters (Ex. 9-22). Similarly, a second commenter noted that 
HEPA filters were no longer listed in the NIOSH certification 
categories, and that OSHA should update the language in the Respiratory 
Protection Standard to be consistent with these categories (Ex. 10-59). 
A third commenter recommended that the Agency remove references to HEPA 
filters from a number of its substance-specific standards because 
"[p]article properties such as size and form are no longer needed in 
filter selection" (Ex. 9-37). Another commenter stated that P100 
filters were equivalent to HEPA filters, and that OSHA should 
"[p]rovide clear generic guidance on when HEPA or P100 filters should 
be used, as opposed to another less efficient filter"(Ex. 9-42).
    In addressing other issues, one commenter stated that OSHA would be 
breaching an earlier decision if it superseded dust-mist-fume 
respirators with respirators using HEPA filters at lead levels that are 
equal to or below 0.5 mg/m3 (Ex. 10-4).\11\ Another 
commenter recommended limiting the use of all electrostatic (fiber) 
filters (Ex. 18-5). This commenter based this recommendation on 
evidence presented at the 1994 NIOSH hearing on the proposed filter 
certification requirements of 42 CFR 84. This commenter stated that the 
evidence showed, when tested with a heated DEHP aerosol challenge 
agent, the average filter efficiency for electrostatic P100 filters was 
less than the average filter efficiency for respirators that used a 
mechanical filter media. In one of these tests, the average filter 
efficiency for a P100 electrostatic filter was as low as 84.5%.
---------------------------------------------------------------------------

    \11\ OSHA published this decision at 44 FR 5446 (January 26, 
1979).
---------------------------------------------------------------------------

    While it is beyond the scope of this rulemaking to make the 
revisions recommended by these commenters, the Agency notes that the 
definition of HEPA filters in paragraph (b) of 29 CFR 1910.134 equates 
these filters with high-end filters tested under the NIOSH 
certification scheme specified by 42 CFR 84. In this regard, the 
definition notes that, under 42 CFR 84, HEPA filters are equivalent to 
the N100, R100, and P100 particulate filters certified by NIOSH. 
Therefore, the Respiratory Protection Standard already describes HEPA 
filters in language that equates them to N100, R100, and P100 filters 
certified by NIOSH (i.e., the terms are interchangeable). OSHA 
Directive No. CPL 2-0.120 of September 25, 1998 ("Inspection 
Procedures for the Respiratory Protection Standard") also states, 
"When HEPA filters are required by an OSHA standard, N100, R100, and 
P100 filters can be used to replace them." In addition, an Agency 
letter of interpretation to Neoterik Health Technologies, Inc. dated 
March 18, 1996 concludes that, "when any OSHA standard requires the 
use of HEPA filters[,] then the employer may satisfy
the requirement by choosing to use a P100, N100, or R100 filter 
certified under 42 CFR 84, since such filters would exhibit minimum 
leakage." Therefore, for over eight years, OSHA has consistently 
equated HEPA filters to the high-end filters certified by NIOSH under 
42 CFR 84.
    OSHA believes that this definition is sufficient to meet the 
recommendations of these commenters regarding the need to update the 
description of HEPA filters consistent with the NIOSH certification 
program, including the need to provide the "clear generic guidance" 
requested by one of the commenters (Ex. 9-42). As noted by another 
commenter (Ex. 9-37), the definition of HEPA filters contained in the 
Respiratory Protection Standard also specifies the filtering criterion 
that these filters must meet in terms of particulate size. The 
definition recognizes that the N100, R100, and P100 filters meet this 
criterion, thereby updating the HEPA definition as recommended by this 
commenter.
    Contrary to the assertions made by one of the commenters (Ex. 10-
4), the Agency is not breaching its earlier decision to permit the use 
of dust-mist-fume respirators (instead of respirators configured with 
HEPA filters) when employees are exposed to lead levels that are equal 
to or below 0.5 mg/m3. Although this commenter mentioned 
that the decision covered N95 respirators as well, N95 respirators were 
not even available in 1979 when the Agency published the decision and, 
therefore, were never part of the decision. The remarks of the last 
commenter (Ex. 18-5) described special testing conditions (using a 
heated DEHP aerosol challenge agent) that appeared to degrade specific 
types of filters. While this information may be of interest to NIOSH in 
determining the efficacy of its filter certification program, it is 
unclear how useful this information would be in selecting respirators 
for use in workplaces that vary substantially from these specialized 
testing conditions.
     Substituting N95 Filters for HEPA Filters. A 
representative for the 3M Company (3M) argued strongly that OSHA should 
require only N95 particulate filters for respirators, noting that OSHA 
based the existing requirement to use HEPA filters under some exposure 
conditions on NIOSH's outdated filter certification process specified 
in 30 CFR 11 (Tr. at 396). The 3M Company then described a WPF study 
conducted by Jensen et al. in a steel foundry on employees who 
performed a grinding operation involving a heavy work load (i.e., as 
shown by high airflow rates through the filters) and exposure to an 
iron aerosol. The 3M Company claimed that under these conditions, no 
significant difference existed between P95 and P100 particulate filters 
used by these employees with regard to the percentage of workplace iron 
penetration inside the filter. In addition, they asserted that neither 
type of filter permitted any detectable oil mist penetration (Ex. 18-7; 
Tr. at 397).
    Later in the hearing, when asked about the test conditions under 
which NIOSH certifies filter efficiency, the 3M representative stated:

    NIOSH's testimony yesterday, which I agree with, is that they've 
got a worst case, or close to worst case, testing, and, as they've 
stated, * * * they expect performance in the workplace to be better 
than that rating. * * * So I believe that in the N95 filter[s], 
while you see a difference in their performance in the laboratory, 
when they're used against workplace aerosols, there is no 
difference. (Tr. at 429.)

    In his testimony the previous day, the NIOSH representative made 
the following statement:

    Well, NIOSH does not accept the premise that efficiency levels 
for filters that we test should be considered at higher efficiency 
levels. The approval program designates an efficiency level for the 
filters, which is well known to be tested with a near-worst case 
aerosol. However, this is done so that every workplace does not have 
to conduct sizing tests before they selected proper filters in the 
workplace. We think that this is a proper way to go, and we also do 
not think that assuming particle sizes and greater efficiencies on 
the filters is a very wise approach for protecting workers. (Tr. at 
121.)

    The 3M Company also mentioned that another justification for 
substituting N95 filters for N100 filters is that "increased breathing 
resistance caused by use of a 100 filter may decrease overall 
respirator effectiveness by reducing user comfort and thereby reducing 
the time the respirator is worn" (Ex. 18-7).
    In its post-hearing comments, NIOSH acknowledged, "It is possible 
that a specific NIOSH certified 95-level filter may have filter 
penetration less than 5% in a specific workplace. However, this type of 
workplace-specific result may not be generalized to all 95-level 
filters in all workplace settings"' (Ex. 17-7-1). Later in these 
comments it stated, "NIOSH has included rigorous certification tests 
to help assure that filter performance in the workplace will be 
maintained at least at the certification level even under severe 
conditions," and "the NIOSH certification criteria are designed to 
assure that filters meet minimum performance requirements. NIOSH does 
not certify that they will perform any better than these criteria."
    Revising the existing respirator selection requirements for HEPA 
filters, or for filters certified by NIOSH as N100, R100, and P100 
under 42 CFR part 84, is beyond the scope of the present rulemaking. 
Additionally, the commenters did not provide any evidence demonstrating 
that 95-level filters would protect employees when used under the 
worst-case conditions simulated during the NIOSH certification tests. 
However, from the evidence presented here, OSHA believes that NIOSH's 
filter certification program provides a substantial margin of 
protection to employees who use respirators. In addition, it is unclear 
from the study discussed by these commenters whether the results are 
applicable to the extreme range of exposure conditions used by NIOSH in 
its filter certification testing. Consequently, the Agency believes 
that adopting the recommendations made by these commenters may enable 
employers to purchase respirators that do not perform at the designated 
level of efficiency under extreme workplace exposure conditions, 
thereby jeopardizing seriously the health of their employees. Absent 
data demonstrating that 95-level filters perform effectively under near 
worst-case experienced conditions, OSHA is retaining its existing HEPA 
filter requirements.
     Mixed-Versus Single-Substance Contaminants. Several 
commenters recommended superseding the individualized canister/
cartridge change-out schedules in the substance-specific standards with 
the performance-based provisions for developing change-out schedules 
described in OSHA's Respiratory Protection Standard. Their rationale 
for this recommendation is that schedules developed using the 
Respiratory Protection Standard provisions are capable of accommodating 
employee exposure to multiple contaminants, while the schedules 
provided in the substance-specific standards are limited to a single 
atmospheric contaminant. For example, 3M noted that:

    [T]he benzene standard requires the cartridges be changed before 
the beginning of the next shift. In a refinery, workers may be 
exposed to benzene along with [toluene] and [x]ylene. The change 
schedule should be based on the exposure to the mixture as required 
by 29 CFR 1910.134, not just the benzene, because the mixture may 
result in requiring the cartridge to be changed sooner than eight 
hours. By following the requirements of 134, a change schedule would 
be established resulting in changing the cartridge before loss of service 
life, thereby, increasing worker protection. (Tr. at 396.)

