In what it described as “the single largest deregulatory action in US history,” the Environmental Protection Agency (EPA) on February 12 repealed its finding under the Clean Air Act that greenhouse gas emissions endanger public health and welfare—the so-called “endangerment finding.”[1] The decision eliminates not only federal greenhouse gas emission standards for vehicles and engines from model year 2012 forward, but also the legal foundation for almost all federal climate regulation. Other regulations premised on the now-rescinded endangerment finding—from power plant standards to aircraft emissions rules to methane regulations—are now at risk.[2]

The Administration’s position is categorical: EPA claims that the Clean Air Act never authorized federal greenhouse gas regulation in the first place.[3] That position has faced a series of legal challenges. But litigation could take two years or more to resolve, leaving companies to navigate an uncertain regulatory future as courts review the repeal.

In the meantime, states may step in to fill the void. States may seek to set new greenhouse gas rules for a variety of sources. Companies would then have to navigate a patchwork of conflicting state requirements—the very compliance challenge that federal regulation was meant to solve.

The rollback may also breathe new life into climate-related tort lawsuits, as will be discussed in more detail in tomorrow’s post. Under the Supreme Court’s decision in American Electric Power v. Connecticut, federal regulation of greenhouse gas emissions under the Clean Air Act displaced federal tort lawsuits that sought to abate greenhouse gas emissions.[4] With federal regulation now eliminated—and EPA taking the position that it never had the authority to regulate—plaintiffs will argue that the Supreme Court’s rationale in American Electric Power no longer applies. Expect a new wave of climate tort litigation with uncertain traction in the courts.

Finally, the repeal reflects—and may accelerate—a wider push by federal and state governments to target climate and environmental, social, and governance (ESG) programs. Thus far, the Department of Justice (DOJ) has brought suit against state efforts to bring climate litigation against the fossil fuel industry. And, with backing from a coalition of states, state attorney generals have brought antitrust claims against asset managers for allegedly conspiring to suppress US coal production. Companies should expect federal and state scrutiny of climate commitments and ESG programs to intensify.

[1] President Trump and Administrator Zeldin Deliver Single Largest Deregulatory Action in U.S. History, EPA (Feb. 12, 2026), https://www.epa.gov/newsreleases/president-trump-and-administrator-zeldin-deliver-single-largest-deregulatory-action-us.

[2] See, e.g., New Source Performance Standards for Greenhouse Gas Emissions From New, Modified, and Reconstructed Fossil Fuel-Fired Electric Generating Units, 89 Fed. Reg. 39798, 39799 & n.1 (May 9, 2024) (power plant regulations citing the endangerment finding); Finding That Greenhouse Gas Emissions From Aircraft Cause or Contribute to Air Pollution That May Reasonably Be Anticipated To Endanger Public Health and Welfare, 81 Fed.

Reg. 54422, 54423 (Aug. 15, 2016) (“In this final action, the EPA is informed by and places considerable weight on the extensive scientific and technical evidence in the record supporting the 2009 Endangerment and Cause or Contribute Findings under CAA section 202(a).”); Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review, 89 Fed. Reg.

16820, 16837 (Mar. 8, 2024) (methane regulations relying on the endangerment finding).

[3] See generally EPA, Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air Act (Feb. 12, 2026) (pre-publication version), https://www.epa.gov/system/files/documents/2026-02/preamble-rule-san12715-ef-vehiclerule-frm-20260212.pdf.

[4] Am. Elec. Power Co. v. Connecticut, 564 U.S. 410, 424 (2011).