## Facts

- MSHA administers the Federal Mine Safety and Health Act and issued reporting regulations in 1977 (30 C.F.R. pt. 50) through notice-and-comment rulemaking.
- Part 50 requires mine operators to report each “occupational illness” within ten days of when the illness is “diagnosed,” including pneumoconioses.
- MSHA issued several Program Policy Letters (PPLs) stating that certain chest x-ray readings (ILO-type classifications by qualified readers) qualify as “diagnoses” of pneumoconiosis that trigger Part 50 reporting.
- MSHA did not use notice-and-comment procedures for the PPLs and treated them as interpretive rules under the APA.
- Trade associations representing mine operators petitioned for review, arguing the PPLs imposed new legal duties and were invalid legislative rules because they were not adopted through notice-and-comment.
- The PPLs included an element of enforcement forbearance (e.g., deferring enforcement in some circumstances if a second reading by a certified “B-reader” was obtained).

## Issues

1. Whether MSHA’s PPLs treating certain x-ray readings as “diagnoses” under Part 50 are interpretive rules exempt from APA notice-and-comment, or legislative rules requiring notice-and-comment rulemaking.

## Decision

- The D.C. Circuit held the PPLs were interpretive rules under the APA.
- The court concluded the PPLs did not create new law, rights, or duties; they explained how MSHA understood “diagnosed” as used in Part 50.
- The court dismissed the petitions for review.

## Legal Principles

- Interpretive rules advise the public of an agency’s construction of the statutes and regulations it administers and do not themselves have independent legal force.
- A rule is treated as legislative (and generally must be issued through notice-and-comment) if any one of these is true:
  - Without the rule, there is no adequate legal basis for enforcement or agency action.
  - The agency publishes the rule in the Code of Federal Regulations.
  - The agency explicitly invokes its general legislative authority.
  - The rule effectively amends a prior legislative rule.
- An agency may issue interpretive guidance that supplies more specific applications of a general regulatory term, so long as the interpretation stays within the scope of the existing regulation and does not function as an amendment.

## Conclusion

Because Part 50 already required reporting when pneumoconiosis is “diagnosed,” and the PPLs merely clarified what evidence MSHA would treat as a diagnosis without amending the regulation or invoking legislative authority, the court upheld the PPLs as interpretive guidance not subject to APA notice-and-comment procedures.


Am. Mining Cong. v. Mine Safety & Health Admin., 995 F.2d 1106 (D.C. Cir. 1993)