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• Publication Date: 08/10/1992
• Publication Type: Final Rules
• Fed Register #: 57:35630
• Standard Number: 1910.19; 1910.1050; 1926.60
• Title: Occupational Exposure to 4,4' Methylenedianiline (MDA)

DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910 and 1926

[Docket No. H040]

Occupational Exposure to 4,4' Methylenedianiline (MDA)

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

ACTION: Final rule.

SUMMARY: By this document, the Occupational Safety and Health Administration is promulgating new standards regulating exposure to MDA. The basis for this action is a determination by the Assistant Secretary, based on animal and human data, that exposure to MDA at the current occupational exposure levels causes adverse effects on employee health including an increased risk of cancer and that limiting occupational exposure to MDA to an eight-hour time-weighted average (TWA) of 10 parts per billion (ppb), establishing a short-term exposure limit (STEL) of 100 ppb, and implementing associated provisions will significantly reduce this risk. In addition to establishing permissible exposure limits (PELs) for MDA, this regulation includes requirements such as medical surveillance, exposure monitoring, hygiene facilities, engineering controls and work practices, proper respirator use, and recordkeeping. An action level of 5 ppb is included in this final standard as a mechanism for exempting employers from the obligation to comply with certain requirements, such as employee exposure monitoring, in instances where the employer can demonstrate that employee exposures are at or below the action level.

The standards apply to all industries covered by the OSH Act including general industry, construction, and maritime.

For the most part, the provisions adopted by OSHA in these final regulations were recommended by the MDA Mediated Rulemaking Advisory Committee (Committee). Effective Date: These final rules shall become effective on September 9, 1992. ADDRESSES: In compliance with 28 U.S.C. 2112(a), the Agency designates for receipt of petitions for review of the standard, 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. Any such petitions for review must be filed not later than the 59th day following the promulgation of the standard. See §6(f) of the OSH Act; 29 CFR 1911.18(d) and United Mine Workers of America v. Mine Safety and Health Administration, 900 F.2d 384 (D.C. Cir. 1990).

FOR FURTHER INFORMATION CONTACT: Mr. James F. Foster, Director Office of Public Affairs, OSHA, Rm. N-3641, 200 Constitution Avenue, N.W., Washington, D.C., 20210, Telephone (202) 523-8151. Copies of this document may be obtained two weeks after the publication date from the OSHA Publication Office, Rm. N-3101, at the above address, or by calling (202-523-9667) or at any OSHA regional or area office.

SUPPLEMENTARY INFORMATION:

Table of Contents
I Introduction
II Pertinent Legal Authority
III Events Leading to the Final Standard
IV Properties, Manufacture, and Uses of MDA
V Health Effects
Acute Effects
Chronic Effects
Reproductive Effects
Teratogenic Effects
Absorption, Distribution and Deposition
VI Risk Assessment
VII Significance of Risk
VIII Summary of the Regulatory Impact Analysis and Regulatory
Flexibility Analysis
IX Summary and Explanation of the
Standard for General Industry
X Summary and Explanation of the
Standard for the Construction Industry
XI Environmental Assessment; Findings of No Significant Impact
XII State Plan Requirements
XIII Federalism
XIV Clearance of Information Collection Requirements
XV Authority and Signature
XVI Regulatory Text

General Industry

Appendix A to section 1910.1050-Substance Data Sheet For 4,4'-Methylenedianiline Appendix B to section 1910.1050-Substance Technical Guidelines, MDA Appendix C to section 1910.1050-Medical Surveillance Guidelines for MDA Appendix D to section 1910.1050-Sampling and Analytical Methods for MDA Monitoring and Measurement Procedures Appendix E to section 1910.1050-Qualitative and Quantitative Fit Testing Procedures

Construction Industry

Appendix A to section 1926.60-Substance Data Sheet For 4,4'-Methylenedianiline Appendix B to section 1926.60-Substance Technical Guidelines, MDA Appendix C to section 1926.60-Medical Surveillance Guidelines for MDA Appendix D to section 1926.60-Sampling and Analytical Methods for MDA Monitoring and Measurement Procedures Appendix E to section 1926.60-Qualitative and Quantitative Fit Testing Procedures

I. INTRODUCTION

The standards apply to all occupational exposures to MDA and include a standard in 29 CFR 1910 and 29 CFR 1926. Occupational exposure to MDA in construction is covered by a separate standard. Coverage includes exposures which occur in maritime, primary chemical manufacture, reprocessing, filament winding, potting and encapsulation, etc.

The standard excludes mixtures containing less than 0.1% MDA and also excludes "finished articles containing MDA" as defined.

II. PERTINENT LEGAL AUTHORITY

Authority for issuance of this standard is found primarily in sections 4, 6(b), 8(c), and 8(g)(2) of the Occupational Safety and Health Act of 1970 (the Act), 29 U.S.C. 653, 655(b), 657(c), and 657(g)(2). Section 6(b)(5) governs the issuance of occupational safety and health standards dealing with toxic materials or harmful physical agents. Section 3(8) of the Act, 29 U.S.C. 652(8), defines an occupational safety and health standard as:

    ...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 and places of employment.

    The Supreme Court has said that section 3(8) applies to:

    ...all permanent standards promulgated under the Act and requires the Secretary, before issuing any standard, to determine that it is reasonably necessary and appropriate to remedy a significant risk of material health impairment. Industrial Union Department v. American Petroleum Institute, 448 U.S. 607 (1980).

The "significant risk" determination constitutes a finding that, absent the change in practices mandated by the standard, the workplaces in question would be "unsafe" in the sense that workers would be threatened with a significant risk of harm. Id. at 642. A significant risk finding, however, does not require mathematical precision or anything approaching scientific certainty if the "best available evidence" does not warrant that degree of proof. Id. at 655-656; 29 U.S.C. 655 (b)(5). Rather, the Agency may base its finding largely on policy considerations and has considerable leeway with the kinds of assumptions it applies in interpreting the data supporting it. Id. 655-656; 29 U.S.C. 655(b)(5). The Court's opinion indicates that risk assessments, which may involve mathematical estimates with some inherent uncertainties, are a means of demonstrating the existence of significant risk.

After OSHA has determined that a significant risk exists and that such risk can be reduced or eliminated by the proposed standard, it must 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 ***". Section 6(b)(5) of the Act. The Supreme Court has interpreted this section to mean that OSHA must enact the most protective standard necessary to eliminate a significant risk of material health impairment, subject to the constraints of technological and economic feasibility. American Textile Manufacturers Institute, Inc. v. Donovan, 452 U.S. 490 (1981). The Court held that "cost-benefit analysis is not required by the statute because feasibility analysis is." Id. at 509.

Authority to issue this standard is also found in section 8(c) of the Act. In general, this section requires the Secretary to require employers to make, keep, and preserve records regarding activities related to the Act. In particular, section 8(c)(3) gives the Secretary authority to require employers to "maintain accurate records of employee exposure to potentially toxic materials or harmful physical agents which are required to be monitored or measured under section 6." Provisions of OSHA standards which require the making and maintenance of records of medical examinations, exposure monitoring, and the like are issued pursuant to section 8(c) of the Act.

The Secretary's authority to issue this standard is further supported by the general rulemaking authority granted in section 8(g)(2) of the Act. This section empowers the Secretary to "prescribe such rules and regulations as he may deem necessary to carry out (his) responsibilities under this Act" -- in this case as part of or ancillary to a section 6(b) standard. The Secretary's responsibilities under the Act are defined largely by its enumerated purposes, which include:

Encouraging employers and employees in their efforts to reduce the number of occupational safety and health hazards at their places of employment, and to stimulate employers and employees to institute new and to perfect existing programs for providing safe and healthful working conditions (29 U.S.C. 651(b)(1));

Setting mandatory occupational safety and health standards applicable to business affecting interstate commerce, and by creating an Occupational Safety and Health Review Commission for carrying out adjudicatory functions under the Act (29 U.S.C. 651(b)(3));

Building upon advances already made through employee and employer initiative for providing safe and healthful working conditions (29 U.S.C. 651(b)(4));

Providing for the development and promulgation of occupational safety and health standards (29 U.S.C. 651(b)(9));

Providing for appropriate reporting procedures with respect to occupational safety and health which procedures will help achieve the objectives of this Act and accurately describe the nature of the occupational safety and health problem (29 U.S.C. 651(b)(12));

Exploring ways to discover latent diseases, establishing causal connections between diseases and work in environmental conditions ***. (29 U.S.C. 651(b)(6));

Encouraging joint labor-management efforts to reduce injuries and diseases arising out of employment (29 U.S.C. 651(b)(13)); and

Developing innovative methods, techniques, and approaches for dealing with occupational safety and health problems (29 U.S.C. 651(b)(5)).

Because the MDA standards are reasonably related to these statutory goals, the Secretary finds that these standards are necessary to carry out her responsibilities under the Act.

III. EVENTS LEADING TO THE FINAL STANDARD EPA issued a notice under Section 4(f) of the Toxic Substances Control Act (TSCA) on April 27, 1983 (48 FR 19078) which indicated that MDA presents a significant cancer risk to humans. EPA was then required to either initiate "appropriate action" or announce that the risk was not "unreasonable."

The Section 4(f) notice was based on a draft study undertaken by the National Toxicology Program (NTP). The study demonstrated that the dihydrochloride salt of MDA is carcinogenic in both sexes of rats and mice at two oral dose levels. This study plus the following factors formed the basis for the Section 4 (f) notice: (1) a lack of any mandatory workplace standard; (2) the apparent inadequacy of protection afforded at the American Conference of Governmental Industrial Hygienists (ACGIH) recommended threshold limit value (0.1 parts per million (ppm)); (3) evidence that some processors may be exceeding even the ACGIH limit; and (4) evidence that several thousand workers may be exposed.

The "appropriate action" taken by EPA was the issuance of an Advance Notice of Proposed Rulemaking (ANPR) on September 20, 1983 (48 FR 42898). The ANPR announced the joint effort by EPA and OSHA to initiate regulatory action to determine and implement the most effective means of controlling occupational exposure to MDA. At the time of the issuance of the ANPR, only limited data were available on exposure levels and the number of workers potentially exposed. The ANPR requested detailed information on the operations used to manufacture and process MDA; the potential for exposure at each stage, including air and work surface monitoring data; and descriptions of workplace practices. The second area of inquiry was the production and use of MDA. Detailed descriptions of the uses of MDA and updated information of the identity of processors and users was sought. The third area of inquiry was the availability, costs, and the suitability, and toxicity of substitutes for MDA. Finally, information was sought on methods of controlling exposure. The ANPR invited views and data from interested parties in any of these areas.

In response to the ANPR, comments were received from four parties: Diamond Shamrock; National Resources Defense Council, Inc.; DuPont; and CMA. These comments have been analyzed and where appropriate are reflected in this document.

On July 5, 1985, EPA published a Federal Register notice, in accordance with section 9 TSCA provisions (50 FR 27674) which described the occupational risks associated with worker exposure to MDA and requested that OSHA respond to EPA and indicate what regulatory activity would be implemented, if any. Under section 9(a)(2) of TSCA, EPA was prohibited from taking any regulatory action pending a response from OSHA.

In response (51 FR 6748, February 26, 1986), OSHA determined that there is a reasonable basis to believe that the manufacture and use of MDA presents a significant risk to the health of exposed workers and that the risk described by EPA may be eliminated or reduced to a significant extent by a workplace standard which regulates workers exposure. Further, OSHA determined on the basis of preliminary data, that the adoption of an occupational standard for worker exposure to MDA is economically and technologically feasible.

In the course of considering an appropriate regulatory action under the Occupational Safety and Health Act of 1970 (84 Stat. 1590; 29 U.S.C. 655) ("OSH Act"), OSHA examined various regulatory scenarios before determining the process which might be followed in developing a comprehensive regulation for occupational exposure to MDA. The Administrative Conference of the United States (ACUS) had recently studied the rulemaking process of various federal agencies and found that:

    The complexity of government regulation has increased greatly compared to that which existed when the Administrative Procedure Act [APA] was enacted, and this complexity has been accompanied by a formalization of the rulemaking process beyond the brief, expeditious notice and comment procedures envisioned by section 553 of the APA. Procedures in addition to notice and comment may, in some instances, provide important safeguards against arbitrary or capricious decisions by agencies and help ensure that agencies develop sound factual basis for the exercise of the discretion entrusted them by Congress, but the increased formalization of the rulemaking process has also had adverse consequences. The participants, including the agency, tend to develop adversarial relationships with each other causing them to take extreme positions, to withhold information from one another, and to attack the legitimacy of opposing positions. Because of the adversarial relationships, participants often do not focus on creative solutions to problems, ranking of the issues involved in a rulemaking, or the important details involved in a rule. Extensive factual records are often developed beyond what is necessary. Long periods of delay result and participation in rulemaking proceedings can become needlessly expensive. Moreover, many participants perceive their roles in the rulemaking proceeding more as positioning themselves for the subsequent judicial review than as contributing to a solution on the merits at the administrative level. Finally, many participants remain dissatisfied with the policy judgments made at the outcome of rulemaking proceedings.

(Recommendation 82-4 "Procedures for Negotiating Proposed Regulations," 47 FR 30708, June 18, 1982).

Therefore, ACUS recommended that agencies consider using regulatory mediation, in which the parties in interest identify the major issues, gauge their importance, identify the information necessary to resolve the issues, and develop a rule that is acceptable to the respective interests, all within the contours of the regulatory agency's statute.

In considering whether this approach would be suitable in developing regulations controlling workplace exposure to MDA, OSHA considered the selection criteria adopted by the Environmental Protection Agency. (See 49 FR 17576, 17579; April 24, 1984.) OSHA concluded that MDA met the selection criteria for mediation: the regulatory effort was at the pre-proposal phase of development; affected parties were relatively few in number and readily identifiable; there were indications that affected parties would mediate in good faith; and sufficient information was available to resolve key issues. Thus, OSHA employed mediated rulemaking in developing an occupational standard for worker exposure to MDA.

A number of parties interested in OSHA affairs have expressed concern regarding the use of mediated rulemaking in developing complex health regulations. Strictly speaking, it appears inappropriate to suggest that human suffering and lives become the trade off items in a mediation attempt. The Agency's use of mediated rulemaking in this instance did not anticipate that would be the methodology of these endeavors. Instead, OSHA expected to produce a consensus recommendation on the various aspects or issues involved in developing a complex health standard. This differs from the typical labor-management negotiations where a limited number of issues must be resolved and bargaining or trade-off become the method to form a compromise. The key difference involves the final product expected. On the one hand, a compromise is reached; on the other hand, a consensus is achieved.

OSHA indicated in its Federal Register notice of October 22, 1985 (50 FR 42789) that Mediated Rulemaking would be used to assist OSHA in its MDA rulemaking activities. This notice also set forth the basic concepts of negotiated rulemaking and outlined the participant selection criteria which OSHA expected to use in establishing an MDA Advisory Committee.

OSHA established the committee in accordance with the Federal Advisory Committee Act (FACA, 5 U.S.C. App. I); and section 7(b) of the Occupational Safety and Health Act (OSH Act; 29 U.S.C. 656 (b)) to mediate issues associated with the development of a Notice of Proposed Rulemaking (NPRM) on MDA.

This notice also solicited participants for the mediation process. As a result of the request for participants, three unions, the United Auto Workers (UAW), the United Steelworkers of America (USWA) and the Oil, Chemical, and Atomic Workers (OCAW) offered names of potential representatives for the Committee. OSHA selected representatives from the UAW and Steelworkers to participate in these mediation activities. The International Association of Machinists and Aerospace Workers (IAM) submitted a request for representation on the Committee and a representative from this group was appointed. Later, as a result of scheduling conflicts, the UAW representative resigned and was replaced by a labor representative from the United Brotherhood of Carpenters and Joiners of America.

In addition to the unions that nominated participants, three trade associations representing employer groups also expressed an interest in participating in this rulemaking effort: the National Electrical Manufacturers Association (NEMA), the Suppliers of Advanced Composite Materials Association (SACMA) and the Chemical Manufacturers Association (CMA). Representatives from these groups reflect employer interest in primary and secondary manufacturing and, to some extent, downstream use of MDA in the construction industry. The other recommendations for representation came from the Department of Energy, Brookhaven National Laboratory, Sandia National Laboratories, the National Institute for Occupational Safety and Health (NIOSH), EPA, and the Occupational Safety and Health Administration for the State of California. A list of the candidates selected, the date of the first meeting, and the agenda for the first meeting were published in the Federal Register on July 3, 1986 (51 FR 24452).

OSHA also clearly denoted, in the October 22nd notice, the relevance which the Mediated Rulemaking efforts would have in the development of its proposed rule for occupational exposure to MDA:

    While the Committee's work product will likely serve as the basis for a proposed rule, it will not negate the need for adherence to traditional rulemaking procedures. This negotiated rulemaking procedure is supplemental to the normal section 6(b) rulemaking procedures specified in the OSH Act and is intended to aid OSHA in developing a proposed standard for occupational exposure to MDA (at 42790).

Furthermore, OSHA's participation in these mediated rulemaking endeavors was clearly delineated and was, in fact, to be substantial. OSHA would be an active participant in these efforts. An OSHA representative provided draft regulatory text and the necessary expertise in standard drafting which the Committee needed.

To the extent that OSHA could not accept the Committee's recommendations as its notice of proposed rulemaking, OSHA agreed to publish its rationale for such non-acceptance. OSHA, for the most part, based its NPRM on the Committee's recommendations.

In addition, OSHA's approach entailed the Agency setting forth the issues on which the Committee must come to consensus. OSHA had the knowledge and experience needed to develop complex health standards. Furthermore, OSHA is cognizant of its own legal requirements and limitations. Thus, OSHA provided the Committee with the issues to be resolved, the record evidence accumulated to date, and the suggested draft regulatory language. The Committee used the record evidence and draft language provided by OSHA, along with information supplied by some of its members and, of course, the personal expertise of its members to achieve its consensus recommendations. The recommendations developed by the Committee reflect the consensus reached regarding the risk associated with occupational exposure to MDA, the PELs and standard provisions necessary to reduce this risk, and the technological and economic feasibility of implementing these standards. The Committee's products were comprehensive regulations with accompanying rationales.

The Committee also agreed that unanimous agreement on all the issues was not necessary for consensus to be reached. This is different than typical negotiations in which all the issues must be resolved in order to culminate successfully.

OSHA also required that the Committee be established in accordance with, and that it follow the requirements established by, the Federal Advisory Committee Act. The Mediated Rulemaking Committee was set up in the fashion that OSHA previously had established Advisory Committees under section 7(b) of the OSH Act. Thus, all the Committee's meetings, unlike typical labor/management negotiations, were open to the public and a record was kept and made available to the public.

Further, representation of the interests involved was mandatory; not representation of all the parties, but of all the interests. The recommendations proposed by this consensus building group were developed by representatives from labor, management, and state and federal interests.

The Committee met formally on seven occasions. The first meeting consisted of organizational activities (defining consensus, establishing agendas and topics for discussions). The subsequent meetings were used to develop consensus recommendations. The last meeting ended on May 21, 1987. In this meeting the Committee made and rendered its final recommendations on the proposed standards regulating occupational exposure to MDA in both general industry and the construction industry to the Assistant Secretary. These recommendations were published on July 16, 1987 (50 FR 26776).

OSHA based its NPRM primarily upon the recommendations made by the Committee. Furthermore, in the infrequent situations where the Committee's recommendations could not be used by OSHA in its NPRM, OSHA, as agreed, provided its rationale for this non-acceptance.

OSHA also consulted, as required by §107 (e) of the Contract Work Hours and Safety Standards Act (40 U.S.C. 333 (e)) and 29 CFR 1912.3, with the Construction Advisory Committee concerning this proposed rule for Construction. This meeting took place on November 3, 1987. This Committee advised that OSHA adopt the recommendations made by the MDA Mediated Rulemaking Advisory Committee for the construction industry and use such as the basis for its NPRM for construction.

On May 12, 1989, OSHA published a Notice of Proposed Rulemaking (NPRM) which proposed new standards regulating occupational exposure to MDA (54 FR 20672). The comment period and the time for requesting a hearing was extended to July 11, 1989. OSHA received twenty-six comments including two hearing requests; one from the A.O. Smith Co. and the other from United Technologies. Accordingly, pursuant to Section 6(b)(3) of the OSH Act, OSHA held hearings on the proposal on March 20 and 21, 1990. In response to the Notice of Hearing published on January 22, 1990 (55 FR 2101), OSHA received eleven comments and twelve Notices of Intention to Appear (NOIA) indicating the participants at the hearing. Interestingly, neither party who had requested the hearing filed a NOIA or participated at the hearing in any way. During the two day hearing, the Administrative Law Judge admitted twelve exhibits and established post-hearing comment periods that ran until May 23, 1990. OSHA has received eight timely post-hearing comments. The hearing record was certified by the Administrative Law Judge on October 10, 1990.

The final standard, like the proposed rule, is based primarily on the recommendations made by the MDA Mediated Rulemaking Committee. In those few instances where OSHA has amended the proposal and established different requirements in the final standard, these changes have been noted.

IV. PHYSICAL PROPERTIES, MANUFACTURE, AND USES OF MDA Methylenedianiline (CAS 101-77-9) (MDA) is a light brown, or tan, crystalline solid with a faint amino-like odor. MDA is slightly soluble in water and very soluble in alcohol and benzene.

MDA is produced commercially by the condensation of aniline and formaldehyde. Crude MDA (40-60% MDA) is a liquid or a hard wax-like substance. Purified (99%) MDA is in the form of either light yellow crystalline flakes or white granules.

Ninety-eight percent of the MDA produced is used directly in the manufacture of methylenediphenyl diiosocyanate (MDI). The remaining two percent is used as a precursor for the manufacture of plastic fibers, antioxidants, dyestuff intermediates, corrosion preventatives, and special polymers.

The MDI is produced in two grades, monomeric (pure) and polymeric. Ninety percent of the crude MDA is used to produce polymeric MDI, and another 8% of the crude MDA is converted to monomeric MDI. MDI is used to produce flexible and rigid polyurethane foams, elastomers, coatings, thermoplastic resins, foundry core binders, adhesives, sealants, and spandex fibers.

The remaining MDA is produced in the pure form for other uses:

epoxy resin curing agents, wire coating applications, polyurethane co-reactants, in pigments and dyes, and defense applications.

There are eleven principal industry sectors where workers are potentially exposed to MDA. These sectors are:

(1) MDA Production for MDI Synthesis/MDA Sale and Import;

(2) Reprocessing;

(3) Filament Winding;

(4) Potting and Encapsulation;

(5) Molding/Bonding of Tools and Specialty Small Parts;

(6) Wire Coating;

(7) Application of Coatings;

(8) Intermediate for TGMDA and PACM-20 Production;

(9) Polyurethane Curing;

(10) Advanced Composite Materials Production; and

(11) Use of PMR-15 Pre-preg Materials.

There are also seven other industrial sectors where MDA was once used and may still be used on a limited basis. These minor sectors are :

(1) Coatings (Polybismalimides) of Printed Circuit Boards and Fabrication of Airplane Parts;

(2) Dyes and Pigments;

(3) Quiana Yarn;

(4) Intermediate for Pharmaceuticals, Herbicides, etc.;

(5) Rubber Processing;

(6) Anti-Oxidants; and

(7) Ketamine Production.

Maintenance workers have been separately identified from each of these sectors for purposes of analysis. Occupational exposure to MDA also occurs in the Construction and Maritime industries.

There are six firms which produce MDA for MDI production, MDA for sale, or which import MDA. MDA is manufactured by 6 companies at 7 locations in four states: Dow Chemical Co.(LaPorte, Texas); BASF (Geismar, La); E.I. Dupont (Belle, WV); Mobay Chemical (New Martinsville, WV and Baytown, TX); Rubicon Chemical (Geismar, La); and Uniroyal Chemicals division of Avery (Naugtuck, Ct). Three of these companies, Mobay, Rubicon, and Dow account for over 90% of the MDA production. It is estimated that approximately 600 million pounds of MDA are produced for MDI conversion, 4,474,000 pounds are produced domestically for sale, and an additional 1.8 million pounds are imported. In addition, it is estimated that the percentage of MDA in the product made domestically ranges from 40-70% while the percentage in the imported product is approximately 98%.

