Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Air Contaminants
• Section: 1
• Title: Section 1 - I. Executive Summary

I. Executive Summary

A. Background

Soon after adoption of the OSH Act in 1970, the Occupational Safety and Health Administration (OSHA) promulgated Permissible Exposure Limits (PELs) for many substances pursuant to the authority granted by Section 6 (a) which allowed the Agency to promulgate existing Federal Standards or national consensus standards as enforceable OSHA standards. Most of the PELs contained in the Z-Tables of 29 CFR 1910.1000 were adopted from the Walsh Healy Public Contracts Act as existing Federal Standards. These in turn had been adopted from the 1968 Threshold Limit Values of the American Conference of Governmental Industrial Hygienists (ACGIH). Some consensus standards from the American Standards Association were also adopted at that time, following the 6(a) procedures.

Industrial experience, new developments in technology, and scientific data clearly indicate that in many instances these adopted limits are not sufficiently protective of worker health. In addition there are no PELs for many toxic materials commonly used in the workplace. This has been demonstrated by the reduction in allowable exposure limits recommended by many technical, professional, industrial, and government organizations, both inside and outside the United States. In addition, these organizations have identified many other substances for which allowable exposure limits are needed to supplement the existing Z-Tables. Many large industrial organizations have felt obligated to supplement the existing OSHA PELs with their own internal corporate guidelines.

OSHA has focused its past priorities on the development of detailed and broad regulations for some high priority substances. This has resulted in major reductions in deleterious health effects for those 24 substances for which regulations have been adopted. However, OSHA has not been able to consider the need for regulating the thousands of substances commonly found in the workplace, or to review the scientific information to determine if different limits are required for the more than 400 substances now regulated under the provisions of the Z-Tables.

OSHA determined that it was necessary to modify this approach through the use of generic rulemaking, which would simultaneously cover many substances. The Hazard Communication Standard is an example of a regulation using such an approach. At this time, OSHA is also in the process of considering the need for development of generic standards to cover: respiratory protection; medical surveillance; and exposure monitoring. Without a generic approach OSHA would not be able to provide the level of health protection required for many work situations.

OSHA concludes that it is of first priority to modify existing PELs, and to establish PELs for substances for which no exposure limits exist. The existing health literature and expert judgment indicates that such actions are required to protect against: kidney and liver diseases; respiratory diseases; nerve disorders; carcinogenicity; irritation to various body organs; and many other material impairments to health. Millions of employees are potentially exposed to substances of concern, and adoption of such a regulation would represent one of the most significant steps to ensure the adequacy of health protection for workers. This regulation will achieve these objectives.

B. Proposal

On June 7, 1988, OSHA proposed to amend and expand the PELs for substances covered in the 29 CFR 1910.1000 Z-Tables and add new PELs to address this deficiency. To facilitate this major change for a large number of substances, OSHA initially considered available, generally accepted guidelines or recommendations as its starting point for establishing new PELs. Initially, this involved a review of 14 data bases which might serve this purpose. After analyses of the characteristics of each data base, compared to OSHA requirements, it was decided that OSHA would utilize the already published and widely accepted 1987-88 Threshold Limit Values (TLVs) published by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Recommended Exposure Limits (RELs) developed by the National Institute for Occupational Safety and Health (NIOSH) as the starting point for its analysis. OSHA used both the TLVs and RELs as a starting point for making its own independent judgment regarding selection of the proper PEL. The TLV listing was used to define the bounds of substances included in this rulemaking.

The Proposal considered new PELs for 428 substances. OSHA reviewed the health evidence for each individual substance and preliminarily determined that available evidence would form a reasonable basis for proposing a new limit. It also preliminarily concluded that the new limits were technically and economically feasible. This proposed regulation was intended to reduce diseases (resulting from workplace exposure to chemicals) such as liver and kidney impairments; neuropathy; cardiovascular effects; respiratory effects; lung function deterioration; narcosis; biochemical and metabolic changes; and other material impairment of health. During the Public Hearing, extensive additional information was developed to permit OSHA to make a final determination of the health effects and risk associated with each substance under consideration for adoption of a new PEL.