    The International Safety Equipment Association and Thomas Nelson of 
NIHS, Inc., made similar statements (Tr. at 518 and Ex. 18-9). In 
further justification, 3M remarked that "[r]espirator program 
administrators may not be aware that the cartridge change schedules 
contained in the substance specific [standards] may not be protective 
if multiple contaminants are present" (Ex. 18-7).
    These comments are a variation of the comments cited earlier in 
this section that recommended removing the change-out schedules 
specified for substance-specific standards and replacing them with the 
provisions of 29 CFR 1910.134 governing change-out schedules. This 
recommendation involves a major revision to these standards, and, 
therefore, is beyond the scope of this rulemaking. However, such a 
revision likely is unnecessary because change-out schedules involving 
multiple-contaminant exposures would not be covered under the 
substance-specific standards. Instead, employers must develop these 
change-out schedules for air-purifying respirators not equipped with an 
end-of-service-life indicator according to the requirements of the 
Respiratory Protection Standard, notably paragraph (d)(3)(iii)(B)(2).
     Retaining APF Tables for Lead and Asbestos. Several unions 
requested that OSHA retain the revised APF tables in the construction 
standards for lead and asbestos. During the hearing, a representative 
from the Building Construction Trades Department of the AFL-CIO (BCTD) 
stated that union-management training centers "conduct a great deal of 
worker training on lead and asbestos," and that "these tables * * * 
greatly facilitate the understanding of appropriate respirator 
selection" (Tr. at 615). This representative stated further:

    It is much more usable for these parties to go directly to the 
substance-specific standard with the air-monitoring results and 
choose the appropriate type of respirator. If employers had to do 
calculations to determine the appropriate type of respirator to 
select, that is simply an added barrier to compliance. Additionally, 
the tables are of great help when communicating the need for 
respirators to employers who may not normally be engaged in lead and 
asbestos work. (Tr. at 615.)

    The BCTD representative later noted that "[i]t's the idea of 
jumping from [the respiratory protection] standard to [the lead/
asbestos construction] standard, that's why we don't want the table 
[removed]" (Tr. at 647). The BCTD post-hearing comments expanded on 
this testimony, stating, "Calculations to determine appropriate 
respirator add [a] barrier to compliance * * *" (Ex. 9-29).
    A representative of the Insulators and Asbestos Workers 
International ("IAWI") found the tables to be invaluable as a 
teaching aid, and added that:

    I am asked by all types of people, regulators, legislators, 
facility engineers, owners of companies, [and] consultants where to 
find the information [about APFs]. I just tell them [to] look in the 
tables. * * * The common worker knows where to find this. It is 
where it should be. There are no OSHA libraries on the job sites. * 
* * I am asked by a lot of people in charge of sites where these 
[APFs] are in writing. If it is taken out of the rules, if it is not 
written, it will not be adhered to. (Tr. at 623.)

    However, this representative later admitted that "[e]very one of 
our supervisors gets a copy of an updated [construction] standard," 
and "[h]e gets the 1910.134 [i.e., the Respiratory Protection 
Standard]" (Tr. at 645.) Similarly, another commenter remarked that 
"[e]mployers covered by [substance-]specific standards are already 
required to refer to 29 CFR 1910.134 for most respirator program 
elements including fit testing, inspection and cleaning, and program 
evaluation," and that "[i]f some employers would not bother to 
consult 29 CFR 1910.134 for APFs, these same employers are most likely 
not complying with other necessary program elements"(Ex. 18-7).
    The Agency believes that employers know they are required to use 
the Respiratory Protection Standard. Retaining the APF tables in the 
construction standards for lead and asbestos is unlikely to result in 
any savings or convenience to employers or other parties because these 
tables cannot be used safely and effectively without consulting the 
requirements of 29 CFR 1910.134. Even one of the union representatives 
recognized this necessity when stating that supervisors must have 
access to both the construction standards and the Respiratory 
Protection Standard at the job site (Tr. at 646). In addition, OSHA 
believes that any respirator selection requirements that are unique to 
a substance-specific standard (i.e., not subsumed by this rulemaking 
under the Respirator Protection Standard) will remain available for 
easy access under the particular standard. In this regard, the Agency 
concludes that it is unnecessary to retain the APF tables for the lead 
and asbestos standards in the construction standards because the 
required APF tables can be assembled readily for training purposes from 
the available information in the revised substance-specific standards 
and the Respiratory Protection Standard.
     Upgrading Respirator Type at Employee Request. At the 
hearing, the BCTD representative mentioned that several of the 
substance-specific standards required employers to upgrade respirators 
when requested to do so by employees. The representative encouraged the 
Agency to include such a requirement in current and future substance-
specific standards (Tr. at 616). The IAWI representative commented:

    [S]ome of our members, for a variety of reasons, like working in 
PAPRs. * * * Some people work in them, feel comfortable in them. 
They want them. And it makes them more at ease at doing their work. 
* * * It makes the person more productive, cools them down; there's 
a variety of reasons. (Tr. at 648.)

    When asked how often employers upgrade respirators when doing so is 
discretionary, this representative replied, "I wouldn't say it's 100 
percent. I'd say a portion of them would allow somebody that activity" 
(Tr. at 649).
    Placing a burden on employers to upgrade respirators at an 
employee's request is beyond the scope of this rulemaking. However, the 
Agency recognizes the advantages, as well as disadvantages, to 
upgrading a respirator at an employee's request. As it stated in the 
preamble to the Respiratory Protection Standard with regard to PAPRs:

    OSHA continues to believe that under some circumstances PAPRs 
provide superior acceptability. These include situations where 
employees wear respirators for full shifts, where employees 
frequently readjust their negative pressure respirators to achieve 
what they consider a more comfortable or tighter fit, and where the 
air flow provided by a PAPR reduces the employee's psychological and 
physiological discomfort. However, where ambient temperatures are 
extremely high or low, PAPRs are often unacceptable because of the 
temperature of the airstream in the facepiece. * * * (63 FR 1201.)

    OSHA noted further, "The Agency continues to believe that it is 
good industrial hygiene practice to provide a respirator that the 
employee considers acceptable" (63 FR 1201). Therefore, employers are 
free to upgrade respirators voluntarily at an employee's request when 
the employee meets the medical qualifications for using the respirator 
and receives the necessary training.
5. Summary of Superseding Actions
    The following table summarizes final revisions to the existing 
respirator selection provisions of OSHA's substance-specific standards. 
Section VIII ("Amendments to Standards") of this rulemaking notice 
provides the full, plain-language regulatory text of these final revisions.

     Summary of Superseding Actions for Substance-Specific Standards
------------------------------------------------------------------------
        Existing provisions                      Final action
------------------------------------------------------------------------
29 CFR 1910.1001(g)(2)(ii).........  Revise.
.1001(g)(3)........................  Remove Table 1 and revise.
.1001(l)(3)(ii)....................  Redesignate Table 2 as Table 1.
.1017(g)(3)(i).....................  Remove table and revise.
.1017(g)(3)(iii)...................  Remove.
.1018 (Tables I and II)............  Remove.
.1018(h)(3)(i).....................  Revise.
.1018(h)(3)(ii)....................  Remove.
.1018(h)(3)(iii)...................  Redesignate as .1018 (h)(3)(ii).
.1025(f)(2)(ii)....................  Remove Table II.
.1025(f)(3)(i).....................  Revise.
.1027(g)(3)(i).....................  Remove Table 2 and revise.
.1028(g)(3)(ii)....................  Remove Table 1.
.1028(g)(2)(i).....................  Revise.
.1028(g)(3)(i).....................  Revise.
.1029(g)(3)........................  Remove Table I and revise.
.1043(f)(3)(i).....................  Remove Table I and revise.
.1043(f)(3)(ii)....................  Revise.
.1044(h)(3)........................  Remove Table 1 and revise.
.1045(h)(2)(i).....................  Revise.
.1045(h)(3)........................  Remove Table I and revise.
.1047(g)(3)........................  Remove Table 1 and revise.
.1048(g)(2)........................  Revise.
.1048(g)(3)........................  Remove Table 1 and revise.
.1050(h)(3)(i).....................  Remove Table 1 and revise.
.1052(g)(3)........................  Remove Table 2 and revise.
29 CFR 1915.1001(h)(2)(i) through    Remove Table 1 and revise.
 (h)(2)(v).
29 CFR 1926.60(i)(3)(i)............  Remove Table 1 and revise.
.62 (f)(3)(i)......................  Remove Table 1 and revise.
.1101(h)(3)(i) through (h)(3)(iv)..  Remove Table 1 and revise.
.1127(g)(3)(i).....................  Remove Table 1 and revise.
------------------------------------------------------------------------

6. Use of Plain Language
    In the proposal, OSHA rewrote into plain language the respirator-
selection provisions of the substance-specific standards retained in 
this final rule. The Agency received no comments on these proposed 
revisions. OSHA believes that using plain language will improve the 
uniformity and comprehensibility of these provisions. These 
improvements will, in turn, enhance employer compliance with the 
provisions and, concomitantly, increase the protection afforded to 
employees. The Agency also found that rewriting the respirator-
selection provisions of the existing substance-specific standards into 
plain-language provisions did not alter the substantive requirements of 
the existing provisions. (The following table lists the plain-language 
provisions in the final rule and the corresponding provisions in the 
existing standards.) Therefore, OSHA is retaining these plain-language 
revisions in the final rule.

