## Facts

- Environmental plaintiffs sued the U.S. Nuclear Regulatory Commission (NRC) and the New Mexico Environmental Improvement Agency (NMEIA) seeking to bar issuance of New Mexico uranium mill licenses without preparation of environmental impact statements (EISs).
- The suit asserted that NRC’s delegation/coordination with New Mexico under Atomic Energy Act § 274(b) did not eliminate NEPA obligations and that licensing without EISs was unlawful.
- NMEIA issued a license to United Nuclear Corporation (UNC) for a uranium mill; UNC moved to intervene as a defendant and was allowed to do so without opposition.
- Kerr-McGee Nuclear Corporation (a uranium mill operator) and the American Mining Congress (AMC) (an industry association) moved to intervene as defendants under Federal Rule of Civil Procedure 24(a)(2) (as of right) and 24(b) (permissive).
- The district court denied intervention as of right, finding Kerr-McGee’s and AMC’s interests were adequately represented by existing defendants, including UNC and the governmental defendants.
- The district court also denied permissive intervention, and Kerr-McGee and AMC appealed; the appeal concerned only intervention, not the merits of the NEPA/Atomic Energy Act claims.

## Issues

1. Whether Kerr-McGee and AMC were entitled to intervene as of right under Rule 24(a)(2), including whether existing parties inadequately represented their interests.
2. Whether the district court abused its discretion in denying permissive intervention under Rule 24(b).

## Decision

- The court of appeals affirmed the order denying intervention as of right.
- The court held that, although Kerr-McGee and AMC had interests that could be affected by the litigation, they failed to show inadequate representation by existing parties.
- The court emphasized that UNC’s interests as a uranium mill operator were substantially identical to Kerr-McGee’s and aligned with AMC’s industry interests.
- The court also affirmed denial of permissive intervention, holding the district court did not abuse its discretion in concluding additional intervenors were unnecessary and could complicate or delay the case.

## Legal Principles

- Rule 24(a)(2) requires a timely motion, a protectable interest, possible impairment of that interest, and inadequate representation by existing parties.
- When an existing party and a proposed intervenor share the same ultimate objective, adequate representation is presumed; the movant must show a concrete basis for divergence, collusion, or failure to defend.
- The presence of an intervening private party with materially similar economic interests may defeat intervention as of right for additional similarly situated applicants.
- Permissive intervention under Rule 24(b) is committed to the district court’s discretion; denial is affirmed absent abuse of discretion, including where added parties would add little and risk delay or complication.

## Conclusion

The Tenth Circuit affirmed denial of intervention because Kerr-McGee and AMC did not rebut the presumption that their interests were adequately represented by existing defendants, and it upheld denial of permissive intervention as a proper exercise of district court discretion.


Nat. Res. Def. Council, Inc. v. U.S. Nuclear Regul. Comm'n, 578 F.2d 1341 (10th Cir. 1978)