The US Supreme Court reversed a lower court’s decision involving the National Environmental Policy Act (NEPA) on Thursday, effectively narrowing the scope of the statute’s required environmental review of major infrastructure projects.

The NEPA is an environmental impact review statute that was promulgated in the 1970s, along with a slew of other environmental protection statutes like the Clean Air Act of 1972 and the Endangered Species Act of 1973. Unlike these two statutes, the NEPA is procedural. The statute merely requires an agency to produce an environmental impact statement (EIS) that must address the significant environmental effects of a proposed project and propose alternative measures to mitigate these effects. There is no particular way the statute says that an agency must review the environmental impacts, that discretion in manner is left to the agencies to do as they see fit.

The Supreme Court in this case was asked to review a lower court decision from the US Court of Appeals for the D.C. Circuit, which found that the US Surface Transportation Board (Board) did not produce an EIS that sufficiently analyzed all of the potential environmental effects of a project proposed by seven Utah counties. The proposed project concerned the construction and operation of an approximately 88-mile railroad line in northeastern Utah that would connect Utah’s oil-rich Uinta Basin to the national rail network.

The lower court specifically stated that the Board did not analyze the potential upstream and downstream effects of the oil drilling in the Basin. The court reversed this notion in a majority decision. Justice Kavanaugh, in the majority opinion joined by the four other conservative members of the Court, stated that:

First, the D. C. Circuit did not afford the Board the substantial judicial deference required in NEPA cases. Second, the D. C. Circuit ordered the Board to address the environmental effects of projects separate in time or place from the construction and operation of the railroad line. But NEPA requires agencies to focus on the environmental effects of the project at issue. Under NEPA, the Board’s EIS did not need to address the environmental effects of upstream oil drilling or downstream oil refining. Rather, it needed to address only the effects of the 88-mile railroad line. And the Board’s EIS did so.

Justice Kavanaugh continued by rejecting the petitioners’ attempt to use the NEPA as a way to air their policy disagreements with the construction of the proposed railroad. He concluded the opinion by stating, “[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.” The three liberal justices stated in a concurring opinion written by Justice Sotomayor agreed with the approval of the project, but stated that they would have taken a narrower path grounded in case precedent.

This decision follows the push from President Donald Trump’s administration for oil drilling in the US and the shift away from former President Joe Biden’s focus on renewable energy.