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1943. PERMISSIBLE EXPOSURE LIMITS (PELS) FOR AIR CONTAMINANTS
Priority: Economically Significant. Major under 5 USC 801. Unfunded Mandates: This action may affect the private sector under PL 104-4.
Legal Authority: 29 USC 655 (b)
CFR Citation: 29 CFR 1910.1000; 29 CFR 1915.1000; 29 CFR 1917.1(a)(2)(ii); 29 CFR 1918.1(b)(a); 29 CFR 1926.55
Legal Deadline: None
Abstract: OSHA enforces hundreds of permissible exposure limits (PELs) for toxic air contaminants found in U.S. workplaces. Most of the air contaminant limits were adopted by OSHA in 1971 from recommendations issued by the American Conference of Governmental Industrial Hygienists and the American National Standards Institute. These PELs, which have not been updated since 1971, thus reflect the results of research conducted in the 1950s and 1960s. Since then, much new information has become available that indicates that, in many cases, these early limits are outdated and insufficiently protective of worker health. To correct this situation, OSHA issued a final rule in 1989 (54 FR 2332); it lowered the existing PELs for 212 toxic air contaminants and established PELs for 164 previously unregulated air contaminants. On June 12, 1992 (57 FR 26001), OSHA proposed a rule that would have extended these limits to workplaces in the construction, maritime, and agriculture industries. However, on July 10, 1992, the Eleventh Circuit Court of Appeals vacated the 1989 final rule on the grounds that "(1) OSHA failed to establish that existing exposure limits in the workplace presented significant risk of material health impairment or that new standards eliminated or substantially lessened the risk; (2) OSHA did not meet its burden of establishing that its 428 new permissible exposure limits (PELs) were either economically or technologically feasible." The Court's decision forced the Agency to return to the earlier, insufficiently protective limits.
OSHA continues to believe that establishing a rulemaking approach that will permit the Agency to update existing air contaminant limits and establish new ones as toxicological evidence of the need to do so becomes available is a high priority. The rulemaking described in this Regulatory Plan entry reflects OSHA's intention to move forward with this process. In determining how to proceed, OSHA is being guided by the OSH Act and the Eleventh District Court decision regarding quantifying the risk and analyzing the feasibility of any new air contaminant limits. State-of-the-art risk assessment methodologies will be utilized for both carcinogens and noncarcinogens, and the determinations of feasibility contained in the economic analysis accompanying the proposal will be extensive. OSHA published (61 FR 1947) the name of the 20 substances from which the proposed new PELs for the first update were chosen: carbon disulfide, carbon monoxide, chloroform, dimethyl sulfate, epichlorohydrin, ethylene dichloride, glutaraldehyde, n-hexane, 2-hexanone, hydrazine, hydrogen sulfide, manganese and compounds, mercury and compounds, nitrogen dioxide, perchloroethylene, sulfur dioxide, toluene, toluene diisocyanate, trimellitic anhydride, and vinyl bromide. The specific hazards associated with the air contaminants preliminarily selected for regulation include cancer, neurotoxicity, respiratory and skin irritation and sensitivity, and cardiovascular disease, etc. Using the same criteria as those used in the Priority Planning Process, OSHA has evaluated for each substance: the severity of the health effect, the number of exposed workers, toxicity of the substance, uses and prevailing exposure levels of the substance, the potential risk reduction, and the availability and quality of information useful in quantitative risk assessment to ensure that significant risks are addressed and that workers will experience substantial benefits in the form of enhanced health and safety.
Although OSHA has evaluated factors for the twenty substances and plans to develop more PELs in the future, for this first stage in the current rulemaking process OSHA has decided to propose new PELs for four chemicals - carbon disulfide, glutaraldehyde, hydrazine, and trimellitic anhydride - that have different adverse health effects, both carcinogenic and non-carcinogenic, requiring different risk assessment approaches. For these four chemicals, OSHA has modified or developed new quantitative risk assessment approaches for cancer, respiratory sensitization and irritation, cardiovascular disease and neurotoxicity effects. Publication of the proposal will allow OSHA to continue to develop a mechanism for updating and extending its air contaminant limits, that will, at the same time, provide added protection to many workers who are currently being overexposed to toxic substances in the workplace.
