EPA rescinds the endangerment finding on three independent bases

The Environmental Protection Agency published a final rule on 18 February 2026 rescinding “the Administrator’s 2009 findings of contribution and endangerment and repealing all greenhouse gas (GHG) emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines.”¹ The rule runs 111 pages, takes effect 20 April 2026, amends 40 CFR parts 85, 86, 600, 1036, 1037 and 1039, and was signed by Administrator Lee Zeldin, who announced the reconsideration on 12 March 2025 after reviews directed by two executive orders.¹²³ It was proposed at 90 FR 36288 on 1 August 2025.¹⁴ EPA received “approximately 572,000 written comments from more than 31,000 unique entities and 169 mass letter writing campaigns,” and held four days of virtual hearings from 19 to 22 August 2025 hearing “more than 600 speakers.”¹ The rule does not rest on a single proposition: EPA concludes it lacks authority “for multiple reasons,” and says that “[o]n these multiple and independent bases” it reaches the rescission.¹⁵

1. The statutory argument turns on two words that are not the same word. In Massachusetts v. EPA the Supreme Court held that greenhouse gases “fit well within the Clean Air Act’s capacious definition of ‘air pollutant’” at CAA section 302(g).⁶⁷ EPA does not contest that. It relocates the question: “[r]egardless whether GHGs are ‘agents of air pollution’ under the Act-wide definition of ‘air pollutant’ in CAA section 302(g), we cannot regulate under CAA section 202(a) unless emissions … ‘cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.’”¹ On EPA’s reading that phrase “targets ‘air pollution’ that threatens public health or welfare through local or regional exposure,” which global concentrations of well-mixed gases do not satisfy.¹ The rule reads three further terms the same way, arguing that climate causation is “too uncertain, conjectural, remote, and convoluted by intervening and confounding factors” to fit “cause,” “contribute,” and “reasonably be anticipated to endanger,” and that the 2009 finding “rested on a profound misreading” of Massachusetts.¹

2. The interpretive method is explicitly post-Chevron. EPA invokes Loper Bright for the proposition that statutes “have a single, best meaning” that is “fixed at the time of enactment,” and West Virginia for the requirement of more than “a colorable textual basis” to decide a major question.¹⁸⁹ Its position is that “[s]cientific understanding of environmental issues may be continuously evolving, but the scope of the EPA’s authority under CAA section 202(a)(1) is fixed by the terms Congress used when enacting and amending the language … from 1965 to 1977” — a history the rule traces from the Motor Vehicle Pollution Control Act of 1965 forward.¹ The major questions doctrine is offered as corroboration of the statutory reading.¹

3. A third basis is finalised, and it runs EPA’s own climate modelling. Section V.C concludes that eliminating vehicle GHG emissions altogether “would not alter predicted trends in global mean surface temperature … or global mean sea level rise … beyond de minimis levels.”¹ Using its OMEGA and MOVES emissions models with the FaIR climate emulator and the BRICK sea-level model, EPA estimates that eliminating all U.S. vehicle and engine GHG emissions would produce “an approximately 0.013 degree Celsius ([deg]C) difference in GMST increase by 2050” and “approximately 0.037 [deg]C … by 2100,” and roughly 0.09 cm and 1.40 cm of sea-level rise respectively; it notes that measurement variability from 2016 to 2025 was 0.14 °C, “almost four times greater than the modeled GMST impact.”¹ EPA states that this futility conclusion is “an independent basis to revoke those standards, separate and apart from the question of statutory interpretation.”¹

4. What EPA declined to finalise is narrower than the science as a whole. The proposed rule had offered an alternative under which the Administrator would exercise discretion to rescind the finding by making a superseding scientific finding, and submissions on it “constituted the largest share of public comments received.”¹ EPA did not finalise it, saying that although the Administrator “continues to harbor concerns regarding many of the scientific inputs,” the authority conclusion “renders it unnecessary and inappropriate” to exercise that judgment “regarding global climate change concerns in the regulatory context of CAA section 202(a)(1).”¹ A footnote adds that the rule “should not be understood as an additional endorsement or ratification of the scientific analysis in the Endangerment Finding.”¹ The comment record ran both ways: EPA “received supportive and adverse comments on virtually all substantive aspects of the proposal,” from vehicle manufacturers and suppliers, “nearly all 50 States and the District of Columbia,” elected representatives at local, State and Federal level, consumer and labour groups, EV advocates, educational institutions, environmental groups and individual citizens.¹

Review is channelled: under CAA section 307(b)(1) “judicial review of this final action is available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit (D.C. Circuit) by April 20, 2026.”¹¹⁰ Section 307(d)(7)(B) separately allows a petition for reconsideration where an objection was “impracticable to raise” in the comment period or its grounds “arose after the period for public comment,” and is “of central relevance to the outcome of the rule.”¹¹⁰ The rule is “an economically significant regulatory action,” is subject to the Congressional Review Act, and “meets the criteria set forth in 5 U.S.C. 804(2),” which is what places the effective date 61 days out.¹¹¹