Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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


DATE: January 24, 2003
SUBJECT: Enforcement Policy for Respiratory Hazards Not Covered by OSHA Permissible Exposure Limits



As you are aware, the General Duty Clause (Section 5(a)(1) of the Occupational Safety and Health Act) is occasionally used to cite air contaminant hazards that are not presently covered by any OSHA Permissible Exposure Limit (PEL). In the last two years, five (5) such 5(a)(1) citations were issued by federal OSHA for an air contaminant not presently covered by an OSHA PEL.

In order to effectively evaluate worker exposure, Agency industrial hygienists must evaluate all workplace chemical hazards, including those hazards not presently covered by a PEL. In those cases where an OSHA PEL has not been issued, OSHA will review available occupational exposure references and recommendations. The most commonly available sources or reference points are the occupational exposure levels established by the National Institute for Occupational Safety and Health (NIOSH) in their Recommended Exposure Limits (RELs), the Threshold Limit Values (TLVs) published by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Workplace Environmental Exposure Levels (WEELs) published by the American Industrial Hygiene Association (AIHA). In some cases, manufacturers have also conducted literature searches or studies and have proposed occupational exposure recommendations for chemicals they manufacture. Care should be taken that these recommendations or references are not considered or used as either OSHA PELs or as "national consensus standards" such as referenced under Section 12(d) of the National Technology Transfer and Advancement Act of 1995.

Section 5(a)(1) of the OSHAct requires each employer to "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm." The general duty provisions are to be used only where there is no standard that applies to the particular hazard involved, as outlined in 29 CFR 1910.5(f). In addition, the Occupational Safety and Health Review Commission and court precedent have determined that the following elements must be established in order to prove a violation of the general duty clause:



  1. The employer failed to keep the workplace free of a hazard to which employees of that employer were exposed;
  2. The hazard was recognized;
  3. The hazard was causing or was likely to cause death or serious physical harm; and
  4. There was a feasible and useful method to correct the hazard.

It is important to note that in workplaces where an employer has workers exposed to chemicals and where OSHA did not have a PEL for the contaminant, those employers would not automatically receive a citation if the exposure is above the recommendation. In the majority of cases, the employer would receive a letter from the local OSHA Area Office advising that a worker(s) at the establishment had exceeded an occupational exposure recommendation. The letter would also provide a series of recommended exposure control suggestions.

Further, as has been discussed during several recent Regional Administrator/Enforcement Issues conference calls, it is important for OSHA Compliance Officers to document, prior to citing the General Duty Clause, that a hazardous exposure is occurring or has occurred at the workplace, not just that a recognized occupational exposure recommendation has been exceeded. OSHA must document that an exposure to a physical agent or chemical at a hazardous level or amount, i.e., an exposure (amount) which is capable of causing death or serious physical harm, has occurred and that employees are or could be experiencing adverse health effects if exposure continues. This must be done in order for an employer to be cited for a violation of 5(a)(1) of the OSHAct. Exceeding an occupational exposure recommendation therefore is not the hazardous or violative condition, but rather that employees were exposed to harmful levels of a chemical. Recommended occupational exposure levels such as TLVs are guidelines developed for industrial hygienists to be used in their professional evaluation of worker exposures and are not meant to be enforced, in and of themselves, by government agents. When evaluating a potential hazard, the compliance officer should document how the chemical is being used, any efforts the employer has taken to reduce the hazard and any adverse health effects that may be experienced by employees.

If there is an established OSHA PEL which applies to a given workplace air contaminant, Section 5(a)(1) cannot normally be used to impose a stricter requirement than that required by the standard. An exception to this rule may apply if it can be documented that, "an employer knows a particular safety or health standard is inadequate to protect his workers against the specific hazard it is intended to address." International Union, UAW. v. General Dynamics Land Systems Div., 815 F.2d 1570 (D.C. Cir. 1987).


In order to assure that the Agency is consistently applying the General Duty Clause with regard to workplace air contaminant hazards, citations for such violations shall not be issued without prior approval by the Regional Administrator.

Establishing serious physical harm for some recommended exposures may be particularly difficult if the resulting illness would require a substantial period of time to occur. In some of these situations expert testimony may be crucial to establish that serious physical harm would occur with such illnesses. In general, the compliance officer must establish that the hazard causes or is likely to cause death or serious physical harm when such illness or death will occur only after a substantial period of time. In order to do so, the CSHO needs to substantiate the following:

  1. Regular and continuing employee exposure at the workplace to the toxic substance at the measured levels reasonably could occur;
  2. Illness reasonably could result from such regular and continuing employee exposure; and
  3. If illness does occur, its likely result is death or serious physical harm.

Please distribute this memorandum, which reiterates our policy on this issue, to all compliance officers. If you have any questions on this, please contact the Office of Health Enforcement at (202) 693-2100.