V. HEALTH EFFECTS OF EXPOSURE TO MDA A. Summary of the Committee's Recommendations

1. Introduction The Committee reviewed the record evidence concerning the acute and chronic effects of exposure to MDA in both animals and humans and concluded that MDA should be treated as a hepatotoxic agent and as a suspect human carcinogen. The Committee also concluded that an occupational standard regulating worker exposure to MDA should be developed. The following discussion provides the Committee's findings with respect to the hepatotoxic and carcinogenic hazards posed by occupational exposure to MDA.

2. Acute Effects of Exposure to MDA A. Hepatotoxicity. The record evidence on the acute effects of occupational exposure to MDA indicates that occupational exposure to MDA may result in hepatotoxicity (poisoning of the liver). The Committee relied on an abundance of human and animal data to support this finding. (See Hepatotoxicity Section of the Committee's Document, Ex. 9.) The Committee found that one or a few exposures to high doses of MDA may result in toxic hepatitis. However, in all cases the clinical signs and symptoms of hepatitis produced by this exposure were reversible. The Committee's discussion concerning the acute effects resulting from acute exposures can be found at 52 FR 26779 and 26780. In summary the Committee stated clearly that "The predominance of data reflect the induction of disease as a result of dermal absorption of MDA" and further provides a data analysis from Kopelman, McGill and Motto, and Brooks et al. An analysis of the data did not rule out the possibility that liver toxicity might result from low doses. Furthermore, the analysis did not determine the effects long term low doses might have on liver function. However, the Committee tentatively did conclude that at the present occupational levels the clinically observed non-neoplastic effects of exposure to MDA appear to be totally reversible. This conclusion was based solely on review of the data found in the acute human studies (human chronic exposure studies are not available). Animal data however, did indicate that long term MDA dosing at low levels produced various levels of liver damage. Thus while making a finding that occupational exposure to MDA may result in liver toxicity, the Committee was unable to develop dose- response data which could predict with some certainty the exposure necessary to produce liver toxicity. More precisely, the Committee was unable to conclude that at 5 ppb, liver toxicity would not occur.

In an effort to make these findings, the Committee extensively reviewed the record evidence to determine the levels of exposure at which a No Observed Effect Level (NOEL) for the clinical observation of hepatitis could be expected to occur in a worker population. The available literature on workers occupationally exposed to MDA provided limited data on the occupational doses to which the workers were exposed. This is due in part to a lack of ambient sampling data but more often because the primary mode of exposure was through the skin and not through inhalation. The Committee further acknowledged that in the case of MDA, unlike many acutely toxic chemicals which are associated with acute inhalation effects such as irritation and pulmonary edema, the primary effect has been liver damage following ingestion or skin absorption. The only available data the Committee could use to estimate a NOEL for liver toxicity due to occupational exposure to MDA are the data reported by Kopelman et al. from the Epping Jaundice incident. This data suggested that levels in excess of 100 ppb would be necessary to produce acute hepatitis in worker populations. The Committee relied on these findings in making its recommendations for the TWA and the STEL.

B. Dermal Irritation. The Committee believed that the ability of MDA to induce contact sensitization has not been studied sufficiently to conclude that MDA causes sensitization.

C. Retinal Effects. The Committee reviewed the record evidence concerning the effects which might result from eye contact with MDA. The Committee concluded that direct contact between MDA and the eye should be avoided. In addition, the Committee noted that ingestion of MDA might also result in damage to the eye and as such should also be avoided.

3. Chronic Effects of Exposure to MDA

A. Hepatotoxicity. The Committee found that at the present occupational levels, the observed or clinical non-neoplastic effects resulting from exposure appear to be totally reversible (Ex. 9). This conclusion is based on review of the data found in the acute human studies. Animal data indicate that long term MDA dosing at low levels produces various levels of liver damage, but since most of the studies have involved the dosing of the animals until sacrifice, it is difficult to determine if the observed effects would or could have been reversed if sufficient time had been allotted for healing.

B. Carcinogenicity. The Committee concluded that MDA is a carcinogen in F344/N rats and B6C3F1 mice of each sex. Furthermore, it appears that carcinogenicity is induced either through ingestion, inhalation, or dermal absorption of the substance.

The Committee considered extensively the type of data needed to determine carcinogenicity in animals and to relate the observed effects in animals with that expected in humans. The Committee generally accepted the policy set forth by public health agencies, that test results in mammalian species (including the mouse), are acceptable data for predicting potential hazards to exposed humans.

The Committee also recognized that confounding factors associated with long term bioassays could cause carcinogenicity findings to be questioned. First , the Committee recognized the need to use control groups, as was done in the NTP and ORNL bioassays, and to validate the carcinogenic findings in rodent species that normally exhibit a high spontaneous incidence of tumors.

Second the Committee also discussed the effect that high dosing and subsequent acute toxicity may have on the production of liver and thyroid tumors found in the female mice of the NTP study. The Committee determined that the observed incidence of tumors found in the female mice of the NTP study did not occur as a result of high dosing but occurred from exposure to MDA.

Third the Committee noted that the presence of tumor viruses in mice does not necessarily invalidate the identification of MDA as a carcinogen. In making this determination, the Committee made use of the policies advocated by numerous health agencies, including OSHA, which requires that, to make a viral etiology finding, the virus must be established to be the sole direct mechanism producing the carcinogenic effect. Not finding this necessary evidence, the Committee agreed that the carcinogenic response was not the result of viral etiology.

The Committee found that the NTP study was conducted properly, and therefore used this study as the principal basis for its carcinogenicity findings.

In addition, a majority of the Committee members concluded that MDA induces cancer by a genotoxic rather than a non-genotoxic mechanism and, as such, a threshold level for the carcinogenic response did not exist. The Committee concluded that the evidence offered for the existence of thresholds for this carcinogen was insufficient to overcome the extant evidence for a genotoxic mechanism. The Committee relied on two basic concepts to make this decision. First, the members required that if a threshold was to be considered, data indicating at what level a threshold would occur must be provided. Secondly, once a threshold is established in experimental animals, the threshold must be shown to be applicable to any exposed group of workers. No evidence was offered which meets these minimum criteria and thus the Committee made a recommendation that a no-threshold-effect be used to predict the risk associated with occupational exposure to MDA. In addition, the Committee believed that, even if a threshold for specific carcinogens could be demonstrated in experimental test animals or even in a specific human population, it might not be applicable to any given human population at risk. No data were furnished which equated a threshold observed in animals with that expected in humans.

Other concerns raised by some of the Committee members involve the use of MDA dihydrochloride rather than MDA itself as the administered dose in the NTP bioassays. The Committee noted that test animals in the Oak Ridge National Laboratories study were exposed dermally to MDA and not the hydrochloride as in the NTP study. Furthermore, the Committee noted that in the Oak Ridge test animals the carcinogenic response seen in the female mouse livers was approximately double that noted in the NTP study. Thus, the Committee concluded that exposure to MDA produced the carcinogenic effect, and not exposure to the salt.

The Committee also examined supportive evidence of carcinogenicity derived from short term mutagenicity tests. The Committee recognized that the various short-term tests do not measure the same mutagenic endpoint; thus positive and negative findings are not uncommon, since no single short-term test can measure all the events which might lead to mutagenesis. The Committee agreed that there is a wide variety of opinions on the reliability of using short-term studies as indicators of potential carcinogenicity. Many of the Committee members believed, however, that such tests provide meaningful indicative results and that substances which give positive results in well validated systems are likely to be carcinogenic. Further, it appears that the probability of a false-positive result for a chemical which is positive in one well conducted bioassay and one well validated short term-test is extremely small. Thus, based on record evidence consisting of both bioassays and short-term tests the Committee concluded that MDA causes cancer in experimental animals.

The Committee also analyzed the data to relate the findings of "pooled tumors" incidence in mice to some common site in man. The Committee acknowledged that scientific investigations have shown that target sites for the carcinogenic action of a substance in humans are not necessarily the same as those found in animal experiments. There were basically three pieces of suggestive evidence examined by the Committee to link the carcinogenic response in animals to the expected response in humans (bladder cancer):

    (1) The NIOSH-Vertol Health Hazard Evaluation (HHE) study (Ex. 1-255);

    (2) The presence of bladder transitional cell papillomas in three MDA treated rats in the NTP-Bioassay (Ex. 1-36); and

    (3) Some structure-activity links with the proven human and animal bladder carcinogen, benzidine, and the dog bladder carcinogen, methylenebis-(2-chloroaniline)(MBOCA).

The only available human data implicating MDA as a human carcinogen were from the HHE. The Committee reviewed these data thoroughly before concluding that the data were insufficient to positively identify MDA as a human bladder carcinogen or to use the data contained in this report to establish permissible exposure limits. However, the Committee did not exclude the fact that the report did develop a hypothesis regarding MDA exposure and bladder cancer which warrants further investigation using the more rigorous epidemiologic methods.

The Committee also found that the development of bladder transitional cell papillomas in the female rats in the NTP bioassays to be significant. These relatively rare tumors were benign although progression to malignancy in this class of tumors may occur. Furthermore, the Committee recognized that theappearance of transitional cell papillomas in MDA treated rats was unique and demonstrated the chemical specificity of the results observed.

The Committee analyzed the structure activity relationships between MDA and several other substances identified by EPA as structural analogs. A majority of the Committee members maintained that there are significant structural differences between benzidine and MDA and that a strong analogy does not exist. The Committee generally believed, however, that while the structural analogy data are not conclusive, nonetheless these data should be relied upon to suggest that MDA may cause bladder cancer in humans. Although the Committee could not positively link occupational exposure to MDA with bladder cancer in workers, the Committee recommended stringent standard provisions to protect workers against the carcinogenic potential posed by MDA regardless of the target site.

4. Reproductive Effects

The majority of the Committee members concluded that, while the data suggest that there may be hormonal changes at relatively high doses, the occupational significance of these changes could not be assessed.

5. Teratogenic Effects

The Committee has reviewed the data on the teratogenic effects of exposure to MDA and could not relate the significance of these observed effects in animals with those anticipated in the occupational setting.

6. Absorption, Distribution, and Deposition

The majority of the Committee members agreed that where sufficient data exist which are MDA specific (e.g., dermal absorption data), these data should be used to determine the biological activity of the chemical. However, the Committee found that data obtained through the El-Hawari study (Ex. 1-251) were not sufficient to make determinations concerning the gastrointestinal and respiratory absorption of MDA. The Committee anticipated that future research on the gastrointestinal and respiratory absorption of MDA will also substantiate the findings made from the structural analog comparisons and demonstrate that these assumptions are also conservative.

The Committee agreed that a 100% absorption through the gastrointestinal tract of the mouse be used in generating the risk assessment model rather than 50% absorption proposed by EPA. The Committee realizes that this is a conservative approach because it assumes that the observed effect is a result of absorption of the entire dose administered and not a result of the absorption of a lesser portion of the administered dose. This assumption has the effect of reducing the expected risks predictable from occupational exposure to MDA by 50%.

The Committee agreed, however, with EPA's assumption that absorption through lung tissue is roughly equivalent to gastro- intestinal absorption (50%), especially if MDA is in the vapor phase or has a particle size of less than 2 microns.

The Committee also concluded that MDA is actually dermally absorbed at approximately 2% per hour and not 1% as previously assumed (Ex. 1-251). Therefore, an absorption rate of 2% can also be applied to MDA exposure which occurs through dermal deposition and absorption.

The Committee also stressed the significance which the hazard of dermal exposure posed. Data from the Oak Ridge National Laboratory study (Ex. 8) heightened the Committee's concern over these hazards. The Committee concluded that when a chemical is ingested, it is transported through the hepatocellular detoxification system and is not generally diluted as a result of passing through the general circulatory system. In the case of chemicals applied to the skin, however, a significant dilution takes place as a result of the absorbed chemical passing through the general circulatory system before passing through the hepatocellular detoxification system. Compared with the findings of the NTP study in which animals were exposed through ingestion, the Oak Ridge data reported almost a two-fold increase in the liver tumor incidence observed in the female test animals dermally exposed to MDA. These findings are additional evidence that occupational dermal exposure to MDA should be prevented.

In addition, the Committee was concerned with the findings of El-Harawi (Ex. 1-251) indicating that once deposited on the skin, MDA cannot be completely removed by cleansing. The data suggest that the use of solvents to remove MDA from the skin actually increases the absorption of MDA. It also appears that soap and water provide the best medium for removing the substance from the skin, but only remove approximately 60% of the material deposited on the skin. These findings support the provisions of the final standard which require the use of personal protective clothing and equipment to prevent MDA exposure and medical surveillance to assure that the integrity of the protective equipment and clothing is being maintained.

B. OSHA's Findings

The following discussion of the health effects associated with occupational exposure to MDA is merely a summary account of the extensive analysis and findings made by [the Committee and] OSHA. Complete discussions of the health effects conclusions reached by the Committee [and accepted by OSHA] are found at 52 FR 26779 et seq. (July 16, 1987) [and 54 FR 20677 et seq. (May 12, 1989), respectively]. All of these health effects findings were essentially unchallenged by commenters and parties at the hearing.

The record evidence on the acute effects of occupational exposure to MDA indicates that exposure may result in hepatotoxicity (poisoning of the liver). These findings are based on an abundance of human and animal data. (52 FR 26779).

Evidence also indicates that direct contact between MDA and the eye as well as ingestion might result in damage to the retina of the eye.(52 FR 26780).

OSHA also finds that at the present occupational levels, the observed non-neoplastic effects on the liver resulting from exposure appear to be reversible (Ex 9). This conclusion is based on review of the data found in studies of acute liver disease in humans.

OSHA concludes that MDA is a carcinogen based on studies of F344/N rats and B6C3F1 mice of each sex. Furthermore, it appears that carcinogenicity is induced either through ingestion, inhalation, or dermal absorption of the substance. There were basically three pieces of evidence examined by OSHA which related the carcinogenic response of MDA in animals to the expected response in humans (bladder cancer):

    (1) The NIOSH-Vertol Health Hazard Evaluation (HHE) study which demonstrated a significantly elevated PCMR for bladder cancer among workers exposed to MDA (Ex.1-255);

    (2) The presence of bladder transitional cell papillomas in three MDA treated rats in the NTP-Bioassay (Ex. 1-36); and

    (3) Some structure-activity links with benzidine, a proven human and animal bladder carcinogen, and with methylenebis-(2-chloroaniline) (MBOCA) a substance known to cause bladder cancer in the dog and suspected of causing bladder cancer in humans (52 FR 26787).

Although the evidence was not conclusive in demonstrating a causal link between occupational exposure to MDA and bladder cancer, OSHA nonetheless developed standard provisions to protect workers against the carcinogenic potential posed by MDA regardless of the target site.

OSHA also finds that, while the data suggest that there may be hormonal changes at relatively high doses, the occupational significance of these changes can not be assessed. (52 FR 26783).

Furthermore, OSHA has reviewed the data on the teratogenic effects of exposure to MDA and can not relate the significance of these observed effects in animals with those anticipated in the occupational setting. (52 FR 26784).

OSHA has also determined that the available data on the ability of MDA to induce contact sensitization has not been studied sufficiently to conclude that MDA causes sensitization. (52 FR 26786).

In reviewing the record evidence concerning the acute and chronic effects of exposure to MDA in both animals and humans, OSHA concludes that MDA must be regulated as both a hepatotoxic agent and a human carcinogen. OSHA tentatively made these findings in its NPRM and the Agency's conclusions remain unchanged. In fact, there was no evidence submitted in response to the NPRM which would cause OSHA to amend its earlier conclusions that MDA should be treated as a hepatotoxic agent and a suspect human carcinogen.

VI. RISK ASSESSMENT OSHA's approach to risk assessment is guided by Supreme Court interpretations of the OSH Act, namely decisions involving benzene (Industrial Union Department, AFL-CIO v. American Petroleum Institute, 448 U.S. 607 (1980)); and cotton dust (American Textile Manufacturers Institute v. Donovan, 452 U.S. 490 (1981)). The Court has ruled that OSHA may not promulgate a standard unless it has determined, based on substantial evidence in the record considered as a whole, that there is a significant risk of health impairment at existing permissible exposure levels and that issuance of a new standard is necessary to achieve a significant reduction in that risk. Although in the cotton dust case the Court rejected the use of cost-benefit analysis in setting OSHA standards, it reaffirmed its earlier holding in the benzene case that a risk assessment relating to worker health is not only appropriate, but is, in fact, required in order to identify a significant worker health risk and to determine whether a proposed standard will achieve a reduction in that risk. Although the Court did not require OSHA to perform a quantitative risk assessment in every case, the Court implied, and OSHA as a policy matter agrees, that such assessments should be put in quantitative terms to the extent possible (48 FR 17292).

Several approaches can be used to estimate cancer risk from exposure to toxic agents. A standard approach uses mathematical models to describe the relationship between dose (such as airborne concentration) and response (e.g., cancer). Generally, curves are fit to the data points observed at different exposure levels and these curves are used to predict the risk that would occur at exposure levels which were not observed. The shape of these curves is varied, ranging from linear extrapolations from the observed points through the origin (zero exposure and zero risk) to curves which may deviate far from linearity at the very highest and very lowest doses. The use of a particular model or curve can be justified in part by a statistical measure of "fit" to available data points, that is, a statistical test which measures how closely a predicted dose-response curve is to the actual observed data.

In all cases it is assumed that the mathematical curves are reflective of biological processes that control the biological fate and action of the toxic compound. To date, many of these factors have not been quantitatively linked to the mathematical models. Biological factors which may play important roles in the risk assessment are:

(1) Dose of the material at the sensitive tissue;

(2) the sensitive tissue(s) itself;

(3) the nature of the response(s);

(4) rates and sites of biotransformation;

(5) toxicity of metabolites;

(6) chronicity of the compound (cumulative nature of the material or its actions);

(7) pharmacokinetic distribution of the material (especially effects of dose on the distribution);

(8) the effect of biological variables such as age, sex, species and strain of test animal; and

(9) the manner and method of dosing the test animals (48 FR 45969).

It is clear that all of these factors cannot be easily incorporated into a single mathematical model. Therefore, careful selection of the data and general assumptions necessary for evaluation in the model is important to the risk assessment in order to make use of as much information as possible.

In doing its risk assessment for MDA, OSHA has considered various assumptions that it believes to be the most reasonable. The risk estimates are found in Table 1 below (Table 1, Ex. 1-247). Some of the underlying assumptions used in predicting these risks are:

1) 100% GI absorption;

2) two 4-hour work shifts;

3) 2% dermal absorption rate;

4) body weight scaling factor; and

5) upper body absorption as set forth in Table 1. A body weight scaling factor is a quantative adjustment of the dose used in the NTP study to account for the differences in weight between humans and rodents.

Using these estimates of risk, approximately 6 to 30 per 1000 workers may be at risk of developing cancer when exposed at worst case existing conditions to MDA over a working lifetime (Table 1, Senario 1). OSHA also notes that these estimates of risk are not based on the application of a scaling factor based upon surface area. When this surface area scaling factor is applied, the estimates of risk significantly increase to ten times the risk levels shown in Table 1. OSHA did not adopt this scaling factor because there was no evidence that this was a more appropriate approach to use than the traditional body weight conversions used by OSHA.

In addition, OSHA notes that in making the estimates of risk, OSHA has gone beyond the traditional regulatory methodology and added to this assessment the estimates of risk which can be expected from dermal deposition. OSHA recognizes that substantial exposure may occur through deposition and subsequent absorption of MDA on the upper body, neck, etc., and has considered these confounding factors in assessing risk (in certain situations approximately 95% of exposure results from dermal absorption).

While OSHA was able to make estimates of risk which might result from dermal exposure, OSHA was unable to establish allowable dermal exposure limits. There are a number of reasons why this is impractical, among which are the difficulty of quantifying dermal exposures, the inability to select a reliable biological indicator, and finally the difficulty in correlating the amount absorbed with a precise adverse health affect. OSHA has not quantified risks resulting from dermal exposure in other toxic substance standards. In order, to adequately regulate dermal exposure to MDA, OSHA requires adherence to permissible exposure limits (which reduces surface contamination by MDA thereby reducing the opportunity for skin contact and reduces potential for re-entrainment into the air) and the use of personal protective clothing and equipment and the other standard provisions, all of which aid in preventing dermal exposure.

No evidence was provided subsequent to the issuance of the NPRM which would cause OSHA to change any of the findings herein stated.

VII. SIGNIFICANCE OF RISK

OSHA previously made a preliminary finding of significant risk resulting from occupational exposure to MDA in responding to EPA's referral (51 FR 6748), and in the proposed rule at 54 FR 20682. In making this determination, OSHA was guided by a number of factors that are consistent with recent court interpretations of the OSH Act and rationale, and policy formulation regarding significance of risk. As prescribed by Section 6(b)(5) of the OSH Act, the Agency examined the body of "best available evidence" on the toxic effects of MDA to determine the nature and extent of possible health consequences resulting from workplace exposure. The quantitative risk assessment found in Table 1 was used with other relevant information by OSHA to determine whether establishing a permissible exposure limit and other standard provisions would substantially reduce the risk.

For guidance in determining whether regulatory activity would substantially reduce the risk, OSHA followed general guidance given to the Agency by the Court for arriving at findings of the significance of an occupational health risk. The Court stated as follows:

    It is the Agency's responsibility to determine in the first instance what it considers to be a "significant" risk. Some risks are plainly acceptable and others are plainly unacceptable. If, for example, the odds are one in a billion that a person will die from cancer by taking a drink of chlorinated water, the risk clearly could not be considered significant. On the other hand, if the odds are one in a thousand that regular inhalation of gasoline vapors that are 2% benzene will be fatal, a reasonable person might well consider the risk significant and take appropriate steps to decrease or eliminate it (IUD v. API, 448 U.S. at 655).

Although the Court's example is based on a quantitative expression of the risk, the Court indicated that the significant risk determination required of OSHA is not "a mathematical straightjacket," and that "OSHA is not required to support the finding that a significant risk exists with anything approaching scientific certainty." The Court ruled that:

    ...a reviewing court [is] to give OSHA some leeway where its findings must be made on the frontiers of scientific knowledge [and] ....the Agency is free to use conservative assumptions in interpreting the data with respect to carcinogens, risking error on the side of overprotection rather than underprotection (448 U.S. at 655, 656).

OSHA largely bases its findings that a particular level of risk is "significant" on policy considerations (IUD v. API, 448 U.S. 655, 656, n. 62). As part of the significant risk determination, OSHA examined a number of factors consistent with its policy (see Arsenic, 48 FR 1864, January 14,1983; Ethylene Oxide, 48 FR 17284, April 21, 1983; Asbestos, 51 FR 22611, June 20, 1986)); and Formaldehyde, 52 FR 46167, December 4, 1987. These include the type of risk presented, the quality of the underlying data, the reasonableness of the risk assessments, and the statistical significance of risk. Table 1 was adopted by the Committee from the OSHA MDA risk assessment found in the Docket at Exhibit 1-247.