Plain-Language Provisions in the Final Rule and Corresponding Provisions
                        in the Existing Standards
------------------------------------------------------------------------
     Plain-language provisions               Existing provisions
------------------------------------------------------------------------
Sec.   1910.1001(g)(2)(ii).........  Sec.   1910.1001(g)(2)(ii).
Sec.   1910.1001(g)(3)(i)..........  Sec.   1910.1001(g)(3); Table 1.
Sec.   1910.1001(g)(3)(ii).........  Sec.   1910.1001(g)(3); Table 1.
Sec.   1910.1017(g)(3)(i)(B).......  Sec.   1910.1017(g)(3)(i);
                                      undesignated table.
Sec.   1910.1017(g)(3)(i)(C).......  Sec.   1910.1017(g)(3)(i);
                                      undesignated table.
Sec.   1910.1018(h)(3)(i)(B).......  Sec.   1910.1018(h)(3)(i); Table II
                                      (footnote 2).
Sec.   1910.1018(h)(3)(i)(C).......  Sec.   1910.1018(h)(3)(i); Table I
                                      and Table II.
Sec.   1910.1018(h)(3)(i)(D)(1)....  Sec.   1910.1018(h)(3)(ii).
Sec.   1910.1018(h)(3)(i)(D)(2)....  Sec.   1910.1018(h)(3)(i); Table
                                      II.
Sec.   1910.1025(f)(3)(i)(B).......  Sec.   1910.1025(f)(3)(i); Table II
                                      (footnote 2).
Sec.   1910.1025(f)(3)(i)(C).......  Sec.   1910.1025(f)(3)(i); Table
                                      II.
Sec.   1910.1025(f)(3)(ii).........  Sec.   1910.1025(f)(3)(ii).
Sec.   1910.1027(g)(3)(i)(B).......  Sec.   1910.1027(g)(3)(i)(B); Table
                                      2 (footnote b).
Sec.   1910.1027(g)(3)(i)(C).......  Sec.   1910.1027(g)(3)(i)(B); Table
                                      2.
Sec.   1910.1028(g)(3)(i)(B).......  Sec.   1910.1028(g)(3)(i); Table 1.
Sec.   1910.1028(g)(3)(i)(C).......  Sec.   1910.1028(g)(3)(i); Table 1.
Sec.   1910.1028(g)(3)(i)(D).......  Sec.   1910.1028(g)(3)(i); Table 1
                                      (footnote 1).
Sec.   1910.1029(g)(3).............  Sec.   1910.1029(g)(3); Table I.
Sec.   1910.1043(f)(3)(i)(A).......  Sec.   1910.1043(f)(3)(i); Table I.

[[Page 50184]]


Sec.   1910.1043(f)(3)(i)(B).......  Sec.   1910.1043(f)(3)(i); Table I.
Sec.   1910.1043(f)(3)(ii).........  Sec.   1910.1043(f)(3)(ii).
Sec.   1910.1044(h)(3)(ii).........  Sec.   1910.1044(h)(3); Table 1.
Sec.   1910.1045(h)(3)(ii).........  Sec.   1910.1045(h)(3); Table I.
Sec.   1910.1047(g)(3)(i)..........  No provision of the original
                                      ethylene oxide standard contains
                                      this text. However, the only
                                      respirators designated for
                                      selection are either full
                                      facepiece respirators or
                                      respirators with hoods and
                                      helmets. Also, Sec.
                                      1910.1047(g)(4) ("Protective
                                      clothing and equipment") states,
                                      "When employees could have eye or
                                      skin contact with EtO or EtO
                                      solutions, the employer must
                                      select and provide * * *
                                      appropriate protective clothing or
                                      other equipment * * * to protect
                                      any area of the employee's body
                                      that may come in contact with the
                                      EtO or EtO solution * * *."
Sec.   1910.1047(g)(3)(ii).........  Sec.   1910.1047(g)(3); Table 1.
Sec.   1910.1047(g)(3)(iii)........  Sec.   1910.1047(g)(3); Table 1.
Sec.   1910.1048(g)(2)(ii).........  Sec.   1910.1048(g)(2)(ii).
Sec.   1910.1048(g)(3)(i)(B).......  Sec.   1910.1048(g)(3)(i); Table 1.
Sec.   1910.1048(g)(3)(i)(C).......  Sec.   1910.1048(g)(3)(i); Table 1.
Sec.   1910.1048(g)(3)(ii).........  Sec.   1910.1048(g)(3)(i); Table 1
                                      (footnote 2).
Sec.   1910.1048(g)(3)(iii)........  Sec.   1910.1048(g)(3)(ii).
Sec.   1910.1050(h)(3)(i)(B).......  Sec.   1910.1050(h)(3)(i); Table 1.
Sec.   1910.1050(h)(3)(i)(C).......  Sec.   1910.1050(h)(3)(i); Table 1.
Sec.   1910.1050(h)(3)(i)(D).......  Sec.   1910.1050(h)(3)(i); Table 1
                                      (footnote 2).
Sec.   1910.1052(g)(3)(i)..........  No provision of the original
                                      methylene chloride standard
                                      contains this text. However, the
                                      only respirators designated for
                                      selection are either full
                                      facepiece respirators or
                                      respirators with hoods and
                                      helmets. Also, Sec.
                                      1910.1052(h)(1) ("Protective work
                                      clothing and equipment") states,
                                      "Where needed to prevent MC-
                                      induced skin and eye irritation,
                                      the employer shall provide clean
                                      protective clothing and equipment
                                      which is resistant to MC * * *."
Sec.   1910.1052(g)(3)(ii).........  Sec.   1910.1052(g)(3); Table 2.
Sec.   1915.1001(h)(2)(i)..........  Sec.   1915.1001(h)(2)(i); Table 1.
Sec.   1915.1001(h)(2)(ii).........  Sec.   1915.1001(h)(2)(i); Table 1.
Sec.   1915.1001(h)(2)(iii)........  Sec.   1915.1001(h)(2)(iii)(A).
Sec.   1915.1001(h)(2)(iv).........  Sec.   1915.1001(h)(2)(iv).
Sec.   1915.1001(h)(2)(v)..........  Sec.   1915.1001(h)(2)(v).
Sec.   1926.60(i)(3)(i)(B).........  Sec.   1926.60(i)(3)(i); Table 1.
Sec.   1926.60(i)(3)(i)(C).........  Sec.   1926.60(i)(3)(i); Table 1.
Sec.   1926.60(i)(3)(i)(D).........  Sec.   1926.60(i)(3)(i); Table 1
                                      (footnote 2).
Sec.   1926.62(f)(3)(i)(B).........  Sec.   1926.62(f)(3)(i); Table 1
                                      (footnote 2).
Sec.   1926.62(f)(3)(i)(C).........  Sec.   1926.62(f)(3)(i); Table 1.
Sec.   1926.1101(h)(3)(i)(A).......  Sec.   1926.1101(h)(3)(i); Table 1.
Sec.   1926.1101(h)(3)(i)(B).......  Sec.   1926.1101(h)(3)(i); Table 1.
Sec.   1926.1101(h)(3)(ii).........  Sec.   1926.1101(h)(3)(ii).
Sec.   1926.1101(h)(3)(iii)........  Sec.   1926.1101(h)(3)(iii).
Sec.   1926.1101(h)(3)(iv).........  Sec.   1926.1101(h)(3)(iv).
Sec.   1926.1127(g)(3)(i)(B).......  Sec.   1926.1127(g)(3)(i); Table 1
                                      (footnote b).
Sec.   1926.1127(g)(3)(i)(C).......  Sec.   1926.1127(g)(3)(i); Table 1.
------------------------------------------------------------------------

