The Occupational Safety & Health Administration (OSHA), an agency of the U.S. Department of Labor, sets enforceable Permissible Exposure Limits (PELs) to protect workers against the health effects of exposure to hazardous substances. PELs are regulatory limits on the amount or concentration of a substance in the air. They may also contain a skin designation.
OSHA PELs are based on an 8-hour time weighted average (TWA) exposure. There exist also short-term exposure limits and different types of ceiling limits.
PELs are addressed in specific standards for the general industry, shipyard employ-ment, and the construction industry. They are codified in 29 CFR (Code of Federal Regulations) 1910 Subpart Z - Toxic and Hazardous Substances. Most of the PELs are listed in Tables Z-1, Z-2, or Z-3, while some are listed as part of substance-specific standards.
So far, approximately 500 PELs have been established, many originally based on the 1968 recommendations of the American Conference of Industrial Governmental Hygienists (ACGIH). OSHA PELs are being updated via a substance-by-substance approach.
OSHA can begin standards-setting procedures on its own initiative, or in response to petitions from other parties, including the Secretary of Health and Human Services (HHS), the National Institute for Occupational Safety and Health (NIOSH), state and local governments, any nationally-recognised standards-producing organisation, employer or labour representatives, or any other interested person.
If OSHA determines that a specific standard is needed, any of several advisory committees may be called upon to develop specific recommendations. There are two standing committees, and ad hoc committees may be appointed to examine special areas of concern to OSHA. All advisory committees, standing or ad hoc, must have members representing management, labour, and state agencies, as well as one or more designees of the Secretary of HHS. The two standing advisory committees are:
OSHA is not authorised to adopt the most restrictive standard possible as dictated solely by health or safety considerations. On the one hand, OSHA must demonstrate the need for a new or changed standard based on risk factors. On the other hand the standard to be implemented must be (now or in the foreseeable future) technologically and economically feasible.
Once OSHA has developed plans to propose, amend or revoke a standard, it pub-lishes these intentions in the Federal Register as a "Notice of Proposed Rulemaking," or often as an earlier "Advance Notice of Proposed Rulemaking." Prior to publication of proposed and final major rules OSHA consults with the Office of Management and Budget (OMB) under procedures established by Executive Order. OSHA consults with small business on proposed rules which significantly affect them through a panel with participation by the Small Business Administration and OMB, as required by the Small Business Regulatory Enforcement and Fairness Act (SBREFA).
An "Advance Notice" is used, when necessary, to solicit information that can be used in drafting a proposal. The Notice of Proposed Rulemaking will include the terms of the new rule and provide a specific time (at least 30 days from the date of publication, usually 60 days or more) for the public to respond.
Interested parties who submit written arguments and pertinent evidence may request a public hearing on the proposal when none has been announced in the notice. When such a hearing is requested, OSHA will schedule and will publish, in advance, the time and place for it in the Federal Register. An administrative law judge is appointed to preside over the hearing, accept evidence, regulate the course of the hearing, and permit cross-examination of witnesses. The judge also has the power to order and accept posthearing comments and arguments.
After the close of the comment period and public hearing, if one is held, a recom-mendation is prepared for the Assistant Secretary for Labor, who makes the final decision on the rule. This final rule is based on the record developed during the rule-making and may vary from the proposed rule. OSHA must publish in the Federal Register the full, final text of any standard amended or adopted and the date it becomes effective, along with an explanation of the standard and the reasons for implementing it. OSHA may also publish a determination that no standard or amendment needs to be issued.