OSHA also prepared a Preliminary Regulatory Impact Analysis (PRIA) which estimated average annual costs per establishment to achieve compliance, and total costs by industry sector. Preliminarily, OSHA determined that compliance with the proposed PELs would be technologically and economically feasible. As part of this analysis OSHA also identified health related benefits which would be achieved. These benefits included the reduction of occupational illness cases, lost workdays and fatalities.

C. Final Regulation

On the basis of all the information in the record, including the data upon which OSHA based its Proposal, public submissions, additional health and feasibility data (some of which became available during this rulemaking process), additional analyses of all data, and consideration of the statutory requirements defined by the OSH Act, a revised set of PELs is issued in this regulation.

Through this regulation, the Occupational Safety and Health Administration (OSHA) is amending its existing Air Contaminants standards, 1910.1000 including Tables Z-1, Z-2 and Z-3. This amendment is limited to changing many of the Permissible Exposure Limits (PEL) listed in these three Tables while maintaining other PELs unchanged. All PELs are listed in a new Table Z-1-A which replaces Table Z-1.

This amendment reduces the PEL for 212 substances now listed in the Z-Tables, and sets new PELs for 164 substances currently not regulated by OSHA. Changes include revision of the PEL; inclusion of Short Term Exposure Limits (STEL) to complement 8 hour time weighted average (TWA) limits; and, as appropriate, establishment of a skin designation and/or ceiling limits.

All of the revised PELs are included in a single new Table Z-1-A, which also includes the existing PELs enforced by OSHA. This side-by-side format is provided as a user convenience, and as a reference source since this regulation permits the use of any compliance procedures for the first 4 years following publication of the regulation. However, during this time period the established OSHA hierarchy of controls with preference for engineering controls will continue to be applied to achieve the level of the existing PELs.

Tables Z-2 and Z-3 are temporarily maintained since they cannot conveniently be included in the format for Table Z-1-A. The original Table Z-1 has been deleted from the regulation because all of the PELs in that Table have been included in the new Table Z-1-A. The design of this new Table Z-1-A makes identification of all changes to PELs possible by simply comparing Transitional Limits (left side of Table) with Revised Limits (right side of Table).

OSHA has reviewed health, risk and feasibility evidence for all 428 substances for which changes to the PEL were considered. In each instance where a revised or new PEL is adopted, OSHA has determined that the new limits substantially reduce a significant risk of material impairment of health or functional capacity among American workers, and that the new limits are technologically and economically feasible. This determination has been based on further review of the material discussed in the Proposal, public comments and a detailed review of the entire record for this rulemaking.

OSHA's analysis of all the data available following the issuance of the Proposal, receipt of comments and testimony during the public hearing resulted in changes to the proposed PELs. Details of these changes and determination of the PELs adopted in this regulation are included as part of the discussion of specific substances in Section VI. The changes noted above include:
(a) reducing the PEL noted in the proposal;

(b) increasing the PEL (not to exceed the existing Table Z-1 PEL) noted in the proposal; and

(c) identifying the acceptability of respirators, due to feasibility considerations, to achieve compliance with the PEL for a small number of specific operations involving 4 substances.
The final Standard in 29 CFR 1910.1000 covers a total of 600 substances, this includes 428 substances for which OSHA opened the rulemaking process for consideration of revising or establishing new PELs.
(1) Addition of PELs for 164 new substances.

(2) Adoption of more protective PELs for 212 substances. For one of the 212 OSHA raised the TWA but added a STEL.

(3) No changes for 52 substances which were considered in this rulemaking.
In addition to these changes, the new final standard in 29 CFR 1910.1000 reprints existing exposure limits for the following substances which were either not covered or not considered for change in this rulemaking.
(a) No change to existing PELs for 9 substances which are currently undergoing 6(b) rulemaking.