TABLE 1 - Estimated Cancer Risks for Worker Exposure to MDA
CASE I(a) (b) II(a) (b) III(a) (b)
Airborne mg/m(3) (ppb) 0.57(70) 0.38(47) 0.00 0.00 0.01(1) 0.001(12)
Dermal depos- ition ug/cm(2) /hr 9.0(palms and 2.5 (upper body) 250(palms 27 (upper body) 4.2(palms 2.1(palms 0.03 (upper body) 0.003 (upper body)
Inhala- tional exposure kg/day 0.021 0.014 0.00 0.00 0.00036 0.000036
Dermal exposure kg/day 0.0749 0.4186 0.0041 0.0021 0.00087 0.000087
Total exposure kg/day 0.096 0.43 0.0041 0.0021 0.0012 0.00012
Cancer risk MLE (U95CL) Excess 6(7)/1000 3(3)100 3(3)/ 10,000 1(2)/ 10,000 8(9)/ 100,000 7(9)M(1)
Comments Worst Existing case for manufac- turing Worst Existing case for proc- essing Hypothe- tical case to show palm exposure Hypothe- tical case to show palm exposure Regullatory alternative considered Regullatory alternative considered


TABLE 1 - Estimated Cancer Risks for Worker Exposure to MDA
(continued below)
CASE III(c) (d) (e)
Airborne mg/m(3) (ppb) 0.0001(012) 0.16 (20) 0.1 (10)
Dermal deposition ug/cm(2) /hr 0.0003 (upper body) 0.6 (upper body) 0.3 (upper body)
Inhalational exposure kg/day 0.0000036 0.0072 0.0036
Dermal exposure kg/day 0.0000087 0.0175 0.00875
Total exposure kg/day 0.000012 0.025 0.12
Cancer risk MLE (U95CL) Excess 7(9)/10M 2(2)/1000 8(9)/10,000
Comments Regulatory alternative considered Regulatory alternative considered Regulatory alternative adopted
Footnote:(1) M designates 1,000,0000

OSHA reviewed the toxicological and epidemiological literature and the record evidence on MDA described in the Health Effects section. The record, as summarized herein, shows that MDA exposure is associated with a number of adverse health effects. The NTP study indicates that MDA is carcinogenic in both rats and mice (Ex. 1-36). The study appears to have been conducted in accordance with good laboratory practices and is adequate for use as the basis for quantitative risk assessment. The Oak Ridge National Laboratories data also support the findings that MDA is a carcinogen in test animals (52 FR 26782). The ability of MDA to induce tumors in animals, evidence that MDA induces cancer in humans, and data indicating that MDA interacts with genetic material lead to the conclusion that this chemical is an animal carcinogen and is probably carcinogenic to humans.

In animals, MDA has also been associated with genotoxicity, retinopathy, allergic dermatitis, and hepatotoxicity. In addition, human studies strongly indicate that MDA causes a characteristic acute toxic hepatitis.

The quantitative risk assessment, which is used to estimate risk in humans is based on animal studies by NTP. This correlation is achieved by reliance upon generally accepted health policies, which indicate that carcinogenicity demonstrated by a chemical in mammalian species is sufficient to conclude that carcinogenicity is possible to humans. The fit of the experimental cancer data to the model used in making the extrapolations is good and the risk assumptions are reasonable. Therefore, the resulting assessment appears appropriate.

Currently, there is no OSHA standard regulating occupational exposure to MDA. The estimates of occupational risk resulting from inhalation and dermal contact with MDA were made from data (approximately 1983) collected by NIOSH, EPA, and CMA which indicate that current ambient exposures are in the range of 50 to 70 ppb (Scenarios I(a) and I(b) of Table I). The estimates of lifetime risk resulting from these ambient exposures together with dermal deposition were approximately 6-30 per 1000. OSHA concludes that the exposure data and the data used to make risk predictions are appropriate and finds that occupational exposure to MDA constitutes a significant risk of harm to workers. These findings are consistent with OSHA determinations from other rulemakings, such as: Ethylene Oxide (April. 21, 1983; 48 FR 17284, 17295); Benzene (September 11, 1987; 52 FR 34460, 34497); and Formaldehyde (December 4, 1987; 52 FR 46168, 46223). Those estimates per 1000 employees for a working life-time exposure were 63-109 excess cancer deaths from ethylene oxide; 95 excess leukemia deaths from benzene; and .4 - 18 excess cancer deaths from formaldehyde, based on the PEL's which applied prior to the completion of new lower standards.

In evaluating significant risk a framework is provided by an examination of occupational risk rates and legislative intent. For example, in the high risk occupations of fire fighting and mining and quarrying the average risk of death from an occupational injury or an acute occupationally related illness from a lifetime of employment (45 years) is 27.45 and 20.16 per 1,000 employees respectively. Typical lifetime occupational risks of death in occupations of moderate risk are 2.7 per 1,000 for all manufacturing and 1.62 per 1,000 for all service employment. Typical lifetime occupational risks of death in occupations of relatively low risk are 0.48 per 1,000 in electric equipment and 0.07 per 1,000 in retail clothing. These rates are derived from 1979 and 1980 Bureau of Labor Statistics data from employers with 11 or more employees adjusted to 45 years of employment for 46 weeks per year.

In light of the above, OSHA concludes that the estimates of risk associated with occupational exposure to MDA (6 to 30 per 1000) fit well within the range of other risks which OSHA has previously concluded are significant. These estimates are higher than risks of fatality in occupations of average risk, and are substantially higher than the examples presented by the Supreme Court (IUD v. API, Id.).

OSHA finds that the implementation of the final standards will substantially reduce the risks associated with occupational exposure to MDA. OSHA estimates that the risks associated with the PEL of 10 ppb in conjunction with other provisions of the standard will be reduced to less than 0.8 excess cancer deaths per 1000 workers exposed over a working life-time (See Table 1, Scenario III(e)). This represents an 87 to 98 percent reduction in risk. OSHA considers such a reduction to be substantial. Although OSHA is not able to quantify the reduction in the incidence of other diseases that would occur with the implementation of the standard, OSHA finds that these would also be reduced.

OSHA believes that the presence of the additional provisions in the MDA standards act together to reduce the risks associated with occupational exposure to MDA. Provisions, such as annual training, medical surveillance, hazard communication, emergency plans, housekeeping, and exposure monitoring, work together in an inextricable manner to provide additional protection to workers both from cancer and from other toxic effects (52 FR 46234).

No evidence was provided as a result of the issuance of the NPRM which would cause OSHA to change any of the risk assessment analyses or conclusions. A more complete discussion of the significant risk of occupational exposure to MDA can be found in the NPRM (54 FR 20672, May 12, 1989) and the Committee's Recommendations (52 FR 26776, July 16, 1987).

VIII. SUMMARY OF THE REGULATORY IMPACT ANALYSIS AND REGULATORY FLEXIBILITY ANALYSIS.

General Industry OSHA examined the following three regulatory alternatives in the analysis:

(1) a 20 ppb (0.160 mg/m(3)) PEL with a 10 ppb action level,

(2) a 10 ppb (0.08 mg/m(3)) PEL with a 5 ppb action level, and

(3) a 1 ppb (0.008 mg/m(3)) PEL with a 0.5 ppb action level.

The technological feasibility of implementing a STEL was assumed to be feasible for any of the TWA/PEL alternatives examined, in that the same controls needed to reduce the TWA would also assure that the STEL is met. OSHA's findings are as follows:

  • It is technologically feasible for industry to comply with a 10 ppb PEL by installing some readily available engineering controls and incorporating some new work practices. Although it may also be feasible for some industry sectors to achieve 1 ppb as an exposure level, that level is not feasible for major sectors of industry.

  • Lowering the PEL from the present levels to 10 ppb, in conjunction with other provisions of the standard, would result in annualized compliance costs of approximately $10 million and save an estimated 1.8 to 18 production workers lives per year of exposure. In addition, compliance with the new standard will cost an estimated $ 0.7 million and save an estimated 0.5 maintenance workers' lives per year of exposure.

  • The standard is economically feasible for the sectors studied and will not significantly affect either the competitive structure or the long-term profitability of these sectors.

  • The standard is economically feasible and will not result in significant or differential impacts on small business establishments covered under the scope of the standard.

  • There are no nonregulatory alternatives that adequately protect most workers from the adverse health effects associated with MDA exposure. A summary of the benefits and costs estimated by the Committee for the recommended PEL of 10 ppb and two other alternative PELs (20 ppb and 1 ppb) is provided in Exhibit 12, OSHA's PRIA.

a. Industry and Exposure Profiles There are eleven principal industry sectors (maintenance workers for each sector have been separately identified for purposes of analysis) where workers are potentially exposed to MDA. These sectors are:

(1) MDA Production for MDI Synthesis/MDA Sale and Import;

(2) Reprocessing;

(3) Filament Winding;

(4) Potting and Encapsulation;

(5) Molding/Bonding of Tools and Specialty Small Parts;

(6) Wire Coating;

(7) Coatings;

(8) Intermediate for TGMDA and PACM-20 Production;

(9) Polyurethane Curing;

(10) Advanced Composite Materials Production; and

(11) use of PMR-15 Pre-preg Materials.

Further, there are also seven other industrial sectors where MDA was once used and may still be rarely found. These minor sectors are :

(1) Coatings (Polybismalimides) of Printed Circuit Boards and Fabrication of Airplanes Parts;

(2) Dyes and Pigments;

(3) Quiana Yarn;

(4) Intermediate for Pharmaceuticals, Herbicides, etc.;

(5) Rubber Processing;

(6) Anti-Oxidants; and

(7) Ketamine Production.

OSHA also finds that MDA is made primarily to serve as an intermediate in the production of methylenediphenylisocyanate (MDI) and MDI is used in a wide variety of products. However, one to two percent of all MDA produced is sold for uses such as epoxy or polyurethane curing, or production of polyamides. In addition, some MDA is imported and used to produce a crude MDI known as PAPI or used for other non-MDI uses such as tetraglycidyl methylenedianiline (TDGMA) or PMR-15 manufacture. Occupational exposure to MDA occurs in the Construction and Maritime industries, as well.

OSHA also finds that there are six firms which produce MDA for MDI production, MDA for sale, or which import MDA. MDA is manufactured by 6 companies at 7 locations in four states. Dow Chemical Co.(LaPorte, Texas); BASF (Geismar, La); E.I. Dupont (Belle, WV); Mobay Chemical (New Martinsville, WV and Baytown, TX); Rubicon Chemical(Geismar, La); and Uniroyal Chemicals division of Avery (Naugtuck, Ct). Three of these companies, Mobay, Rubicon, and Dow, account for over 90% of the MDA production. Further, OSHA estimates that approximately 600 million pounds of MDA are produced for MDI conversion, 4,474,000 are produced domestically for sale, and an additional 1.8 million pounds are imported. In addition, it is estimated that the percentage of MDA in the product made domestically ranges from 40-70%, while the percentage in the imported product is approximately 98%.

Uses of MDI are far reaching and include areas of construction, refrigeration, transportation, tank and pipe insulation, packaging, casting systems for solid products, and systems for microcellular products. Consumer products include polyurethane foams (rigid, and flexible), elastomers, coatings, thermoplastic resins, foundry core binders, adhesives and sealants, and spandex fibers. Thus, because MDA is the reactant chemical in the production of MDI, the significance of and the need for MDA depends upon the need to produce MDI. However, since there are so many products containing MDI and the extent of MDI use is increasing, it can be assumed that MDA use will also continue to increase. In addition, the non-MDI uses of MDA (2% of total MDA consumption) are also expected to increase as product demand in the areas of nuclear energy, weapons manufacture, and space exploration increases.

OSHA estimated that the number of exposed production workers is 3,836 in the eleven principal industry sectors and an additional 189 maintenance workers are also exposed in these sectors. The average weighted exposure levels ranged from 1 ppb in PMR-15 use to 19 ppb in Filament Winding. For maintenance workers the estimated average exposure level is 250 ppb. The average days of MDA exposure per year ranged from 47 for Advanced Composite Manufacture to 250 for Production and some of the other sectors.

b. Benefit Analysis The major benefit of the standard would be a reduction in the occurrence of occupational illnesses. Some aspects of these benefits can be quantified, such as the reduced risk of cancer due to direct exposure to MDA. The number of cancer deaths that may be prevented because of the MDA regulation is based on the model for quantitative assessment of the risk of cancer deaths resulting from occupational exposure to MDA in conjunction with the estimates of the number of workers exposed to MDA levels in various operations. The model and the exposure estimates are generally based on "realistic worst-case" assumptions; yet, in some respects, the use of the model also tends to underestimate the true benefits of the final regulation, because the only benefits quantified in the analysis are those resulting from a reduced incidence of cancer. They do not include an estimate of the reduction in the incidence of other adverse health effects potentially associated with MDA exposure such as liver disease or dermatitis. Because of data limitations, OSHA could not quantify these additional benefits. OSHA's benefit analysis reflects the estimated number of lives saved that will occur when the standards are implemented. OSHA used risk estimates to determine benefits. OSHA is cognizant of the fact that many regulatory agencies, such as EPA, recommend using the surface area scaling factor because application of this factor makes the correlation between dose in animal and dose in man more precise. The application of the surface area scaling factor increases the benefits by one order of magnitude.

OSHA estimates, using "realistic worst case" assumptions, that implementing a 10 ppb PEL and the associated duty provisions may result in 2.3 cancer deaths averted per year of exposure. In addition, if the surface area scaling factor is applied, OSHA estimates that 23 cancer deaths per year could be averted.

c. Technological Feasibility OSHA has determined that the final standard is technologically feasible. The methods that can be used to reduce employee exposure to MDA include conventional technologies such as general and local exhaust ventilation, pneumatic feed systems, glove boxes, and work practices. Such technologies are commonly known and currently used in the affected industries. In addition, provisions of the standard that are not related to the PEL, such as medical surveillance and training, are judged to be feasible.

d. Costs of Compliance OSHA made estimates of the compliance costs that would be incurred by employers in the eleven principal industry sectors which handle MDA and would be primarily affected by the standard. Because there are industry-specific differences in exposure characteristics and equipment usage, cost estimates for each sector were developed separately.

A baseline of current industry practice was identified for each sector. This baseline was derived from information on current production methods, exposure levels, and hazard control techniques. The costs of the controls which would be needed to achieve each successively lower PEL were then estimated based on the assumption that new controls could be added to those controls already in place.

It should be noted that the lower the target PELs, the higher the uncertainty associated with estimates of the effectiveness of control technology and housekeeping practices and their related costs. OSHA is confident that a 10 ppb PEL can generally be reached and maintained on an 8-hour TWA basis but is unsure that all industry sectors could generally achieve a 1 ppb PEL.

OSHA has estimated the total annualized compliance cost (for production workers) as $10 million for the 10 ppb permissible exposure limit. The major component of the estimated costs for production workers are the costs of hygiene facilities and practices, which constitute approximately 50% of the total estimated costs for the 10 ppb PEL. The second major element of cost is for protective clothing and equipment, which is approximately 30% of the total cost of compliance of achieving the 10 ppb PEL. Housekeeping costs constitute approximately 10% of the total estimated costs. The estimated costs of engineering controls constitute only a small percentage (4%) of the total estimated annualized costs of compliance for production workers.

e. Economic Feasibility Analysis The overall conclusions reached by OSHA regarding economic impact assessment are: (1) most, if not all, of the affected industries ought to be able to pass the regulation's costs through to product purchasers (because of market and other considerations described below); (2) any price increases required are not likely to be very large, relative to the pre-regulation prices of the products; and (3) to the extent that prices of products do not rise (so that pass-through of these regulatory costs to product purchasers does not occur), the regulatory costs are not large relative to the other production costs and the net income of the companies examined. Consequently, OSHA has concluded that the final regulations will not pose a substantial burden to the affected industries, their employees, or consumers of their products.

Hence, OSHA's conclusion is that it is economically feasible for the eleven principal industry sectors to comply with the provisions of the MDA standard and that none of the sectors studied by OSHA would experience significant economic impacts.

f. Regulatory Flexibility Analysis Pursuant to the Regulatory Flexibility Act of 1980 (P.L.

96-353, 94 Stat. 1164 [5 U.S.C. 601 et seq.], OSHA has given special consideration to the mitigation of the economic impacts of the final standard on small entities. OSHA does not anticipate that the standard would adversely affect small entities.

In developing a standard for occupational exposure to MDA, OSHA carefully considered size factors such as number of employees, total assets, and gross revenues to ensure that the final standard would minimize the impact on small firms while continuing to protect workers. Furthermore, OSHA determined in the economic feasibility analysis that most, if not all, of the affected industries would be able to pass the regulatory costs through to product purchasers reasonably rapidly. Thus, most of the affected firms probably will not have to bear all of the compliance costs for these regulations.

Finally, OSHA examined the financial conditions of a sample of firms affected by the regulations and determined that even if these firms were to bear the compliance costs of the regulations, these would not impose substantial burdens for these firms. Therefore, OSHA concluded that the regulation will not significantly affect small entities.

g. Assessment of Nonregulatory Alternatives OSHA believes that there are no nonregulatory alternatives that would adequately protect most workers from the adverse health effects associated with MDA exposure. The tort liability and Workers' Compensation systems do not provide adequate worker protection due to their unpredictability and inconsistency from state to state. Other government regulations do not provide adequate worker protection due to their limited scope. OSHA does not have a current workplace standard for occupational exposure to MDA; thus, no regulatory protection is currently being provided [Note: many employers offer voluntary protection e.g. personal protective equipment, showers, change rooms, etc.].

Summary. In the NPRM OSHA discussed the economic and technological feasibility of implementing the proposed standard for occupational exposure to MDA. OSHA found that the 10 ppb PEL the 100 ppb STEL, and the accompanying standard provisions will substantially reduce the risk to worker health; and that the standard is feasible. OSHA's findings regarding the economic and technological feasibility of implementing the proposed standard were not challenged. In light of the above, OSHA concludes that this final standard is feasible.

Construction Industry

OSHA examined the following three regulatory alternatives in the analysis: (1) a 20 ppb (0.160 mg/m(3)) PEL with a 10 ppb action level, (2) a 10 ppb (0.08 mg/m(3)) PEL with a 5 ppb action level, and (3) a 1 ppb (0.008 mg/m(3)) PEL with a 0.5 ppb action level. Implementing a STEL was assumed to be technologically feasible for any of the TWA/PEL alternatives examined because the controls needed to reduce the TWA would also assure that the STEL is met. OSHA's findings are as follows:

  • It is technologically feasible for the construction industry to comply with a 10 ppb PEL by installing some readily available engineering controls and incorporating some new work practices. Although it may also be feasible for some construction applications to achieve lower limits, this is greatly dependent upon the technique for application. The method for achieving the PEL is dependent on the method of application. If roll-on application is being used, it is easier to reduce exposures below the required PELs through use of very limited technology. On the other hand, when application is through spray technique it may be that a respirator, in addition to engineering controls and workpractices, would be necessary to achieve compliance with the PEL. Use of a respirator, because the type required for spray application is the most effective, would result in exposures below the required PEL.

  • Lowering the PEL from the present exposure levels in the workplace to 10 ppb, in conjunction with other provisions of the standard, would result in annualized compliance costs of approximately $355,428/year.

  • The standard is economically feasible for the construction industry and will not significantly affect either the competitive structure or the long-term profitability of these sectors.

  • The standard is economically feasible and will not result in significant or differential impacts on small business establishments covered under the scope of the standard.

  • There are no nonregulatory alternatives that adequately protect most workers from the adverse health effects associated with MDA exposure. A summary of the benefits and costs estimated for the PEL of 10 ppb and two other alternative PELs (20 ppb and 1 ppb) is provided in Exhibit 12, OSHA's PRIA. The remainder of this discussion summarizes the analyses upon which these findings are based.

Industry Profile For the purposes of estimating costs, risks, and benefits, OSHA made a number of reasonable assumptions in order to estimate the number of potentially exposed employees. These assumptions are based on the amount of MDA which reportedly goes into paints and coatings, the rate (lbs/hr) of paint application under spray and roll-on conditions, and the average hours of work of a typical painter. Assuming that 200,000 lbs of MDA are used yearly in coatings, and that it constitutes 20% by weight of the final product, OSHA estimated that one million pounds of MDA-containing coatings are applied each year. Estimates provided to OSHA by the International Brotherhood of Painters and Allied Trades suggest that the average application rate of spray methods is 20 lbs/hr, while that for the roll-on methods is 30 lbs/hr. OSHA combined these estimates with the assumption that a typical painter spends only four hours/day painting, with the rest of the time taken up by preparation, set-up and clean-up of work areas. OSHA assumed, in the absence of any available data, that a typical painter would spend only 10% of his work time (25 days) each year using MDA-containing coatings. The result of these assumptions is that a typical painter would spend some 100 hours/year applying MDA coatings.

For spray applications, each painter would thus apply 2000 lbs/yr; and for roll-on application, 3000 lbs/yr. Since an estimated 400,000 lbs of MDA paint are consumed each year in spray operations and 600,000 lbs in roll-on operations, the sum of these assumptions yields an estimate of 200 potentially exposed workers (400,000 lbs/yr divided by 2000 lbs/worker year) in spray operations and 200 workers (600,000 lbs/year divided by 3000 lbs/worker-year) in roll-on applications. These estimates are obviously tenuous, but OSHA considers them the best available evidence and a reasonable basis to estimate costs, risks, and benefits. OSHA believes that both spray and roll-on application methods entail risk of airborne and dermal exposure. Spray applications, in the view of OSHA, are especially likely to pose potentially serious hazards. In addition, OSHA is aware of two reported cases involving acute hepatitis after application of MDA-containing coating products, and sources in the scientific literature and at least one trade union have reported that skin problems are common among painters using epoxy paints (52 FR 26847). The latter reports confirm the common occurrence of dermal exposures, and thus the potential for skin absorption of MDA.

For the purpose of risk estimation in spray operations, OSHA assumed that TWA airborne levels of exposure to MDA could reasonably be estimated to be similar to those experienced by maintenance workers, 250 ppb (2 mg/m(3)). Dermal exposure levels were also assumed to be 0.50 mg/cm 2-hr for the palms and 0.00134 mg/cm 2-hr for the forearms and upper body. These are twice that expected for maintenance workers. OSHA believes that the spray applications presented twice the potential for skin deposition and absorption as would be expected for maintenance workers. For manual roll-on applications, it is reasonable to assume lower levels of both airborne and dermal exposures. OSHA estimated that airborne and dermal exposures would be comparable to those estimated for the polyurethane curing sector, or 0.160 mg/m(3) (airborne), 0.25 mg/cm 2-hr for the palms, and 0.00067 mg/cm 2-hr for the forearms and upper body.

OSHA has estimated that 400 workers are exposed to MDA-containing paints and coatings, 200 in spray applications and 200 in roll-on applications. Based on the limited data available, an average of 6 painters per employer or firm was assumed. The total number of potentially affected firms would thus be approximately 66 (400 workers/6 workers per firm). Spray applications were assumed to entail higher exposure, both airborne and dermal, than roll-on applications. Data describing exposure levels, number of employers, or number of employees were not available to OSHA, so that the exposure profiles were constructed with the use of reasonable assumptions.

b. Benefits In this section, OSHA estimated the potential benefits (in terms of deaths avoided) accruing as a result of its standard for the Construction Industry. The analysis of this section demonstrates that as a result of the standard approximately .042 painters applying MDA containing coatings through spray applications and .019 painters applying MDA containing coatings through roll-on applications will be saved for every year of reduced exposure by establishing a permissible exposure limit of 10 ppb and by establishing requirements to limit dermal exposure to MDA. A significant proportion of the estimated lives saved are the result of the reduction in dermal exposure, whereas the reduction in airborne exposure levels makes a much smaller contribution to the reduction in risk.

While OSHA was able to estimate the benefits from reducing the risks due to occupational cancer, it was unable to quantify the effects that the standard's provisions would have on reducing other occupational risks resulting from MDA exposure (e.g., reduced incidence of dermatitis, liver toxicity, etc.).

c. Technological Feasibility This section assesses the technological feasibility of achieving the alternative levels. OSHA has reviewed the technological feasibility and believes that while it may be feasible and necessary in some instances to use local or general exhaust ventilation to reduce exposures, these controls alone will not provide adequate protection for painters (applying coatings through spray application). These controls in conjunction with the use of respiratory protection will be necessary to ensure that workers applying paints through a spray technique are adequately protected. In many instances, OSHA believes that it will not be feasible to use local or general exhaust ventilation, and in these cases only respiratory protection will be used. OSHA recognizes that many coating applications in the Construction Industry will be to concrete structures, pipes, flooring, etc. These surfaces may be located inside or outside of buildings but are usually outdoors. It is often times difficult to use traditional control technologies in these instances. However, OSHA acknowledges that some of these construction activities may be conducted inside of facilities or perhaps in confined spaces (e.g., tanks, pipes). In these instances, OSHA expects that employers will provide the usual and necessary engineering controls in addition to the necessary respiratory protection. OSHA also recognizes that the use of engineering controls in these instances is mandated by existing OSHA regulations (e.g. confined spaces, spray painting).