VII. Procedural Determinations

A. Legal Considerations

    The purpose of the Occupational Safety and Health Act, 29 U.S.C. 
651 et seq. ("the Act") is to "assure so far as possible every 
working man and woman in the Nation safe and healthful working 
conditions and to preserve our human resources" (29 U.S.C. 651(b)). To 
achieve this goal, Congress authorized the Secretary of Labor to 
promulgate and enforce occupational safety and health standards (see 29 
U.S.C. 654(b) (requiring employers to comply with OSHA standards) and 
29 U.S.C. 655(b) (authorizing promulgation of standards pursuant to 
notice and comment)).
    A safety or health standard is a standard "which requires 
conditions, or the adoption or use of one or more practices, means, 
methods, operations, or processes, reasonably necessary or appropriate 
to provide safe or healthful employment or places of employment." (29 
U.S.C. 652(8)). A standard is reasonably necessary or appropriate 
within the meaning of Section 652(8) of the Act when it substantially 
reduces or eliminates significant risk, and is technologically and 
economically feasible, cost effective, consistent with prior Agency 
action or supported by a reasoned justification for departing from 
prior Agency action, and supported by substantial evidence; it also 
must effectuate the Act's purposes better than any national consensus 
standard it supersedes (see International Union, UAW v. OSHA (LOTO II), 
37 F.3d 665 (DC Cir. 1994; and 58 FR 16612-16616 (March 30, 1993)).
    The APFs specified by this final rule are an integral part of 
OSHA's Respiratory Protection Standard. This standard ensures that 
respirators reduce or eliminate the significant risk to employee health 
resulting from exposure to hazardous airborne substances. Accordingly, 
employers need the APFs provided in this final rule to select 
appropriate respirators for employees use when the employers
must rely on respirators to maintain hazardous substances at safe 
levels in the workplace. The APFs in this final rule will help ensure 
that the Respiratory Protection Standard achieves the annual health 
benefits estimated for that standard (i.e., 932 averted work-related 
deaths (best estimate) and 4,046 work-related illnesses (best 
estimate)) (see 63 FR 1173).
    In this rulemaking, OSHA also is superseding the existing APF 
requirements in its substance-specific standards. As noted in section V 
of this preamble ("Summary of the Final Economic Analysis and 
Regulatory Flexibility Analysis"), the Agency estimates that the final 
APFs will reduce significantly employee exposures to the hazardous 
airborne substances regulated by these substance-specific standards, 
especially asbestos, lead, cotton dust, and arsenic. Consequently, 
employees will receive additional protection against the chronic 
illnesses resulting from exposure to these hazardous substances, 
notably a variety of cancers and cardiovascular diseases.
    The Agency believes that a standard is technologically feasible 
when the protective measures it requires already exist, can be brought 
into existence with available technology, or can be developed using 
technology that can reasonably be expected to be available (see 
American Textile Mfrs. Institute v. OSHA (Cotton Dust), 452 U.S. 490, 
513 (1981); American Iron and Steel Institute v. OSHA (Lead II), 939 
F.2d 975, 980 (DC Cir. 1991)). A standard is economically feasible when 
industry can absorb or pass on the costs of compliance without 
threatening the industry's long-term profitability or competitive 
structure (see Cotton Dust, 452 U.S. at 530 n. 55; Lead II, 939 F.2d at 
980), and a standard is cost effective when the protective measures it 
requires are the least costly of the available alternatives that 
achieve the same level of protection (see Cotton Dust, 452 U.S. at 514 
n. 32; International Union, UAW v. OSHA (LOTO III), 37 F.3d 665, 668 
(DC Cir. 1994)).
    All standards must be highly protective (see 58 FR 16612, 16614-15 
(March 30, 1993); LOTO III, 37 F.3d at 669). Accordingly, section 
8(g)(2) of the Act authorizes OSHA "to prescribe such rules and 
regulations as [it] may deem necessary to carry out its 
responsibilities under the Act" (see 29 U.S.C. 657(g)(2)). However, 
health standards also must meet the "feasibility mandate" of section 
6(b)(5) of the OSH Act, 29 U.S.C. 655(b)(5). Section 6(b)(5) of the Act 
requires OSHA to select "the most protective standard consistent with 
feasibility" needed to reduce significant risk when regulating health 
hazards (see Cotton Dust, 452 U.S. at 509). Section 6(b)(5) also 
directs OSHA to base health standards on "the best available 
evidence," including research, demonstrations, and experiments (see 29 
U.S.C. 655(b)(5)). In this regard, OSHA must consider "in addition to 
the attainment of the highest degree of health and safety protection * 
* * the latest scientific data * * * feasibility and experience gained 
under this and other health and safety laws" (Id.). Furthermore, 
section 6(b)(5) of the Act specifies that standards must "be expressed 
in terms of objective criteria and of the performance desired" (see 29 
U.S.C. 655(b)(7)).
    The APF and MUC provisions in this final rule are integral 
components of an effective respiratory protection program. Respiratory 
protection is a supplemental method used by employers to protect 
employees against airborne contaminants in workplaces when feasible 
engineering controls and work practices are not available, have not yet 
been implemented, or are not in themselves sufficient to protect 
employee health. Employers also use respiratory protection under 
emergency conditions involving, for example, the accidental release of 
airborne contaminants. The amendments to OSHA's Respiratory Protection 
Standard, and the Agency's substance-specific standards, specified in 
this final rule will provide employers with critical information to use 
when selecting respirators for employees exposed to airborne 
contaminants found in general industry, construction, shipyard, 
longshoring, and marine terminal workplaces. Since it is generally 
recognized that different types of respiratory protective equipment 
provide different degrees of protection against hazardous exposures, 
proper respirator selection is of critical importance. Failure to 
select the proper respirator for use against exposure to hazardous 
substances may result in employees being overexposed to these 
substances, thereby resulting in an increased incidence of cancer, 
cardiovascular disease, and other illnesses. The APF and MUC provisions 
in this final rule will greatly enhance an employer's ability to select 
a respirator that will adequately protect employees.
    The Agency also developed the provisions of this final rule to be 
feasible and cost effective, and is specifying them in terms of 
objective criteria and the level of performance desired. In this 
regard, section V of this preamble ("Summary of the Final Economic 
Analysis and Regulatory Flexibility Screening Analysis") provides the 
benefits and costs of the final rule, and describes several other 
alternatives as required by section 205 of the Unfunded Mandates Reform 
Act of 1995 (2 U.S.C. 1535). Based on this information, OSHA concludes 
that the APF and MUC provisions of the final rule constitute the most 
cost-effective alternative for meeting its statutory objective of 
reducing risk of adverse health effects to the extent feasible.
    Several benefits will accrue to respirator users and their 
employers from this rulemaking. First, the standard benefits workers by 
reducing their exposures to respiratory hazards. Improved respirator 
selection augments previous improvements to the Respiratory Protection 
Standard, such as better fit-test procedures and improved training, 
contributing substantially to greater worker protection. At the time of 
the 1998 revisions to the Respiratory Protection Standard, the Agency 
estimated that the standard would avert between 843 and 9,282 work-
related injuries and illnesses annually, with a best estimate (expected 
value) of 4,046 averted illnesses and injuries annually (63 FR 1173). 
In addition, OSHA estimated that the standard would prevent between 351 
and 1,626 deaths annually from cancer and many other chronic diseases, 
including cardiovascular disease, with a best estimate (expected value) 
of 932 averted deaths from these causes. The APFs in this rulemaking 
will help ensure that these benefits are achieved, as well as provide 
an additional degree of protection. These APFs also will reduce 
employee exposures to several Sec.  6(b)(5) chemicals covered by 
standards with outdated APF criteria, thereby reducing exposures to 
chemicals such as asbestos, lead, cotton dust, and arsenic. While the 
Agency did not quantify these benefits, it estimates that 29,655 
employees would have a higher degree of respiratory protection under 
this APF standard. Of these employees, an estimated 8,384 have exposure 
to lead, 7,287 to asbestos, and 3,747 to cotton dust, all substances 
with substantial health risks.
    In addition to health benefits, OSHA believes other benefits result 
from the harmonization of APF specifications, thereby making compliance 
with the respirator rule easier for employers. Employers also benefit 
from greater administrative ease in proper respirator selection. 
Employers no longer have to consult several sources and several OSHA 
standards to determine the best choice of respirator, but can make 
their choices based on a single, easily found
standard. Some employers who now hire consultants to aid in choosing 
the proper respirator should be able to make this choice on their own 
with the aid of this rule. In addition to having only one set of 
numbers (i.e., APFs) to assist them with respirator selection for 
nearly all substances, some employers may be able to streamline their 
respirator stock by using one respirator type to meet their respirator 
needs instead of several respirator types. The increased ease of 
compliance also yields additional health benefits to employees using 
respirators.

