The decision emphasizes the importance of judicial deference to agencies on NEPA and narrows the scope of environmental analyses.
On May 29, 2025, the US Supreme Court issued a decision (Decision) in Seven County Infrastructure Coalition v. Eagle County, Colorado, No. 23-975 (2025), significantly narrowing the scope of environmental reviews required under the National Environmental Policy Act (NEPA). Specifically, the Court held that the US Surface Transportation Board (STB) was not required to consider the environmental effects of upstream oil drilling and downstream oil refining when approving the construction of a railroad line in Utah. The 8-0 Decision reversed the D.C. Circuit Court of Appeals and included both a majority and concurring opinion, with Justice Gorsuch recusing himself from the case.
In the majority opinion, the Court emphasized that while NEPA is a procedural statute that mandates federal agencies prepare an environmental impact statement (EIS) for certain projects, NEPA does not require agencies to evaluate the environmental impacts of separate projects that are not directly under their regulatory authority. In this post, we discuss the Decision and its potential implications for environmental reviews under NEPA.
Background
The case centers around STB’s approval of a new 88-mile railroad line connecting oil fields in Utah’s Uinta Basin to the national rail network. The Uinta Basin Railway Project aims to facilitate the transportation of crude oil from the Basin to refineries along the Gulf Coast. STB prepared a lengthy EIS for the project, which acknowledged the potential environmental effects of increased upstream oil drilling in the Basin and increased downstream refining of crude oil. The EIS did not, however, fully analyze these upstream and downstream effects. The D.C. Circuit vacated STB’s EIS and the 2021 order approving the project, finding that STB failed to adequately consider these effects. Supported by Utah counties, the Seven County Infrastructure Coalition appealed to the US Supreme Court, arguing that NEPA does not obligate agencies to assess environmental impacts beyond the immediate scope of the project within their regulatory authority.
The case drew the attention of a wide range of interests, with more than 30 briefs of amicus curiae / amici curiae filed. Members of Congress on both sides of the issue participated in the case. Six Senators filed an amicus brief in support of the project proponents, arguing that judicial overreach transformed NEPA into a broad environmental mandate beyond what Congress intended and imposed significant procedural burdens. These amici expressed concern that the D.C. Circuit’s decision would empower agencies to regulate beyond their statutory authority, threatening the separation of powers by requiring agencies to address issues (both downstream and upstream) that Congress has not delegated to them and that are not in their “wheelhouse.” These amici also argued that the negative economic impact of the expanded NEPA review process delays critical infrastructure projects and harms national interests. They also asserted that the D.C. Circuit’s decision undermined legislative efforts to streamline NEPA processes.
A separate group of 30 Senators and House of Representatives members filed an amicus brief in support of the D.C. Circuit’s decision, arguing that NEPA’s legislative history indicates Congress’ intent for proactive and coordinated environmental review, rather than the reactive, narrow, and fragmented approach to environmental policy prior to NEPA’s passage. These amici also asserted that Congress has left NEPA’s core mission and requirement of interagency coordination in place, despite subsequent passage of multiple streamlining efforts, industry-specific special procedures, and targeted exemptions. Further, they argued that Congress has declined to exclude indirect and cumulative impacts from NEPA review or to exempt oil and gas transportation (or the project at issue here, specifically) from NEPA review.
Supreme Court Reverses D.C. Circuit
The Supreme Court reversed the D.C. Circuit’s decision, holding that STB was not required to evaluate the indirect environmental effects of upstream and downstream projects that are separate from the railroad line. Justice Kavanaugh delivered the majority opinion of the Court, joined by Chief Justice Roberts and Justices Thomas, Alito, and Barrett. The Court stated that agencies should have broad discretion to determine the scope of their environmental reviews and that courts should afford substantial deference — “the bedrock principle of judicial review in NEPA cases” — to these agency decisions. Further, the ruling clarifies that NEPA does not obligate agencies to consider the environmental effects of projects that are separate in time or place from the project at hand, particularly when those projects fall outside the agency’s regulatory jurisdiction. While the Court found STB’s EIS to be adequate, it emphasized NEPA’s status as a procedural statute, and only one input to an agency’s decision-making process, clarifying that a deficient EIS “would not necessarily require a court to vacate the agency’s approval” of a project. According to the Court, “NEPA is a procedural cross-check, not a substantive roadblock.”