For purposes of feasibility, OSHA believes that compliance will be achieved primarily through the use of the appropriate respiratory equipment and not through the use of engineering controls. OSHA makes these conclusions based on its findings that in the construction sector MDA appears to be used exclusively in coating application. No other use was identified. While workers applying coatings through roll-on techniques were not expected to need respirators, those engaged in spray application would be required to use a respirator.

    Based on the analysis discussed above, the following determination of feasibility in these sectors was reached by OSHA: o It is technologically feasible for the painters applying MDA-containing coatings to achieve compliance with a PEL of 10 ppb or less through the use of the appropriate engineering controls and workpractices along with the use of respiratory protective equipment for spray operations. o It is also considered feasible to limit dermal exposure by the use of appropriate personal protective equipment and clothing, and through other means as required under the final standard.

d. Costs of Compliance This discussion presents estimates of the compliance costs that would be incurred by employers in the Construction Industry subsequent to the promulgation of a PEL of 10 parts per billion (0.08 mg/m(3)), with an action level of 5 parts per billion. The cost to achieve this PEL would be the result of the use of personal protective equipment, hygiene measures, education, and other measures. The costs of engineering controls are not included in the analysis, since such controls would only occasionally be implemented. The total estimated cost of compliance is $355,428/year for the entire sector to achieve compliance with any of the PELs whether it be 1, 10, or 20 ppb.

e. Economic Feasibility and Regulatory Flexibility Analysis In accordance with Executive Order No. 12991 (46 FR 13193, February 19, 1981), OSHA has assessed the potential economic impacts of the MDA standard. The final determination is that the regulatory requirement limiting MDA exposure in the workplace, including PEL levels reduced to 10 ppb, will not result in significant adverse economic impact on any of the industry sectors for which detailed financial and compliance data are available.

Pursuant to the Regulatory Flexibility Act of 1980 (P.L. 96-353, 94 Stat. 1164 [5 U.S.C. 601 et seq.]), consideration has been given to the mitigation of the economic impacts of the final standard on small entities. Based on the available data, it is not anticipated that the final standard would significantly affect a substantial number of small entities.

The final standard limiting exposure to MDA in the construction industry affects workers in approximately 66 firms. OSHA conducted an assessment of the economic impact on these 66 firms and has determined that it is minimal based on the nature of the applications involved and the probability that these compliance costs will be passed through to the purchasers of their services. The supporting analysis for this finding is presented below, and is based on the same methodology for determining economic impacts used to assess the impact of the proposed regulations on the producers and primary users of MDA.

The annualized compliance costs faced by the affected construction firms will be approximately $5,450. Several factors suggest that these costs will be passed through to the purchasers of the services of these construction firms. First, the purchasers of these firms' services are large firms and government entities managing large projects (e.g., chemical plants, reactors, and defense-related activities). As such, the incremental costs associated with limiting worker exposure to MDA are likely to be extremely small relative to the economic size of these projects. Second, in many cases, contractual and engineering specifications may require that the MDA-related products be used for their desirable physical properties. In these cases, the incremental compliance cost will certainly be passed through to these purchasers. Given these considerations, it is likely that these compliance costs will be fully passed through in a relatively short period of time.

If these compliance costs are passed through to purchasers of these firms' services, the increase in the price of these services is likely to be extremely small. The annual compliance costs per firm are quite low, and constitute a small portion of each firm's total operating cost. Thus the compliance costs of several thousand dollars per year are unlikely to result in price increases leading to contractor failures or employment contractions.

Finally, if the compliance costs are not passed through to the purchasers of the services of these affected firms, given the size of the incremental costs, it is highly unlikely that these costs would pose a significant burden to the firms involved. Relative to the workers' salaries and other costs of construction activities affected by the regulations, the incremental compliance costs of $5,450 per firm are extremely small.

Based on these considerations OSHA concludes that the final standard will not cause significant economic impacts to the affected construction firms because the compliance costs are small relative to the economic size of the affected firms and the activities into which these construction services are inputs.

Summary. OSHA has reviewed the economic and technological feasibility of implementing the final standard for occupational exposure to MDA in the construction industry. OSHA finds that the 10 ppb PEL, the 100 ppb STEL, and the accompanying standard provisions will substantially reduce the risk to worker health, and it is feasible. OSHA's findings regarding the economic and technological feasibility of implementing the proposed standard were not challenged. In light of the above, OSHA concludes that this final standard is feasible.

IX. SUMMARY AND EXPLANATION OF THE STANDARD FOR GENERAL INDUSTRY

Paragraph (a). Scope and Application

(a)(1) OSHA's final standard applies to all "occupational exposures" to MDA with the specific exceptions set forth in the scope and application section and would apply to all workplaces in all industries, except for construction, where MDA is produced, released, stored, handled, used, or transported, and over which OSHA has jurisdiction.

OSHA developed a separate standard for the construction industry, section 1926.60. The two standards, general industry and construction, do, however, cover all industries covered by the Act. The general industry standard covers all activities and operations including ship repair and rebuilding, manufacturing, secondary processing, and downstream use of MDA. Employees of the Construction Industry are covered by the construction standard. Construction activities are defined in 29 CFR 1910.12(b) as work for construction, alteration and/or repair, including painting and decorating.

As noted above, ship repair and shipbreaking activities are covered by the general industry standard. OSHA believes the provisions of the general industry standard are appropriate for the operations involving MDA which will occur on ships. (See the new 29 CFR 1910.19(i) that is promulgated below.) (a)(2) This paragraph contains exclusions for workplaces that process, handle, or use products containing MDA where initial monitoring data show that the product cannot release MDA at or above the action level and where no "dermal exposure to MDA" can occur (see discussion under Paragraph (b), Definitions, as to what constitutes "dermal exposure to MDA"). The criterion for exemption under paragraph (a)(2) requires monitoring data that show that the material is incapable of releasing airborne MDA at or above the action level under the expected conditions of processing, handling or use. The material also must not be a material that results in "dermal exposure to MDA," as defined. Paragraphs (a)(8) and (e)(5) are exceptions to this exemption. Since the exemption is based on initial monitoring, paragraph (a)(8) requires that these monitoring records be maintained. Similarly, paragraph (e)(5) requires additional monitoring when changes occur that might affect employee exposure.

This exemption and the underlying rationale for this exemption were adopted by OSHA from the Mediated Rulemaking Committee's recommendations (Exhibit 9). During the Committee's deliberations, various situations were discussed pertaining to this exemption which the Committee believed should be excluded from the requirements of any final regulations. For example, MDA based epoxy resins are often shelved in hardware stores. Unless the containers are broken, these resins pose no hazard for employees stocking shelves etc. In this situation, it is clear that handling these materials does not result in exposures above the action level nor will dermal contact with the MDA material occur. A second example involved the mechanical transportation of MDA through an automated piping system. Unless the pipe ruptures, the Committee believed that it was not possible for employees to be exposed to MDA transported in this manner. Thus dermal exposure was not expected. Therefore, the Committee believed that this type of situation should also be excluded from the standard.

In both of the examples described above, the Committee only addressed worker exposure which resulted from either ambient exposure above the action level or the potential for dermal exposure to non-airborne forms of MDA. Consideration was not given to any dermal exposure which might result from ambient exposure and subsequent "fall out" (airborne particles or vapors settling on the skin). It was the Committee's belief that dermal absorption hazards resulting from this "fall out" of airborne MDA had already been adequately addressed by establishing very low permissible exposure limits and action level. OSHA fully concurs with the Committee on these points. The exemption, under paragraph (a)(2), therefore, is available when two conditions exists, i.e. exposure above the action level does not occur and "dermal exposure to MDA," as defined, is not possible.

(a)(3) This paragraph allows the employer to rely on objective data as the basis for an exemption when the data indicate that MDA is not capable of being released ambiently and where no "dermal exposure to MDA" can occur. OSHA believes that the primary and intermediate users will be in the best position to test their products and to supply the necessary objective data. The final standard would not require downstream employers to generate their own objective data on the MDA levels likely to be released from a product if they can obtain it from producers or other processors. There was no objection to the proposed allowance of the use of "objective data" as exemption criteria. Thus, the final standard contains this provision as specified in the proposed rule.

(a)(4) The final standard also exempts the storage, transportation, distribution, or sale of MDA in intact containers sealed in such a manner as to contain the MDA dusts, vapors, or liquids, except for the provisions of 29 CFR 1910.1200 as incorporated into this standard and the emergency provisions of this standard. Containers are covered by the Hazard Communication standard, 29 CFR 1910.1200 (52 FR 31852; Aug. 24, 1987), which requires, in conjunction with the MDA standard, labeling containers to indicate that they contain MDA (a suspect carcinogen), employee training specifying what to do if the container was opened or broken, and supplying material safety data sheets to users/employees.

The basis for this exemption is that sealed containers are unlikely on a regular basis to leak sufficient MDA to expose employees over the action level or pose a dermal exposure problem. The labeling and training provisions of the Hazard Communication standard provide sufficient protection in those situations where a container breaks so that employees will know how to handle and clean up a spill safely. The intention of this exemption is to cover most warehouses, distributors, supply rooms, and similar operations where chemical containers are stored, transported, or sold, and not normally opened. However, operations where the containers are opened and the contents used or tested would be covered by the standard because of the possibility of exposure in excess of the action level or dermal exposure.

Other than the concerns over the omission of the 0.1% exclusion, there was no comment on this paragraph. The 0.1% exclusion is addressed in relation to paragraph (a)(6) and that discussion applies to this paragraph as well.

(a)(5) This paragraph contains provisions establishing a separate standard for construction and excluding construction activities from the scope of the general industry standard.

(a)(6) This paragraph was not contained in the NPRM. It establishes a de minimis exclusion for MDA mixtures or materials which contain MDA in concentrations of less than 0.1% by weight or volume. OSHA implicitly incorporated a de minimis exclusion in its NPRM as recommended by the Committee. In OSHA's notice of hearing found at 55 Federal Register 2101 (January 22, 1990), OSHA clearly states,

    The exclusion found in the proposed MDA rule, although not explicit, implicitly states that a 0.1% exclusion will be part of the MDA rule.

OSHA was guided in adopting this exclusion by the data furnished by the Mediated Rulemaking Committee. In the recommendations rendered by the Committee, data were provided which indicated that worker exposure to mixtures or materials of MDA containing less than 0.1% MDA did not create any hazards other than those expected from worker exposure beneath the action level (Ex. 9). Additionally, the requirements found in 29 CFR 1910.1200 (d)(5) state,

    ...that the mixture shall be assumed to present a carcinogenic hazard if it contains a component in concentrations of 0.1 percent or greater which is considered to be a carcinogen...

Thus, having given consideration to both the Committee's recommendations and OSHA's Hazard Communication standard provisions, OSHA decided in the NPRM to be consistent with the Hazard Communication requirements. This exclusion was the basis for the majority of the concerns expressed by the commenters to the NPRM. As a result of these concerns OSHA, in its Federal Register notice of January 22, 1990, invited testimony on,

    . . .the appropriateness of expressly establishing a 0.1% exclusion by weight or volume for all operations involving mixtures containing MDA from the proposed regulation. (Id.)

In addition, several commenters and hearing participants recommended a de minimis percentage exclusion of 0.1% be adopted, thus reflecting the Hazard Communication standard (Lockheed, Ex. 11-22; United Technologies, Ex. 11-23; Monsanto, Ex. 11-26; United States Air Force, Tr. II-5; etc). On the other hand, no data were furnished by any of the hearing participants or in the post-hearing comments which would suggest that establishing a 0.1% exclusion, as suggested in the hearing notice, would not be appropriate. Thus, OSHA has added to the scope and application section of both the general industry and the construction standards a paragraph adding this percentage exclusion.

(a)(7) The final standard contains an exemption for "finished articles containing MDA" (See discussion under Definitions) (a)(8) This paragraph requires that the employer appropriately document the information which supports any exemption, and the employer must maintain a record of this information. There was no comment made to the provisions contained in this paragraph. The final standard contains this paragraph as originally proposed.

Paragraph (b). Definitions

Paragraph (b) of the final MDA standard for general industry defines a number of terms used in the standard. In some instances, the definitions are consistent with those found in other OSHA standards, e.g., "Director," "Assistant Secretary," and "Authorized person". However, certain other terms will be discussed to clarify their meanings in this standard.

ACTION LEVEL

OSHA establishes an "action level" of one-half of the established TWA in the final standard. The purpose of the action level is to relieve the burden on employers by providing a cut-off point for required compliance activities under the standard.

The statistical basis for determining the action level is discussed in connection with several other OSHA health standards (see, for example, Acrylonitrile, 43 FR 4794). In brief, although all measurements on a given day may fall below the permissible exposure limit, some possibility exists that on unmeasured days the employee's actual exposure may exceed the permissible limit. Where exposure measurements are above one-half of the permissible exposure limit, i.e. the action level, the employer cannot reasonably be confident that the employee may not be overexposed. (Leidel, N.A. et al., "Exposure Measurement Action Level and Occupational Environmental Variability." DHEW, PHS, DCD, NIOSH, DLCK (August 1975)). Therefore, requiring periodic employee exposure measurements to begin at the action level provides the employer with a reasonable degree of confidence in the results of the measurement program.

In the absence of a demonstrated safe level of exposure for a carcinogen, it is appropriate to begin some protective actions, for example monitoring provisions, shower requirements and medical surveillance, at one-half the PEL or, in the case of MDA, 5 parts per billion. Establishing an action level serves such a purpose, as well.

EMERGENCY

The final standard includes a definition of an emergency. Emergency is defined to mean any occurrence such as, but not limited to, equipment failure, rupture of containers, or failure of control equipment which results in an unexpected and potentially hazardous release of MDA. Sections of the final standard that include provisions to be met in case of emergencies include respiratory protection, medical surveillance, and employee information and training.

There was some comment on the NPRM regarding the definition of an emergency situation. Objectors argue that the courts have restricted the requirement for implementing an emergency plan to circumstances where the probability of harm is present rather than requiring emergency provisions be triggered by the potential for a hazardous release. They argue that the definition contained in the proposed rule, because of the over inclusive nature of the term "potential," requires that an emergency plan, including alarms, evacuation, and all other elements specified in section 1910.38, be implemented in situations which are questionably emergencies.

General Dynamics (Ex. 11-9), on the other hand, reads the definition of emergency very narrowly to mean that only primary manufacturers need establish emergency programs.

OSHA reviewed all of the comments regarding the definition of an emergency and believes that the language recommended by the MDA Mediated Rulemaking Committee and proposed by OSHA in the NPRM is the appropriate language. OSHA acknowledges that every spill or leak does not constitute an emergency situation. The exposure to employees must be significant and pose a hazard. OSHA believes that this is a performance oriented provision relying on judgement and that it is not possible to specify detailed circumstances which constitute an emergency. Further, OSHA believes that the definition as proposed allows the employer sufficient flexibility in exercising judgement as to which situations constitute an emergency. In addition, the emergency provisions of this standard are consistent with similar provisions of other OSHA toxic substance standards ( See for example, 29 CFR 1910.1003-.1016, 1910.1017(i), 1910.1045(i), and 1910.1047(h).

Employers must provide emergency plans and employees must be trained to implement these plans. The definition is promulgated as proposed.

EMPLOYEE EXPOSURE

OSHA's final regulation also defines "employee exposure" to mean that exposure which would occur if the employee were not using a respirator or personal protective equipment. The employee's exposure measurements would be made without regard to any use of personal protective equipment. OSHA believes that exposure monitoring is not a single-purpose activity. It is necessary to know employee exposure levels without the use of respiratory protection or personal protective equipment to evaluate the effectiveness of engineering and work practice controls and to determine whether additional controls must be instituted. In addition, monitoring is necessary to determine which respirator, if any, must be used by the employee. This definition is consistent with OSHA's previous use of the term "employee exposure" in other health standards.

FINISHED ARTICLES CONTAINING MDA

The final standard exempts "finished articles containing MDA"

from the regulation. A "finished article containing MDA" is defined as a manufactured item: (i) which is formed to a specific shape or design during manufacture; (ii) which has end use function(s) dependent in whole or part upon its shape or design during end use; and (iii) where applicable, is an item which is fully cured by virtue of having been subjected to the conditions (temperature, time) necessary to complete the desired chemical reaction.

As discussed below, OSHA is basing this action on testimony by rulemaking participants that end use articles, including cured articles, do not present a hazard with respect to exposure to MDA; on quantitative data evaluating the extent to which unreacted residual MDA remains on or within finished articles; and on experience gained by OSHA during development of its Hazard Communication standard (48 FR 53280).

The Air Force, in its testimony, recommended "...exempting finished articles from the standard, and the definition of 'finished article' should include fully cured products, that is, those that a user may only have to drill assembly holes or finish sand and this goes back to the hazard communication standard" (TR. 2-5). The Air Force further commented that:

    In our testimony we recommended finished articles be exempted from the MDA ruling [sic] and further recommended the definition of finished article included cured products. Our definition of a cured product is any item which has been subjected to the conditions [necessary] to complete the desired chemical reaction. The purpose of this definition is to exempt those composite parts which only require final machining (limited to debarring and final hole drilling) but not exempt prepreg materials which can be further cut and shaped to form a final product. (Ex. 35).

Exemption for cured, MDA products was also supported by Dr. JoAnne Pigg, a technical health professional member of the OSHA Mediated Rulemaking Advisory Committee:

    I recommend that all cured materials utilizing MDA including adhesives, encapsulates, coatings, etc., in addition to composites, be exempted from requirements of the proposed standard. It is agreeable that finite, but undetectable levels of MDA can exist in those materials, but no health hazards from employee exposure exist. (Ex. 20).

With respect to the question of why curing eliminates concern over MDA exposure, Brunswick testified that:

    During the curing process the MDA is cross linked chemically with the epoxy resin or polymerized with the polyamide resins. The cross linking results in a formation of a solid epoxy product. The raw components, MDA, epoxy resins and polyamide resins lose their identity in the process that is not reversible. The resulting mass of cured resin is considered to be a non-hazardous product as defined by the EPA (TR. 1- 194).

The CMA pointed out that "...curing procedures and times and temperatures are all designed ... to... [result in products that are]...essentially MDA-free," and "...if they are improperly cured...then they're not going to have the physical properties that the supplier was trying to impart to them." (TR. 1-205).

Sampling data submitted to the record substantiates the assertion that it is appropriate to exempt cured MDA materials from the standard. Data were submitted by Sandia National Laboratories (Ex. 20B) on three cured materials: an epoxy containing 25% MDA, a polyurethane containing 10% MDA and a polyamide formulation containing 4% MDA. Wipe sampling performed on the products after full completion of the curing processes revealed no free or unreacted MDA at the detection method limits of 0.2 micrograms per hundred square centimeters. Sandia indicated that these materials were tested for unreacted surface MDA because ". . .when it's cured it certainly . . . would be physically bound inside but we wanted to make sure there was nothing on the outside. . ." (Tr. 1-185).

In addition to surface sampling for MDA, Sandia analyzed dust generated from drilling of a finished cured circuit board derived from the polyamide formulation containing 4% MDA. Analyses revealed the dust to be free of MDA at the limit of detection of 2 ppb (Tr. 1-182). Rhone-Poulene, Inc. testified that ". . .final products produced from our resins do not contain detectable MDA. For example, test efforts to detect free MDA in copper clad cured laminates to a detection level of 0.0001 percent had been unsuccessful." (Tr. 1-134).

Finally, the Air Force cited data showing ". . .swipe samples averaging 0.4 micrograms per 100 centimeters squared used in an epoxy putty which air cures." (Tr. 2-7). Although measurable surface MDA was detected on this material, the Air Force submitted calculations illustrating the relative degree of health hazard associated with such exposure. The Air Force estimated that a surface contamination of 2,400 micrograms per 100 square centimeters would be required in order to pose a health risk equivalent to that of the proposed 10 ppb airborne exposure. The Air Force asserted that it is unlikely that cured products would ever have surface contamination approaching this level. (Ex. 35).

Based on comment and data in the record, such as that cited above, OSHA concludes that it is appropriate to exempt finished articles containing MDA, including cured products, from the requirements of the MDA standard. OSHA is convinced that finished articles do not present a health hazard to employees to the extent that it is necessary to regulate such hazards under the MDA standard. OSHA believes that the health benefits derived from compliance with this rule will best be served by obligating employers to focus resources on control of employee exposure to MDA forms and uses only in those instances where a health hazard exists.

The specific language in the definition of "finished articles containing MDA" is derived from two sources. Items (i) and (ii), discussed further below, are taken from the definition "article" in the Hazard Communication standard which defines items exempt from that rule. Item (iii) has been adopted from language recommended by the Air Force (Ex. 35) for use in identifying what a cured product is (e.g. ". . .subjected to the conditions necessary to complete the desired chemical reaction.") OSHA believes that the language in item (iii) is sufficiently explicit that employers know at what stage their products can be considered fully cured for the purposes of this regulation. The term ". . .subjected to the conditions. . ." clearly means that the article must experience its full curing time at the temperatures designed to effectuate the curing process. The article will be considered cured if the desired chemical reaction has been completed as a result of it having been subjected to the specified curing time(s) and temperature(s). Items (i) and (ii) under the definition are derived from OSHA's Hazard Communication standard, as was suggested during the rulemaking hearing (Tr. 2-6). The Hazard Communication standard exempts any "article" which, defined in part, is a ". . .manufactured item: (i) which is formed to a specific shape or design during manufacture; [and] (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use." For example, pre-pregs, by their very design and application, would ordinarily not be exempted by the "Finished Article" criteria. (See Ex. 11-24, Ex. 19A, Tr. 1-136.) The preamble to the Hazard Communication standard explains the rationale underlying this exemption as follows:

    Several commenters suggested that OSHA exempt "articles" from the scope of the standard. The purpose of this exemption is to ensure that items which may contain hazardous chemicals, but in such a manner that employees won't be exposed to them, not be included in the hazard communication programs. Examples of such items would be nuts and bolts or tools. The exemption has been added to the final standard and a definition was added as well. It was further suggested that OSHA adopt the definition for "article" used by the Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA). OSHA found that the definition used by EPA was appropriate for this standard in part. The EPA definition in part is essentially as follows: "article" means a manufactured item: (i) which is formed to a specific shape or design during manufacture; and (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use. 48 FR 53280

For the same reasons cited under the Hazard Communication standard, parts (i) and (ii) of EPA's definition of "article" is being adopted by OSHA under the MDA standard.

DERMAL EXPOSURE TO MDA

The final standard requires the employer to take certain protective actions where employees, engaged in the handling application or use of mixtures or materials containing MDA, are subject to dermal exposure to MDA. "Dermal exposure to MDA" can occur with any of the following non-airborne forms of MDA: (i) liquid, powdered, granular, or flaked mixtures containing MDA in concentrations greater than 0.1% by weight or volume; and (ii) materials other than "finished articles" containing MDA in concentrations greater than 0.1% by weight or volume. In situations where employees handle, apply or use any MDA mixtures or materials as defined above, dermal exposure to MDA is considered to occur. The agency believes that correlating dermal exposure with handling, applying or using specific forms of MDA removes the confusion that has arisen from using such terms as "likelihood of dermal exposure." Simply put, dermal exposure to MDA is assumed to occur when employees handle, apply or use any MDA falling under the definition of "Dermal exposure to MDA." Where such exposure occurs employers must do the following: provide affected employees with appropriate protective equipment, as required under paragraph (i) of this section; establish regulated areas, as required under paragraph (f) of this section; establish hygiene practices and lunch areas, as required under paragraph (j) of this section; and implement a medical surveillance program for affected employees as required under paragraph (m) of this section.

