EPA has finalized the Rescission Rule, the rescission of the greenhouse gas Endangerment Finding. EPA called it the “single largest deregulatory action in U.S. history.” Administrator Zeldin announced EPA’s intention to rescind the Endangerment Finding in March 2025 when he announced a series of sweeping deregulatory actions.
The genesis of the Endangerment Finding was an October 1999 petition for rulemaking submitted to EPA by various environmental organizations seeking regulation of greenhouse gases. The petition was based on Clean Air Action Section 202(a)(1), which states that EPA shall prescribe standards applicable to the emission of any air pollutant from new vehicles or engines “which in his judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.”
EPA originally denied the petition in September 2003, a decision that was upheld by the D.C. Circuit. However, in 2007, the Supreme Court decided Massachusetts v. EPA, reversing the appeal court’s decision and finding that the definition of ‘air pollutant’ in the Clean Air Act was broad enough to encompass greenhouse gases. The Supreme Court did not hold that greenhouse gases constituted an endangerment or that EPA must make an affirmative endangerment finding. Instead, it found that EPA must respond to the petition and make a determination as to whether greenhouse gases from vehicles and engines meet the applicable standards for regulation under the CAA.
In response, EPA originally expressed a reluctance to regulate greenhouse gases. However, the incoming Obama Administration changed course. In December 2009, EPA issued the Endangerment Finding, determining generally that the global concentrations of greenhouse gases led to increased global temperatures that were responsible for various health risks. EPA also issued the Cause and Contribute Finding, generally determining that greenhouse gases from vehicles and engines contribute to air pollution. Those findings sparked a wave of regulations as to greenhouse gases, including regulation of greenhouse gases from light-duty, medium-duty, and heavy-duty vehicles.
EPA asserts that the 2009 Endangerment Finding “was a political move” and not one based on the best reading of the Clean Air Act. While CAA Section 202(a) allows EPA to prescribe standards applicable to emissions of air pollutants from vehicles and engines that endanger the public health or welfare, EPA has historically utilized this provision to address traditional air pollutants (such as hydrocarbons and particulate matter) and has not utilized this section to regulate in response to global climate change. After reviewing developments since 2009 in science, economics, and mitigation, as well as significant Supreme Court decisions, EPA “determined that the Endangerment Finding should be reconsidered to address legal and scientific developments that present reason to question the ongoing validity and reliability of its conclusions.”
To support the rescission, EPA utilizes three legal arguments, each of which it claims is separate and independent of the others and each of which would support repeal standing alone. First, EPA determined that Section 202(a) does not authorize the EPA to prescribe standards for GHG emissions based on global climate change concerns. That section is best read to regulate air pollution that threatens to endanger health and welfare through local and regional exposure, as it has been traditionally read, as opposed to global concerns. Second, under the ‘major questions doctrine,’ EPA determined that Section 202(a) lacks the clear congressional authorization required for the EPA to assert authority to regulate greenhouse gas emissions in response to global climate change concerns. Finally, EPA’s modeling establishes that even the elimination of all greenhouse emissions from vehicles in the United States would not yield any appreciable impacts on global greenhouse gas levels.
The Rescission Rule repeals greenhouse gas standards for light-duty, medium-duty, and heavy-duty vehicles. EPA claims that the rescission will result in over $1.3 trillion in savings from 2027 through 2055. Approximately $1.1 trillion of those savings are from reduced costs for new vehicles, with an estimate of the average per-vehicle cost savings to be over $2,400 per vehicle.
The Rescission Rule takes effect on April 20, 2026. But, it has already been challenged in the D.C. Circuit. It is likely that the matter will end up in the Supreme Court.
John B. King is a partner with Breazeale, Sachse & Wilson LLP in Baton Rouge, Louisiana. For more information, check http://www.bswenviroblog.com, or contact John B. King at jbk@bswllp.com or (225) 381-8014.
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