B. Paperwork Reduction Act

    After a thorough analysis of the final provisions, OSHA believes 
that these provisions do not add to the existing collection-of-
information (i.e., paperwork) requirements regarding respirator 
selection. OSHA determined that its existing Respiratory Protection 
Standard at 29 CFR 1910.134 has two provisions that involve APFs and 
also impose paperwork requirements on employers. These provisions 
require employers to: Include respirator selection in their written 
respiratory protection program (29 CFR 1910.134(c)(1)(i)); and inform 
employees regarding proper respirator selection (29 CFR 1910.(k)(ii)). 
The information on respirator selection addressed by these two 
provisions must include a brief discussion of the purpose of APFs, and 
how to use them in selecting a respirator that affords an employee 
protection from airborne contaminants. The burden imposed by this 
requirement remains the same whether employers currently use the APFs 
published in the 1987 NIOSH RDL or the ANSI Z88.2-1992 Respiratory 
Protection Standard, or implement the final APFs in this rulemaking. 
Therefore, the use of APFs in the context of these two existing 
respirator selection provisions does not require an additional 
paperwork-burden determination because OSHA already accounted for this 
burden under its existing Respiratory Protection Standard (see 63 FR 
1152-1154; OMB Control Number 1218-0099).
    Both OSHA's existing Respiratory Protection Standard and the final 
APF provisions require employers to use APFs as part of the respirator 
selection process. This process includes obtaining information about 
workplace exposure to an airborne contaminant, identifying the exposure 
limit (e.g., permissible exposure limit) for the contaminant, using 
this information to calculate the required level of protection (i.e., 
the APF), and referring to an APF table to determine which respirator 
to select. Admittedly, this process involves the collection and use of 
information, but it does not require employers to inform others, either 
orally or in writing, about the process they use to select respirators 
for individual employees, or the outcomes of this process. By not 
requiring employers to communicate this information to others, OSHA 
removed this process from the ambit of the Paperwork Reduction Act of 
1995 (PRA-95) (44 U.S.C. 3506(c)(2)(A)). In the alternative, even if 
PRA-95 applies, the final provisions involve the same information 
collection and use requirements with regard to APFs as the existing 
standard (see paragraphs (d)(1) and (d)(3)(i) of 29 CFR 1910.134, and 
the rationale for the existing APF requirements in the preamble to the 
final Respiratory Protection Standard, 63 FR 1163 and 1203-1204). 
Accordingly, the paperwork burden imposed by the final standard would 
be equivalent to the burden already imposed under the existing 
standard.

C. Federalism

    The Agency reviewed the final APF provisions according to the most 
recent Executive Order on Federalism (Executive Order 13132, 64 FR 
43225, August 10, 1999). This Executive Order requires that federal 
agencies, to the extent possible, refrain from limiting state policy 
options, consult with states before taking actions that restrict their 
policy options, and take such actions only when clear constitutional 
authority exists and the problem is of national scope. The Executive 
Order allows federal agencies to preempt state law only with the 
expressed consent of Congress. In such cases, federal agencies must 
limit preemption of state law to the extent possible.
    Under section 18 of the Occupational Safety and Health Act ("the 
Act"), Congress expressly provides OSHA with authority to preempt 
state occupational safety and health standards to the extent that the 
Agency promulgates a federal standard under section 6 of the Act. 
Accordingly, section 18 of the Act authorizes the Agency to preempt 
state promulgation and enforcement of requirements dealing with 
occupational safety and health issues covered by OSHA standards unless 
the state has an OSHA-approved occupational safety and health plan 
(i.e., is a state-plan state) (see Gade v. National Solid Wastes 
Management Association, 112 S. Ct. 2374 (1992)). Therefore, with 
respect to states that do not have OSHA-approved plans, the Agency 
concludes that this final rule conforms to the preemption provisions of 
the Act. Additionally, section 18 of the Act prohibits states without 
approved plans from issuing citations for violations of OSHA standards; 
the Agency finds that this final rulemaking does not expand this 
limitation.
    OSHA asserts that it has authority under Executive Order 13132 to 
issue final APF requirements because the problems addressed by these 
requirements are national in scope. As noted in section V ("Summary of 
the Final Economic Analysis and Regulatory Flexibility Screening 
Analysis") of this preamble, hundreds of thousands of employers must 
select appropriate respirators for millions of employees. These 
employees are exposed to many different types and levels of airborne 
contaminants found in general industry (including healthcare), 
construction, shipyard, longshoring, and marine terminal workplaces. 
Accordingly, OSHA concludes that the requirements in this final rule 
will provide all covered employers in every state with critical 
information to use when selecting respirators to protect their 
employees from the risks of exposure to airborne contaminants. However, 
while OSHA drafted the final APF and MUC requirements to protect 
employees in every state, section 18(c)(2) of the Act permits state-
plan states to develop their own requirements to deal with any special 
workplace problems or conditions, provided these requirements are at 
least as effective as the requirements specified by this final rule.

D. State Plans

    The 26 states and territories with their own OSHA-approved 
occupational safety and health plans must adopt provisions comparable 
to the provisions in this final rule within six months after the Agency 
publishes the rule. These State-Plan states and territories are: 
Alaska, Arizona, California, Hawaii, Indiana, Iowa, Kentucky, Maryland, 
Michigan, Minnesota, Nevada, New Mexico, North Carolina, Oregon, Puerto 
Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, Washington, 
and Wyoming. Connecticut, New Jersey, New York, and the Virgin Islands 
have OSHA-approved State Plans that apply to state and local government 
employees only. Until a state-plan state promulgates its own comparable 
provisions, federal OSHA will provide the state with interim 
enforcement assistance, as appropriate.

E. Unfunded Mandates

    The Agency reviewed the final APF and MUC provisions according to 
the Unfunded Mandates Reform Act of 1995 (UMRA) (2 U.S.C. 1501 et seq.) 
and Executive Order 12875. As discussed in
section V ("Summary of the Final Economic Analysis and Regulatory 
Flexibility Screening Analysis") of this preamble, OSHA estimates that 
compliance with this final rule will require private-sector employers 
to expend about $4.6 million each year. However, while this final rule 
establishes a federal mandate in the private sector, it is not a 
significant regulatory action within the meaning of section 202 of the 
UMRA (2 U.S.C. 1532).
    OSHA standards do not apply to state and local governments, except 
in states that have voluntarily elected to adopt an OSHA-approved state 
occupational safety and health plan. Consequently, the provisions of 
this final rule do not meet the definition of a "Federal 
intergovernmental mandate"(see section 421(5) of the UMRA (2 U.S.C. 
658(5)). Therefore, based on a review of the rulemaking record, the 
Agency believes that few, if any, of the affected employers are state, 
local, and tribal governments. Therefore, the requirements of this 
final rule do not impose unfunded mandates on state, local, and tribal 
governments.

F. Applicability of Existing Consensus Standards

    Section 6(b)(8) of the Occupational Safety and Health Act (29 
U.S.C. 655(b)(8)) requires OSHA to explain "why a rule promulgated by 
the Secretary differs substantially from an existing national consensus 
standard," by publishing "a statement of the reasons why the rule as 
adopted will better effectuate the purposes of the Act than the 
national consensus standard." Regarding APFs, the American National 
Standard Institute (ANSI) issued in 1992 is the only publicly available 
consensus standard (i.e., ANSI Z88.2-1992, "Respiratory Protection") 
that provided APFs for the various respirators covered by this final 
rule (i.e., "the 1992 ANSI APFs") (Ex. 1-50). However, ANSI withdrew 
this consensus standard in 2003, and it has yet to officially adopt a 
replacement standard.
    The Agency relied heavily on the 1992 ANSI APFs in developing this 
final standard. Nevertheless, the APFs specified in this final rule 
differ in important ways from the 1992 ANSI APFs. For example, the APFs 
for full facepiece air-purifying respirators differ substantially 
between the two standards. Additionally, the APF of 1,000 for powered 
air-purifying respirators with helmets or hoods listed in Table 1 of 
this final rule is based on achieving specific test results, while the 
1992 ANSI APF for this respirator class is not contingent on any test 
results. As noted above in section VI of the preamble to this final 
rule ("Summary and Explanation of the Final Standard"), OSHA has 
determined that the differences between the APFs specified in this 
final rule and the 1992 ANSI APFs will afford employees increased 
protection when they are exposed to hazardous airborne contaminants. 
Therefore, the Agency did not adopt outright the 1992 ANSI APFs under 
this final rule.
    In addition to the differences between the APF standards described 
in the previous paragraph, use of the 1992 ANSI APFs depends on meeting 
six other respirator-selection provisions, several of which differ 
substantially from the respirator-selection provisions specified in 
OSHA's Respiratory Protection Standard. In this regard, use of the 1992 
ANSI APFs is contingent on "the nature of the hazardous operation or 
process," "the location of the hazardous area in relation to the 
nearest area having respirable air," "the activities of workers in 
hazardous areas," and "the physical characteristics and functional 
capabilities and limitations of the various types of respirators"; 
none of these conditions is specified in this manner in the Agency's 
Respiratory Protection Standard. Revising OSHA's Respiratory Protection 
Standard to accommodate the six respirator-selection provisions that 
are an integral part of the 1992 ANSI APFs is beyond the scope of this 
rulemaking, which provides additional justification for the Agency not 
adopting directly the 1992 ANSI APFs.
    Finally, the APFs adopted here represent a clear enforceable 
requirement, not merely a recommendation. When employers and employees 
can easily determine what respirator is appropriately protective, 
compliance is simplified and enhanced.

