Tribal groups argued NMFS violated NEPA in adopting the harvest specifications because they relied on outdated EISs despite dramatic changes to the ecosystem that necessitated an updated environmental analysis. The court found the specifications were not arbitrary and capricious because NMFS concluded, based on its reasoned evaluation of new information regarding changes in the region, that the specifications would not result in significant impacts to the human environment that were not considered in the 2007 EIS, and that a supplemental EIS was not required. It granted summary judgment for NMFS and dismissed the suit.

A district court granted in part summary judgment for an environmental group in a lawsuit concerning ESA §7 consultations on six pesticides. The group argued FWS violated the ESA by unreasonably delaying completion of consultations on chlorpyrifos, diazinon, carbaryl, methomyl, atrazine, and simazine. The court found FWS had unreasonably delayed completing consultations for chlorpyrifos, diazinon, carbaryl, atrazine, and simazine, and ordered the Service to issue biological opinions (BiOps) on carbaryl, atrazine, and simazine by deadlines mutually agreed upon by both parties. It further ordered FWS to complete consultation and issue BiOps on chlorpyrifos and diazinon by the Service's proposed date of September 30, 2028.

The D.C. Circuit partially granted petitions for rehearing in a challenge to FERC's reauthorization of two liquefied natural gas terminals and an associated pipeline in Texas. In a prior opinion, the court held FERC erred by failing to issue supplemental EISs addressing its updated environmental justice analysis, failing to treat a proposed carbon capture and sequestration system as a connected action, failing to treat that system as a reasonable alternative, and failing to adequately explain why it declined to consider air quality data from a nearby monitor; it vacated the reauthorization orders. The projects' applicants petitioned for rehearing, disputing portions of the opinion and arguing that any errors in FERC's orders did not warrant vacatur. The court found the procedural steps FERC skipped were important but not fundamental, and that the seriousness of the deficiencies did not outweigh the disruptive effects of vacatur. It remanded without vacatur to FERC to conduct further proceedings.

The Seventh Circuit vacated a preliminary injunction that had barred enforcement of an Indiana statute giving incumbent electric companies rights of first refusal (ROFRs) to build and operate new interstate transmission facilities that connect to facilities they own. Companies seeking to build and operate transmission lines in Indiana sued the Indiana Utility Regulatory Commission (IURC), arguing the statute violated the dormant Commerce Clause, and sought to enjoin the Commission from enforcing it. The district court issued a preliminary injunction, finding the companies had standing because IURC enforced the ROFRs and concluding that if it enjoined IURC from enforcing the statute, the Midcontinent Independent System Operator (MISO)—which plans, approves, and assigns construction for new interstate transmission projects in Indiana—would no longer be able to recognize an incumbent's ROFR. The appellate court held the companies lacked standing because the injunction did not oblige MISO—the entity responsible for assigning these projects and for the harm the companies feared—to act in any particular way, nor did it prompt MISO to modify its actions. It vacated the preliminary injunction and remanded to the district court.

The Eleventh Circuit affirmed dismissal of aviculturalist groups' lawsuit challenging FWS' denial of their petition to add two parrot species to the list of species approved for import under the Wild Exotic Bird Conservation Act. The groups had petitioned FWS to add members of the cactus conure and the green form of the lineolated parakeet that had been captive-bred in certain European countries to the list. FWS denied the petitions as invalid because the Act's implementing regulations didn't allow it to approve species country-by-country. The groups sued, arguing FWS must add captive-bred species to the exemption list on a country-by-country basis. A district court found the text of the Act instructed FWS to consider addition of different species as a whole to the list of approved species, rather than the addition of a species from particular countries; it dismissed the suit. The appellate court agreed, finding the Act did not permit FWS to consider exempting a species from the moratorium on a country-by-country basis. It affirmed dismissal.

A district court granted New York City's motion to dismiss a challenge to its statute prohibiting the use of fossil fuels in newly constructed residential buildings. Trade groups and a union argued the statute was preempted by the Energy Policy Conservation Act (EPCA) because it concerned "the energy use" of covered products, in that it banned an appliance from using any energy, setting its maximum energy use to zero; they sought a permanent injunction. The city moved to dismiss for failure to state a claim. The court concluded the statute did not "relate to," and thus did not concern, "energy use" within the meaning of EPCA. Because the statute was not preempted by EPCA, the court granted the city's motion to dismiss.

The U.S. Supreme Court held, 5-4, that the CWA does not authorize EPA to include "end-result" provisions in NPDES permits, in a lawsuit concerning the Agency's issuance of a renewal permit for the city of San Francisco that added two such requirements. The city petitioned for review, arguing the requirements, which prohibited one of its treatment facilities from making any discharge that contributed to a violation of any applicable water quality standard for receiving waters and provided that the city could not perform any treatment or make any discharge that created pollution, contamination, or nuisance as defined in the California Water Code, exceeded EPA's statutory authority. The Ninth Circuit denied the petition, holding that CWA §1311(b)(1)(C) authorized EPA to impose "limitations ensuring applicable water quality standards are satisfied in a receiving body of water." The Supreme Court held that the text, structure, and purpose of §1311(b)(1)(C) did not authorize permit requirements conditioning compliance on receiving water quality, and that resorting to such requirements was not necessary to protect water quality. It reversed the Ninth Circuit's denial and remanded for further proceedings. Alito, J., delivered the opinion of the Court, in which Roberts, C.J., and Thomas and Kavanaugh, JJ., joined, in which Gorsuch, J., joined as to all but Part II, and in which Sotomayor, Kagan, Barrett, and Jackson, JJ., joined as to Part II. Barrett, J., filed an opinion dissenting in part, in which Sotomayor, Kagan, and Jackson, JJ., joined.

In an unpublished opinion, the Ninth Circuit affirmed in part and reversed in part a district court ruling in a lawsuit over a logging project in Kootenai National Forest. Conservation groups sued the Forest Service and FWS, arguing the project's approval violated the ESA, NEPA, and the National Forest Management Act (NFMA). The district court concluded FWS violated the ESA's best available data requirement by failing to consider documented grizzly bear mortalities and failing to adequately credit annual minimum count data that showed a decline in the number of bears, and that the Forest Service violated the ESA by relying on the legally flawed biological opinion (BiOp). It also concluded the Forest Service violated NEPA by relying on stale bear population data in establishing the environmental baseline in its final EA and by failing to take a "hard look" at unauthorized road use, and violated NFMA by failing to demonstrate compliance with an access standard in the 2015 forest plan. The appellate court found FWS relied on a sound statistical method and considered all relevant factors in establishing the environmental baseline in its BiOp, that it was not arbitrary and capricious for the Forest Service to have approved the project pursuant to the BiOp, and that the Service's reliance on stale population data was a harmless error; but that the Service did fail to demonstrate substantial compliance with the access standard in violation of NFMA and failed to take the required hard look at road use. It affirmed in part, reversed in part, and remanded for further proceedings.

The Tenth Circuit denied environmental groups' petition to review an EPA rule that partially approved Colorado's SIP to reduce ozone pollution. The groups sought vacatur of the approval, arguing the Agency violated the CAA by approving the reasonable further progress and motor vehicle emissions budget components in 2022 to lower ozone levels after the state missed its 2021 deadline for meeting national ozone standards; that Colorado improperly included state-only emissions reductions in its reasonable further progress calculations; and that the SIP violated the CAA's anti-backsliding provision. The court found EPA acted lawfully in approving the reasonable further progress and motor vehicle emissions budget components, and that those approvals neither impermissibly depended on emissions reductions from state-only measures nor contravened the anti-backsliding provision. It denied the petition for review.