Explaining EPA’s Revocation of the 2009 Endangerment Finding: No More Rules About Greenhouse Gases

Last July, we blogged about a proposal by the U.S. Environmental Protection Agency (EPA) to revoke its 2009 finding that greenhouse gas emissions from new motor vehicles in the United States endangered the public health and welfare by contributing to the global warming crisis.

Known as the 2009 Endangerment Finding, it was the predicate for EPA’s increasingly stringent regulation of new motor vehicles’ greenhouse gas emissions, by which EPA intended to force the electrification of America’s new motor vehicle fleet by the 2030s. 

As we blogged more recently, in early February 2026 EPA formally announced its revocation of the 2009 Endangerment Finding. The final, published version of the revocation is available here. 

As part of its revocation of the 2009 Endangerment Finding, EPA will remove all requirements related to greenhouse gas  emission standards for new motor vehicles from the Code of Federal Regulations. 

Originally, EPA claimed that it had the authority to make the 2009 Endangerment Finding under section 202(a)(1) of the Clean Air Act. 

Section 202(a)(1) deals with motor vehicle emissions only, and reads (in pertinent part):

The Administrator shall by regulation prescribe (and from time to time revise) in accordance with the provisions of this section, standards applicable to the emission of any air pollutant from any class or classes of new motor vehicles or new motor vehicle engines, which in his judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare. 

The 2009 Endangerment Finding followed a 2007 decision by the U.S. Supreme Court called Massachusetts v. EPA.

In Massachusetts v. EPA, the Supreme Court ruled that greenhouse gases were air pollutants within the meaning of section 202(a)(1) but did not determine that EPA was required to find that motor vehicles’ greenhouse gas emissions cause or contribute to air pollution “which may reasonably be anticipated to endanger public health or welfare.”

EPA made that determination on its own in the 2009 Endangerment Finding.

Thus, EPA’s revocation of the 2009 Endangerment Finding is a reminder that what EPA can do on its own under one president, it can undo on its own under another.

In its revocation of the 2009 Endangerment Finding EPA provides three final, “separate and independent” rationales for its action. The fact that EPA calls the rationales “separate and independent” means that EPA believes that each rationale stands on its own as a reason sufficient to revoke the 2009 Endangerment Finding. 

In order to defeat the revocation, a court would need to reject all three rationales.

First, EPA determined that by its own terms, section 202(a)(1) does not apply to vehicles’ greenhouse gas emissions. 

According to EPA, section 202(a)(1):

• applies only to air pollution that endangers public health or welfare through local or regional (not global) exposure by its own terms and all precedent before Massachusetts v. EPA.  Yes, this inserts language into section 202(a)(1) that isn’t there, but (as EPA notes) it is consistent with the way the Clean Air Act was interpreted from the time of its enactment in 1970 up and until the 2009 Endangerment Finding.  Obviously, EPA’s GHG emission standards for new motor vehicles were aimed at the consequences of global warming, not a strictly local or regional problem;  

• requires that an endangerment finding be issued with the emission standards meant to limit the air pollution causing the endangerment.  This rationale is strained.  Section 202(a)(1) provides EPA with the authority to “prescribe … standards,” not to make endangerment findings.  EPA’s first greenhouse gas emission standards for vehicles were issued in 2010, separately and about six months after it published the 2009 Endangerment Finding (which did not incorporate any emission standards); and

• requires that any emission standards issued under its authority make a material impact on the dangers from “air pollution” to which they were meant to respond.  In other words, a regulation promulgated under section 202(a)(1) must be designed to reduce emissions to improve public health or welfare, rather than to make emission reductions that have no discernible impact on public health or welfare. In the revocation, EPA relied on its determination that even if all greenhouse gas emissions from new motor vehicles were eliminated, there would be only minimal reductions to the dangers posed by global warming.

Second, EPA determined that section 202(a)(1) of the Clean Air Act did not clearly authorize EPA to regulate vehicles’ greenhouse gas emissions, as it must according to the “Major Questions Doctrine” developed by a string of Supreme Court decisions issued since 2009 (most specifically the Utility Air Regulatory Group case from 2014 and West Virginia v. EPA from 2022; we blogged about West Virginia v. EPA and the regulatory history that surrounded it here). 

Based on these cases, EPA now claims that it cannot rely on the Clean Air Act’s vagueness with respect to greenhouse gas emissions to seize the authority to regulate them, and that such authority has not been delegated to it clearly by Congress.

Third, as noted above, EPA determined that section 202(a)(1) requires that any emission standards promulgated under its authority make more than a minimal contribution toward reducing or eliminating the danger to public health or welfare to which the standards were addressed

 In other words, any greenhouse gas emission standards for motor vehicles that EPA promulgates under the authority of section 202(a)(1) must make some real difference toward reducing the dangers from global warming. 

EPA now claims that its greenhouse gas emission standards for motor vehicles fail this requirement because “[e]ven a complete elimination of all greenhouse gas emissions from new motor vehicles would not address the risks attributed to elevated global concentrations of GHGs.”

“The revocation of the 2009 Endangerment Finding and the Supreme Court decisions that deny EPA the power to regulate GHG emissions from stationary sources under the Clean Air Act are the death knell for the idea that the Act may be used to respond to the challenge of global warming,” GASP Senior Attorney John Baillie said. “It is now up to Congress to craft a response to the global warming crisis.”