OSHA believes that the protective measures prescribed under the paragraphs cited above are necessary in order to minimize the adverse health effects associated with dermal exposure to MDA. OSHA's risk assessment analyzed the risk associated with dermal exposure and found that a 20 fold increase in risk could be prevented by not allowing dermal contact with MDA. MDA is easily absorbed through the skin at the rate of 2 µg/cm(2) per hour. In addition, recent studies by El-hawari (Ex. 1-251) indicate that the absorption of MDA peaks 5 hours after the end of the work shift and that 80% of the substance is cleared from the body within 24 hours of exposure. It is difficult to correlate the amount deposited on the skin with a biological indicator, such as the amount found in the urine, because of the characteristics of MDA absorption and elimination in humans. MDA easily enters the body through the skin. Once deposited on the skin absorption continues although the worker may have long since left the work place and the apparent exposure area. Once absorbed into the body the chemical is rapidly eliminated so that using a biological indicator, such as urine measurement, may not detect the apparent exposure. All in all, MDA can be considered a chemical with poor biological warning properties or biological indicators of exposure. The best protective measures which can be taken are to prevent skin contact and subsequent absorption by regulating the handling, applying or using of forms of MDA which can result in "dermal exposure to MDA." This will in turn reduce both the risk of cancer and the potential for hepatotoxicity.

REGULATED AREAS

Regulated areas are defined as areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA."

DEFINITION OF MDA

The final standard includes a definition of MDA. Included in the definition are the salts of MDA. The rationale for including the salts in the definition of MDA was not challenged in the response to the NPRM. Thus the compounds covered by the proposed definition remains the same in the final standard.

The NPRM definition contained an exclusion for finished products which is now part of the scope and application section of this final rule.

Paragraph (c). Permissible exposure limit (PEL)

The final standard will limit exposure to MDA by establishing a PEL of 10 ppb as an 8-hour TWA. In addition, OSHA believes that airborne exposure will be further reduced by establishing a STEL for airborne MDA exposures of 100 ppb determined in any 15-minute sampling period (See discussions at 52 FR 26858 and 54 FR 20702). The requirements contained in the final standard are supported by OSHA's findings that occupational exposure to MDA under current occupational conditions poses a significant risk to the health of employees and that the final standard can achieve a substantial reduction in that risk. The permissible exposure limits proposed by OSHA have not been challenged by the rulemaking participants. Thus, the requirements in the final standard remain the same as proposed.

While the permissible exposure limits were not challenged, many of the commenters suggested a biological indicator as a permissible exposure limit. Specifically, the commenters recommend that OSHA adopt an acceptable level of MDA which can be detected in the urine as a permissible exposure limit. Additionally, they contend that the absence of any detectable level of MDA in the urine or a level below the established standard should be used to exclude an employer from coverage of the standard. This concept is similar to that of using the action level as a point below which compliance with specific provisions of the standard is not required. Dr. James Hathaway, the corporate medical director for Rhone-Poulenc Inc. states this position very precisely:

    OSHA (should) include in the standard an option for employers to demonstrate lack of likelihood of significant dermal exposure through biological monitoring. Consistent findings at the end of the shift, end of work week levels of MDA in the urine of less than 160 micrograms per liter should exempt employers from provisions of the standard, other than the ones that would relate to an accidental exposure where, you know, I think it's logical then that certain things would have to be done. (TR. I, 132)

Dr. Hathaway made this recommendation based on earlier calculations which he had made in which he estimates the 5 ppb action level could be comparable to MDA urine levels of 160 µg/l. Thus, since the exposures were nearly comparable, he suggests that the risks were also comparable. (TR. I, 117-133) The Boeing Co. through the written comments of James Vinson also urged that OSHA make use of biological monitoring as a means of exempting the employer from the requirements of the standard. He states:

    The regulation provides an exemption from the requirements where the likelihood of dermal exposure does not exist. It does not, however, provide a mechanism of determining the likelihood of dermal exposure. It is therefore proposed that OSHA require medical monitoring if the "no likelihood of dermal exposure" exemption is to be used. Urine MDA below 100 ppb, for example, would indicate no likelihood of dermal exposure and would allow an exemption from the requirements (Ex. 14-7).

The use of urinary monitoring results to establish a biological PEL was considered by the Mediated Rulemaking Committee. The Committee's discussions were provided to OSHA as well as its recommendations (Ex. 9). OSHA summarized the Committee's recommendations at 54 FR 20694 as follows:

    It is difficult to correlate the amount deposited on the skin with a biological indicator, such as the amount found in the urine. There are many confounding factors which lead to these findings. Firstly, through absorption rates it is apparent that MDA easily enters the body. Secondly, once deposited on the skin absorption continues although the worker may have long since left the work place and the apparent exposure area. Thirdly, once absorbed into the body the chemical is rapidly eliminated so that using a biological indicator, such as urine measurement, may not detect the apparent exposure. All in all MDA can be considered a chemical with poor biological warning properties or biological indicators of exposure.

During the hearings, the Chemical Manufacturer's Association pointed out that the sampling protocol for MDA urinary monitoring is not sufficiently developed at this time to demonstrate a correlation between levels of MDA or its metabolites in the urine and disease development. Furthermore, they contend that there is no correlation between amount of metabolite found in the urine and the total body burden which can be attributed to this form of exposure. (Tr. II, 173) OSHA believes that the recommendations made by the Committee and the testimony provided by CMA regarding the use of biological monitoring are sound and for these reasons is not including a biological PEL in the standard. OSHA, on the other hand, agrees with NIOSH that biological monitoring has some practical application in the standard setting process. NIOSH states at TR I, 25-28 that:

    In regard to biological monitoring, NIOSH recommends biological monitoring to assess the degree of protection offered by the use of recommended protective clothing and equipment, and to assess the effectiveness of other controls such as work practices...It may be noted that biological monitoring assesses exposure by all routes...dermal, inhalation and ingestion.

OSHA also recognizes that the recommendations made by NIOSH regarding the use of biological monitoring in the standard setting process are the same recommendations made by the Mediated Rulemaking Advisory Committee, i.e., biological monitoring can be effectively used to determine the effectiveness of personal protective clothing and equipment, engineering controls, or work practices. OSHA recognizes as did both these groups that if a positive urine sample is found and the worker is wearing personal protective equipment that some or all of the equipment is not operating effectively. The employer armed with this information can then attempt to determine the source of the exposure. Although OSHA does not require that the employer conduct biological monitoring to determine the effectiveness of engineering controls, work practices, or personal protective clothing or equipment, the employer can voluntarily use biological monitoring to supplement the safety and health program. OSHA will continue to review any technological developments regarding biological monitoring for MDA exposure. Additionally, OSHA will consider changes to the standard that involve the establishment of a biological PEL if evidence sufficient for regulatory purposes becomes available.

Paragraph (d). Emergency Situation

OSHA believes that the available health data suggest that elevated short-term exposure to MDA should be viewed with concern. OSHA believes that an unexpected high exposure must be viewed as an emergency situation. The final standard requires that a written plan be developed where there is a possibility of an emergency and that written procedures be developed for alerting employees in the event that an emergency occurs.

The standard provisions also include a requirement to alert employees other than those who have the potential to be directly exposed in an emergency situation. Such employees may be employees from neighboring work sites who may inadvertently approach the emergency site. They may also include employees from other work shifts or employees who may be later exposed to work surfaces or equipment contaminated as a result of the emergency.

OSHA also requires the development of a written plan for each workplace where there is a possibility of an emergency. The plan shall include the elements prescribed in 29 CFR 1910.38, "Employee emergency plans and fire prevention plans."

OSHA believes that the performance language of the emergency situation paragraph will give employers the flexibility to choose any effective method of alerting employees, including communications systems, voice communication, or a bell or other alarm. OSHA believes that emergency plans are necessary and must be made a part of every standard.

In response to the NPRM, some of the commenters expressed concern with the difficulties expected from implementing the emergency provisions of the standard. United Technologies (Ex.11-17) commented that emergency plans should only be required when there is a reasonable probability of MDA release in an emergency situation. They contend that the broadness of the term "possibility" makes every situation a potential emergency and thus becomes economically prohibitive. They commented that changing the term "possibility" to "probability" makes it easier to determine what is an emergency and when planning is required.

Many other commenters suggested that OSHA amend the requirement by changing the term "possibility" to "probability." The Brunswick Company states:

    "Possibility" is an open-ended term that is defined in a legal term as presenting unlimited liability. "Probability" limits the scope of the intent of the requirements for the need to develop emergency plans to define parameters. The ideal legal terminology would be to include "reasonable probability" in the wording of the regulation to specify the development of an emergency plan which requires alarms and evacuation plans.(Ex. 15-4)

The basis for their contentions is that in small operations, such as those conducted by the Brunswick Company, the use of a full-scale emergency plan does not seem warranted. Further they urge OSHA to establish some action levels or criteria for developing and implementing an emergency plan.

United Technologies (Ex. 11-17) further states that the Courts have held that OSHA cannot require employers to abate the mere possibility of hazard but that there must be a reasonable probability of harm. Further they state that almost any situation can present the possibility of an emergency but it is difficult to imagine an emergency involving pre-pregs that is likely to present a significant risk to employees. Therefore, they argue, to be consistent with the Court's interpretation, the word "possibility" in this paragraph should be changed to "reasonable probability."

In addition, Chemical Manufacturer's Association (CMA) commented that an emergency plan should be required where there is a reasonable possibility of an emergency. (Ex. 11-13).

OSHA reviewed these written comments and finds that supportive evidence was not furnished which suggests that changing the term possibility to probability would facilitate compliance without compromising the benefits afforded the worker through these emergency planning provisions. Additionally, no hearing participant provided information supportive of United Technologies contentions. Finally, since United Technologies did not appear as a hearing participant, OSHA was unable to discover through cross- examination what, if any, probative evidence exists to support such a change.

OSHA, however, has the written recommendations of the Mediated Rulemaking Committee and the supportive rationale for the provisions contained in the NPRM. George Robinson, representing the IAM, testified during the Mediated Rulemaking Committee deliberations on the appropriateness of using the term "possibility" to trigger the emergency situations provisions. He provided the Committee with his experiences regarding workers who died as a result of the lack of emergency planning (Ex. 9). He felt that the broadest term, e.g. possibility, must be used when describing an emergency situation. His testimony convinced the entire Mediated Rulemaking Committee and subsequently OSHA when the NPRM was developed. OSHA agrees with the Committee's findings and, for the reasons stated in those recommendations, has adopted the term "possibility" as part of the emergency planning requirements.

Other commenters expressed concerns with what they believed to be a requirement to have two sets of duplicate written plans. Specifically, McDonnell Aircraft Company (Ex. 11-6) provided a written submission which stated that the requirements for two written plans, 1910.1050 (d) and (g)(2) are not necessary. They were referring to the requirement to have (1) a written emergency plan and (2) the requirement to develop a written plan for compliance with the PEL. The two requirements do not overlap. As previously mentioned, OSHA relied on the recommendations of the Mediated Rulemaking Committee in adopting the provisions contained in the NPRM. The rationale in support of a written emergency plan can be found in Exhibit 9, the Committee's recommendations. No evidence was provided by McDonnell Aircraft to support its assertions. Furthermore, in their written submission, they acknowledge that hazardous chemicals are present in most large manufacturing facilities and in abundant supply and diversity. Given the abundant supply and diversity expressed by the commenter, it hardly seems inappropriate to have a written plan which identifies the chemical and the emergency procedures. Furthermore, OSHA notes that the emergency provisions contained in the final standard are consistent with what OSHA has required in other standards. In light of the above, OSHA promulgates the emergency requirements as proposed.

Paragraph (e). Exposure Monitoring

Section 6(b)(7) of the Act (29 U.S.C. 655) mandates that any standard promulgated under section 6(b) shall, where appropriate, provide for monitoring or measuring employee exposure at such locations and intervals and in such manner as may be necessary for the protection of employees.

OSHA believes that it is appropriate for employers to measure employee exposure to MDA for the following reasons. First, exposure monitoring informs the employer whether the employer's legal obligation to keep employee exposure below the permissible exposure levels is being met. Second, exposure monitoring evaluates the effectiveness of engineering and work practice controls and informs the employer whether additional controls need to be instituted. Third, exposure monitoring is necessary to determine whether respiratory protection is required at all and, if so, which respirator is to be selected. Fourth, Section 8(c)(3) of the Act (29 U.S.C. 657) requires employers to notify promptly any employee who has been or is being exposed to toxic materials or harmful physical agents at levels which exceed those prescribed by an applicable occupational safety or health standard, and to inform such employee of the corrective action being taken. Finally, the results of exposure monitoring constitute a vital part of the information which must be supplied to the physician and may contribute information on the causes and prevention of occupational illness.

The final standard requires that the employer determine the exposure for each employee exposed to MDA. It is not necessary to provide separate measurements for each employee. If a number of employees perform essentially the same job under the same conditions, it may be sufficient to monitor only some of such employees to obtain data that are representative of the remaining employees. Representative personal sampling for employees engaged in similar work and exposed to similar MDA levels can be achieved by measuring that member of the exposed group reasonably expected to have the highest exposure. This result would then be attributed to the remaining employees of the group.

In many specific work situations, the representative monitoring approach can be more cost-effective in identifying the exposures of affected employees.

Because of the nature of the MDA exposure hazard, it is necessary that the scope of the final standard be as broad as possible to protect potentially exposed employees. However, many employers will be required only to perform initial monitoring to determine employee exposures. If the results of initial monitoring demonstrate that an employee's exposure to MDA is below the action level, the employer is allowed to discontinue monitoring and other activities under this provision of the standard for that employee. OSHA established this provision to reduce the burden on employers, while providing them with an objective means of determining whether they must take additional steps for compliance with the standard.

The final standard also contains provisions for periodic monitoring. The more frequent the measurement, the higher the accuracy of the employee exposure profile. Selecting an appropriate interval between monitoring efforts is a matter of judgment. Where exposure measurements are determined to be above the permissible exposure limits, the employer is required to monitor every 3 months. Where exposure measurements are above the action level but at or below the PELs, monitoring is required only at 6 month intervals. Additional monitoring is also required for a particular job position if any changes in production, processes, control measures, or personnel result in new or additional exposure to MDA. The redetermination of employee exposure is necessary to assure that the most recent results accurately represent existing exposure conditions. This is necessary so the employer may take appropriate action such as instituting additional engineering controls or providing appropriate respiratory protection.

The final standard also contains provisions for visual monitoring of exposed skin areas. The employer would be required to make routine inspections of the face, hands, and forearms of employees potentially exposed to MDA. If the inspection reveals yellow staining or other abnormalities associated with dermal exposure to MDA or if the employee attests to such abnormalities elsewhere on the employee's body, the employer shall send the employee to a medical professional for evaluation. If the employer determines that the employee has been exposed to MDA the employer shall:

    (a) Determine the source of exposure;
    (b) Implement protective measures to correct the hazard; and
    (c) Maintain records of the corrective actions in accordance with paragraph (n) of this section.

Many of the commenters presented testimony regarding the difficulty anticipated from implementing the visual monitoring requirements. The testimony was in three general areas: establishing responsibilities for the employer which are non- performable, invasion of privacy associated with the employer conducting visual monitoring of workers' skin and the specificity of the yellow staining.

Regarding the first issue, non-performable responsibilities, Westinghouse Electric Corporation (Ex. 11-11) argued that the requirement in the proposed rule to make routine inspections of employee dermal areas potentially exposed would be difficult to do. They contend that this requirement would make the first line supervisor a diagnostician. Furthermore, they contend that if the first line supervisors are not medically experienced, they can not be adequately trained to examine the skin surfaces sufficiently to detect exposure from MDA or any other dermal conditions. General Dynamics (Ex.11-3), although not concerned with the non- performability aspects of this provision, argued that some guidelines on what constitutes an employee skin inspection (presumably signs of yellow or red-itchy cracked skin) are necessary.

OSHA believes that the first line supervisor can conduct visual monitoring. OSHA is guided in making this decision by the recommendations made by the Mediated Rulemaking Committee. In the rationale provided by the Committee, it is clear that the first line supervisor is responsible only for examining the skin and looking for abnormal conditions such as yellow staining, red- cracked skin, browning of the finger tips, or whatever can be noticed by a simple visual inspection (Ex. 9). It should be noted that the purpose of this requirement is to determine whether or not personal protective equipment should be worn by the worker and, if so, is effective. The first line supervisor needs only to detect a change and then the worker must be referred to a physician for follow-up and determination. The Committee's rationale was that visual monitoring should be the first line of defense used when exposure to a skin absorbable substance is apparent. OSHA agrees with the Committee's rationale and has not been provided with any conflicting evidence. Thus, the requirement for the employer to conduct visual monitoring remains in the final standard.

Regarding the second issue, invasion of privacy, McDonnell Douglas (Ex. 11-6) stated that the visual monitoring requirements must delicately avoid invasion of privacy. They state:

    It must clearly state that the employer may inspect face, hands, and forearms, and send the employee to a medical professional if other areas of contamination are suspected or attested to by the employee.

OSHA agrees that the privacy aspects of conducting dermal monitoring must be strictly adhered to. OSHA believes that if an employer follows the recommendations given by McDonnell Douglas as stated above that workers privacy will not be invaded. For example, the hands, face, forearms or in general the exposed areas of the body can be viewed without removing any clothing. The employer can examine the hands to determine if MDA exposure has occurred. The employee is capable of identifying staining on other parts of the body and should be referred to a physician for follow- up. During the Committee's deliberations, one of the employer groups presented data which indicated that yellow staining of lower body parts had been noted in his work force. The question of conducting visual monitoring in this instance was discussed at length for this particular situation. The Committee agreed and OSHA agrees with the Committee's conclusions that the best thing to do in this situation was to refer the worker to the appropriate medical personnel for follow-up.

Once the determination has been made that skin contact has occurred the appropriate corrective actions must be taken. Thus, the visual monitoring requirements contain the obligations of the employer for conducting this type of monitoring.

Many of the commenters stated that pure MDA does not produce yellow staining but that the staining results from handling of specific MDA mixtures. The Department of Energy (Ex. 11-8) contended that:

    Visual monitoring of exposed body areas needs further consideration. Often meta-phenylene diamine (MPDA) is present in MDA liquid mixtures. While MDA alone does not stain skin or clothing significantly, MPDA stains both skin and clothing much more intensely. Thus with MDA-MPDA mixtures there could be considerable visible staining of skin and clothing resulting in unwarranted alarm if MDA is the major concern.

OSHA agrees that these concerns of the hearing participants are well founded. However, OSHA did not propose the provisions to conduct visual monitoring of workers' skin based solely on the belief that yellow staining could be used as a positive indicator of exposure. Instead, it was OSHA's view and that of the Committee that if a worker was wearing personal protective clothing, e.g. gloves, that dermal contact to whatever chemical was being handled should not occur. Therefore, if such exposure did not occur, then any noticeable changes in the skin, be it yellow stain, redness, cracked hands, etc. should not occur. OSHA believes, however, that yellow staining can be used as one of the indicators of exposure. This view is based on OSHA's analysis of a control study which reported that MDA produced yellow staining (Ex. 9). Later, during the MDA hearings, an additional study, conducted by the same examiner, was presented which indicated that it was not pure MDA but instead a mixture which caused yellow staining. While OSHA now agrees that yellow staining may result from exposure to a MDA mixture, OSHA also recognizes that MDA skin exposure can occur without skin staining. What remains apparent is that if there are noticeable changes to the skin and the worker is wearing personal protective equipment, these changes may be the result of the failure of the personal protective clothing to prevent exposure. The fact that visual monitoring helps to make this determination is the reason that this provision was recommended by the Committee, included in the NPRM, and is now part of the final standard.

Paragraph (f) Regulated Areas

The final standard requires that the employer establish regulated areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA." The regulatory text in the final standard was modified to conform to the definition of regulated area (See 52 FR 26857).

The final standard requires that regulated areas are to be demarcated in any manner that minimizes the number of employees exposed to MDA within these areas. To increase the performance-orientation of the standard and minimize recordkeeping, no detailed requirements were specified regarding the demarcating of an area. Unauthorized employees are restricted from entering the regulated areas. Employees working in regulated areas are required to wear the appropriate type of personal protective equipment and are prohibited from activities such as smoking and eating. Other purposes of this section are to designate those areas where precautionary signs are to be posted and to designate areas where employees may be subject to three-month monitoring when their exposure is above the PEL.

Regulated areas are required where airborne exposures exceed or can reasonably be expected to exceed the PEL and where dermal exposure to MDA can occur. Establishing regulated areas at all worksites where the potential exists for exposure above the permissible exposure limits is a regulatory approach that has been adopted by OSHA in many occupational health standards. This approach covers areas within worksites where there are frequent leaks, or where exposures may be of high concentration but of short duration, e.g., maintenance operations. Where only dermal exposure to MDA can occur, a regulated area shall be established where employees are engaged in routine or non-routine processes requiring the handling, application, or use of MDA. OSHA recognizes that where the potential for dermal contact and inadvertent exposure to non-airborne forms of MDA is great, a mechanism to prevent incidental exposure of employees not actively engaged in the process is very much needed. The purpose of a regulated area is to ensure that employers make employees aware of the presence of MDA and attempt to restrict access. By limiting access, the number of employees inadvertently splashed and subsequently exposed to MDA can be minimized.

The establishment of regulated areas is an effective means of limiting the risk of exposure to as few employees as possible. This is consistent with good industrial hygiene practice when exposure to a toxic substance can cause serious health effects. Access to the regulated areas is restricted to "authorized persons"; that is, those persons required by their job duties to be present in the area. More specifically, access is restricted to those authorized entry by the employer, this final standard, or the OSH Act. By limiting access to these areas to authorized persons only, the additional obligation imposed by the final standard when PPE is used will be limited to as few persons as possible, thus reducing the economic implications of compliance with this standard.

The reasons that regulated areas are to be established in all work areas where the PEL is exceeded, including maintenance operations, is that the existence of a hazard, rather than the type of operation or work being performed, should be the basis for establishment of a regulated area. Areas where exposures are temporarily over the PELs while maintenance is being performed need to be demarcated to warn employees not performing the repairs, and access needs to be temporarily restricted. Further, employees who enter the area are thereby warned to wear the appropriate protective equipment when entering.

There were several other concerns expressed during the hearings regarding how to regulate and deregulate an area. The performance language which is used in the requirement to establish a regulated area allows the employer to establish a regulated area based on the handling, application, or use of non-airborne MDA and to deregulate this area when these activities stop.

Some of the commenters expressed concern with triggering the establishment of regulated area based on the handling, application, or use of non-airborne MDA. More specifically, they argue that the requirement as written would force even the use of small quantities of MDA to be done in regulated areas. The Department of the Air Force (Ex.11-19) states that:

    . . .consideration must be given to operational uses of small quantities of MDA containing materials versus large scale manufacturing processes. This specifically applies to regulated areas for repair processes. We anticipate the use of small MDA-containing patches for repairing aircraft structures. By the definition of regulated area, a certain area of the hangar or repair dock would become a regulated area during the application of a small (2-6 square inch) pre-preg patch. Recommend (sic) a use quantity be established below which either a regulated area is not required or less stringent regulated area requirements are specified.

During the hearings, OSHA questioned the representatives from the Air Force extensively concerning the requirement to establish a regulated area. OSHA clearly stated during the presentation made by the Air Force that it was not the Agency's intent to require that an entire facility become a regulated area just to patch on a 2 inch square on one airplane's wing. The regulated area should be confined to prevent access by unauthorized workers and should establish limits for workers engaged in work activities within these areas. In this instance, this could easily be accomplished without making the entire plant a regulated area.

In fact, OSHA questioned Col. Bishop from the Air Force on precisely this example. After Col. Bishop had agreed that establishing a regulated area in the situation described above was feasible and not difficult, the OSHA attorney summarized Col. Bishop's actual concerns as follows:

    I mean you're not suggesting that a compliance officer would come in after reading this language just like you've just read it and assume because your two workers are putting this patch on an airplane wing--there's one on the wing and there's one down handling materials--that that entire hanger will be considered a regulated area because of the dermal exposure situation... (Tr. II, 48)

Colonel Bishop responded: "We have our fears." (Tr. II, 48 ).

OSHA believes that the concerns expressed by Col. Bishop and other hearing participants regarding the difficulties in establishing regulated areas when small amounts of MDA are being used or small repair projects are being done are unfounded. The rationale provided in this preamble for establishing regulated areas will serve as guidance in determining if compliance with these provisions have been achieved. Clearly, in instances when small operations are taking place, it is not the agency's intent to require entire facilities to become regulated areas.