List of Subjects in 29 CFR Parts 1910, 1915, and 1926

    Assigned protection factors, Airborne contaminants, Health, 
Occupational safety and health, Respirators, Respirator selection.

Authority and Signature

    Edwin G. Foulke, Jr., Assistant Secretary of Labor for Occupational 
Safety and Health, U.S. Department of Labor, 200 Constitution Ave., 
NW., Washington, DC 20210, directed the preparation of this notice. The 
Agency issues these final sections under the following authorities: 
Sections 4, 6(b), 8(c), and 8(g) of the Occupational Safety and Health 
Act of 1970 (29 U.S.C. 653, 655, 657); Section 3704 of the Contract 
Work Hours and Safety Standards Act (the Construction Safety Act) (40 
U.S.C. 3701 et seq.); Section 41, the Longshore and Harbor Worker's 
Compensation Act (33 U.S.C. 941); Secretary of Labor's Order No. 5-2002 
(67 FR 65008); and 29 CFR part 1911.

    Signed at Washington, DC on August 9, 2006.
Edwin G. Foulke, Jr.,
Assistant Secretary of Labor.

VIII. Amendments to Standards

0
For the reasons stated in the preamble of this final rule, the Agency 
is amending 29 CFR parts 1910, 1915, and 1926 to read as follows:

PART 1910--[AMENDED]

Subpart I--[Amended]

0
1. Revise the authority citation for subpart I of part 1910 to read as 
follows:

    Authority: Sections 4, 6, and 8 of the Occupational Safety and 
Health Act of 1970 (29 U.S.C. 653, 655, and 657); and Secretary of 
Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 
FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-2000 (62 FR 
50017), or 5-2002 (67 FR 65008), as applicable.
    Sections 1910.132, 1910.134, and 1910.138 of 29 CFR also issued 
under 29 CFR part 1911.
    Sections 1910.133, 1910.135, and 1910.136 of 29 CFR also issued 
under 29 CFR part 1911 and 5 U.S.C. 553.


0
2. Amend Sec.  1910.134 as follows:
0
a. Add the text of the definitions for "Assigned protection factor 
(APF)" and "Maximum use concentration (MUC)" to paragraph (b);
0
b. Add the text of paragraphs (d)(3)(i)(A), including Table 1, and 
(d)(3)(i)(B); and
0
c. Revise paragraph (n).
    The added and revised text reads as follows:


Sec.  1910.134  Respiratory protection.

* * * * *
    (b) * * *
    Assigned protection factor (APF) means the workplace level of 
respiratory protection that a respirator or class of respirators is 
expected to provide to employees when the employer implements a 
continuing, effective respiratory protection program as specified by 
this section.
* * * * *
    Maximum use concentration (MUC) means the maximum atmospheric 
concentration of a hazardous substance from which an employee can be 
expected to be protected when wearing a respirator, and is determined 
by the assigned protection factor of the respirator or class of 
respirators and the exposure limit of the hazardous substance. The MUC 
can be determined mathematically by multiplying the assigned protection 
factor specified for a respirator by the required OSHA permissible exposure 
limit, short-term exposure limit, or ceiling limit. When no OSHA exposure 
limit is available for a hazardous substance, an employer must 
determine an MUC on the basis of relevant available information and 
informed professional judgment.
* * * * *
    (d) * * *
    (3) * * *
    (i) * * *
    (A) Assigned Protection Factors (APFs). Employers must use the 
assigned protection factors listed in Table 1 to select a respirator 
that meets or exceeds the required level of employee protection. When 
using a combination respirator (e.g., airline respirators with an air-
purifying filter), employers must ensure that the assigned protection 
factor is appropriate to the mode of operation in which the respirator 
is being used.

                                    Table 1.--Assigned Protection Factors \5\
----------------------------------------------------------------------------------------------------------------
                                                                                                        Loose-
           Type of respirator \1,\\2\              Quarter     Half mask       Full     Helmet/hood    fitting
                                                     mask                   facepiece                 facepiece
----------------------------------------------------------------------------------------------------------------
1. Air-Purifying Respirator....................            5       \3\ 10           50  ...........  ...........
2. Powered Air-Purifying Respirator (PAPR).....  ...........           50        1,000      \4\ 25/           25
                                                                                              1,000
3. Supplied-Air Respirator (SAR) or Airline
 Respirator
     Demand mode.......................  ...........           10           50  ...........  ...........
     Continuous flow mode..............  ...........           50        1,000      \4\ 25/           25
                                                                                              1,000
     Pressure-demand or other positive-  ...........           50        1,000  ...........  ...........
     pressure mode.............................
4. Self-Contained Breathing Apparatus (SCBA)
     Demand mode.......................  ...........           10           50           50  ...........
     Pressure-demand or other positive-  ...........  ...........       10,000       10,000  ...........
     pressure mode (e.g., open/closed circuit).
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Employers may select respirators assigned for use in higher workplace concentrations of a hazardous
  substance for use at lower concentrations of that substance, or when required respirator use is independent of
  concentration.
\2\ The assigned protection factors in Table 1 are only effective when the employer implements a continuing,
  effective respirator program as required by this section (29 CFR 1910.134), including training, fit testing,
  maintenance, and use requirements.
\3\ This APF category includes filtering facepieces, and half masks with elastomeric facepieces.
\4\ The employer must have evidence provided by the respirator manufacturer that testing of these respirators
  demonstrates performance at a level of protection of 1,000 or greater to receive an APF of 1,000. This level
  of performance can best be demonstrated by performing a WPF or SWPF study or equivalent testing. Absent such
  testing, all other PAPRs and SARs with helmets/hoods are to be treated as loose-fitting facepiece respirators,
  and receive an APF of 25.
\5\ These APFs do not apply to respirators used solely for escape. For escape respirators used in association
  with specific substances covered by 29 CFR 1910 subpart Z, employers must refer to the appropriate substance-
  specific standards in that subpart. Escape respirators for other IDLH atmospheres are specified by 29 CFR
  1910.134 (d)(2)(ii).

    (B) Maximum Use Concentration (MUC). (1) The employer must select a 
respirator for employee use that maintains the employee's exposure to 
the hazardous substance, when measured outside the respirator, at or 
below the MUC.
    (2) Employers must not apply MUCs to conditions that are 
immediately dangerous to life or health (IDLH); instead, they must use 
respirators listed for IDLH conditions in paragraph (d)(2) of this 
standard.
    (3) When the calculated MUC exceeds the IDLH level for a hazardous 
substance, or the performance limits of the cartridge or canister, then 
employers must set the maximum MUC at that lower limit.
* * * * *
    (n) Effective date. Paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of 
this section become effective November 22, 2006.
* * * * *

Subpart Z--[Amended]

0
3. Revise the authority citation for subpart Z of part 1910 to read as 
follows:

    Authority: Sections 4, 6, and 8 of the Occupational Safety and 
Health Act of 1970 (29 U.S.C. 653, 655, and 657); Secretary of 
Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 
35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), or 3-2000 (62 FR 
50017); and 29 CFR part 1911.
* * * * *

0
4. Amend Sec.  1910.1001 by:
0
a. Removing Table 1 in paragraph (g)(3);
0
b. Redesignating Table 2 in paragraph (l)(3)(ii) as Table 1;
0
c. Removing the reference to "Table 2" in paragraph (l)(3)(ii) and 
adding "Table 1" in its place; and
0
d. Revising paragraphs (g)(2)(ii) and (g)(3).
    The revisions read as follows:


Sec.  1910.1001  Asbestos.

* * * * *
    (g) * * *
    (2) * * *
    (ii) Employers must provide an employee with a tight-fitting, 
powered air-purifying respirator (PAPR) instead of a negative pressure 
respirator selected according to paragraph (g)(3) of this standard when 
the employee chooses to use a PAPR and it provides adequate protection 
to the employee.
* * * * *
    (3) Respirator selection. Employers must:
    (i) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, 
employers must not select or use filtering facepiece respirators for 
protection against asbestos fibers.
    (ii) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
* * * * *

0
5. In Sec.  1910.1017, remove the table in paragraph (g)(3)(i), remove 
paragraph (g)(3)(iii), and revise paragraph (g)(3)(i) to read as 
follows:


Sec.  1910.1017  Vinyl chloride.

* * * * *
    (g) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide an organic vapor cartridge that has a service life of 
at least one hour when using a chemical cartridge respirator at vinyl 
chloride concentrations up to 10 ppm.
    (C) Select a canister that has a service life of at least four 
hours when using a powered air-purifying respirator having a hood, 
helmet, or full or half facepiece, or a gas mask with a front-or back-
mounted canister, at vinyl chloride concentrations up to 25 ppm.
* * * * *
0
6. In Sec.  1910.1018, remove Tables I and II and paragraph (h)(3)(ii), 
redesignate paragraph (h) (3)(iii) as paragraph (h)(3)(ii), and revise 
paragraph (h)(3)(i) to read as follows:


Sec.  1910.1018  Inorganic arsenic.