(b) No change to existing PELs for 3 substances (benzene, cotton dust, and formaldehyde) where some segments are not covered by an individual 6(b) Regulation.

(c) PELs for 160 substances, which are unchanged, and were not evaluated during this rulemaking.
The final rule also includes minor changes to the introductory text, and definitions for the tabular listing of the new PELs in 29 CFR 1910.1000.

Specific changes between the Proposal and the final Regulation are noted below:

(A) Reducing the PEL
   (1) Camphor
   (2) Fluorine
   (3) Perchloroethylene
(B) Increasing PEL (less than the previous PEL in 29 CFR 1910.1000)
   (1) Acetone
   (2) Acetonitrile
   (3) Ammonia
   (4) Borates
   (5) Carbon disulfide
   (6) Carbon tetrachloride
   (7) Chlorine
   (8) Chloroform
   (9) Grain dust
   (10) Mesityl Oxide
   (11) Methyl ethyl ketone peroxide
   (12) Trichloroethylene
   (13) Wood dust
(C) Increasing PEL to Previously Existing Level in 29 CFR 1910.1000
   (1) Acetic acid
   (2) Calcium oxide
   (3) Chromium metal
   (4) DDT
   (5) Iron oxide
   (6) Oil mist
   (7) o-Toluidine
   (8) Physical Irritants: 17 individual substances which might otherwise classified as
   "Particulates Not Otherwise Regulated" (PNOR) and the generic PNOR classification.
   (See Section VI-C-10 for details).
(D) No PEL
   (1) Asphalt (delaying decision)
   (2) Chromyl chloride
   (3) Fibrous glass (delaying decision)
   (4) Mineral wool (delaying decision)
(E) Increasing PEL Carbon dioxide (adding STEL and also increasing TWA)
(F) Special Respirator Provisions
   (1) Carbon monoxide - Selected operations to meet the requirements of
   the STEL in the non-ferrous foundries and ferrous steel industry (SIC 33)
   (2) Carbon Disulfide-Selected Rayon Fiber Manufacturing Processes
   (3) Carbon Disulfide- Selected Sausage Casing Manufacturing Processes
   (4) Styrene - Selected Open Molding Boat Manufacturing Processes
   (5) Sulfur dioxide - Selected operations for meeting requirements of the STEL in the
   non-ferrous foundries and ferrous steel industry (SIC 33)
(G) Deletion of Skin and STEL limitations for some substances are identified in Section VI.

Details of the rationale for changing these PELs is provided in the substance specific portions of Section VI. This includes general discussions of health effects in the introductory material to the individual sub-parts of Section VI, as well as detailed discussions for 428 substances.

The revised PELs will protect workers against a wide variety of health effects which could cause material impairment of health or functional capacity. This includes protection against catastrophic effects previously noted as well as more subtle effects such as decrements to the central nervous system which produce significant sensory irritation. For each substance, the health evidence in the record provides an adequate basis for establishing a new or revised PEL.

Because of the nature of this rulemaking, OSHA relied heavily on the already published and widely accepted Threshold Limit Values (TLV) published by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Recommended Exposure Limits (RELs) developed by the National Institute for Occupational Safety and Health (NIOSH). OSHA considered both the TLVs and RELs in making its own independent judgment regarding selection of the proper PEL.

Table Z-1-A is designed to include all substances covered by Subpart Z whether or not the PEL has been changed and whether or not it was opened for consideration in this rulemaking.

For four substances used in specific operations, the full record indicates that it is presently not technically feasible to achieve the PEL which is necessary (based on available health information) through engineering controls. For these few specific operations, the use of engineering controls to fully achieve the new PEL is required only where the Assistant Secretary demonstrates that such controls are feasible. In the absence of such a finding by the Assistant Secretary, the employer must use engineering controls to meet at least the level of the PEL existing prior to this revision as listed in Table Z-1-A, (Transitional Limits columns) and Tables Z-2 and Z-3. However, any methods of control may be used in these identified situations to achieve the new PELs noted in Table Z-1-A. The specific operating situations falling in this category are identified in the individual substance discussions in Section VI, and the general concept is discussed in the Summary and Explanation of the Standard (Section VIII).

