The D.C. Circuit denied a chemical manufacturer's and two trade groups' petitions to review EPA's 2020 rule regulating emissions from miscellaneous organic chemical manufacturing facilities. The petitioners challenged EPA's assessment of cancer risk from exposure to ethylene oxide emissions. The court found petitioners failed to show EPA's modeling of the lymphoid cancer risk of ethylene oxide was arbitrary and capricious, and found no merit in their arguments that EPA committed procedural errors in promulgating the rule and issuing a reconsideration decision. It denied the petitions for review.

In a per curiam opinion, the D.C. Circuit dismissed in part and denied in part challenges to EPA's 2022 denial of pending Renewable Fuel Standard (RFS) exemption petitions filed by small refineries. EPA had determined the only costs relevant to showing economic hardship were those caused by compliance with the RFS program, that refineries fully and efficiently passed such costs onto their customers, and that small refineries did not face any economic hardship imposed by compliance. Because that rationale departed from prior practice, the Agency provided alternative compliance options to small refineries that had previously received exemptions. A trade group challenged those, and two refineries argued the April option did not provide them adequate relief. The court concluded EPA's rationale for denying the exemptions was contrary to law and arbitrary and capricious, and vacated the denials except with respect to two refineries that EPA correctly determined were ineligible on other grounds unaffected by vacatur. It dismissed the group's petition for lack of standing, denied one refinery petition because EPA's decision was adequately explained, and dismissed the other because it did not challenge a final agency action.

The D.C. Circuit granted in part and denied in part a trade group's petition to review the Pipeline and Hazardous Materials Safety Administration's (PHMSA's) 2022 revised safety standards for natural gas transportation. The group challenged five of the standards, alleging flaws in the rulemaking process and inadequacies in PHMSA's final justifications. The court agreed that PHMSA failed to adequately explain why benefits of four of the final standards outweighed their costs, but found the agency properly promulgated the fifth standard concerning pipeline segments. It vacated the four standards based on PHMSA's inadequate final analyses.

The Third Circuit reversed a ruling that held FIFRA did not preempt state-law tort duties to include a cancer warning on a weedkiller label. A landscaper had argued the agrochemicals company that produces the weedkiller violated Pennsylvania law by omitting the cancer warning from its label. The appellate court concluded that because FIFRA implementing regulations required health warnings on a pesticide's label to conform to the proposed label approved by EPA during the registration process, and because during the company's registration process EPA approved labels omitting a cancer warning following extensive review of scientific evidence concerning the weedkiller's possible carcinogenicity, the alleged state-law duty to include the cancer warning on the label imposed requirements that were different from those imposed under FIFRA, and it was thus preempted by FIFRA.

In an unpublished opinion, the Ninth Circuit reversed a lower court's vacatur of an incidental take statement (ITS) issued by NMFS authorizing a troll fishery in Alaska to harvest Chinook salmon despite potential reduction in prey for the endangered southern resident killer whale, and affirmed its decision not to vacate the Service's approval of a program funding Chinook salmon hatcheries to increase prey for the whale. An environmental group had challenged NMFS' 2019 biological opinion, arguing the Service had violated the ESA and NEPA. The appellate court found the district court abused its discretion by vacating the authorization of the fishery's Chinook salmon harvests because the ESA and NEPA errors, although serious, were unlikely to affect the substance of the decision adopted on remand; but that the court did not abuse its discretion by concluding that the disruptive consequences of vacating the prey increase program outweighed the seriousness of NMFS' errors. It reversed in part, affirmed in part, and remanded without vacatur to NMFS.

A district court granted summary judgment for environmental groups in a challenge to NMFS' biological opinion (BiOp) on the impact of oil and gas extraction in the Gulf of Mexico on protected marine life. The groups argued NMFS violated the APA and the ESA by issuing a flawed BiOp that underestimated the risks of harm to protected species and took inadequate measures to mitigate the risks. The court found the BiOp underestimated the risk and harms of oil spills to protected species; falsely assumed in its jeopardy analysis for the Rice's whale and Gulf sturgeon that the species' populations remained as large as before the Deepwater Horizon oil spill, despite record evidence and NMFS' findings indicating the spill significantly diminished their populations; only considered two of five stressors likely to jeopardize the Rice's whale; and failed to recognize oil spill take as incidental take. It vacated the BiOp and remanded to NMFS for further proceedings.

A district court affirmed BLM's resource management plan (RMP) amendment and record of decision (ROD) concerning wild horse management in southern Wyoming. Conservation and wild horse advocate groups argued BLM's decision to revert two herd management areas to "herd area" status, of which the appropriate management level for wild horse populations is typically zero, violated the Wild Free-Roaming Horses and Burros Act (WHA), FLPMA, and NEPA. The court found the groups' WHA arguments conflated the RMP amendment with a final horse removal decision and misconstrued BLM's obligations, and determined that the Bureau both complied with, and was justified in complying with, its obligations under FLPMA and NEPA. It upheld the RMP amendment and ROD.

In a per curiam opinion, the D.C. Circuit granted industry groups' petitions and denied environmental groups' petition to review EPA's application of a 2022 rule that classified industrial boilers built after 2010 as "new" rather than "existing" sources of hazardous air pollutants. The industry groups challenged the rule's definition of "new," arguing the application of emission standards promulgated in 2022 to equipment built in 2010 violated the CAA, and the environmental groups challenged EPA's exclusion of post-2013 data when calculating the new standards. The court held the rule misinterpreted the definition of "new source," granted the industry petitions, and set the rule aside to the extent it defines sources constructed or reconstructed before August 24, 2020, as new. It further held EPA's decision to rely on the same 2013-era dataset it had used for other, still-valid emission standards promulgated for boilers in 2013 did not violate the CAA, and it denied the environmental groups' petition.

The D.C. Circuit denied environmental groups' petitions to review NRC's denial of their requests to intervene in licensing proceedings for construction and operation of a spent nuclear fuel storage facility in New Mexico. An energy company had applied for a license to construct and operate the facility, and the groups sought to intervene. A board established by NRC found the groups' contentions inadmissible and denied their petitions to intervene, and NRC affirmed. The groups challenged NRC's denial, arguing the Commission acted unreasonably and contrary to law. The court found NRC reasonably declined to admit the groups' factual contentions and otherwise complied with statutory and regulatory requirements when rejecting their requests to intervene. It denied the petitions for review.

A district court granted an Indian tribe's motion for a temporary restraining order (TRO) in a challenge to BLM's approval of a lithium mine exploration project in Arizona. The tribe argued BLM violated the National Historic Preservation Act (NHPA) when it found that no historical properties were affected, and violated NEPA by failing to consider a reasonable range of alternatives and failing to take a "hard look" at impacts on water resources. The court found the tribe was likely to suffer irreparable injury as the next phase of drilling was already scheduled to take place on lands adjacent to a medicinal spring sacred to the tribe, and that the tribe had raised sufficiently serious questions regarding BLM's compliance with NHPA to justify a TRO. It temporarily enjoined BLM from authorizing or allowing any ground disturbance, construction, operation, or other activity approved for the project.