* * * * *
    (h) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Ensure that employees do not use half mask respirators for 
protection against arsenic trichloride because it is absorbed rapidly 
through the skin.
    (C) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
    (D) Select for employee use:
    (1) Air-purifying respirators that have a combination HEPA filter 
with an appropriate gas-sorbent cartridge or canister when the 
employee's exposure exceeds the permissible exposure level for 
inorganic arsenic and the relevant limit for other gases.
    (2) Front-or back-mounted gas masks equipped with HEPA filters and 
acid gas canisters or any full facepiece supplied-air respirators when 
the inorganic arsenic concentration is at or below 500 mg/m\3\; and 
half mask air-purifying respirators equipped with HEPA filters and acid 
gas cartridges when the inorganic arsenic concentration is at or below 
100 [mu]g/m\3\.
* * * * *

0
7. In Sec.  1910.1025, remove Table II in paragraph (f)(2)(ii) and 
revise paragraphs (f)(3)(i) and (f)(3)(ii) to read as follows:


Sec.  1910.1025  Lead.

* * * * *
    (f) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide employees with full facepiece respirators instead of 
half mask respirators for protection against lead aerosols that cause 
eye or skin irritation at the use concentrations.
    (C) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
    (ii) Employers must provide employees with a powered air-purifying 
respirator (PAPR) instead of a negative pressure respirator selected 
according to paragraph (f)(3)(i) of this standard when an employee 
chooses to use a PAPR and it provides adequate protection to the 
employee as specified by paragraph (f)(3)(i) of this standard.
* * * * *

0
8. In Sec.  1910.1027, remove Table 2 in paragraph (g)(3)(i) and revise 
paragraph (g)(3)(i) to read as follows:


Sec.  1910.1027  Cadmium.

* * * * *
    (g) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide employees with full facepiece respirators when they 
experience eye irritation.
    (C) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
* * * * *

0
9. In Sec.  1910.1028, remove Table 1 in paragraph (g)(3)(ii) and 
revise paragraphs (g)(2)(i) and (g)(3)(i) to read as follows:


Sec.  1910.1028  Benzene.

* * * * *
    (g) * * *
    (2) * * *
    (i) Employers must implement a respiratory protection program in 
accordance with 29 CFR 1910.134 (b) through (d) (except (d)(1)(iii)), 
and (f) through (m).
* * * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide employees with any organic vapor gas mask or any self-
contained breathing apparatus with a full facepiece to use for escape.
    (C) Use an organic vapor cartridge or canister with powered and 
non-powered air-purifying respirators, and a chin-style canister with 
full facepiece gas masks.
    (D) Ensure that canisters used with non-powered air-purifying 
respirators have a minimum service life of four hours when tested at 
150 ppm benzene at a flow rate of 64 liters per minute (LPM), a 
temperature of 25 [deg]C, and a relative humidity of 85%; for canisters 
used with tight-fitting or loose-fitting powered air-purifying 
respirators, the flow rates for testing must be 115 LPM and 170 LPM, 
respectively.
* * * * *

0
10. In Sec.  1910.1029, remove Table I in paragraph (g)(3) and revise 
paragraph (g)(3) to read as follows:


Sec.  1910.1029  Coke oven emissions.

* * * * *
    (g) * * *
    (3) Respirator selection. Employers must select, and provide to 
employees, the appropriate respirators specified in paragraph 
(d)(3)(i)(A) of 29 CFR 1910.134; however, employers may use a filtering 
facepiece respirator only when it functions as a filter respirator for 
coke oven emissions particulates.
* * * * *

0
11. In Sec.  1910.1043, remove Table I in paragraph (f)(3)(i) and 
revise paragraphs (f)(3)(i) and (f)(3)(ii) to read as follows:


Sec.  1910.1043  Cotton dust.

* * * * *
    (f) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, 
employers must not select or use filtering facepieces for protection 
against cotton dust concentrations greater than five times (5 x) the 
PEL.
    (B) Provide HEPA filters for powered and non-powered air-purifying 
respirators used at cotton dust concentrations greater than ten times 
(10 x) the PEL.
    (ii) Employers must provide an employee with a powered air-
purifying respirator (PAPR) instead of a non-powered air-purifying 
respirator selected according to paragraph (f)(3)(i) of this standard 
when the employee chooses to use a PAPR and it provides adequate 
protection to the employee as specified by paragraph (f)(3)(i) of this 
standard.
* * * * *

0
12. In Sec.  1910.1044, remove Table 1 in paragraph (h)(3) and revise 
paragraph (h)(3) to read as follows: Sec.  1910.1044 1,2-Dibromo-3-
chloropropane.
* * * * *
    (h) * * *
    (3) Respirator selection. Employers must:
    (i) Select, and provide to employees, the appropriate atmosphere-
supplying respirator specified in paragraph (d)(3)(i)(A) of 29 CFR 
1910.134.
    (ii) Provide employees with one of the following respirator options 
to use for entry into, or escape from, unknown DBCP concentrations:
    (A) A combination respirator that includes a supplied-air 
respirator with a full facepiece operated in a pressure-demand or other 
positive-pressure or continuous-flow mode, as well as an auxiliary 
self-contained breathing apparatus (SCBA) operated in a pressure-demand 
or positive-pressure mode.
    (B) An SCBA with a full facepiece operated in a pressure-demand or 
other positive-pressure mode.
* * * * *

0
13. In Sec.  1910.1045, remove Table I in paragraph (h)(3) and revise 
paragraphs (h)(2)(i) and (h)(3) to read as follows:


Sec.  1910.1045  Acrylonitrile.

* * * * *
    (h) * * *
    (2) * * *
    (i) Employers must implement a respiratory protection program in 
accordance with 29 CFR 1910.134 (b) through (d) (except (d)(1)(iii)), 
and (f) through (m).
* * * * *
    (3) Respirator selection. Employers must:
    (i) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (ii) For escape, provide employees with any organic vapor 
respirator or any self-contained breathing apparatus permitted for use 
under paragraph (h)(3)(i) of this standard.
* * * * *

0
14. In Sec.  1910.1047, remove Table 1 in paragraph (g)(3) and revise 
paragraph (g)(3) to read as follows:


Sec.  1910.1047  Ethylene oxide.

* * * * *
    (g) * * *
    (3) Respirator selection. Employers must:
    (i) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, 
employers must not select or use half masks of any type because EtO may 
cause eye irritation or injury.
    (ii) Equip each air-purifying, full facepiece respirator with a 
front-or back-mounted canister approved for protection against ethylene 
oxide.
    (iii) For escape, provide employees with any respirator permitted 
for use under paragraphs (g)(3)(i) and (ii) of this standard.
* * * * *

0
15. In Sec.  1910.1048, remove Table 1 in paragraph (g)(3)(i) and 
revise paragraphs (g)(2) and (g)(3) to read as follows:


Sec.  1910.1048  Formaldehyde.

* * * * *
    (g) * * *
    (2) Respirator program. (i) Employers must implement a respiratory 
protection program in accordance with 29 CFR 1910.134 (b) through (d) 
(except (d)(1)(iii)), and (f) through (m).
    (ii) When employees use air-purifying respirators with chemical 
cartridges or canisters that do not contain end-of-service-life 
indicators approved by the National Institute for Occupational Safety 
and Health, employers must replace these cartridges or canisters as 
specified by paragraphs (d)(3)(iii)(B)(1) and (B)(2) of 29 CFR 
1910.134, or at the end of the workshift, whichever condition occurs 
first.
    (3) Respirator selection. (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Equip each air-purifying, full facepiece respirator with a 
canister or cartridge approved for protection against formaldehyde.
    (C) For escape, provide employees with one of the following 
respirator options: A self-contained breathing apparatus operated in 
the demand or pressure-demand mode; or a full facepiece respirator 
having a chin-style, or a front-or back-mounted industrial-size, 
canister or cartridge approved for protection against formaldehyde.
    (ii) Employers may substitute an air-purifying, half mask 
respirator for an air-purifying, full facepiece respirator when they 
equip the half mask respirator with a cartridge approved for protection 
against formaldehyde and provide the affected employee with effective 
gas-proof goggles.
    (iii) Employers must provide employees who have difficulty using 
negative pressure respirators with powered air-purifying respirators 
permitted for use under paragraph (g)(3)(i)(A) of this standard and 
that affords adequate protection against formaldehyde exposures.
* * * * *

0
16. In Sec.  1910.1050, remove Table 1 in paragraph (h)(3)(i) and 
revise paragraph (h)(3)(i) to read as follows:


Sec.  1910.1050  Methylenedianiline.