A phased enforcement schedule of 6 months (any control methods) following the March 1, 1989, effective date and approximately 4 years (December 31, 1992) following the regulation publication date (engineering controls preferred) is adopted. In certain circumstances, the December 31, 1992, deadline may be extended to December 31, 1993. See 29 CFR 1910.1000 (f) in Section X of this preamble.

The final regulation is limited to consideration of revising the PELs. There is no consideration of the ancillary requirements which are typically developed as part of individual substance rulemaking but were not included in the original 1910.1000 standard. OSHA has published ANPR's for Exposure Monitoring (53 FR 32591-32595), and Medical Surveillance (53 FR 32595-32598), and is developing a proposal covering revision to the respirator provisions of the OSHA Standards. OSHA has issued a final rule expanding the Hazard Communication Standard.

While medical surveillance, exposure monitoring and other industrial hygiene practices are important, OSHA is not in a position to develop these requirements while at the same time developing PELs for several hundred substances. OSHA has determined that lowering exposures through the development of reduced PELs is of higher priority because it is more effective in reducing occupational diseases and material impairment of health. These ancillary requirements will be addressed as priorities dictate.

OSHA has also determined that it is appropriate to limit this rulemaking to the General Industry sector. Application to the Construction, Maritime and Agriculture Segments may require some modifications to this proposed rule because of differences in exposures and work situations in the established PELs for these segments, and differences regarding feasibility for these sectors. OSHA will pursue this as part of second stage rulemaking and has informally notified the Construction Advisory Committee of it plans.

The average annual cost, per establishment affected by this rule, is estimated to range from $77,000 for petroleum refining (SIC 29) down to $400 per year for auto dealers (SIC 55). The annual cost is approximately $170 per worker protected, and is never more than a fraction of 1 percent of sales and less than 2 percent of profits (usually substantially less) except for a very few segments. Benefits will accrue to approximately 5. million workers who are currently exposed excess of the PEL and are expected to include the reduction of over 55,000 occupational illness cases, including almost 24,000 lost workday illness cases and approximately 520,000 lost workdays annually. If not prevented, these illnesses would eventually result in approximately 700 fatalities each year.

OSHA will continue its practice of rulemaking for individual substances when substance specific regulations are necessary and appropriate. An expanded discussion is provided in Section IV-D.

OSHA has also considered the concerns identified regarding the need for extensively tested analytical methods (Ex. 3-960; Ex. 8-47) for enforcement purposes. OSHA believes that enforcement can be initiated without such detailed methods. The OSHA docket includes: (1) reference to a fully developed and extensively tested OSHA or NIOSH sampling and analytical procedure or, (2) a description of an OSHA in-house sampling and analytical method for all but the seven substances listed in Table IV-E-1. OSHA therefore believes there will be no problems with enforcement of the PELs for all but seven substances. This is consistent with conclusions of NIOSH regarding implementation (Ex. 8-47). Since development of sampling and analytical procedures is a dynamic, rapidly progressing technology, OSHA also believes it is appropriate to adopt PELs for these seven substances, but stay enforcement of these PELs until adequate sampling and analytical methods are available. At such time, OSHA will publish in the Federal Register its determination that such methods exist (together with a copy of the method), and indicate the proposed effective date for enforcement of the PEL for the substance in question.

As resources permit, OSHA will attempt to initiate a program in conjunction with NIOSH to develop more extensively tested sampling and analytical methods for those substances where only in-house methods are noted in the Proposal. OSHA believes that this balanced approach is consistent with the statutory requirements of the OSH Act.

[54 FR 2332, Jan. 19, 1989; 54 FR 14909, April 13, 1989; 54 FR 28154, July 5, 1989]



Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents