EPA’s Rescission of GHG Endangerment Finding Sets Up a High‑Stakes Legal Fight
The Environmental Protection Agency (EPA)’s rescission of the 2009 greenhouse gas (GHG) “endangerment finding” has thrown significant uncertainty into future regulation of GHG emissions in the United States. EPA had concluded in 2009 that emissions of “greenhouse gases from new motor vehicles and new motor vehicle engines contribute to the greenhouse gas air pollution that endangers public health and welfare” under § 202(a)(1) of the Clean Air Act (CAA). In this recent action, EPA also rescinded all subsequent GHG vehicle and engine emissions standards predicated on the 2009 endangerment finding. This alert explores the legal issues that EPA will confront in the rescission litigation now filed in the U.S. Court of Appeals for the District of Columbia and in its holistic deregulatory approach to greenhouse gas regulation.
EPA stated its primary basis for the recission is a lack of statutory authority to regulate GHG emissions. Specifically, EPA asserts that
§ 202(a)(1) does not permit regulation of motor vehicle emissions of an air pollutant based on global climate change concerns. Instead, EPA now appears to read the CAA to permit regulation of an air pollutant only upon finding that the resulting air pollution endangers public health and welfare “through local or regional exposure.”
According to EPA, its new interpretation is the “best reading” of § 202(a)(1)—language drawn from the Supreme Court’s 2024 Loper Bright decision. In Loper Bright, the Court overturned the Chevron doctrine, under which courts had deferred to an agency’s reasonable interpretation of its authority under an ambiguous statute.1 Loper Bright held that courts must determine and apply the “best reading” of a statute when assessing whether an agency acted within its statutory authority.2
The agency also invokes the “major questions” doctrine, formally recognized in the Supreme Court’s 2022 West Virginia v. EPA decision,3 to argue that regulation of global climate change concerns is an issue “of significant economic and political importance” that Congress would not have left for EPA to address without express authorization. EPA additionally argues that the GHG standards are futile, asserting that even if all GHG emissions from new motor vehicles and engines in the United States were eliminated, there would be at best a de minimis impact on the global climate change concerns identified in the 2009 endangerment finding.
EPA explained that after reviewing the nearly 572,000 public comments on its proposed rule, the agency “made substantial updates to the final rule.” Most prominent, EPA’s abandonment of all scientific arguments from its proposed rule, including that the harms identified in 2009 were overblown and data since 2009 demonstrates the uncertainty of public health and welfare impacts from GHG emissions. See our previous alert outlining these arguments. EPA explained because it lacks the authority to regulate GHG emissions in the first place, it is “unnecessary and inappropriate” to resolve those scientific questions. EPA also stated it no longer was relying on the Department of Energy’s Climate Working Group report “in light of concerns raised by some commenters.” This report, which EPA relied on significantly for the scientific arguments in its proposed rule, was heavily criticized, and a court in January found that the secretive group formation and report drafting processes violated transparency requirements under the Federal Advisory Committee Act.
What’s Next?
Publication of the final rule in the Federal Register on February 18, 2026, triggered the 60-day deadline for parties to file a lawsuit challenging EPA’s action. Within hours of the rule’s publication, a group of 17 environmental and public health organizations filed a petition for review in the D.C. Circuit, and two groups filed a separate petition on behalf of a group of children. Two days later, an electric vehicle trade association filed its own petition on behalf of its member companies. Many of these organizations vowed to sue when EPA released its proposed rule in August 2025, as did several states and other trade organizations. Additional parties likely will file petitions or at least intervene in the litigations.