* * * * *
    (h) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
    (C) For escape, provide employees with one of the following 
respirator options: Any self-contained breathing apparatus with a full 
facepiece or hood operated in the positive-pressure or continuous-flow 
mode; or a full facepiece air-purifying respirator.
    (D) Provide a combination HEPA filter and organic vapor canister or 
cartridge with powered or non-powered air-purifying respirators when 
MDA is in liquid form or used as part of a process requiring heat.
* * * * *

0
17. In Sec.  1910.1052, remove Table 2 in paragraph (g)(3) and revise 
paragraph (g)(3) to read as follows:


Sec.  1910.1052  Methylene chloride.

* * * * *
    (g) * * *
    (3) Respirator selection. Employers must:
    (i) Select, and provide to employees, the appropriate atmosphere-
supplying respirator specified in paragraph (d)(3)(i)(A) of 29 CFR 
1910.134; however, employers must not select or use half masks of any 
type because MC may cause eye irritation or damage.
    (ii) For emergency escape, provide employees with one of the 
following respirator options: A self-contained breathing apparatus 
operated in the continuous-flow or pressure-demand mode; or a gas mask 
with an organic vapor canister.
* * * * *

PART 1915--[AMENDED]

0
18. Revise the authority citation for part 1915 to read as follows:

    Authority: Section 41, Longshore and Harbor Workers' 
Compensation Act (33 U.S.C. 941); Sections 4, 6, and 8 of the 
Occupational Safety and Health Act of 1970 (20 U.S.C. 653, 655, and 
687); and Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 
(41 FR 25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 
111), 3-2000 (62 FR 50017), or 5-2002 (67 FR 65008) as applicable.
    Sections 1915.120 and 1915.152 of 29 CFR also issued under 29 
CFR part 1911.

Subpart Z--[Amended]

0
19. In Sec.  1915.1001, remove Table 1 in paragraph (h)(2)(iii) and 
revise paragraph (h)(2) to read as follows:


Sec.  1915.1001  Asbestos.

* * * * *
    (h) * * *
    (2) Respirator selection. (i) Employers must select, and provide to 
employees at no cost, the appropriate respirators specified in 
paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, employers must not 
select or use filtering facepiece respirators for use against asbestos 
fibers.
    (ii) Employers are to provide HEPA filters for powered and non-
powered air-purifying respirators.
    (iii) Employers must:
    (A) Inform employees that they may require the employer to provide 
a tight-fitting, powered air-purifying respirator (PAPR) permitted for 
use under paragraph (h)(2)(i) of this standard instead of a negative 
pressure respirator.
    (B) Provide employees with a tight-fitting PAPR instead of a 
negative pressure respirator when the employees choose to use a tight-
fitting PAPR and it provides them with the required protection against 
asbestos.
    (iv) Employers must provide employees with an air-purifying, half 
mask respirator, other than a filtering facepiece respirator, whenever 
the employees perform:
    (A) Class II or Class III asbestos work for which no negative 
exposure assessment is available.
    (B) Class III asbestos work involving disturbance of TSI or 
surfacing ACM or PACM.
    (v) Employers must provide employees with:
    (A) A tight-fitting, powered air-purifying respirator or a full 
facepiece, supplied-air respirator operated in the pressure-demand mode 
and equipped with either HEPA egress cartridges or an auxiliary 
positive-pressure, self-contained breathing apparatus (SCBA) whenever 
the employees are in a regulated area performing Class I asbestos work 
for which a negative exposure assessment is not available and the 
exposure assessment indicates that the exposure level will be at or 
below 1 f/cc as an 8-hour time-weighted average (TWA).
    (B) A full facepiece, supplied-air respirator operated in the 
pressure-demand mode and equipped with an auxiliary positive-pressure 
SCBA whenever the employees are in a regulated area performing Class I 
asbestos work for which a negative exposure assessment is not available 
and the exposure assessment indicates that the exposure level will be 
above 1 f/cc as an 8-hour TWA.
* * * * *

PART 1926--[AMENDED]

Subpart D--[Amended]

0
20. Revise the authority citation for subpart D of part 1926 to read as 
follows:

    Authority: Section 3704 of the Contract Work Hours and Safety 
Standards Act (40 U.S.C. 3701 et seq.); Sections 4, 6, and 8 of the 
Occupational Safety and Health Act of 1970 (29 U.S.C. 653, 655, and 
657); Secretary of Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR 
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-
2000 (62 FR 50017), or 5.2002 (67 FR 650008); as applicable; and 29 
CFR part 11.
    Sections 1926.58, 1926.59, 1926.60, and 1926.65 also issued 
under 5 U.S.C. 553 and 29 CFR part 1911.
    Section 1926.62 of 29 CFR also issued under section 1031 of the 
Housing and Community Development Act of 1992 (42 U.S.C. 4853).
    Section 1926.65 of 29 CFR also issued under section 126 of the 
Superfund Amendments and Reauthorization Act of 1986, as amended (29 
U.S.C. 655 note), and 5 U.S.C. 553.


0
21. In Sec.  1926.60, remove Table 1 and revise paragraph (i)(3)(i) to 
read as follows:


Sec.  1926.60  Methylenedianiline.

* * * * *
    (i) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
    (C) For escape, provide employees with one of the following 
respirator options: Any self-contained breathing apparatus with a full 
facepiece or hood operated in the positive-pressure or continuous-flow 
mode; or a full facepiece air-purifying respirator.
    (D) Provide a combination HEPA filter and organic vapor canister or 
cartridge with air-purifying respirators when MDA is in liquid form or 
used as part of a process requiring heat.
* * * * *

0
22. In Sec.  1926.62, remove Table 1 in paragraph (f)(3)(ii) and revise 
paragraph (f)(3)(i) to read as follows:


Sec.  1926.62  Lead.

* * * * *
    (f) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide employees with a full facepiece respirator instead of a 
half mask respirator for protection against lead aerosols that may 
cause eye or skin irritation at the use concentrations.
    (C) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
* * * * *

Subpart Z--[Amended]

0
23. Revise the authority citation for subpart Z of part 1926 to read as 
follows:

    Authority: Section 3704 of the Contract Work Hours and Safety 
Standards Act (40 U.S.C. 3701 et seq.); Sections 4, 6, and 8 of the 
Occupational Safety and Health Act of 1970 (29 U.S.C. 653, 655, 
657); Secretary of Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR 
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-
2000 (62 FR 50017), or 5-2002 (67 FR 65008) as applicable; and 29 
CFR part 11.
    Section 1926.1102 of 29 CFR not issued under 29 U.S.C. 655 or 29 
CFR part 1911; also issued under 5 U.S.C. 553.


0
24. In Sec.  1926.1101, remove Table 1 in paragraph (h)(3)(i) and 
revise paragraph (h)(3) to read as follows:


Sec.  1926.1101  Asbestos.

* * * * *
    (h) * * *
    (3) Respirator selection. (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, 
employers must not select or use filtering facepiece respirators for 
use against asbestos fibers.
    (B) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
    (ii) Employers must provide an employee with tight-fitting, powered 
air-purifying respirator (PAPR) instead of a negative pressure 
respirator selected according to paragraph (h)(3)(i)(A) of this 
standard when the employee chooses to use a PAPR and it provides 
adequate protection to the employee.
    (iii) Employers must provide employees with an air-purifying half 
mask respirator, other than a filtering facepiece respirator, whenever 
the employees perform:
    (A) Class II or Class III asbestos work for which no negative 
exposure assessment is available.
    (B) Class III asbestos work involving disturbance of TSI or 
surfacing ACM or PACM.
    (iv) Employers must provide employees with:
    (A) A tight-fitting powered air-purifying respirator or a full 
facepiece, supplied-air respirator operated in the pressure-demand mode 
and equipped with either HEPA egress cartridges or an auxiliary 
positive-pressure, self-contained breathing apparatus (SCBA) whenever 
the employees are in a regulated area performing Class I asbestos work 
for which a negative exposure assessment is not available and the 
exposure assessment indicates that the exposure level will be at or 
below 1 f/cc as an 8-hour time-weighted average (TWA).
    (B) A full facepiece supplied-air respirator operated in the 
pressure-demand mode and equipped with an auxiliary positive-pressure 
SCBA whenever the employees are in a regulated area performing Class I 
asbestos work for which a negative exposure assessment is not available 
and the exposure assessment indicates that the exposure level will be 
above 1 f/cc as an 8-hour TWA.
* * * * *

0
25. In Sec.  1926.1127, remove Table 1 in paragraph (g)(3)(i) and 
revise paragraph (g)(3)(i) to read as follows:


Sec.  1926.1127  Cadmium.

* * * * *
    (g) * * *
    (3) * * *
    (i) Employers must:
    (A) Select, and provide to employees, the appropriate respirators 
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
    (B) Provide employees with full facepiece respirators when they 
experience eye irritation.
    (C) Provide HEPA filters for powered and non-powered air-purifying 
respirators.
* * * * *
[FR Doc. 06-6942 Filed 8-23-06; 8:45 am]

BILLING CODE 4510-26-P

Federal Registers - Table of Contents

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