OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.


January 24, 2003

The Honorable Charlie Norwood
Committee on Education and the Workforce
Subcommittee on Workforce Protections
U.S. House of Representatives
Washington, D.C. 20515

Dear Chairman Norwood:

Thank you for your October 11, 2002 letter to the Occupational Safety and Health Administration (OSHA) concerning OSHA's enforcement of occupational exposure levels (OELs) recommended by non-governmental organizations which need not adhere to the same process for standard setting as does OSHA. In your letter you express concern that OSHA is relying upon non-consensus recommended OELs for regulatory or enforcement purposes.

I appreciate the reasons for your concern. Having worked for most of my career on the "regulated" side of OSHA, I am very aware of the potential unfairness and the costs when government tries to circumvent the protections of the rulemaking process.

As you know, the issue of using OELs generally arises when OSHA encounters a workplace chemical hazard not covered by an OSHA Permissible Exposure Level (PEL). Unfortunately not all workplace chemical hazards are presently covered by an OSHA PEL. In those cases OSHA may enforce the "general duty clause" (OSHAct Section 5(a)(1)), when a serious hazard is observed. If a citation in that situation is issued, however, it is not issued for exceeding an OEL but for failing to control or eliminate a "recognized hazard." An OEL is sometimes used as a reference point to support a finding of a "recognized hazard," but it should be only to buttress other evidence that a hazard exists. OSHA refers to several sources for OELs, including those developed by NIOSH, prior to referring to the American Conference of Government Industrial Hygienists's Threshold Limit Values (TLVs); a General Duty Clause violation would not be based solely on a TLV. OELs are not considered or used as either PELs or as consensus standards under section 12(d) of the National Technology Transfer and Advancement Act of 1995. Exceeding an OEL recommendation, therefore, is not the hazardous or violative condition, but rather that employees were exposed to harmful levels of a chemical. Moreover, using OELs to support the Agency's finding that a particular chemical exposure constitutes a recognized hazard is not very common. Only five such OSHAct Section 5(a)(1) citations referencing OELs were issued over the last two years.

I have enclosed a copy of a memorandum recently sent to our Regional Administrators that re-addresses our enforcement policy for respiratory hazards not covered by OSHA Permissible Exposure Limits in order to ensure a uniform enforcement policy. In it we have reminded them that recommended non-consensus occupational exposure levels such as TLVs are guidelines developed for industrial hygienists to be used as a supplement to a workplace safety and health program and are not meant to be enforced, in and of themselves, by government agents. To further ensure this policy is being followed, we will now require all General Duty Clause violations for workplace air contaminant hazards to be approved by the Regional Administrator. This guidance is also being transmitted to OSHA's State Plan Designees. We will be discussing our Federal policy with them during the next Occupational Safety and Health State Plan Association (OSHPA) meeting in Seattle, Washington at the end of January. As you know, State OSHA programs operate under authority of State law and, while required to be "at least as effective" as the Federal program, may have different Permissible Exposure Limits as well as different implementing policies and procedures.

I hope this provides the clarification you were seeking. If you have any further questions, please feel free to contact [the Office of Congressional and Intergovernmental Affairs at (202) 693-2000].


John L. Henshaw
Assistant Secretary

[Corrected 09/29/2008]