The U.S. Supreme Court’s recent 8-0 ruling limited the scope of the National Environmental Policy Act (NEPA), the national environmental law that mandates federal agencies to assess the environmental effects of their proposed actions before making decisions. In the May 29, 2025, decision in Seven County Infrastructure Coalition v. Eagle County, Colorado, the Supreme Court found that substantial judicial deference should be afforded to agencies under NEPA, and that NEPA does not require agencies to consider the environmental effects of projects that are separate in time or place from the project at hand.
The case concerned construction of an 88-mile railroad line connecting Utah’s oil-rich Uinta Basin to the national freight rail network to facilitate the transportation of crude oil to refineries along the Gulf Coast. As part of its project review, the Surface Transportation Board (Board) prepared a 3,600-page environmental impact statement (EIS) that addressed significant environmental effects of the project and identified feasible alternatives, as required under NEPA. The Board concluded that the project’s transportation and economic benefits outweighed its environmental impacts and approved the railroad line. Eagle County, Colorado, and several environmental organizations challenged the Board’s EIS and final approval order in federal court. The U.S. Court of Appeals for the D.C. Circuit ultimately vacated the Board’s EIS and final approval order, holding that the Board’s analysis of environmental effects should have included reasonably foreseeable impacts from upstream oil drilling and downstream oil refining projects.
The Supreme Court characterized the D.C. Circuit’s decision as belonging to a line of NEPA cases guided by an overly aggressive judicial approach. According to the Court, NEPA is a purely procedural statute that requires an agency to prepare an EIS, but does not require an agency to weigh environmental consequences in any particular way. The Court further emphasized that NEPA is a “procedural cross-check” to inform agency decision-making, not a “substantive roadblock.” It further criticized the use of NEPA by project opponents as a “blunt and haphazard tool” to stop or slow new infrastructure and construction projects.
When determining whether an agency’s EIS is compliant with NEPA, the Court affirmed that courts should afford “substantial deference” to the agency. The essential determination is “not whether an EIS in and of itself is inadequate, but whether the agency’s final decision was reasonable and reasonably explained.” Thus, courts must defer to agencies so long as they are operating within this “broad zone of reasonableness.”
The Court distinguished Seven County from its recent landmark decision in Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024), which applied de novo judicial review in cases when an agency interprets a statute. In cases in which an agency exercises discretion granted by statute, judicial review is conducted under the Administrative Procedure Act’s “arbitrary and capricious” standard, under which a court asks whether the agency action was reasonable.
This judicial deference in NEPA cases extends to factual determinations made by agencies about what details are relevant in an EIS. The Court affirmed that an EIS must address the reasonably foreseeable environmental effects of the project at hand. However, the Court also noted that courts should defer to agencies about the scope of analysis, including decisions about how far to go in considering indirect environmental effects from the project at hand and whether to analyze environmental effects from other projects separate in time or place from the project at hand.
Seven County’s limitations on the required scope of agency analysis under NEPA to the direct and indirect environmental effects of the project at hand may streamline agency review of infrastructure, construction, and energy projects. However, uncertainty remains as agencies determine the extent of analysis required during project review, which may differ by agency or types of projects or may change with administrations. The ruling may also cause environmental groups to reconsider when and how to mount challenges to projects under NEPA.
Alexandra Prendergast contributed to this article