Petitioners are expected to lean on the Supreme Court’s 2007 case, Massachusetts v. EPA, which expressly rejected several of the arguments now advanced by EPA. For example, petitioners may argue that EPA’s conclusion that § 202(a)(1) does not authorize the regulation of global climate change concerns directly conflicts with Massachusetts, in which the Court had “little trouble concluding” that § 202(a)(1) “authorizes EPA to regulate greenhouse gas emissions” if EPA finds “that such emissions contribute to climate change” or “global warming.”4
EPA has asserted that because it lacks statutory authority to regulate GHGs, it is not required to make a new scientific finding under
§ 202(a)(1). This determination, however, also appears to be at odds with Massachusetts, in which all nine Justices agreed that the standard to regulate an air pollutant under § 202(a)(1) is EPA’s judgment whether the air pollutant contributes to air pollution that endangers public health or welfare.5 EPA now claims that it does not have authority to regulate GHGs because they do not contribute to air pollution that endangers public health or welfare through local or regional exposure, but without taking steps necessary to make that scientific finding of no endangerment.
Though EPA heavily relies on the Supreme Court’s recent decisions in Loper Bright and West Virginia, the Court in Massachusetts found § 202(a)(1) to be “unambiguous” and to “reflect[] an intentional effort” by Congress to provide EPA with the flexibility to regulate dangerous air pollution while accounting for “changing circumstances and scientific developments.”6 Those holdings will complicate EPA’s attempts to rely on Loper Bright’s rejection of Chevron deference and West Virginia’s recognition of the major questions doctrine as grounds for narrowing EPA’s authority.
Petitioners may also argue that EPA’s claims about the efficacy (and thus futility) of GHG standards is a policy consideration that the Massachusetts Court prohibited the agency from considering when determining whether to regulate. That is because such policy considerations “have nothing to do with whether greenhouse gas emissions contribute to climate change.”7 In fact, in Coalition for Responsible Regulation, which upheld the 2009 endangerment finding, the D.C. Circuit relied on Massachusetts to hold that the efficacy of standards is a policy consideration that does not belong in an endangerment determination.8
If the rescission goes to the Supreme Court, the outcome will depend on how the Court decides to apply (or limit) its decision in Massachusetts. As the Court has done more frequently in recent years, it is possible the Court could conclude that Massachusetts should be limited or overruled entirely. EPA’s revival of several arguments rejected by the D.C. Circuit in Coalition for Responsible Regulation—a decision the Supreme Court declined to review at the time—also provides the Court with another opportunity to weaken or overrule the D.C. Circuit’s reasoning.
It is expected that petitioners will move to stay the new rule pending appeal. If a stay is granted, vehicle manufacturers and their related supply chains will face uncomfortable uncertainty in planning the manufacture of their vehicle fleets during the pendency of the litigation. If the courts ultimately strike down the rescission, the current Biden GHG standards will remain in place, unless and until EPA or Congress attempts to rewrite or withdraw them in a separate action. If the courts uphold the rescission, agreeing that EPA does not have authority to regulate GHGs under § 202(a)(1) based on EPA’s adoption of limiting parameters not within the statutory text, future administrations would need to rethink their approach to GHG emission regulations from new motor vehicles or engines given that more limited scope of statutory authority or receive further direction from Congress. The outcome will also call into question how EPA may treat regulation of other sources of greenhouse gases, such as stationary sources.
Akin will continue to monitor this rule as it moves through the courts. We are available to assist our clients in determining the potential impacts of this action.
1 Chevron U.S.A., Inc. v. Nat. Res. Def. Council, 467 U.S. 837 (1984).
2 Loper Bright Enters. v. Raimondo, 600 U.S. 369 (2024).
3 West Virginia v. EPA, 597 U.S. 697 (2022).
4 Massachusetts v. EPA, 549 U.S. 497, 528, 534 (2007) (emphasis added).
5 Id. at 532-34 (finding that “the exercise of EPA’s authority” under § 202(a)(1) is conditioned on “its formation of a ‘judgment’” that “must relate to whether an air pollutant ‘cause[s], or contribute[s] to, air pollution which may reasonably be anticipated to endanger public health or welfare’”); id. at 552 (Scalia, J., dissenting) (“When [EPA] makes a judgment whether to regulate greenhouse gases, that judgment must relate to whether they are air pollutants that ‘cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.’” (emphasis omitted)).
6 Id. at 529, 532.
7 Id. at 533.
8 Coal. for Responsible Reg. v. EPA, 684 F.3d 102, 117-18 (D.C. Cir. 2012).
