Background

On August 1, 2025, the Environmental Protection Agency (EPA) published a proposed rule entitled “Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards.” The rule makes numerous arguments why the Clean Air Act (CAA) and specifically Section 202 of the statute that deals with new motor vehicles and engines does not authorize greenhouse gas vehicle standards.

As background, the U.S. Supreme Court in Massachusetts v. EPA (2007) held that the EPA shall regulate greenhouse gas emissions from new motor vehicles if the agency determines there is endangerment based on the analysis required under Section 202. This analysis requires the agency to determine if the GHG emissions “from any class or classes of new motor vehicles or new motor vehicle engines…cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.”

The Obama EPA concluded that such GHG emissions do cause the requisite endangerment. This endangerment finding has served as a predicate for the agency to regulate GHG emissions from new motor vehicles and it has inappropriately been relied upon for the EPA’s other greenhouse gas regulations.

The proposed rule discusses numerous flaws with the EPA’s 2009 endangerment finding, many of which are legal in nature and in no way depend on climate science. However, the rule does also bring up flaws with the science as well.

The importance of the 2009 endangerment finding can’t be overstated. The EPA has used it as the basis to regulate numerous aspects of our economy. Greenhouse gas regulation is not typical regulation. It gives the EPA the ability to reshape major portions of the economy and change the way Americans live their lives. All of this has been done without Congress ever speaking directly on whether such regulations are appropriate. The agency’s claimed power to regulate greenhouse gas emissions has led to rules such as the Biden EPA’s $760 billion de facto EV mandate, a rule that not only has a shocking price tag but is also an even more shocking attack on individual freedom.

Below are comments on the proposed rule from CEI and our allies.

Read CEI’s comment on the proposed rule here.


Comments from our Friends