U.S. Supreme Court Affirms NEPA Requires Substantial Deference to Federal Agencies

06.25.2025

On May 29, 2025, the United States Supreme Court issued an 8-0 decision in Seven County Infrastructure Coalition et. Al. v. Eagle County, Colorado, et al., holding that the scope of an Environmental Impact Statement (“EIS”) under the National Environmental Policy Act (“NEPA”)  is purely procedural and it “does not require the agency to weigh environmental consequences in any particular way [rather] an agency may weigh environmental consequences as the agency reasonably sees fit under its governing statute and any relevant substantive environmental laws.”  Additionally, that judicial review of environmental reports prepared under NEPA must give substantial deference to federal agencies.

Case Background

In 2020, the Seven County Infrastructure Coalition, a group of seven Utah counties, submitted a proposal to the U.S. Surface Transportation Board (“Board”) to approve a project for a new railroad line to transport crude oil from Utah’s Uinta Basin (“Basin”), an oil-rich territory, to the national freight rail network (“Project”). The connection of the new railroad would connect the Basin to refineries in Louisiana, Texas, and other destinations.

Federal law required the Board to undergo an environmental NEPA review of the proposed Project to address the environmental effects and feasible alternatives of the Project, which includes the preparation of an EIS. NEPA required that the Board weigh the “environmental consequences as the agency reasonably sees fit” and consider feasible alternatives to mitigate any potential environmental consequences of the proposed project.

The Board prepared an EIS that spanned more than 3,600 pages of analysis, addressing the “adverse impacts that occur as a result of [the Project],” such as “disruptions to the local wetlands, land use, and recreation.” The EIS noted that potential impacts on future oil and gas development projects in the regions could lead to increased downstream refining of crude oil. The Board ultimately determined that further analysis in the EIS regarding the future oil and gas development projects was unnecessary because those future projects would be subject to approval by other local, state, federal, and tribal agencies. Further, the EIS determined that potential impacts were too attenuated from the Project. The Board approved the Project in December 2021.

Several environmental organizations filed an action in federal appellate court, challenging the Board’s approval of the Project. The court found “numerous NEPA violations arising from the EIS” and stated that the Board failed to consider all environmental impacts of the Project. The court also determined that the Board should have considered the “reasonably foreseeable environmental impacts” from future projects, such as the Project’s impact on increased oil drilling in the Basin and oil refining along the Gulf Coast. The court vacated the Board’s EIS and approval of the Project.

Supreme Court’s Decision

The Supreme Court reversed the lower court’s decision. The Court held that the Board should have been given substantial judicial deference, so long as the resulting level of detail in the EIS is “reasonable” under the Board’s statutory authority. The Court analyzed that under NEPA, agencies, not the courts, have the final determination of the adequacy of an environmental study (including an EIS), so long as the agency’s final decision is “reasonably explained.” The Court reaffirmed an earlier decision, Department of Transportation v. Public Citizen (2004) 541 U. S. 752, which held that NEPA does not require agencies to analyze the effects of projects over which they do not exercise regulatory authority. The Court further held that even if environmental effects from a separate project may be factually foreseeable, it is not reasonable to hold agencies responsible for those effects.

Ultimately, the Court found that the federal appeals court did “not afford the Board the substantial judicial deference required in NEPA cases” and determined that NEPA does not require the Board to address environmental effects for future projects outside of the Board’s regulatory jurisdiction.

Comparison to the California Environmental Quality Act

In California, the California Environmental Quality Act (“CEQA”) is the State’s counterpart to NEPA. CEQA applies to “discretionary projects proposed to be carried out or approved by public agencies.” Like NEPA, CEQA contains procedural requirements, but it also has a “substantive mandate that public agencies refrain from approving projects for which there are feasible alternatives or mitigation measures.” (Mountain Lion Foundation v. Fish & Game Com., (1997) 16 Cal.4th 105, 134.) NEPA only requires governing boards to review impacts within their regulatory jurisdiction. However, under CEQA, when a reviewing agency has evidence of a foreseeable impact, even one outside of its jurisdiction, a court will consider it feasible and require mitigation. (See Tracy First v. City of Tracy (2009) 177 Cal.App.4th 912, 937.) If, as in Tracy, there are no identifiable impacts, but only speculative effects, courts will likely hold the impact as non-feasible and not require governing boards to address them.

Special thanks to our law clerk, Blake Steidlmayer, for his assistance with this alert.

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