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NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.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

April 19, 1995

R. J. Barnhart, Ph.D.
American Chrome and Chemicals Inc.
3800 Buddy Lawrence Drive
Post Office Box 9912
Corpus Christi, Texas 78469

Dear Dr. Barnhart:

You requested clarification of OSHA's current permissible exposure limit (PEL) for occupational exposure to hexavalent chromium in general industry.

OSHA's current PEL for chromic acid and chromates is found in Table Z-2 (29 CFR 1910.1000). This table specifies a ceiling limit of 100 micrograms per cubic meter of air (1.0 mg/10 m(3)), which covers all forms of hexavalent chromium [chromium (VI)] measured as chromium (VI) and reported as CrO(3). The entry has been unchanged since published in 1971.

There is no health basis for a less protective limit. This correspondence replaces any earlier interpretations concerning the PEL.

OSHA's interpretation is that the PEL for chromium (VI) in general industry is a ceiling value of 100 micrograms per cubic meter of air (100 ug/m(3)), measured as chromium (VI) and reported as CrO(3), as it is published. In the construction industry, the PEL is 100 ug/m(3) as an eight-hour, time-weighted-average.

A copy of this letter will be placed in the Hexavalent Chromium Docket (H-054-a) for further reference. OSHA will be addressing this issue in our forthcoming rulemaking on chromium (VI). If you have any questions, please do not hesitate to contact me at 202-219-7075.


John F. Martonik
Acting Director
Health Standards Programs