EPA Issues Final Rule Repealing Its Regulation of GHG Emissions from Motor Vehicles

On February 12, 2026, the U.S. Environmental Protection Agency (“EPA”) issued a final rule repealing its earlier finding made in 2009 that the emission of certain greenhouse gases (“GHGs”) from motor vehicles contributes to air pollution that may reasonably be anticipated to endanger public health or welfare.  On this basis, the final rule repeals all prior EPA regulation of GHG emissions from motor vehicles.

Basis for EPA’s Rulemaking

The proposed rulemaking notice that EPA published in 2025 had stated EPA’s tentative finding that anthropogenic GHG emissions do not contribute to global climate change.  In contrast, the final rulemaking rests on a legal analysis that concludes that EPA lacks authority to regulate GHG emissions from motor vehicles.

The statutory provision at issue is section 202 of the Clean Air Act, which states that the “Administrator shall by regulation prescribe … standards applicable to the emission of any air pollutant from … motor vehicles … which in his judgment cause, or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare.”

The Supreme Court’s 2007 decision in Massachusetts v. EPA held that GHGs are an “air pollutant from motor vehicles” and that section 202 “authorizes EPA to regulate greenhouse gas emissions from new motor vehicles in the event that it forms a ‘judgment’ that such emissions contribute to climate change.”  After the Obama EPA published its “judgment” that such emissions contribute to climate change (known as the “endangerment finding”), the D.C. Circuit, in 2012, upheld the endangerment finding in Coalition for Responsible Regulation, Inc. v. EPA.

EPA’s final rulemaking notice published last week argues that section 202 only authorizes EPA to regulate air pollutant emissions that cause or contribute to air pollution that endangers public health or welfare through local or regional exposure, not to address global climate change concerns.  EPA’s subsidiary contention is that it lacks statutory authority to regulate GHG emissions from motor vehicles because “climate impact modeling … demonstrates that even the complete elimination of all GHG emissions from all new and existing vehicles in the U.S. would have only de minimis impacts that fall well within the standard margin of error for global temperature and sea level measurement.” 

The EPA notice distinguishes prior caselaw as being superseded by the major questions doctrine, which according to the Supreme Court’s 2022 decision in West Virginia v. EPA, requires “clear Congressional authorization” for “extraordinary grants of regulatory authority” over “a fundamental sector of the economy.” 

Immediate Consequences 

The immediate consequence of EPA’s rulemaking is the repeal, effective immediately, of all EPA regulation of GHGs from motor vehicles.  These regulations had required a substantial reduction in GHG emissions from light-duty, medium-duty and heavy-duty motor vehicles.  The regulations had effectively required significant improvements in fuel efficiency and, on a fleet-wide basis, a transition to electric vehicles as a much greater percentage of new motor vehicles sold in the United States. 

Long-Term Consequences

EPA’s regulatory action does not affect the separate fuel efficiency regulations issued by the U.S. Department of Transportation, but on June 11, 2025, DOT published an “interpretative rule” declaring that the fuel efficiency regulations it had published during the Biden administration were unlawful.

In addition to rolling back federal regulation of motor vehicle emissions, the Trump Administration has prevented states from regulating these emissions.  On June 12, 2025, President Trump signed into law resolutions adopted by Congress under the Congressional Review Act to void waivers that EPA has granted under section 209 of the Clean Air Act that had allowed California and participating States to enforce GHG emission regulations for motor vehicles and engines.

Each of the initiatives discussed above have been challenged in court or, in the case of the regulation published on February 12, are expected to be challenged in court.

The combined effect of the Trump Administration initiatives is to more than double the U.S. motor vehicle sector’s projected demand for gasoline and diesel fuel in the coming decades, as compared to the regulatory regime that was in effect before President Trump took office.  It can be expected that this increase in demand will increase fuel prices and motor vehicle emissions, but by reducing the demand for electric vehicles, reduce the growth in the demand for electric energy and the resulting upward pressure on the price of electricity.