Paragraph (g). Methods of Compliance

The standard requires that feasible engineering and work practice controls be used to reduce employee exposures to or below the permissible limits. In situations where engineering controls that can be instituted will not reduce exposures to the permissible exposure limits, these controls must nonetheless be used to reduce exposures to the lowest feasible level and be supplemented by the use of respirators. In addition, a compliance program to reduce exposures to within the permissible exposure limits solely by means of engineering and work practice controls must be developed and implemented. Written plans for this program must be developed and furnished upon request for examination and copying to representatives of the Assistant Secretary, representatives of the Director, and affected employees. These plans must be reviewed and updated annually to reflect the current status of the program.

OSHA believes that there are certain activities, often involving certain maintenance and repair operations, as well as in emergency situations, in which the use of engineering controls to control exposures will not be feasible, regardless of the permissible exposure limits in the standard. Where the employer can show that engineering controls for such operations are not feasible, respirators shall be permitted as a means of control.

It has been OSHA policy to require that employers use feasible engineering and work practice controls to prevent excessive employee exposures and that respirators be used as an alternative only when other methods are not adequate, are not feasible, or have not yet been installed. The compliance hierarchy proposed by OSHA was not challenged and as such appears as proposed in the final standard. Nonetheless, it should be noted that OSHA is conducting a separate generic rulemaking on methods of compliance (OSHA Docket No. H-160; 54 FR 23991 (June 5, 1989)). The outcome of that rulemaking may have some future effect on this paragraph.

Paragraph (h). Respiratory Protection

OSHA requires that where respirators are necessary to limit employee exposures to below the permissible exposure limits, the employer must provide the respirators at no cost to the employee, and require that the employees use them.

A table of respirators for use with MDA is included in the standard provisions. The table is similar to those used in other standards and reflects current OSHA policy and is generally used in standard development.

Respirator use is required during the time necessary to install or implement feasible engineering and work practice controls. Further, respirators must be used in: 1) operations in which engineering and work practice controls are not feasible (e.g., certain maintenance operations); 2) work operations for which the feasible engineering and work practice controls are not sufficient to reduce exposures to or below the PEL; and 3) emergency situations.

The final standard also requires that each employee be properly trained to wear a respirator, to know why the respirator is needed, and to understand the limitations of the respirator. An understanding of the hazard involved is necessary to enable the employee to take steps for his or her own protection. The respiratory protection program implemented by the employer must conform to that set forth in 29 CFR 1910.134. This provision contains basic requirements for proper selection, fit, use, cleaning, and maintenance of respirators.

The final standard also contains provisions for emergency respirator use. OSHA believes that emergencies are situations where respirators must be used to protect employees. Since it is unrealistic to predict the expected contaminant concentrations to which an employee may be exposed in all emergencies, OSHA requires the use of respirators of the type approved for protection against unknown concentrations. If an employee is working in an area and using an approved respirator of the type appropriate for the existing concentration, and an emergency occurs, the employee of course should continue using the respirator during his escape. Provisions to provide proper protection for emergency personnel assigned to enter vessels or workplaces containing an unknown concentration to rescue workers or to control the release of the contaminant or perform any necessary repairs will be required to be a part of the emergency plan. This paragraph requires that respirators be made available to employees in these operations.

The final standard also requires the use of qualitative or quantitative fit tests. When negative pressure respirators are used, proper fit is especially critical to prevent leakage of contaminated air into the facepiece.

The employer must ensure that the employees' respirators fit properly and that leakage is minimal. A rapid qualitative fit test can be performed as either a positive-pressure test, in which the exhalation valve is closed and the wearer exhales into the facepiece to produce a positive pressure, or a negative pressure test, in which the inhalation valve is closed and the wearer inhales so that the facepiece collapses slightly. Employees could be trained to perform this test.

The final standard also requires that the employer use the fit testing appendix (Appendix E) to ensure that the employer conducts the proper testing to achieve adequacy of fit testing. Paragraph (i). Protective work clothing and equipment The employer is required to provide and the employee to wear the appropriate protective clothing to prevent eye and dermal exposure to MDA. The requirements for the use of personal protective clothing and equipment are consistent with those found in sections 1910.132 and 1910.133. The equipment is to be provided at no cost to the employee, and includes the use of those items that may be necessary to protect employees at each particular work situation from exposure to MDA, including, where appropriate, such items as face shields, gloves, aprons, coveralls, or footwear.

Contact with liquid MDA irritates the eyes and may result in corneal burns if the MDA is splashed in the eyes. When there is a reasonable possibility of splashing the eyes, precautions are needed. Eye and face protection is currently required by 29 CFR 1910.133, and the types of safety goggles and face shields required by this section to prevent eye and face injury are readily available from safety products companies nationwide.

OSHA's standard is performance-oriented and requires the employer to survey the work situation in determining the type of protective equipment needed. For example, when handling solid materials the employee may be required to wear full body coveralls and gloves, which must be removed at the end of the shift and laundered before being worn again. This employee would also be required to shower at the end of the work shift. Employees required to work only with non-airborne forms of MDA which can result in "dermal exposure to MDA," may not be required to wear full body coveralls but instead may be required to wear an apron, and gloves. If the employee does become splashed with MDA or other substances containing MDA, the employee must be directed to immediately remove the clothing, wash the affected area, and put on clean clothing if necessary. The employer may require employees to discard gloves when removed and use a new pair of gloves after breaks, lunch, etc. The employee's gloves must be sufficiently protective or changed often enough so that MDA-wetted material is not kept in contact with the skin.

The performance approach grants an employer flexibility to achieve the goal of minimizing MDA contact with the skin in a manner the employer finds most effective. However, being performance oriented, it is of necessity more general and requires the employer to consider the work process in order to achieve the desired goal in the manner that the employer believes is most efficient. This provision is designed to prevent the employee from coming in contact with MDA or MDA contaminated substances that may result in "dermal exposure to MDA."

The employer must be aware that maintaining the effectiveness of the protective equipment and clothing used is also of great importance. Exposure occurs by (1) bulk penetration through pinholes, rips, zippers, seams, etc.; (2) material failure through chemical degradation; or (3) permeation through the material.

While not specifically required, OSHA believes that the employer can use permeation data to determine the effectiveness of protective clothing. Permeation depends on MDA concentration, type of protective material, thickness of protective material, temperature, and age of protective clothing. Liquid MDA that may be spilled on aprons, coveralls, or footwear or protective clothing other than gloves can be wiped off within a few minutes time. Therefore, the materials used to make these types of protective clothes need to be impervious to MDA only for a few minutes. However, the liquid MDA permeability rate for materials used to make gloves needs to be less than that for other protective equipment since it is less likely that gloves will be wiped off when liquid contact occurs. Breakthrough times of MDA through various protective clothing materials differ widely, and the choice of material for protection against MDA breakthrough depends on the type of operation involved and length of time of contact, other solvents present, and other factors. Because of the uncertainty associated with requiring this sort of testing, OSHA chose to adopt regulations which give the employer the option of choosing the methodology relied upon to assure that the effectiveness of protective clothing is achieved. Nonetheless, although there have been limited tests of protective clothing and devices conducted for various toxic materials, OSHA recognizes that all clothing and equipment are not equally protective; and in some cases may actually provide no effective protection. Data analysis indicated that polyvinyl chloride (PVC), natural latex, and polyethylene are currently the best candidates for protection against solutions containing MDA.

Under this provision, employers are obligated to take the appropriate measures to ensure that workers are not dermally exposed to MDA, and to choose the protective clothing or equipment which will achieve this goal. How much clothing and the type of protective clothing needed will depend on the potential for exposure and the conditions of use. The employer in exercising his reasonable judgment in the workplace should be able to select the appropriate clothing or equipment in accordance with the criteria of this paragraph which satisfies the legal obligation defined by this paragraph.

The employer can also use any appropriate method available to determine that the personal protective equipment is functioning properly. For example, the employer may rely on staining of the skin, MDA in the urine, or may conduct dermal monitoring under the protective clothing to determine potential for absorption and consequently the ineffectiveness of personal protective equipment. In addition, the medical surveillance provisions required by OSHA would detect workers who were adversely affected as a result of occupational exposure to MDA.

OSHA also allows the worker to remove some protective clothing outside of the change room. The regulatory text regarding removal of MDA-contaminated protective work clothing and equipment has been slightly modified, both to clarify the provision and to better reflect the Committee's intent (52 FR 26862). These changes also respond to comments that led to Issue #15 in the Notice of Hearing (55 FR 2104). Workers can remove some items like gloves and aprons and discard disposable contaminated protective clothing before leaving a regulated area. Of course, the employer who allows the employee to dispose of contaminated clothing in areas outside of the change rooms is still obligated to comply with the requirements for the proper disposal of MDA contaminated materials. In addition, OSHA requires that clothing not routinely removed throughout the day must be removed at the end of the shift in change rooms.

Paragraph (j). Hygiene facilities and practices

The final standard contains a variety of provisions for the use of shower and change room facilities and lunch rooms for employees exposed to MDA.

For example, whenever food or beverages are consumed at the worksite and employees are exposed to MDA at or above the PEL or are subject to "dermal exposure to MDA" the employer shall provide readily accessible lunch areas. Lunch facilities located in areas where MDA exposures are at or above the PEL must be equipped with a positive pressure filtered air supply. In addition, lunch facilities may not be located in areas where "dermal exposure to MDA" can occur.

Showers are required to be provided for workers exposed to dusts or vapors in concentrations in excess of the action level. Workers subjected only to "dermal exposure to MDA" must be instructed to immediately wash exposed areas with soap and water or any media which does not increase the absorption properties of MDA. This particular requirement was given much consideration by OSHA.

OSHA is concerned with the appropriate manner in which MDA should be removed from the skin. However, OSHA did not want to require that only soap and water be used to remove MDA impregnated resin or accumulations on the skin because something better might be developed in the future. In fact, OSHA believes that it is better, should exposure occur, to remove the hardened resin or other MDA material as soon as possible even if a solvent must be used. OSHA believes that if the employer can demonstrate that a particular solvent does not increase the absorption properties of MDA it should be used to remove MDA from the skin. The final standard also requires that the employer ensure that all employees who have been exposed to MDA at or above the PEL wash their hands and face with soap and water prior to eating, drinking, smoking or applying cosmetics, and taking breaks. This requirement is intended to prevent the accidental ingestion of MDA.

Paragraph (k). Communication of hazards to employees

Signs and Labels. The final standard requires that the employer post and maintain legible signs demarcating regulated areas and entrances or access ways to regulated areas with the following legend:

DANGER
MDA
MAY CAUSE CANCER
LIVER TOXIN
AUTHORIZED PERSONNEL ONLY
RESPIRATORS AND PROTECTIVE CLOTHING
MAY BE REQUIRED TO BE WORN IN THIS AREA

These signs are intended to supplement the training which employees are required to receive under the standard. Even trained employees will need to be reminded of the locations of regulated areas and the dangers of entering these areas. In addition, other personnel, such as employees of independent maintenance contractors authorized to enter regulated areas, need to be informed of the locations of regulated areas, the dangers of entering these areas, and the need to use protective equipment. OSHA has determined that both signs and training are necessary to apprise employees adequately of the hazards associated with MDA exposure.

OSHA also requires specific wording of the warning signs for regulated areas to assure that the proper warning is given to employees. The word "danger" is used to attract the attention of workers, alert them to the fact that they are in a hazardous area and to emphasize the importance of the message that follows. In addition, the use of the word "danger" is consistent with recent OSHA health standards dealing with carcinogens. The sign legend: "Respirators and Protective Clothing May Be Required to Be Worn In This Area," recognizes that there may be a difference between the MDA concentrations in air or the potential to be splashed with liquid mixtures, (the bases which determine when a regulated area must be established), and a particular employee's likely exposure.

The standard also requires labelling of containers of MDA. The labels must state, for (a) MDA:

    DANGER
    CONTAINS MDA
    MAY CAUSE CANCER
    LIVER TOXIN

and for (b) Mixtures containing MDA:

    DANGER
    CONTAINS MDA
    CONTAINS MATERIAL WHICH MAY CAUSE CANCER
    LIVER TOXIN

The final standard is consistent with section 6(b)(7) of the Act, which prescribes the use of labels or other appropriate forms of warning to apprise employees of the hazards to which they are exposed.

It is required that labels remain affixed to containers leaving the workplace. The purpose of this requirement is to assure that all affected employees, not only those of a particular employer, are apprised of the hazardous nature of MDA exposure.

It is OSHA's view that informing employees of the hazards to which they are exposed is an important element in reducing occupational disease and injury and one of the significant purposes of the Act. Section 6(b)(7) of the Act does not limit an employer's obligation to inform employees of hazardous conditions, to the employer's own employees. When an employer manufactures, formulates, or sells a product, the employer may create exposures not only to his or her own employees, but also to the employees of other employers involved in handling, transporting, or using the product.

Material Safety Data Sheet (MSDS) The final standard also requires statements to be incorporated into a material safety data sheet. Information to assist in the preparation of a MSDS can be found in Appendices A and B.

Employee information and training OSHA requires that all employers provide a training program for all employees exposed to MDA, initially at the time of assignment and at least annually thereafter. OSHA also requires an information and training program to inform employees of the hazards to which they are exposed and to provide employees with the necessary understanding of the degree to which each employee can contribute toward minimizing health hazard potentials.

The content of the training program is intended to inform employees of: (1) the hazards to which they are exposed; (2) the necessary steps to protect themselves, including those to be taken during emergency situations; (3) limitations and the proper use of respirators and protective equipment; (4) a description of medical examinations and their purpose; (5) implementation of work practices and the use of available engineering controls; and (6) the contents of this standard. Section 6(b)(7) of the Act makes it clear that these are appropriate goals for an employee training program, and the final standard includes such provisions.

OSHA requires the employer to make a copy of the standard and its appendices available to affected employees and their representatives. This requirement, in combination with the review provided for as part of the training program, is intended to ensure that employees understand their rights and duties under this standard.

The employer is also required to provide, upon request, all materials relating to the training program to affected employees, the Assistant Secretary and the Director. This is intended to provide an objective check of compliance with the requirements under this paragraph. The regulatory text reflecting these access provisions, found in the final standard in paragraph (k)(4), were inadvertently omitted in both the Committee document and the proposal. The preamble discussion in both documents, however, was complete. Also, the regulatory text was included in the construction standard. Since the construction text and the preamble discussions generated no comment and since these requirements are entirely consistent with other OSHA single substance standards, the access provisions are included in the final standard.

OSHA recognizes that MDA may be only one of a number of substances to which an employee may be exposed simultaneously in the workplace. The education and training requirements in this standard contain those elements OSHA has determined to be basic. The format and content of the required training and information program are neither rigid nor extensive.

Paragraph (l). Housekeeping

The final standard requires that employers institute a program to detect leaks, spills and discharges of MDA which includes visual inspections. When leaks, spills, or discharges of MDA are detected, the final language requires the employer to repair promptly all leaks and clean up all spills. These work practices aid in minimizing the number of employees exposed, as well as the extent of any potential for MDA exposure.

Prevention and removal of accumulations of liquid MDA on all surfaces are critically important aspects of minimizing employee exposure. The liquid, if allowed to remain on the floor or work surfaces, will slowly evaporate and contribute to a possible airborne hazard, or it may become a dermal hazard through inadvertent skin contact. MDA's low vapor pressure which results in slow evaporation will contribute to and prolong the hazard. The requirement to clean up spills and drips refers to the prevention and removal of visible accumulations of liquid MDA on all surfaces.

In addition to the hazards of exposure to MDA in its liquid forms, hazards also result from exposure to the dusts of MDA. Thus, the final language contains provisions for maintaining surfaces as free as possible of accumulations of dusts and waste containing MDA. Surfaces contaminated with dusts may not be cleaned by the use of compressed air. The final standard requires HEPA-filtered vacuuming equipment for vacuuming. This equipment must be emptied in a manner which minimizes the reentry of MDA dusts into the workplace.

Paragraph (m). Medical Surveillance

The final standard requires that each employer institute a medical surveillance program for all employees exposed to MDA under the following circumstances:

    (1) Employees exposed at or above the action level to dusts or vapors for 30 or more days per year;
    (2) Employees who are subject to "dermal exposure to MDA" for 15 or more days per year;
    (3) Employees who have been exposed in an emergency situation;
    (4) Employees whom the employer, based on results from compliance with paragraph (e)(8), has reason to believe are being dermally exposed; and
    (5) Employees who show signs or symptoms of MDA exposure.

The standard requires that the medical surveillance program provide each covered employee with an opportunity for a medical examination. Further, all examinations and procedures must be performed by or under the supervision of a licensed physician and be provided without cost to the employee. Clearly, a licensed physician is the appropriate person to supervise and evaluate medical examinations. However, certain parts of the required examination do not necessarily require the physician's expertise and may be conducted by another person under the supervision of the physician.

The standard also requires that examinations be given at a reasonable time and place. It is necessary that examinations be convenient and be provided without loss of pay to the employee to assure that they are taken.

The final standard allows the examining physician to prescribe the specific tests to be included in the medical surveillance program. While unable to make findings regarding the use of bladder cancer testing in the NPRM and therefore not requiring such tests in the regulatory text, OSHA asked for public comment concerning the appropriateness of such a requirement (54 FR 20704). No comments were received in response and OSHA is not including such a requirement in the final rule. Nonetheless some specific requirements are included, such as:

i) comprehensive medical and work histories with special emphasis directed to an evaluation of other carcinogens to which the employee is exposed, and smoking and alcohol use.

ii) comprehensive physical examination, with particular emphasis given to symptoms related to skin disease and liver dysfunction.

iii) urinalysis.

iv) screening for liver damage. It is important to note that the employer is required to make any prescribed tests available more often than specified if recommended by the examining physician.

OSHA also requires that the employer provide examinations advised by the physician to any employee exposed to MDA under emergency conditions. Due to the effects of high short-term exposures, it appears prudent to monitor such affected employees in light of existing health data. However, trivial exposure, for example, to a single drop of an MDA-containing mixture would not trigger the emergency examination requirement, particularly if the employee were able to remove the MDA immediately after exposure.

The employer is also required to provide the physician with the following information: a copy of this standard and its appendices; a description of the affected employee's duties as they relate to the employee exposure level; and information from the employee's previous medical examinations which is not readily available to the examining physician. Making this information available to the physician will aid in the evaluation of the employee's health in relation to assigned duties and fitness to wear personal protective equipment.

The employer is required to obtain a written opinion from the examining physician that contains the results of the medical examination; the physician's opinion as to whether the employee has any detected medical conditions which would place the employee at increased risk of material health impairment from exposure to MDA; any recommended restrictions upon the employee's exposure to MDA or upon the use of protective clothing or equipment such as respirators; and a statement that the employee has been informed by the physician of the results of the medical examination and of any medical conditions which require further explanation or treatment. This written opinion must not reveal specific findings or diagnoses unrelated to occupational exposure to MDA, and a copy of the opinion must be provided to the affected employee.

The requirement that a physician's opinion be in written form will ensure that employers have had the benefit of this information. The requirement that an employee be provided with a copy of the physician's written opinion will ensure that the employee is informed of the results of the medical examination. The purpose in requiring that specific findings or diagnoses unrelated to occupational exposure to MDA not be included in the written opinion is to encourage employees to take the medical examination by removing the concern that the employer will obtain information about their physical condition that has no relation to present occupational exposures.

The standard also includes a multiple physician review mechanism in paragraph (m)(6). In recommending this provision, the Committee relied heavily on the experiences of its members regarding a similar provision under the OSHA lead standard. OSHA accepted this recommendation in the NRPM. Since the provision generated no comment or controversy, other than a limited request for clarification, the provision is substantively promulgated as proposed (52 FR 26865).

This provision is triggered where an employee disagrees with the opinion of a physician, selected by the employer, whose examination disclosed signs or symptoms of occupational exposure to MDA, when the opinion could affect the employee's job status.

In paragraph (m)(9), the standard also contains provisions for removing an employee from exposure in certain circumstances, following a medical examination. In recommending this provision, again the Committee relied heavily on the experiences of its members regarding a similar provision under the OSHA lead standard. OSHA accepted this recommendation in the NRPM. In addition, the regulatory text regarding removal of employees from exposure at or above the action level for MDA or where dermal exposure to MDA may occur has been slightly modified, both to clarify the provision and to better reflect the Committee's intent (52 FR 26865). Since the provision generated no comment or controversy the provision is substantively promulgated as proposed. OSHA believes that employees whose health has been adversely affected as a direct result of occupational exposure to MDA should be removed from exposure and should receive medical removal benefit protections.

Paragraph (n). Recordkeeping

The standard's requirements are consistent with Section 8(c)(3) of the Act which provides for the promulgation of regulations requiring employers to maintain accurate records of employee exposures to potentially toxic or harmful physical agents which are required to be monitored or measured.

The final standard allows that objective data be used for any exemptions from the standard. Records of objective data must be maintained to demonstrate that employees will not be exposed to airborne MDA concentrations and that no "dermal exposure to MDA" can occur.

The standard also requires that records be kept to identify the employee monitored and to reflect the employee's exposure accurately. Specifically, records must include the following information: (a) the names and social security numbers of the employees sampled; (b) the number, duration, and results of each of the samples taken, including a description of the representative sampling procedure and equipment used to determine employee exposure where applicable; (c) a description of the operation involving exposure to MDA which is being monitored and the date on which monitoring is performed; (d) the type of respiratory protective devices, if any, worn by the employee; and (e) a description of the sampling and analytical methods used, and evidence of their accuracy.

The final standard also includes a provision for requiring the employer to keep an accurate medical record for each employee subject to medical surveillance. Section 8(c) of the Act authorizes the promulgation of regulations requiring any employer to keep such records regarding the employer's activities relating to the Act as are necessary or appropriate for the enforcement of the Act or for developing information regarding the causes and prevention of occupational illnesses. OSHA believes that medical records, like exposure monitoring records, are necessary and appropriate to both the enforcement of the standard and the development of information regarding the causes and prevention of illness.

The employer is also required to keep a record of any employee's medical removal and return to work status.

The standard requires that all records required to be kept shall be made available upon request to the Assistant Secretary and the Director of NIOSH for examination and copying. Access to these records is necessary for the agencies to monitor compliance with the standard. These records may also contain information needed by the agencies to carry out their other statutory responsibilities.

The standard would also provide for employees, former employees, and their designated representative to have access to mandated records upon request. Section 8(c)(3) of the Act explicitly provides "employees or their representatives" with an opportunity to observe exposure monitoring and to have access to the records of monitoring procedures and results; several other provisions of the Act contemplate that employees and their representatives are entitled to play an active role in the enforcement of the Act.

Access to exposure and medical records by employees, designated representatives, and OSHA shall be established in accordance with 29 CFR 1910.20. By its terms, it applies to records required by specific standards, such as this MDA standard, as well as records which are voluntarily created by employers. In general, it provides for unrestricted employee and designated representative access to exposure records. Access to medical records is also provided to employees and, if the employee has given specific written consent, to the employee's designated representatives. The standard requires that unrestricted access to both kinds of records be allowed, but access to personally identifiable records is made subject to rules of agency practice and procedure concerning OSHA access to employee medical records, which have been published at 29 CFR 1913.10. An extensive discussion of the provisions and rationale for §1920.20 may be found at 45 FR 35312; the discussion of §1913.10 may be found at 45 FR 35384.

It is necessary to keep records for extended periods because of the long latency periods commonly observed for carcinogens. Cancer often cannot be detected until 20 or more years after onset of exposure. The extended retention period is therefore needed for two purposes. Diagnosis of disease in employees is assisted by having present and past exposure data as well as the results of the medical exams. Retaining records for extended periods also makes it possible at some future date to review the adequacy of the standard.

The time periods recommended for retention of exposure records and medical records are thirty years, and period of employment plus thirty years, respectively. These retention periods are consistent with those found in other OSHA health standards.

The standard would also require certain employers to notify the Director in writing at least 3 months prior to the disposal of the records. Section 1910.20(h) also contains requirements regarding the transfer of records.

