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.


DATE: April 8, 1991




Director, Office of Field Programs
Directorate of Compliance Programs
SUBJECT: Enforcement of the Chromate and Chromic Acid PEL


Attached, for your information, is a recent memorandum from the Directorate of Health Standards Programs stating the Agency's reasoning for retaining the current permissible exposure limit (PEL) of 0.1 mg/m3 for chromates and chromic acid as a ceiling limit.

[This letter was edited on 3/25/2008 to strike information that no longer reflects OSHA policy. Please see OSHA's 2006 Chromium (VI) standard, 29 CFR 1910.1026, which applies to all compounds of chromium (VI), including chromates and chromic acid, with a PEL of 5 µg/m3 as an 8-hour time weighted average (TWA), per 1910.1026(c). This letter and the former PEL shall only be applied to those operations or sectors for which the current PEL in the Chromium (VI) standard is stayed or is otherwise not in effect (see 1910.1000, Table Z-2).]

We are retracting our June 6, 1989, letter to the Dry Color Manufacturers' Association (attached) which stated that a correction to the Air Contaminants Final Rule would be published in the Federal Register. Based on the current promulgation of the chromate and chromic acid PEL as a ceiling limit and not as a time-weighted average (TWA), OSHA will accordingly enforce the PEL as a ceiling limit.


[Corrections bracketed 04/07/2008]

[Reviewed; consistent with current policy 4/07/2008]

DATE: February 14, 1991





Director, Compliance Programs
Director, Health Standards Program
SUBJECT: Permissible Exposure Limit for Chromic Acid and Chromates


Last August you requested Health Standards to clarify the issue of whether the 0.1 mg/M3 ceiling level for chromic acid and chromate should be interpreted as an 8-hour TWA. OSHA made an interpretation in the Industrial Hygiene Technical Manual to enforce the 0.1 mg/M3 limit as a TWA and not as a Ceiling Limit. However, a correction document has never been issued.

The current OSHA PEL for these compounds was adopted from a 1943 ANSI Standard. The justification for the ANSI Standard is based on 1924 and 1928 reports on the non-malignant effects (dermatitis and skin ulceration and perforations of the nasal septum) of chromium compounds. Thus, our current PEL is based on observations reported more than 60 years ago. It has now been established by the International Agency for Research on Cancer (IARC) that Chromium VI compounds are carcinogenic to humans.

In the Final Air Contaminant rule, the Agency concluded that because of the complexities of scientific issues regarding the carcinogenicity of various forms (valencies) of chromates it would evaluate the need for a comprehensive 6(b) rulemaking and not change the Permissible Exposures Limits (PELs) during the Air Contaminants rulemaking. Thus, the 0.1 mg/M3 ceiling limit appears to be the legal limit.

Health Standards is concerned that the current PEL is inadequate. Therefore, it seems inadvisable to raise the current limit in the Z Table through interpretation in light of evidence that the more stringent ceiling limit is too high and needs to be revised downward.

Accordingly, it is our recommendation to retain the ceiling limit value for chromic acid and chromates.

April 4, 1991

Mr. J. Lawrence Robinson
Executive Vice President
Dry Color Manufacturers' Association
Post Office Box 20839
Alexandria, Virginia 22320-1839

Dear Mr. Robinson:

This letter is to inform you that the Occupational Safety and Health (OSHA) is retracting its previous letter to you of June 6, 1989. That letter stated that a correction would be published in the Federal Register clarifying the issue of the chromic acid and chromate Permissible Exposure Limit (PEL) and that, in the interim, OSHA would be enforcing the 0.1 mg/m3 limit as a time-weighted average (TWA) and not as a ceiling limit as listed in 29 CFR 1910.1000 (Air Contaminants Standard).

A correction document has never been issued by OSHA. Based on a recent reevaluation of this enforcement issue and the current promulgation of the chromate and chromic acid PEL as a ceiling limit and not as a TWA, the Agency will accordingly enforce the PEL as a ceiling limit.

Please feel free to contact me if further assistance is needed.


Patricia K. Clark, Director
Directorate of Compliance Programs