- Donald J. Trump’s Environmental Protection Agency prioritized environmental deregulatory actions in 2025 and plans more of the same for this year.
- One EPA priority is continuing action to rescind the key scientific finding behind US climate rules.
- The EPA also plans to delay rules on vehicle emission standards.
The year 2025 was a busy one for both the US Environmental Protection Agency and environmental deregulation in general. The Donald J. Trump administration wasted no time in implementing its deregulatory agenda—on Jan. 31, Trump issued an executive order requiring federal agencies to eliminate 10 existing regulations for each new one implemented.
Picking up this directive, EPA administrator Lee Zeldin announced in March that the agency would review 31 regulatory actions for possible rollback. “We are working hard to develop policies and adhere to the best reading of the law in a way that will make these rules durable,” EPA press secretary Brigit Hirsch tells C&EN by email.
The EPA also took a number of actions in 2025 to update how it reviews chemicals and implements other parts of the Toxic Substances Control Act—actions that are likely to continue in 2026.
But the agency didn’t get to everything on Zeldin’s list in 2025. The EPA will continue to address these unfinished actions in 2026, with a focus on rescinding the endangerment finding that underlies many federal climate rules and delaying vehicle pollution regulations from the Joe Biden administration.
In July, Zeldin announced that the EPA was working to repeal its 2009 endangerment finding, which says that greenhouse gas emissions endanger public health and welfare. Even though the required public comment and hearing period for the proposal closed on Sept. 22, the matter has been slow to move forward because of ongoing lawsuits.
In addition to meeting strong objections from the scientific community, the US Department of Energy report that Zeldin is using as a scientific justification in overturning the endangerment finding prompted a lawsuit (PDF) filed by environmental advocacy groups the Environmental Defense Fund (EDF) and the Union of Concerned Scientists in August. A US district court ordered the DOE to turn over records about the report’s author group in December. According to EDF media director Sharyn Stein, the court hasn’t yet ruled whether the DOE report can legally be used in the endangerment finding repeal.
Stan Meiburg, a former acting deputy EPA administrator, says that the attempted repeal of the endangerment finding during the first Trump administration was unsuccessful because the EPA couldn’t make a strong science case for it, and the current research supporting climate change is even stronger now. The endangerment finding has also withstood multiple legal challenges since it was put into place in 2009.
The chemical industry in general wants to keep the endangerment finding, says Frank Maisano, an energy expert at the law firm Bracewell. Many chemical companies disagreed with the finding at the outset but have incorporated the required changes into their processes, Maisano says.
In addition to the proposal to rescind the endangerment finding, the EPA is prioritizing rolling back emission rules for cars and trucks. In a Dec. 19 op-ed, Aaron Szabo, EPA assistant administrator for the Office of Air and Radiation, says that the agency is planning on reconsidering two Biden-era vehicle emission rules in 2026—one that called for tighter emission restrictions on light- and medium-duty vehicles and one, also called the Clean Trucks Plan, that required cuts to the emissions of nitrogen oxides from heavy-duty engines and vehicles. Both rules apply to vehicles of model years 2027 and later.
The EPA plans to keep the 2026 standards in place for another 2 years, according to a Reuters article confirmed by Hirsch. The delay gives the EPA more time to reconsider the existing standards, she says.
Chemical & Engineering News
ISSN 0009-2347
Copyright ©
2026 American Chemical Society