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.

November 11, 1998

Mr. Lance Edwards, CIH
Director of Health & Safety Affairs
Directorate of Environmental, Industry,
  and International Affairs
1500 Rhode Island Avenue, NW
Washington, DC 20005

Dear Mr. Edwards:

This is in response to your letter of July 9, addressed to Mr. Charles Jeffress, Assistant Secretary, Occupational Safety and Health Administration (OSHA). Your letter requested information regarding the reporting threshold for certain hazardous chemicals under the Hazard Communication Standard (HCS), 29 CFR 1910.1200. Please excuse this delay in responding.

Specifically, you requested information on the reporting threshold for chemicals for which evidence of carcinogenicity exists, even though these chemicals have not been established as a carcinogen (or potential carcinogen) by the three sources listed in paragraph (d)(4) of the standard.

Under the HCS, a chemical is not considered a carcinogen or potential carcinogen unless it is listed as such by the International Agency for Research on Cancer, the National Toxicology Program, or is regulated as a carcinogen by OSHA. The reporting threshold for non-carcinogenic mixtures which have not been tested as a whole to determine their health hazards is one percent. Therefore, until one of the above-mentioned groups validates the carcinogenic findings, the reporting threshold on the material safety data sheets (MSDSs) is one percent.

Please be aware, however, that even though the chemical is not considered a carcinogen for the purposes of the HCS, the results of any study conducted in accordance with scientific principles which shows statistical significance of a health effect must be discussed on the MSDS.

We hope this information will be helpful, and should you need further assistance, please do not hesitate to contact OSHA's Office of Health Compliance Assistance at (202)219-8036.


Richard E. Fairfax
Acting Director
Directorate of Compliance Programs