350 Montana v. Debra Haaland, 29 F.4th 1158

Background

Signal Peak Energy sought approval to expand Bull Mountains Mine No. 1; the expansion is projected to result in ~190 million tons of GHGs (≈240.1 Mt-CO2e over 11.5 years).
Interior’s 2018 Environmental Assessment (EA) concluded a Finding of No Significant Impact (FONSI) after comparing the project’s emissions to annual global, U.S., and Montana emissions and calling the project’s contribution “minor.”
The 2018 EA’s U.S. and Montana comparisons omitted combustion emissions (≈97% of the project’s emissions) because those emissions primarily occur overseas; the EA’s global comparison used total project emissions versus a single-year global total, yielding ~0.44% of annual global emissions (≈0.04% on an annualized basis).
Plaintiffs previously succeeded in vacating a 2015 EA that had also omitted SCC analysis; Interior declined to use the Social Cost of Carbon (SCC) in the 2018 EA for several stated reasons (rulemaking origin of SCC, withdrawn IWG guidance, NEPA not requiring cost-benefit, and concerns about imbalance/uncertainty).
District court vacated portions of the 2018 EA (and remanded limited issues, notably train-derailment risk); Interior issued a 2020 EA that incorporates the 2018 EA. The Ninth Circuit reviewed whether Interior’s 2018 EA satisfied NEPA and what remedy is appropriate.

Issues

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Interior’s 2018 EA satisfied NEPA’s "hard look"/"convincing statement of reasons" requirement for its FONSI on GHG impacts	EA relied on conclusory/global comparison that masks significance; agency failed to articulate science-based criteria and omitted combustion emissions from domestic comparisons	EA summarized climate science and provided numerical comparisons; project’s contribution is "minor" when placed in global context	Reversed as to this issue: EA failed to provide a convincing, science-based statement of reasons and thus violated NEPA
Whether Interior was required to use the Social Cost of Carbon (SCC) to quantify GHG harms	SCC was available, peer-reviewed, and would show damages exceeding project benefits; Interior previously was faulted for not using SCC	SCC was developed for rulemakings, guidance/IWG was withdrawn, SCC uncertain and produces wide ranges, and NEPA does not require monetized cost‑benefit analysis	Court: Interior not required to use SCC; district court did not err in finding agency’s explanation adequate on this point
Mootness: whether the 2018 EA challenge was mooted by Interior’s 2020 EA	Plaintiffs: 2018 EA effects persist because 2020 EA incorporates 2018 EA’s GHG analysis	Signal Peak: 2018 EA superseded by 2020 EA so appeal moot	Court: Not moot — 2020 EA incorporated the 2018 EA’s GHG analysis, so relief remains possible
Remedy: vacatur of agency action and remand (to agency vs district court)	Plaintiffs: vacatur and EIS may be required to vindicate NEPA’s "look before you leap" purpose	Defendants/Intervenor: vacatur disruptive; if error, remand to agency without vacatur preferred	Court: NEPA/APA violation remanded; additional factfinding needed on whether an EIS is required and on vacatur consequences, so remanded to district court for further proceedings (affirmed in part, reversed in part)

Key Cases Cited

Bark v. United States Forest Serv., 958 F.3d 865 (9th Cir. 2020) (agency must provide a convincing statement of reasons to support a FONSI)
Center for Biological Diversity v. Nat’l Highway Traffic Safety Admin., 538 F.3d 1172 (9th Cir. 2008) (EA inadequate where agency fails to analyze cumulative/incremental GHG impacts and provide supporting data)
Barnes v. U.S. Dep’t of Transp., 655 F.3d 1124 (9th Cir. 2011) (context-specific EA comparison of GHGs may be adequate; EAs are project-specific)
Motor Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins., 463 U.S. 29 (U.S. 1983) (APA arbitrary-and-capricious standard)
Dept. of Transp. v. Public Citizen, 541 U.S. 752 (U.S. 2004) (NEPA requires reasonably close causal relationship and foreseability for effects considered)
Alliance for the Wild Rockies v. U.S. Forest Serv., 907 F.3d 1105 (9th Cir. 2018) (vacatur is the presumptive APA remedy; remand without vacatur is limited)
Robertson v. Methow Valley Citizens Council, 490 U.S. 332 (U.S. 1989) (NEPA’s purpose: ensure agencies take a hard look and inform decisionmaking)