Supreme Court Emphasizes Agency Deference in NEPA Review

On May 29, 2025, the Supreme Court issued its long-awaited decision in Seven County Infrastructure Coalition v. Eagle County. In a five-justice majority opinion written by Justice Kavanaugh, the Court held that the National Environmental Policy Act (“NEPA”) does not require review of the environmental impacts of “upstream” or “downstream” related projects, and reiterated: “The bedrock principle of judicial review in NEPA cases can be stated in a word: Deference.”[1] This decision comes as the federal government works to expedite what over the years have become lengthy NEPA review processes, and not long after the White House Council on Environmental Quality rescinded its NEPA regulations.

The case assesses the scope of an agency’s NEPA review and addresses how much reviewing courts should defer to the agency’s exercise of discretion during the NEPA process. The Court held that agencies are entitled to substantial deference in judicial review of NEPA Environmental Impact Statements (“EIS”), which are undertaken to assess the environmental impacts of major federal actions (including issuance of a federal permit or approval for a private project). Reviewing courts are to assess whether an agency’s analysis in an EIS falls within “a broad zone of reasonableness” and whether the agency acted arbitrarily in determining what to consider within its EIS.[2] Additionally, a reviewing court may consider only whether the agency addressed environmental consequences and feasible alternatives for the project at hand; agencies need not consider, and cannot be faulted for not considering, other projects or actions that are “separate in time or place.”[3]

In 2021, the United States Surface Transportation Board (“Board”) issued a 3,600-page EIS and approved the development of an 88-mile railroad line that would be used to carry crude oil from Utah’s Uintah Basin to the national rail network. From that rail network connection point in Utah, the oil would travel farther distances, mainly to Gulf Coast refineries in Texas and Louisiana. The Board’s approval was challenged in the D.C. Circuit which, on review, determined that the Board’s EIS was deficient because it failed to consider upstream and downstream oil projects that might be developed due to the railroad project. The potential impacts of those potential projects included greenhouse gas emissions, risks of wildfire, and train derailments. Reversing, the Supreme Court determined that such “potential future, as yet unplanned” projects were too speculative to be essential to an EIS.[4] The Court held that the D.C. Circuit “incorrectly interpreted NEPA to require the Board to consider the environmental effects of upstream and downstream projects that are separate in time or place from the Uinta Basin Railway.”[5] While the agency may consider interrelated projects that are “close in time and place to the project at hand,”[6] NEPA requires an assessment only of “the environmental effects of the project at issue,” not risks associated with other, entirely separate projects.[7]

The basic test is one of “proximate causation”; a mere “but for” causal relationship between the project and an upstream or downstream effect is not enough. And the Court reiterated its longstanding bright-line rule that this is especially so when the agency lacks regulatory jurisdiction over the effects. Thus, the EIS “needed to address only the effects of the 88-mile railroad line.”[8] The Court also provided guidance on the level of detail appropriate for an EIS, emphasizing that “[b]revity should not be mistaken for lack of detail” and that “[a] relatively brief agency explanation can be reasoned and detailed; an EIS need not meander on for hundreds or thousands of pages.” [9] To backstop this point, the Court noted that the “federal law now strictly prohibits an agency’s EIS from going on endlessly,” because following the 2023 BUILDER Act, EISs “‘shall not exceed 150 pages’ and must be completed in ‘2 years’ or less.”[10]

On deference, the Court distinguished Loper Bright, which applies to de novo review of questions of statutory interpretation. In contrast, when agency discretion is granted by statute, a court reviews under the Administrative Procedure Act’s deferential arbitrary and capricious standard, pursuant to which it may consider only if an agency action was reasonable. NEPA grants broad agency discretion and allows the agency to grant or deny a project application. Reviewing courts, therefore, must not “micromanage” the agency’s decisions when it comes to NEPA review.[11] The majority critically notes that, over the years since NEPA was enacted, some “courts have assumed an aggressive role in policing agency compliance with NEPA,” and thus, the majority reaffirmed that “the central principle of judicial review in NEPA cases is deference.”[12]

The Court expressed a strong desire to reduce lengthy review processes that can result in fewer project approvals and completions, noting that lower court NEPA “rulings have slowed down or blocked many projects and, in turn, caused litigation-averse agencies to take evermore time and to prepare ever longer EISs for future projects.” In criticizing this trend, the Court lamented how “[a] 1970 legislative acorn has grown over the years into a judicial oak that has hindered infrastructure development ‘under the guise’ of just a little more process.”[13] The Court further described the current—at least until this ruling—review process as bordering on the “Kafkaesque,” and leading to the result that “[f]ewer projects make it to the finish line.”[14] With this ruling, the majority appears to be trying to turn the tables on citizen and environmental groups that sue to block infrastructure projects by reimposing guardrails on judicial review under NEPA. Indeed, the Court closed by underscoring that “[c]itizens may not enlist the federal courts, ‘under the guise of judicial review’ of agency compliance with NEPA, to delay or block agency projects based on the environmental effects of other projects separate from the project at hand.”[15] Time will tell whether that is enough to speed up the project review and permitting process.