Over the last half century, federal courts have interpreted the National Environmental Policy Act (NEPA) to require federal agencies to study an ever-growing range of indirect effects and impacts when approving large projects. A few judicial principles planted decades ago to help sensibly guide NEPA reviews – underneath an overarching "rule of reason" – eventually grew into a canopy of environmental considerations. NEPA's statutory text simply requires a "detailed statement" on "reasonably foreseeable environmental effects of the proposed agency action," 42 U.S.C § 4332(C)(i), yet lower courts continually required federal agencies to exhaustively consider effects far removed in time and place from the specific project at hand. Federal agencies – across administrations of both parties – saw high priority infrastructure and other projects fall hopelessly behind schedule, buried under the weight of NEPA-related requirements.
On May 29, 2025, the U.S. Supreme Court issued its highly anticipated decision in Seven County Infrastructure Coalition v. Eagle County, Colorado, 605 U.S. __ (2025), regarding the appropriate scope of NEPA analysis for proposed projects. In a decision in which all eight participating justices concurred in the result, the Court held that agencies reviewing a specific project are not required to consider impacts associated with other projects that are remote in time or place. In "certain" situations, separate projects "may" be reviewed as a single project where they are "interrelated and close in time and place," but the Court instructed lower courts to give "deference" to agencies seeking to navigate those situations. A "reasonably close causal relationship" must exist before an agency should lump separate projects together in a single review, and even then, a clear break occurs when one of the projects is beyond the reviewing agency's purview.
In emphasizing these limits, the five-member majority also engaged in a detailed discussion of the proper role of courts in reviewing challenges to agency NEPA compliance, emphasizing the procedural nature of the statute and the need for courts to grant deference to agencies regarding their determinations as to the scope of review for a particular action. Seven County should help restore a "rule of reason" to the scope of NEPA reviews, though the full impact of the ruling will be seen in the months and years to come as agencies and courts apply the lessons from the Court's ruling, especially in situations where a project has some connection (in time or place, causation, or otherwise) to effects associated with other projects.
Background
In 2020, the Seven County Infrastructure Coalition applied to the U.S. Surface Transportation Board for approval to construct an 88-mile rail line connecting Utah's Uinta Basin to the national freight rail network, facilitating the transportation of crude oil from the Basin to refineries and ports along the Gulf Coast. The Board prepared a 3,600-page EIS analyzing the environmental impacts of the construction and operation of the proposed rail line. The EIS noted, but did not fully analyze, the potential environmental effects of increased upstream oil drilling in the Uinta Basin and increased downstream refining of crude oil. The Board approved the rail line, concluding that the project's transportation and economic benefits outweighed its environmental impacts.
A county in Colorado and several environmental groups filed petitions challenging the Board's action in the U.S. Court of Appeals for the D.C. Circuit. The D.C. Circuit vacated the EIS and the Board's approval order, finding that the Board impermissibly limited its analysis of the environmental effects from upstream oil drilling and downstream oil refining, concluding that those effects were reasonably foreseeable impacts of the new rail line that the EIS should have analyzed more extensively.
First Principles and the Role of the Courts
Justice Kavanaugh's majority opinion acknowledges many industry concerns with the current state of NEPA implementation and associated litigation. The opinion states that "NEPA has transformed from a modest procedural requirement into a blunt and haphazard tool employed by project opponents (who may not always be entirely motivated by concern for the environment) to try to stop or at least slow down new infrastructure and construction projects." The opinion notes that this has led to more agency consideration of attenuated effects and more speculation, with environmental impact statements that "meander on for hundreds or thousands of pages." As a result, the Court concludes, "a course correction of sorts is appropriate to bring judicial review under NEPA back in line with the statutory text and common sense."
The Court went on to lay out several principles for this "course correction," emphasizing a number of tenets laid out by the Court in prior cases.
" NEPA is about procedure – The Court began by reiterating that NEPA is a purely procedural statute and does not mandate particular results, but simply sets forth the process for agency reviews of the environmental impacts of proposed actions. In the past several years, some environmental groups have advocated for CEQ to interpret NEPA's obligations more broadly to place greater emphasis on environmentally preferable outcomes, but the majority squarely rejected the premise of such an approach.
" Judicial deference – The majority's greatest emphasis was on the need for courts to grant substantial deference to agencies when reviewing compliance with NEPA requirements, which the Court described as the "central principle of judicial review in NEPA cases." The Court stated that under NEPA, an agency's only obligation is to prepare an adequate report and the adequacy of that report is relevant only to the question of whether an agency's final decision has been reasonably explained. As long as an EIS addresses environmental effects from the project at issue, courts should defer to agencies' decisions about where to draw the line in terms of the scope of the agency's review. The Court noted that an agency is better equipped to assess what facts are relevant to the agency's decision than a court is and that brevity does not mean the analysis of an environmental impact is inadequate.
" Rule of reason – The Court reiterated the oft-cited principle from its 2004 decision in Department of Transportation v. Public Citizen that inherent in NEPA is a "rule of reason" which ensures that agencies determine whether and to what extent to prepare an EIS based on the usefulness of the information to its decision-making process. Accordingly, the Court stated, courts should "afford substantial deference and should not micro-manage agency choices so long as they fall within a broad zone of reasonableness."