OSHA is also considering supplemental mechanisms proposed by stakeholders to increase the effectiveness and timeliness of the process. The agency is considering the establishment of an advisory committee to review issues related to the PELs process.
Statement of Need: OSHA has permissible exposure limits for approximately 470 toxic substances, many of which are widely used in industrial settings. These PELs, which were adopted wholesale by OSHA in 1971 and have not been revised since then, often lead to adverse effects when workers are exposed to the contaminants at these levels. In addition, new chemicals are constantly being introduced into the working environment, and exposure to these substances can result in both acute and chronic health effects. Acute effects include respiratory and sensory irritation, chemical burns, and ocular damage; chronic effects include cardiovascular disease, respiratory, liver and kidney disease, reproductive effects, neurological damage, and cancer. For these reasons, it is a high OSHA priority to establish an ongoing regular process that will allow OSHA routinely to update existing PELs and to establish limits for some currently unregulated substances. The first step in achieving this goal is to publish an air contaminants proposal for a number of substances that will establish streamlined but scientifically sound and defensible procedures for conducting risk assessments and performing feasibility analyses that will permit regular updating and review of permissible exposure limits for air contaminants. The ability to lower existing limits and establish limits for new contaminants is an essential component of OSHA's mandate to protect the health and functional well-being of America's workers.
Summary of Legal Basis: The legal basis for the proposed PELs for selected air contaminants is a preliminary determination by the Secretary of Labor that the substances for which PELs are being proposed pose a significant risk to workers and that the new limits will substantially reduce that risk.
Alternatives: OSHA has considered a variety of nonregulatory approaches to address the problem of the Agency's outdated exposure limits for air contaminants. These include the issuance of nonmandatory guidelines, enforcing lower limits through the "general duty" clause of the OSH Act in cases where substantial evidence exists that exposure presents a recognized hazard of serious physical harm, and the issuance of hazard alerts. OSHA believes, however, that the problem of overexposure to hazardous air contaminants is so widespread, and the Agency's current limits are so out of date, that only a regulatory approach will achieve the necessary level of protection. The regulatory approach also has advantages for employers, because it gives them the information they need to establish appropriate control strategies to protect their workers and reduce the costs of job-related illnesses. This first phase of an ongoing air contaminants updating and revision process will begin to resolve a problem of long standing and major occupational health import.
Anticipated Cost and Benefits: The scope of the proposed rule is currently under development and thus quantitative estimates of costs and benefits have not been determined at this time. Implementation costs associated with the proposed standard include primarily those related to identifying and correcting overexposures using engineering controls and work practices. Additional costs may be incurred for the implementation of administrative controls and the purchase and use of personal protective equipment. Estimates of the magnitude of the problem of occupational illnesses, both acute and chronic, vary considerably. In 1989, OSHA concluded that its Air Contaminants rule in general industry, which lowered 212 exposure limits and added 164 where none had previously existed, would result in a reduction of approximately 700 deaths, 55,000 illnesses, and over 23,300 lost- workday illnesses annually. Chronic effects include cardiovascular disease, respiratory, liver and kidney disease, reproductive effects, neurological damage, and cancer. Acute effects include respiratory and sensory irritation, chemical burns, and ocular effects.
Risks: Risk assessments for the substances under consideration for this first phase of the air contaminants updating and revision process are being completed at this time.
Regulatory Flexibility Analysis Required: No
Government Levels Affected: Undetermined
Additional Information: During the rulemaking, OSHA will meet with small business stakeholders to discuss their concerns, and will conduct an initial Regulatory Flexibility Screening Analysis to identify any significant impacts on a substantial number of small entities.
Agency Contact: Marthe B. Kent, Acting Director, Directorate of Health
Standards Programs, Department of Labor, Occupational Safety and Health
Administration, Room N3718, 200 Constitution Avenue NW, FP Building,
Washington, DC 20210
Phone: 202 693-1950
Fax: 202 693-1678
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