Substantial Deference
According to the majority opinion, courts “should not micromanage” agency decisions regarding the scope and content of environmental review under NEPA. The Court highlighted that NEPA is a procedural statute that requires agencies to “prepare an adequate report” on the environmental effects of the project at hand, but the agency “is better equipped to assess what facts are relevant to the agency’s own decision” and should determine which details need to be included. The Court stressed that agencies possess the expertise to make these “fact-dependent, context-specific, and policy-laden choices about the depth and breadth” of environmental review, and courts should defer to these agency decisions as long as they fall within “a broad zone of reasonableness.” The majority opinion cautioned against overly intrusive judicial review, which can lead to delays and hinder infrastructure development (in alignment with the Seven County Infrastructure Coalition’s amici). It also reiterated that a court’s review is narrow; judicial review is limited to ensuring that the agency has reasonably explained its final decision. In short, “the central principle of judicial review in NEPA cases is deference,” with courts playing “only a limited role.”
“Manageable Line”
The Court noted that the project was the 88-mile railroad in Utah, not any future oil drilling in the Uinta Basin or refining along the Gulf Coast. STB does not have regulatory authority over oil drilling or refining, and therefore, in an extension of the Court’s decision in Public Citizen,1 STB is not responsible for evaluating the environmental effects of separate projects that could foreseeably occur as a result of the Utah railroad. The Decision underscores that NEPA does not authorize courts to delay or block agency projects based on the environmental effects of other projects outside the agency’s jurisdiction. According to the Court, agencies must be able to draw a reasonable and “manageable line,” and courts “should defer to agencies’ discretionary decisions about where to draw the line—including (i) how far to go in considering indirect environmental effects from the project at hand and (ii) whether to analyze environmental effects from other projects separate in time or place from the project at hand.” Although the Court stated that certain indirect environmental effects such as runoff or emissions from a project may still “sometimes fall within NEPA,” other effects, including so-called growth inducing effects resulting from separate projects, need not be considered as the causal chain is broken. But-for causation remains insufficient as is “mere foreseeability.” “There may be a gray area,” but in any event “a court’s review still must remain deferential.”
Concurring Opinion
Justice Sotomayor, joined by Justices Kagan and Jackson, concurred in the judgment on narrower grounds, emphasizing that STB correctly determined it lacked authority to reject the railway based on the environmental impacts of oil drilling and refining and thus need not review those environmental effects. Justice Sotomayor argued that NEPA requires agencies to consider environmental impacts for which their decisions would be responsible, akin to “the familiar doctrine of proximate cause from tort law,” and STB was not responsible for the consequences of oil production upstream or downstream from the railway. Justice Sotomayor’s concurrence underscores the importance of aligning NEPA reviews with the agency’s statutory authority and decision-making responsibilities.
Looking Forward: Implications for Environmental Review Under NEPA
Given the Court’s emphasis on deference to agency decisions concerning the scope of NEPA analysis, this Decision will narrow opportunities to successfully challenge environmental reviews. This is particularly true for challenges based on attenuated environmental effects, including related but separate projects, especially when those projects fall outside the action agency’s statutory authority. Further, the Court’s statement that a deficient EIS “would not necessarily require a court to vacate the agency’s approval” is a strong indication that courts should not vacate agency decisions due to NEPA insufficiencies “at least absent reason to believe that the agency might disapprove the project if it added more to the EIS.” Moreover, challenges based on an EIS’ thoroughness or adequacy may face judicial resistance, as the Decision indicates that “courts should not insist on length as a prerequisite for finding an EIS to be detailed,” especially given Congressional mandates to streamline reviews. The Court’s Decision aligns with efforts by the Trump administration, in executive orders and memoranda, to speed up the NEPA process and permit reviews, particularly for energy projects.
Additionally, the Decision could open the door for further legislative action concerning the statutory frameworks and language governing agencies’ authority, specifically with regard to environmental review or efforts to further clarify NEPA’s scope and the appropriate level of review. Finally, the opinion follows the Court’s 2024 decision to overturn Chevron deference in Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024). It further develops the post-Chevron legal landscape, clearly distinguishing and underscoring agency deference in judicial review under the Administrative Procedure Act’s arbitrary-and-capricious standard when an agency exercises discretion granted by statute by signaling that courts should not “micromanage” agency decisions under NEPA. We will continue to monitor and report on developments relating to this Decision.