" Brevity is a virtue – The Court stressed that NEPA does not require particularly voluminous or time-consuming reports. While NEPA requires EISs to be "detailed," "courts should not insist on length as a prerequisite" for meeting this requirement. The Court noted the 2023 enactment of NEPA amendments as part of the "BUILDER Act" (Pub. L. 118–5), which set 150 pages and two years as general limits for EISs. The Court explained that these amendments "strongly reinforce[] the basic principles that NEPA, correctly interpreted, already embodied but that have been too often overlooked [by the lower courts]."
Scope of Review
Turning to the merits of the challenge to the EIS in this case, the Court held that the Board's determination that its EIS need not evaluate possible environmental effects from upstream and downstream projects separate from the Uinta Basin Railway complied with NEPA's procedural requirements. The Court pointed to NEPA's textually mandated focus on reviewing the impacts of the "proposed action" under agency review, and not the impacts of other projects, particularly when those other projects are separate in time or place from the project under review. The Court concluded that an agency "may decline to evaluate environmental effects from separate projects upstream or downstream from the project at issue" and remain compliant with NEPA's procedural mandates.
In support of this holding, the Court explained that agencies "are not required to analyze the effects of projects over which they do not exercise regulatory authority." In this case, the Board does not regulate oil drilling, oil wells, oil and gas leases, or oil refineries, and instead approves rail lines. As a result, the Court found no "reasonably close causal relationship" between the 88-mile railroad project and the environmental effects of separate oil drilling and oil refining projects. The Court also emphasized that a "but for" causal relationship between a project and an effect is not sufficient to make an agency responsible for that effect for purposes of NEPA review.
The Court cautioned that "in certain circumstances, other projects may be interrelated and close in time and place to the project at hand", and that the question then is whether the projects are actually a "single project within the authority of the agency in question." Even then, the Court's review "still must remain deferential," meaning that a court should defer to an agency so long as the agency "drew a reasonable and 'manageable line.'"
The Court concluded by noting that neither the language nor the history of NEPA "suggests that it was intended to give citizens a general opportunity to air their policy objections to proposed federal actions." Citizens may not "enlist the federal courts . . . to delay or block agency projects based on the environmental effects of other projects separate from the project at hand."
Concurrence
Justice Sotomayor, joined by Justice Kagan and Justice Jackson, concurred in the judgment. According to Justice Sotomayor, the majority should have simply relied on the proposition from the Court's decision in Public Citizen that, where an organic statute precludes the agency from considering a particular impact in deciding whether to approve the proposed action, the agency may set it aside for purposes of its NEPA review, and that "the proper scope of an agency's NEPA review depends in part on the nature of the agency's statutory authority." Because the Board had no discretion to consider upstream and downstream impacts associated with the commodity that would be carried on the rail line, the three concurring Justices concluded, its decision not to analyze those impacts in detail was consistent with NEPA's requirements. Accordingly, Justice Sotomayor stated, the Court had no need to address issues of judicial deference.
Implications for Infrastructure Projects
The Court's decision represents a positive development for those seeking to develop new infrastructure projects, especially in the energy sector. The Court makes clear that environmental impacts caused by another project separate in time or place from the project under review need not be considered in a NEPA analysis, particularly when those other projects will be carried out by third parties and are not under the jurisdiction of the agency reviewing the project. As a result, agencies no longer need to consider the upstream and downstream impacts of energy projects or growth-inducing impacts of transportation projects or other development projects. While an agency might choose to consider some of those effects in appropriate circumstances, they don't have to.
More broadly, the decision should be helpful in limiting judicial second-guessing of decisions agencies make regarding the scope of their NEPA reviews. By emphasizing the "rule of reason" that governs agency compliance with NEPA and the substantial deference courts should give agencies in determining whether their NEPA compliance efforts are in fact reasonable, the Court has placed renewed emphasis on prior admonitions that lower courts should not flyspeck NEPA documents nor should courts take a more skeptical view of an EIS simply because it is less voluminous or done more expeditiously. It remains to be seen whether lower courts get the message.
If a court did determine that an agency's NEPA analysis for a project was deficient in some respect, the majority states that a deficiency "may not necessarily require a court to vacate the agency's ultimate approval of a project, at least absent reason to believe that the agency might disapprove the project if it added more to the EIS." Thus, the Court makes clear that while some courts cite the principle that if a violation of law is found the court must vacate the agency action, that principle does not apply in NEPA cases. Thus, this language may help companies avoid the worst outcome, i.e., a court vacating the agency action.
In short, the Court's decision represents an attempt by Justice Kavanaugh and his colleagues in the majority to rein in NEPA litigation and the role it plays in driving agencies to prepare EISs that "meander on for hundreds or thousands of pages," pruning back the "judicial oak that has hindered infrastructure development 'under the guise' of just a little more process." The pruning should have a positive effect, although the extent of that effect remains to be determined.
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