Paragraph (o). Observation of Monitoring

The standard also includes a provision for observation of exposure monitoring. This provision is in accordance with section 8(c) of the OSH Act which requires that employers provide employees and their representatives with the opportunity to observe monitoring of employee exposures to toxic substances or harmful physical agents. Any observer must be provided with the personal protective clothing and equipment that is required to be worn by the employees who are working in the area. The employer is required to assure the use of such clothing and equipment or respirators and is responsible for requiring that the observer complies with all other applicable safety and health procedures.

Paragraph (p) Effective dates.

The standard becomes effective thirty (30) days from the publication of the final standard September 9, 1992. The effective date established in the final standard remains the same as the date which appeared in the proposed rule.

Paragraph (q). Appendices

Five appendices have been included at the end of this final standard. Appendices A,B, C, and D have been included primarily for purposes of information. None of the statements contained in Appendices A,B,C, and D should be construed as establishing a mandatory requirement not otherwise imposed by the standard, or as detracting from an obligation which the standard does impose. However, the protocols for respiratory fit testing in Appendix E are mandatory.

Appendix A contains information on the description and exposure levels of MDA. Also provided in Appendix A is information on the health hazards associated with exposure, descriptions of protective clothing and equipment, emergency and first aid procedures, medical requirements, provisions for the observation of monitoring, access to exposure and medical records, and precautions for the safe use, handling, and storage of MDA.

Appendix B contains "substance technical guidelines" for MDA, including physical and chemical data, spill and leak procedures, including waste disposal methods, and other miscellaneous precautions for the safe handling of MDA.

Appendix C contains the medical surveillance guidelines for MDA. Included in these guidelines are the description of the routes of entry, the toxicology and symptoms and signs associated with MDA exposure, information on the treatment of acute toxic effects, and surveillance and preventive considerations, including hematology guidelines which may be useful to physicians in conducting the medical surveillance program required by paragraph (m) of this final standard.

Appendix D gives details of the sampling and analytical methods for use in monitoring employee exposures to MDA.

Appendix E gives detailed fit testing procedures that are to be followed for qualitative or quantitative fit testing of negative pressure respirators. Various protocols for qualitative and quantitative fit tests are outlined in detail.

All the Appendices are designed to aid the employer in complying with the requirements of the standard. Paragraph (k) of this final standard on the "communication of MDA hazards to employees" specifically requires that the contents of the standard and Appendices A and B be made available to affected employees. Information contained in Appendix C on medical surveillance is to be explained to affected employees. Appendix C also provides information needed by the physician to evaluate the results of the medical examination.

Paragraph (r) Start-up dates.

The final standard contains start up dates for the various standard provisions. The dates originally proposed in the MDA rule have been modified to reflect a more logical schedule for compliance. These dates are based on economic and technological considerations discussed in the regulatory impact analysis.

X. SUMMARY AND EXPLANATION OF THE STANDARD FOR THE CONSTRUCTION INDUSTRY

Paragraph (a). Scope and Application

A separate standard for occupational exposure to MDA in the construction industry was developed. OSHA took this action based primarily on the recommendations of the MDA Mediated Rulemaking Committee which recommended that a separate standard be developed for the construction industry. OSHA also consulted, as required by §107 (e) of the Contract Work Hours and Safety Standards Act (40 U.S.C. 333 (e)) and 29 CFR 1912.3, with the Construction Advisory Committee concerning this rule for Construction. This meeting took place on November 3, 1987. This Committee advised that OSHA adopt the recommendations made by the MDA Mediated Rulemaking Advisory Committee for the construction industry and use such as the basis for its standard for construction. The Committee made this recommendation because they felt that the specialized use of MDA in the construction sector could best be addressed through the development of a separate construction standard. OSHA agreed with the recommendations of both committees and has developed a separate standard for the construction industry.

The final standard uses section 1910.12 (b) to define "construction work" as work for construction, alteration, and/or repair, including painting and decorating. Accordingly, the final standard applies to all occupational exposures to MDA in the construction industry. Depending on the nature and extent of exposure, certain provisions of the standard rule may not be applicable in certain situations or may have limited applicability. The applicability of many provisions of the standard is based on the results of initial employee monitoring conducted by the employer or on the availability of other objective data concerning employee exposures or product characteristics. The construction operations listed in paragraph (a)(1) include construction, alteration, repair, maintenance, or renovation of structures, substrates, or portions thereof that contain MDA; the installation or finishing of surfaces with MDA containing products; the removal of MDA spills or emergency clean-up on site; and transportation, disposal, or storage of contaminated products.

MDA spill and emergency situations are included within the scope of the standard, because these events clearly have the potential for serious employee and bystander exposures. MDA spills might occur during the handling of bags or containers of MDA-containing materials to be used at the construction site. The final group of activities listed in the scope and application paragraph includes the transportation, disposal, storage, or containment of MDA or MDA-containing products on the worksites at which construction operations occur. These operations are included because they have considerable potential for excessive employee exposure to MDA, and, if not closely supervised and properly conducted, may lead to serious bystander exposure as well. The Environmental Protection Agency (EPA) has specific requirements for the disposal of hazardous waste, and the MDA standard contemplates compliance with EPA provisions for the safe disposal and handling of MDA-containing wastes and of MDA-contaminated clothing.

The final standard has been carefully structured to relate the stringency of the requirements to the extent and duration of employee exposures. OSHA therefore believes that a compliance burden will not be placed on construction employers who either do not use, handle, or apply MDA-containing products or who maintain MDA exposures in their workplaces at levels below the action level or where dermal exposure to MDA does not exist. In addition, the exemptions found in paragraphs (a)(2) through (a)(6) are identical to exemptions found in the general industry standard. Full discussions regarding the rationale for these exemptions can be found in the general industry preamble and apply equally well here. Essentially, these exemptions apply to workplaces where MDA is present but in such a way as to not present a significant risk of harm to the employee.

Paragraph (b). Definitions

Paragraph (b) of the MDA standard for the construction industry defines a number of terms used in the standard. In some instances, the definitions used are consistent with those of other OSHA standards to be used in the general industry standard, e.g., "Director," "Assistant Secretary," and "Authorized person." However, certain other terms require definition because they are used in accordance with their meanings in the construction industry.

Action level is defined as one-half of the PEL. If employers are engaged in MDA work causing worksite levels of MDA above the action level for 30 or more days per year, they must also institute a medical surveillance program for all employees. In addition, on sites where food and beverages are consumed and the airborne MDA level exceeds the PEL, the standard requires employers to provide lunch areas that have airborne MDA levels below the action level.

Definition of MDA The final construction standard includes a definition of MDA. Included in the definition are the salts of MDA. The rationale for including the salts in the definition of MDA was not challenged in the response to the NPRM. Thus the compounds covered by the proposed definition remains the same in the final standard.

The NPRM definition contained an exclusion for finished products which is now part of the scope and application section of this final rule.

Employee exposure is defined as that exposure to airborne MDA that would occur if the employee were not using respiratory protective equipment or personal protective clothing or equipment. OSHA believes it is essential to determine employee exposure levels without the use of respiratory protection in order to gauge the efficacy of mandated work practice and engineering controls.

Decontamination area is defined as an area outside of but as near as practical to the regulated area, consisting of an equipment storage area, wash area, and clean change area, which is used for the decontamination of workers, materials, and equipment contaminated with MDA. For more discussion see the hygiene facility section.

Dermal exposure to MDA occurs where employees are engaged in the handling, application or use of mixtures or materials containing MDA, with any of the following non-airborne forms of MDA: (i) liquid, powdered, granular, or flaked mixtures containing MDA in concentrations greater than 0.1% by weight or volume; and (ii) materials other than "finished articles" containing MDA in concentrations greater than 0.1% by weight or volume. The final standard requires the employer to take certain protective actions where employees, engaged in the handling application or use of mixtures or materials containing MDA, are subject to dermal exposure to MDA. In situations where employees handle, apply or use any MDA mixtures or materials as defined above, dermal exposure to MDA is considered to occur. The agency believes that correlating dermal exposure with the handling, applying or using specific forms of MDA removes the confusion that has arisen from using such terms as "likelihood of dermal exposure." Simply put, dermal exposure to MDA is assumed to occur when employees handle, apply or use any MDA falling under the definition of "Dermal exposure to MDA."

Historical monitoring data is defined as monitoring data for construction jobs that are substantially similar. The data must be scientifically sound, the characteristics of the MDA containing material must be similar and the environmental conditions comparable. See the monitoring discussion below and the Committee discussion at 52 FR 26868.

Regulated areas are defined as areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA."

Paragraph (c) Permissible Exposure Limit

The final standard requires that the PEL for the construction industry be set at 10 parts of MDA per billion parts of air as an 8-hour time-weighted average (TWA) limit and at 100 ppb as a short term exposure limit (STEL). This is consistent with the final standard for general industry. The requirements contained in the final standard are supported by OSHA's findings that occupational exposure to MDA under current occupational conditions poses a significant risk to the health of employees and that the final standard can achieve a reduction in that risk.

As with the final standard for general industry, the standard for construction establishes a ceiling or short-term exposure limit of 100 ppb (sampled over a 15-minute period) for MDA.

Biological monitoring was also recommended by many of the hearing participants for inclusion into the construction standard. OSHA's rationale for not including biological monitoring provisions in the construction standard are the same reasons stated in the general industry standard.

Paragraph (d) Communication Among Employers

Paragraph (d) of the rule requires that, on multi-employer construction worksites, employers performing MDA work requiring the establishment of a regulated area inform other employers on the site of the nature of their work with MDA and of the existence of and requirements pertaining to regulated areas. OSHA recognizes that several different operations involving workers from numerous trades may simultaneously take place on the same construction site and that the exposures of these workers to MDA should be minimized to the extent possible. OSHA believes that requiring employers who are directly involved in MDA-related activities to inform other employers working nearby on a multi-employer worksite of the existence of hazardous levels of MDA, regulated areas, and the rules pertaining to such areas will contribute substantially to the protection of these nearby employees.

Paragraph (e) Emergency Situations

OSHA believes that available health data suggest that elevated short-term exposure to MDA should be viewed with concern. An unexpected high exposure must be viewed as an emergency situation. A written plan is required for each construction operation where there is a possibility of an emergency. The plan shall include the applicable elements prescribed in 29 CFR 1910.38, "Employee emergency plans and fire prevention plans." OSHA believes that there is no substitute for proper planning for an emergency situation. In the construction industry where the work force and the job sites are constantly changing, the importance of proper emergency planning can not be overstated.

The standard provisions also include a requirement to alert employees other than those who have the potential to be directly exposed in an emergency situation. Such employees may be employees from neighboring work sites who may inadvertently approach the emergency site. They may also include employees of other employers or from other work shifts or employees who may be later exposed to work surfaces or equipment contaminated as a result of the emergency.

OSHA believes that the performance language of the emergency situation paragraph will give employers the flexibility to choose any effective method of alerting employees, including communications systems, voice communication, or a bell or other alarm.

There was considerable testimony provided regarding the difficulty with implementing the proposed emergency requirements for the construction industry. The major difficulty was with the written plan which was proposed at 54 FR 20730 as follows:

    (1) Written plan. (i) A written plan for emergency situations shall be developed for each workplace where there is a possibility of an emergency. Appropriate portions of the plan shall be implemented in the event of an emergency. (Emphasis added.)

The Dow Chemical Company (Ex. 11-20) states that the requirement that a written emergency plan be developed for each construction worksite is infeasible for jobs of short duration. They recommend that OSHA establish a generic emergency plan approach. The Society of the Plastics Industry, Inc. (Ex. 11-16) agrees that it is not feasible to have a specific emergency plan for every work site. Specifically, they state:

    the construction industry. For example, a work crew may apply epoxy floor coverings containing MDA to three or four different worksites in a single day. To develop a written emergency plan for each of these sites could require more time than is necessary to carry out the work. (page 3).

SPI believes that construction employers who have MDA related jobs of short duration should be permitted to develop a written emergency plan that covers emergency situations, typical of a work operation, rather than a particular site. For example, instruction to don respirators in certain described situations, to locate the nearest exit upon arrival at each worksite, and to use that exit to depart from the work area in specified circumstances would provide practical and effective worker protection in an emergency, without imposing a burden far out of proportion to any benefit.

OSHA has reviewed the comments regarding the difficulties expected with implementing the emergency provisions in the construction industry. In addition, OSHA has reviewed both the preambular portion of the Committee's recommendations (52 FR 26868) and the substantive requirements of 29 CFR 1910.38. OSHA believes that the Committee had intended to tailor this provision to better fit the nature of the changing worksites of the construction employee as it did in other areas of the standard. Examples of this are the use of historical monitoring data to satisfy the initial monitoring requirements for substantially similar construction operations, and the portable decontamination areas in the hygiene facilities paragraph. Looking also at the substantive elements found in the existing Employee emergency plan standard cited above, it appears that the only required element that would always be site specific is the emergency evacuation route. In light of these considerations, the language of paragraph (e)(1)(i) of the final construction standard reads as follows:

    (i) A written plan for emergency situations shall be developed for each construction operation where there is a possibility of an emergency. The plan shall include procedures where the employer identifies emergency escape routes for his employees at each construction site before the construction operation begins. Appropriate portions of the plan shall be implemented in the event of an emergency. (Emphasis added.)

OSHA believes that this language will satisfy the concerns of the commenters and give effect to the Committee's intent without compromising the protection of the employee.

Paragraph (f). Exposure Monitoring

The standard also requires that the employers conduct monitoring to determine employee exposures to MDA. The standard requires initial determinations of employee exposures using frequencies and patterns of monitoring sufficient to represent with reasonable accuracy the exposures of employees. The standard would also require that monitoring be conducted no less frequently than once every 3 months if MDA exposure exceeds the PELs and once every 6 months if exposure is between the action level and the PELs. Section 6 (b)(7) of the Act mandates that standards promulgated shall, where appropriate, "provide for monitoring or measuring employee exposures at such locations and intervals, and in such a manner as may be necessary for the protection of employees" (29 U.S.C. 655(b)(7)). Based on the recommendations made by CACOSH in its "Report on Occupational Health Standards for the Construction Industry," May 16, 1980, CACOSH Docket (pp. 35-37), and the provisions of the Act, OSHA requires that the construction industry do the same sort of monitoring that is required of the general industry sectors.

Accordingly, the standard for construction includes several monitoring requirements, i.e., employers must perform monitoring of their employees' breathing zones that will accurately reflect and be representative of their exposures to MDA. In paragraph (f)(2), construction employers are required to conduct initial monitoring of employee exposures, unless: (1) the employer can demonstrate, on the basis of objective data, that the MDA-containing product or material being handled cannot cause exposures above the standard's action level, even under worst-case release conditions; or (2) the employer has historical monitoring or other data demonstrating that exposures on a particular job will be below the action level. Periodic monitoring is addressed in paragraph (f)(3) and is consistent with the toxicity of MDA. In recognizing the unique circumstances of working in a regulated area on a construction site, OSHA allows employers who are conducting MDA operations within a regulated area to forego periodic monitoring if the employees are all wearing supplied-air respirators while working in the regulated area.

Monitoring may be terminated when, in accordance with paragraph (f)(4), employers obtain confirmation by means of periodic monitoring that their employees' exposures are below the action level. Paragraph (f)(5) requires the employer to conduct additional monitoring when there has been a change in production process, chemical present, control equipment, personnel, or work practices which may result in new or additional exposures to MDA, or when the employer has any reason to suspect a change which may result in new or additional exposures. Paragraph (f)(6) provides the accuracy and precision requirements for the sampling methodology selected by the employer. The requirements in paragraph (f)(7) pertain to employee notification of monitoring results.

Although employers are required to determine the exposure of each employee exposed to MDA, this determination is not required to be based on separate measurements taken for each employee. Instead, the standard permits employers to use a "representative" measurement to characterize the exposures of more than one employee when these employees perform essentially the same job under the same conditions. For these types of situations, it may be sufficient for the employer to monitor one or a few of these employees to obtain data that are "representative" of the exposure of the remaining employees in the group. As permitted in paragraph (f)(1)(iii), representative personal sampling for employees engaged in similar work and exposed to similar concentrations of MDA can be achieved by measuring the exposure of that member of the exposed group who can reasonably be expected to have the highest exposure and then attributing this exposure level to the remaining employees in the group. In many work situations, this representative monitoring approach may be more cost-effective than individual monitoring of all employees to determine the exposures of affected employees. However, employers are free to use any monitoring approach that will correctly identify the breathing-zone exposures of their employees to airborne MDA.

Paragraph (f)(2) of the final rule contains requirements for initial monitoring for construction employees exposed to MDA. In this paragraph OSHA requires employers to conduct initial monitoring at the start of each new MDA job in order to assess the effectiveness of existing engineering controls and to provide information necessary for the proper selection of appropriate respirators.

OSHA believes that initial monitoring is essential for protecting employee health because it provides the employer with information for determining the necessity for using engineering controls, instituting or modifying work practices, and selecting appropriate respiratory protection. Recognizing the varied nature of construction projects, OSHA has required that initial monitoring for employee exposures be conducted at the start of each new construction project that involves the handling of MDA-containing materials.

Furthermore, however, Paragraph (f)(2) allows employers to dispense with initial monitoring if they can demonstrate by means of objective data that MDA-containing products or material cannot release airborne MDA in concentrations exceeding the action level. OSHA believes that employers may be able to obtain data from the manufacturers of MDA-containing products that demonstrate that these materials will not release MDA at levels that exceed the action level, even under worst case conditions. This exemption would relieve employers from monitoring when employees are handling MDA containing products that are not capable of releasing a significant amount of MDA.

OSHA also has included in paragraph (f)(2) an exemption from initial monitoring for employers who have historical monitoring data. OSHA included this exemption in recognition of the fact that many employers are currently conducting exposure monitoring on construction sites; this exemption would prevent these employers from having to repeat monitoring activity for construction jobs that are substantially similar to previous jobs for which monitoring was conducted.

However, such monitoring data must have been obtained from projects conducted by the employer that meet the following conditions:

    (1) The data upon which judgments are based are scientifically sound and collected using methods that are sufficiently accurate and precise.
    (2) The processes and work practices in use when the historical monitoring data were obtained are essentially the same as those to be used during the job for which initial monitoring will not be performed.
    (3) The characteristics of the MDA- containing material being handled when the historical monitoring data were obtained are the same as those on the job for which initial monitoring will not be performed.
    (4) Environmental conditions prevailing when the historical monitoring data were obtained are the same as for the job for which initial monitoring will not be performed.

Paragraph (g). Regulated Areas

The standard requires that signs be posted to alert employees to the existence of areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA." Paragraphs (g)(2) and (g)(3) require that the regulated area be demarcated in a manner that restricts entry to the area to authorized persons only. Respirators must be supplied to persons entering regulated areas as specified in paragraph (g)(4) and eating, drinking, smoking, and applying cosmetics are prohibited in such areas by paragraph (g)(5). These requirements are consistent with similar provisions in previous OSHA standards (Acrylonitrile, 29 CFR 1910.1045; Inorganic Arsenic, 29 CFR 1910.1018; Ethylene Oxide, 29 CFR 1910.1047; and Vinyl Chloride, 29 CFR 1910.1017) and with the general industry standard regulating occupational exposure to MDA.

Paragraph (h). Methods of Compliance

The standard governing occupational exposure to MDA requires that a combination of engineering controls and work practices be used to meet the exposure limits contained in the standard. The engineering control methods outlined in the standard include isolation, enclosure, exhaust ventilation, and dust collection. Work practices are also necessary for maintaining exposures at or below the PELs.

Local exhaust ventilation systems that are equipped with HEPA-filtered dust collection systems are required for use in the general industry standards and are likewise being required for use in the construction industry.

OSHA believes that in some instances but not as a general rule, that general exhaust ventilation systems may also be effective in reducing employee exposure to MDA in construction. Such systems are useful for reducing the concentration of MDA-containing materials and removing potentially harmful MDA particulates from the air through a HEPA filtration system. OSHA cautions employers, however, that the use of general exhaust ventilation will tend to spread MDA airborne contaminants unless the return air is passed through a HEPA filter. Vacuum cleaners that are equipped with HEPA filters are effective controls for cleaning MDA spills and performing clean-up, since the HEPA-filtered vacuum systems collect MDA-containing material and prevent it from becoming airborne.

Isolation and enclosure of operations where MDA-containing materials are being applied to surfaces during construction activities is an effective means of containing exposures. The burden would be on the Assistant Secretary, in a particular enforcement proceeding to demonstrate the feasibility of engineering controls required by paragraph (h)(1)(i)(D).

The prompt disposal of MDA-containing materials in leak-tight containers can be an effective work practice because MDA-containing materials sealed in disposal containers while they are still wet are less likely to pose a dermal exposure problem.

OSHA also notes the significance which respirator use has in controlling worker exposure to MDA resulting from spray application. In fact, OSHA believes that, in this instance, for the most part, a properly selected and functioning respirator serves as the only feasible control for ultimately separating the worker from his environment. OSHA recognizes that application of MDA through spray techniques would result in the potential for very high worker exposures and thus in these instances requires that respirators, in addition to the use of feasible engineering, controls be used.

Further, OSHA requires that compressed air not be used to remove MDA-containing materials. Using compressed air to clean MDA dust from surfaces results in the formation of large dust clouds that lead to excessive exposures of the worker and bystanders unless local exhaust ventilation is used. There was no indication, however, that using compressed air to blow MDA-containing dust from surfaces was a current practice.

Paragraph (i). Respiratory Protection

The standard for the construction industry requires that employers provide respirators at no cost to employees:

    (1) during the interval necessary to install or implement feasible engineering and work practice controls;
    (2) in operations such as maintenance and repair activities and spray application processes for which engineering and work practice controls are not feasible;
    (3) in work situations where feasible engineering and work practice controls are not yet sufficient to reduce exposure to or below the PELs; and
    (4) in emergencies.

Employers are required under paragraph (i)(2) of the final rule to select appropriate respirators based on employee exposure levels that exist in the workplace. The required respirators range from half-mask air-purifying respirators equipped with high-efficiency filters for concentrations that do not exceed 10 times the PEL, to full-facepiece supplied-air respirators or SCBA when the concentration of MDA exceeds 1000 times the PEL. Employers are required to select respirators from those that are approved jointly by the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration under the provisions of 30 CFR Part 11.

Under paragraph (i)(3), employers are required to institute a respiratory protection program as required under 29 CFR 1910.134. The required program is to include among other things, (1) criteria for changing filter elements for air-purifying respirators, and (2) a policy permitting employees time to leave work areas to wash their faces and respirator facepieces to prevent skin irritation. Under paragraph (i)(5), the final standard requires that employers conduct qualitative or quantitative fit testing for all employees required to wear a negative-pressure respirator. The requirements for the use, selection, program elements, and fit testing of respirators are the same as those contained in the general industry standard.

Paragraph (j). Protective Work Clothing and Equipment

The construction standard, like the general industry standard, requires that all workers exposed to MDA be provided with personal protective clothing and equipment: i.e., coveralls, aprons, gloves, boot covers, and goggles. OSHA has imposed stringent provisions for the use of personal protective clothing because of the hazards associated with dermal absorption of MDA or MDA-containing materials. When non-disposable protective clothing is used, the employer is required by paragraph (j)(3) to launder the clothing in a manner that prevents the release of airborne MDA in excess of the PEL and to notify the person responsible for laundering. Paragraph (j)(2) requires employers to transport contaminated clothing in sealed impermeable bags or other impermeable containers. The requirements of paragraphs (j)(2) and (j)(3) are identical to the requirements of the general industry standard.

In addition, a requirement has been included that the personal protective equipment worn by employees be examined periodically to detect rips or tears, and that when rips or tears are detected in clothing they must be immediately mended, or the worksuit must be immediately replaced.

Also, OSHA allows disposable work suits to be used by construction workers handling MDA or MDA-containing products. OSHA believes that this type of clothing provides sufficient protection to the worker but eliminates the problems that may be involved in laundering and storing MDA-contaminated clothing on non-fixed work sites. OSHA recognizes that while disposable overalls may not be as durable and comfortable as cotton work clothes, they do not require laundering which would expose another workforce or the worker's family to MDA. OSHA, however, believes that non-disposable work clothes similar to those regulated in the general industry standard will provide sufficient protection for employees engaged in construction activities, provided that such clothing is properly cleaned after work and then laundered. OSHA, nonetheless, chooses to require performance language in its regulatory text which would allow the employer to choose the clothing which is appropriate.

