## Facts

- The Occupational Safety and Health Act assigns the Secretary of Labor authority to promulgate and enforce workplace safety standards, while the Occupational Safety and Health Review Commission (Commission) performs adjudicatory functions in contested enforcement actions.
- The Secretary cited CF&I Steel Corporation for allegedly violating OSHA respiratory protection requirements after employees used loose-fitting respirators that, in the Secretary’s view, exposed them to impermissible coke-oven emission levels.
- The cited OSHA regulation required an employer to “institute a respiratory protection program”; a separate regulation addressed ensuring “a proper fit” of respirators.
- The Commission vacated the citation, interpreting the cited regulation as requiring employee training and related program elements, not a proper-fit obligation (which it viewed as governed by the separate fit regulation).
- The Tenth Circuit affirmed, holding that if the Secretary’s regulations are ambiguous and both the Secretary and the Commission offer reasonable interpretations, courts should defer to the Commission’s interpretation.
- The Supreme Court granted review to resolve which agency’s reasonable interpretation controls under the OSH Act’s split-enforcement structure.

## Issues

1. When the Secretary of Labor and the Commission offer reasonable but conflicting interpretations of an ambiguous OSHA regulation promulgated by the Secretary, whether reviewing courts must defer to the Commission’s interpretation or to the Secretary’s interpretation.

## Decision

- The Supreme Court reversed the Tenth Circuit and remanded.
- The Court held that when both the Secretary and the Commission give reasonable but conflicting interpretations of an ambiguous Secretary-promulgated OSHA regulation, a reviewing court should defer to the Secretary’s interpretation.
- The Court rejected the view that ambiguity triggers deference to the Commission as the adjudicator in contested cases.

## Legal Principles

- Under the OSH Act’s split-enforcement scheme, the Secretary’s rulemaking and enforcement authority includes the power to render authoritative interpretations of the Secretary’s own regulations.
- When an OSHA regulation promulgated by the Secretary is ambiguous, courts defer to the Secretary’s reasonable interpretation, even if advanced in litigation and even if the Commission offers a conflicting reasonable interpretation.
- The Commission’s adjudicatory role does not include superseding the Secretary’s reasonable regulatory interpretation with its own in a manner that reallocates policymaking authority.
- The deference inquiry presupposes the Secretary’s interpretation is reasonable and consistent with the regulation’s text and structure.

## Conclusion

The Court held that interpretive authority over ambiguous OSHA regulations promulgated by the Secretary rests with the Secretary, not the Commission, and that reviewing courts must accept the Secretary’s reasonable interpretation when it conflicts with a reasonable Commission interpretation.


Martin v. Occupational Safety & Health Review Comm'n, 499 U.S. 144 (1991)