OSHA also recognizes that heat stress is a concern when disposable protective clothing is used in hot environments. However, the use of protective clothing is necessary to protect employees from MDA exposure that may result from contaminated clothing. In situations in which heat stress is a concern, OSHA believes that employers should use appropriate work-rest regimens and provide heat stress monitoring that includes measuring employees' heart rates, body temperatures, and weight loss. If such measures are used to control heat stress, disposable protective clothing can be safely worn to provide the needed protection against MDA exposure.

Paragraph (k). Hygiene Facilities and Practices

The hygiene facilities requirements of the construction standard are similar to those in the general industry standard. For example, shower facilities are required wherever the possibility of employee exposure to airborne levels of MDA in excess of the action level exists. All workers required to wear personal protective equipment must have a place to change their street clothes and to store them separately from their work clothes.

Paragraph (k)(1)(i) of the construction standard modifies the language of the general industry standard to allow "decontamination areas," in recognition of the fact that the place where employees change from street clothing to work clothing and back again to street clothing is not always a separate room but may be merely a separate area of a larger space. This difference recognizes that it may not be feasible at some construction sites to provide a separate room with physical barriers.

"Decontamination area" is defined in the final standard to mean an area outside of but as near as practical to the regulated area, consisting of an equipment storage area, wash area, and clean change area, which is used for the decontamination of workers, materials, and equipment contaminated with MDA.

OSHA also requires "separate storage facilities" in recognition of the fact the employers must use portable storage facilities that can be transported from job to job. OSHA's intent in this provision is to ensure that street clothes are sufficiently separated from work and protective clothing and equipment in order to prevent contamination of employees' street clothing, and this can be accomplished by separate lockers, baskets, or other containers.

OSHA also requires the provision of clean lunch areas: i.e., areas that have airborne concentrations of MDA below the action level, where employees may consume food or beverages on site. This addition was recommended by CACOSH in its 1980 report. CACOSH recognized that permanent lunch rooms, such as exist on fixed worksites, were probably not feasible for the construction industry, due to the nonfixed nature of construction project worksites. See "Report on Occupational Health Standards for the Construction Industry," May 16, 1980, CACOSH Docket. The term "lunch area" is adopted by OSHA to indicate that a temporary facility, such as a separate trailer, would serve the purpose of protecting employee health.

Paragraph (l). Communication of MDA hazards to Employees

In paragraph (l) of the standard, includes requirements to ensure that the dangers of MDA-containing materials are communicated to employees by means of signs, labels, and employee information and training. The requirements for the signs and labels mandated in this section parallel those in OSHA's Hazard Communication standard (29 CFR 1910.1200).

(1) Signs and Labels. The construction standard includes specifications for signs to be posted at all locations where regulated areas have been established to indicate that concentrations of airborne MDA exceed or can be reasonably expected to exceed the PEL or where employees are engaged in activities that can result in "dermal exposure to MDA"; such signs are to bear the same legend as that required in the general industry standard.

The purpose of such signs is to minimize the number of employees in a regulated area by alerting them to the fact that they must have authorization from their employer and take the appropriate protective measures before entering. Furthermore, as discussed in the summary and explanation section for the standard for general industry, signs serve to apprise employees of the hazards to which they are exposed in the course of their employment, and foster cooperation between the employee and employer in controlling workplace hazards. The standard also requires that all MDA products and containers of MDA products, including waste containers, be labeled with appropriate information and with a warning statement against inhalation or dermal contact with MDA. These labelling requirements are consistent with those found in 1910.1200.

(2) Employee Information and Training. The training requirements are consistent with those found in 1910.1200, except that annual training is required in both the general industry and construction standards. The standard requires that training be provided to all employees prior to or at the time of initial assignment and at least yearly thereafter. Component areas to be covered in the training program include: (1) methods for recognizing MDA; (2) the health effects associated with MDA exposure; (3) the importance of necessary protective measures to minimize exposure including, as applicable, engineering controls, work practices, respirators, housekeeping and protective clothing, and any necessary instruction in the use of these controls; (4) the purpose, proper use, fitting instructions, and limitations of respirators, as described in 29 CFR 1910.134; (5) the appropriate work practices for performing the MDA related job; and (6) the medical surveillance program requirements. The employer may design and implement his own training program that contains these elements, or rely on third-party training programs. Finally, the standard requires that the employer make readily available to affected employees and provide to OSHA and NIOSH all written materials regarding the employee information and training program.

OSHA strongly believes that informing and training employees can reduce the incidence of work-related diseases caused by exposure to hazardous workplace conditions.

Paragraph (m). Housekeeping

The standard for the construction industry includes a housekeeping provision stipulating that (1) when vacuuming is used for cleanup, only HEPA-filtered equipment may be used; and (2) all waste, scrap, debris, bags, containers, equipment, and contaminated clothing must be collected and disposed of in sealed impermeable bags or in other closed impermeable containers. OSHA believes that these housekeeping practices reflect advances in vacuum filter technology and good hygiene practices, and are essential parts of any effective MDA control program. OSHA believes that the use of HEPA-filtered vacuums and proper disposal practices will considerably diminish the risk of generating airborne MDA during cleanup -- a potentially high-exposure activity -- and minimize the potential for dermal absorption of MDA. The required use of high-efficiency particulate air filters on vacuums employed for cleanup is not intended to preclude the use of other complementary cleanup methods, such as wet methods (where applicable). OSHA believes that the housekeeping requirements will aid in minimizing worker contact with MDA.

Paragraph (n). Medical Surveillance

Section 6(b)(7) of the OSH Act requires that, where appropriate, medical surveillance programs be included in OSHA health standards to aid in determining whether the health of workers is adversely affected by exposure to toxic substances. The medical surveillance requirements contained in this final MDA construction standard are designed to detect changes in liver function and signs or symptoms of acute liver disease.

OSHA requires that each employer must institute a medical surveillance program for all employees exposed to MDA as follows:

    (1) Employees exposed at or above the action level to dusts or vapors for 30 or more days per year;
    (2) Employees who are subject to dermal exposure to MDA for 15 or more days per year;
    (3) Employees who have been exposed in an emergency situation;
    (4) Employees whom the employer, based on results from compliance with (g)(8), has reason to believe are being dermally exposed; and
    (5) Employees who show signs or symptoms of exposure.

The final language requires that the medical surveillance program provide each covered employee with an opportunity for a medical examination. Further, all examinations and procedures must be performed by or under the supervision of a licensed physician and be provided without cost to the employee. Clearly, a licensed physician is the appropriate person to supervise and evaluate a medical examinations. However, certain parts of the required examination do not necessarily require the physician's expertise and may be conducted by another person under the supervision of the physician.

OSHA also requires that exams be given at a reasonable time and place. It is necessary that exams be convenient and be provided without loss of pay to the employee to assure that they are taken.

The final standard allows the examining physician to prescribe the specific protocols to be included in the medical surveillance program. There are, however, some specific requirements, such as:

    i) comprehensive medical and work histories with special emphasis directed to an evaluation of other carcinogens to which the employee is exposed, and smoking and alcohol use;
    ii) comprehensive physical examination, with particular emphasis given to symptoms related to eye and skin irritation, and liver dysfunction;
    iii) complete urinalysis; and
    iv) screening for liver damage.

It is important to note that the employer is required to make any prescribed tests available more often than specified if recommended by the examining physician. OSHA also requires that the employer provide examinations recommended by the physician to any employee exposed to MDA under emergency conditions. Due to the effects of high short-term exposures, it appears prudent to monitor medically such affected employees. However, trivial exposures which are peripherally related to an emergency do not trigger the requirement.

The employer is also required to provide the physician with the following information: a copy of this standard and its appendices; a description of the affected employee's duties as they relate to the employee exposure level; and information from the employee's previous medical examinations which is not readily available to the examining physician. Making this information available to the physician will aid in the evaluation of the employee's health in relation to assigned duties and fitness to wear personal protective equipment.

The employer is required to obtain a written opinion from the examining physician that contains the results of the medical examinations; the physician's opinion as to whether the employee has any detected medical conditions which would place the employee at increased risk of material health impairment from exposure to MDA; any recommended restrictions upon the employee's exposure to MDA or upon the use of protective clothing or equipment, such as respirators; and a statement that the employee has been informed by the physician of the results of the medical examination and of any MDA-related medical conditions which require further explanation or treatment. This written opinion must not reveal specific findings or diagnoses unrelated to occupational exposure to MDA, and a copy of the opinion must be provided to the affected employee.

The requirement that a physician's opinion be in written form will ensure that employers have had the benefit of this information. The requirement that an employee be provided with a copy of the physician's written opinion will ensure that the employee is informed of the results of the medical examination. The purpose of requiring that specific findings or diagnoses, unrelated to occupational exposure to MDA, not be included in the written opinion is to encourage employees to take the medical examination by removing the concern that the employer will obtain information about their physical condition that has no relation to present occupational exposures.

Like the general industry standard this standard would also include a multiple physician review mechanism. This mechanism is required because OSHA believes this would aid in ensuring that employees take physical examinations. Finally, the standard contains provisions for removing an employee from exposure who has suffered reversible material impairment to health as a result of being exposed to MDA. OSHA believes that employees whose health has been adversely affected as a direct result of occupational exposure to MDA must be removed from exposure and must receive medical removal benefit protections. For a fuller discussion of the multiple physician review mechanism and the medical removal provisions, see the general industry summary above.

Paragraph (o). Recordkeeping

The final standard's requirements are consistent with Section 8(c)(3) of the OSH Act which provides for the promulgation of regulations requiring employers to maintain accurate records of employee exposures to potentially toxic substances or harmful physical agents which are required to be monitored or measured.

OSHA permits the use of objective data in order to be exempted from the standard. Records of objective data must be maintained to demonstrate that employees are not exposed to excessive airborne MDA concentrations or "dermally exposed to MDA", as defined.

For this final construction standard, OSHA also permits the use of historical monitoring data in order to meet the requirements for initial monitoring found in paragraph (f)(2) of this section. Records of historical monitoring data must be maintained to demonstrate that employees are not exposed to airborne concentrations of MDA in excess of the action level. While this specific recordkeeping language was not in the NPRM its substantive basis is found both in paragraph (f)(2) found at 54 FR 20731 and the definition of "Objective and historical data" found on the page before. In addition, this language is taken verbatim from the Committee's preamble at 52 FR 26869. OSHA believes that this language will help to clarify what is expected from an employer who chooses to use historical monitoring data to satisfy his initial monitoring obligations under the standard.

OSHA also requires that records be kept to identify the employee monitored and to reflect the employee's exposure accurately. Specifically, records must include the following information: (a) the names and social security numbers of the employees sampled; (b) the number, duration, and results of each of the samples taken, including a description of the representative sampling procedure and equipment used to determine employee exposure where applicable; (c) a description of the operation involving exposure to MDA which is being monitored and the date on which monitoring is performed; (d) the type of respiratory protective devices, if any, worn by the employee; and (e) a description of the sampling and analytical methods used, and evidence of their accuracy.

OSHA also includes a provision for requiring the employer to keep an accurate medical record for each employee subject to medical surveillance. Section 8(c) of the Act authorizes the promulgation of regulations requiring any employer to keep such records regarding the employer's activities relating to the Act as are necessary or appropriate for the enforcement of the Act or for developing information regarding the causes and prevention of occupational illnesses. OSHA believes that medical records, like exposure monitoring records, are necessary and appropriate to both the enforcement of the standard and the development of information regarding the causes and prevention of illness.

As explained above, it is necessary to relate employees' medical conditions to their exposures to develop information regarding cause and prevention. Medical records are necessary and appropriate for this purpose. In addition, medical records are necessary for the proper evaluation of the employee's health.

The employer is also required to keep a record of any employee's medical removal and return to work status.

The standard requires that all records required to be kept shall be made available upon request to the Assistant Secretary and the Director of NIOSH for examination and copying. Access to these records is necessary for the agencies to monitor compliance with the standard. These records may also contain essential information which is necessary for the agencies to carry out their other statutory responsibilities.

The standard also provides for employees, former employees, and their designated representatives to have access to mandated records upon request. Section 8(c)(3) of the Act explicitly provides "employees or their representatives" with an opportunity to observe monitoring and to have access to the records of monitoring and exposures to toxic substances; and several other provisions of the Act contemplate that employees and their representatives are entitled to play an active role in the enforcement of the Act. Employees and their representatives need to know relevant information concerning employee exposure to toxic substances and their health consequences if they are to benefit fully from these statutory rights.

In addition, access to exposure and medical records by employees, designated representatives, and OSHA is to be provided in accordance with 29 CFR 1910.20. Section 1910.20 is OSHA's generic standard for access to employee exposure and medical records (45 FR 35212). By its terms, it applies to records required by specific standards, such as this MDA standard, as well as records which are voluntarily created by employers. In general, it provides for unrestricted employee and designated representative access to exposure records. Unrestricted access to both kinds of records is allowed, but access to personally identifiable records is made subject to rules of agency practice and procedure concerning OSHA access to employee medical records, which have been published at 29 CFR 1913.10. An extensive discussion of the provisions and rationale for §1920.20 may be found at 45 FR 35312; the discussion of §1913.10 may be found at 45 FR 35384.

It is necessary to keep records for extended periods because of the long latency periods commonly observed for carcinogens. Cancer often cannot be detected until 20 or more years after onset of exposure. The extended retention period is therefore needed for two purposes. Diagnosis of disease in employees is assisted by having present and past exposure data as well as the results of the medical exams. Retaining records for extended periods also makes it possible at some future date to review the adequacy of the standard.

The time periods required for retention of exposure records and medical records are thirty years, and period of employment plus thirty years, respectively. These retention periods are consistent with those in the OSHA records access standard.

The standard requires certain employers to notify the Director in writing at least 3 months prior to the disposal of the records. Section 1910.20(h) contains further requirements regarding the transfer of records.

To increase the effectiveness of training goals the standard requires that the training material be made available, without cost, to all affected employees or their representatives.

OSHA recognizes the transient nature of the construction industry and the difficulties which this industry may have with recordkeeping requirements; it is for this reason that OSHA would not mandate the specific methods of recordkeeping. Employers are free to use the services of competent organizations such as industry trade associations and employee associations to maintain the required records. To reduce the costs and facilitate the recordkeeping some groups currently use centralized medical recordkeeping financed through employer contributions. Centralized recordkeeping could be instrumental in alleviating the problem of lost records associated with the transient nature of the construction workforce and the frequency of business closures in this sector.

Paragraph (p). Observation of Monitoring

The final standard also includes a provision for observation of exposure monitoring. This provision is in accordance with section 8(c) of the OSH Act which requires that employers provide employees and their representatives with the opportunity to observe monitoring of employee exposures to toxic substances or harmful physical agents. Observation procedures are set forth which require the observer, whether it be an employee or a designated representative, to be provided with the personal protective clothing and equipment that is required to be worn by the employees who are working in the area. The employer is required to assure the use of such clothing and equipment or respirators and is responsible for requiring that the observer complies with all other applicable safety and health procedures.

Paragraph (q) Effective dates.

The standard becomes effective September 9, 1992. The effective date established in the final standard remains the same as the date which appeared in the proposed rule.

Paragraph (r). Appendices

Five appendices have been included at the end of this final standard. Appendices A,B, C, and D have been included primarily for purposes of information. None of the statements contained in Appendices A,B,C, and D should be construed as establishing a mandatory requirement not otherwise imposed by the standard, or as detracting from an obligation which the standard does impose. However, the protocols for respiratory fit testing in Appendix E are mandatory.

Appendix A contains information on the description and exposure levels of MDA. Also provided in Appendix A is information on the health hazards associated with exposure, descriptions of protective clothing and equipment, emergency and first aid procedures, medical requirements, provisions for the observation of monitoring, access to exposure and medical records, and precautions for the safe use, handling, and storage of MDA.

Appendix B contains "substance technical guidelines" for MDA, including physical and chemical data, spill and leak procedures, including waste disposal methods, and other miscellaneous precautions for the safe handling of MDA.

Appendix C contains the medical surveillance guidelines for MDA. Included in these guidelines are the description of the routes of entry, the toxicology and symptoms and signs associated with MDA exposure, information on the treatment of acute toxic effects, and surveillance and preventive considerations, including hematology guidelines which may be useful to physicians in conducting the medical surveillance program required by paragraph (n) of this final standard.

Appendix D gives details of the sampling and analytical methods for use in monitoring employee exposures to MDA.

Appendix E gives detailed fit testing procedures that are to be followed for qualitative or quantitative fit testing of negative pressure respirators. Various protocols for qualitative and quantitative fit tests are outlined in detail.

All the Appendices are designed to aid the employer in complying with the requirements of the standard. Paragraph (l) of this final standard on the "communication of MDA hazards to employees" specifically requires that the contents of the standard and Appendices A and B be made available to affected employees. Information contained in Appendix C on medical surveillance is to be explained to affected employees. Appendix C also provides information needed by the physician to evaluate the results of the medical examination.

Paragraph (s) Start-up dates.

The final standard contains start up dates for the various standard provisions. These dates go into effect based on the effective date. The dates originally proposed in the MDA rule have been modified to reflect a more logical schecule for compliance. These dates are based on economic and technological considerations discussed in the regulatory impact analysis.

XI. ENVIRONMENTAL ASSESSMENT; FINDINGS OF NO SIGNIFICANT IMPACT

OSHA has reviewed the environmental impact in accordance with the requirements of the National Environmental Policy Act (NEPA) of 1969 (42 U.S.C. 4321 et seq.), the Council on Environmental Quality (CEQ) NEPA regulations (40 CFR Part 1500), and OSHA's NEPA compliance procedures (29 CFR Part 11).

As a result of this review, OSHA has determined that these regulations will have no impact on air, water or soil quality, plant or animal life, or the use of land or aspects of the external environment. Therefore, OSHA concludes there will be no significant impact on the general quality of the human environment outside the workplace, particularly in terms of ambient air quality, water quality, or solid waste disposal. No comments made at the public hearing or submitted to the record contradict this conclusion.

XII. STATE PLAN REQUIREMENTS

The 25 States and territories with their own OSHA-approved occupational safety and health plans must revise their existing standards within six months of the publication date of the final standards or show OSHA why there is no need for action, e.g., because existing state standards are already "at least as effective" as the new Federal standards. These States are: California, Connecticut (State and local government workers only), Hawaii, Indiana, Iowa, Kentucky, Maryland, Michigan Minnesota, Nevada, New Mexico, New York (State and local government workers only), North Carolina, Tennessee, Utah, Vermont, Virginia, Virgin Islands, Washington and Wyoming. Until such time as a State standard is promulgated, Federal OSHA will provide interim enforcement assistance, as appropriate.

XIII. FEDERALISM

The standards have been reviewed in accordance with Executive Order 12612 (52 FR 41685; October 30, 1987) regarding Federalism. This Order requires that agencies, to the extent possible, refrain from limiting State policy options, consult with States prior to taking any actions that would restrict State policy options, and take such actions only when there is clear constitutional authority and the presence of a problem of national scope. The Order provides for preemption of State law only if there is a clear constitutional authority and the presence of a problem of national scope. Additionally, the Order provides for preemption of State law only if there is a clear Congressional intent for the agency to do so. Any such preemption is to be limited to the extent possible.

Section 18 of the Occupational Safety and Health Act (OSH Act), expresses Congress' clear intent to preempt State laws relating to issues with respect to which Federal OSHA has promulgated occupational safety or health standards. Under the OSH Act a State can avoid preemption only if it submits, and obtains Federal approval of, a plan for the development of such standards and their enforcement. Occupational safety and health standards developed by such Plan-States must, among other things, be at least as effective in providing safe and healthful employment and places of employment as the Federal standards.

The Federally promulgated MDA standard is drafted so that workers in every State would be protected by general, performance-oriented standards. To the extent that there are State or regional peculiarities that could alter work practices, States with occupational safety and health plans approved under section 18 of the OSH Act would be able to develop their own State standards to deal with any special problems. Moreover, the performance nature of this final standard, of and by itself, allows for flexibility by States and contractors to provide as much safety as possible using varying methods consonant with conditions in each State.

In short, there is a clear national problem related to occupational safety and health of workers. While the individual States, if all acted, might be able collectively to deal with the safety problems involved, most have not elected to do so in the seventeen years since the enactment if the OSH Act. Those States which have elected to participate under section 18 of the OSHA Act would not be preempted by this final regulation and would be able to deal with special, local conditions within the framework provided by this performance-oriented standard while ensuring that their standards are at least as effective as the Federal standard.

XIV. CLEARANCE OF INFORMATION COLLECTION REQUIREMENTS

5 CFR 1320 sets forth procedures for agencies to follow in obtaining OMB clearance for information collection requirements under the Paperwork Reduction Act of 1980, 44 U.S.C. 3501 et seq. The final MDA standards require the employer to allow OSHA access to records. In accordance with the provisions of the Paperwork Reduction Act and the regulations issued pursuant thereto, OSHA certifies that it has submitted the information collection to OMB for review under section 3504(h) of that Act.

Public reporting burden for this collection of information is estimated to average five minutes per response to allow OSHA compliance officers access to the employer's records. Send comments regarding this burden estimate, or any other aspect of this collection of information, including suggestions for reducing this burden, to the Office of Information Management, Department of Labor, Room N-1301, 200 Constitution Avenue, N.W., Washington, D.C. 20210; and to the Office of Information and Regulatory Affairs Management and Budget, Washington, D.C. 20503.

XV. AUTHORITY AND SIGNATURE

This document was prepared under the direction of Dorothy L. Strunk, Acting Assistant Secretary of Labor for Occupational Safety and Health, U.S. Department of Labor, 200 Constitution Avenue, NW, Washington, DC 20210.

Accordingly, pursuant to 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); Sec. 107, Contract Work Hours and Safety Standards Act (Construction Safety Act) (40 U.S.C. 333); Sec. 41, Longshore and Harbor Workers' Compensation Act (33 U.S.C. 941); and 29 CFR Part 1911; 29 CFR Part 1910 and 1926 are amended as set forth below.

List of Subjects in 29 CFR Part 1910 and 1926 Health, Occupational Safety and Health, Protective Equipment, Respiratory Protection, Carcinogen.

Signed at Washington, DC this 20th day of July, 1992.

Dorothy L. Strunk, Acting Assistant Secretary of Labor for Occupational Safety and Health

XVI. REGULATORY TEXT General Industry Part 1910--[Amended] 1. The authority citation for Subpart Z of 29 CFR Part 1910 continues, in part, to read as follows:

    Authority: Secs. 4, 6 and 8, Occupational Safety and Health Act, 29 U.S.C. 653, 655, 657, Secretary of Labor's Orders Nos. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), or 1-90(55 FR 9033) as applicable; and 29 CFR Part 1911.

2. By revising a new paragraph (i) to §1910.19 to read as follows:

§1910.19 Special provisions for air contaminants * * * * *

(i) 4,4'-Methylenedianiline (MDA). Section 1910.1050 shall apply to the exposure of every employee to MDA in every employment and place of employment covered by §§1910.13, 1910.14, 1910.15, or 1910.16, in lieu of any different standard on exposure to MDA which would otherwise be applicable by virtue of those sections.

* * * *

3. By adding a new §1910.1050 to read as follows: [Full text for 1910.1050 (Methylenedianiline) may be found in OSHA STANDARDS database]

Construction Standard

PART 1926 - [AMENDED]

4. The authority citation for part 1926 continues to read as follows:

Authority: Sec. 107, Contract Work Hours and Safety Standards Act (Construction Safety Standards Act)(Construction Safety Act)(40 U.S.C. 333): secs. 4, 6, and 8. Occupational Safety and Health Act of 1970 (29 U.S.C. 653, 655, and 657); Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), (or 1-90 (55 FR 9033)) as applicable; and 29 CFR part 1911.

5. By adding a new 1926.60 to read as follows: [Full text for 1926.60 (Methylenedianiline) may be found in OSHA STANDARDS database.]


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