While the litigation is now paused, the court denied EPA’s request to remand the 2024 rule without explanation.

In June 2024, industry and environmentalist parties filed a petition in the U.S. Court of Appeals for the District of Columbia Circuit for review of a national emission standards for hazardous air pollutants (NESHAP) regulation applicable to commercial sterilization facilities. The regulation was finalized on April 5, 2024, by the Environmental Protection Agency (EPA) during the Biden administration (89 Fed. Reg. 24090). This 2024 rule set new, tighter emission standards for ethylene oxide (EtO) under the Clean Air Act and required compliance by April 2026. The Biden EPA stated that, through the 2024 rule, they aimed to balance risk reflected in EPA’s Integrated Risk Information System (IRIS) EtO toxicological assessment, completed in December 2016, with the vital role that commercial sterilization facilities play in maintaining an adequate supply of sterilized medical devices for the public’s health. Petitioners’ challenges to the 2024 rule include, among others, that the Biden EPA lacked statutory authority to conduct a second review of health risks after an earlier review conducted in 2006 and that the IRIS risk value is too conservative.

On April 1, 2025, the court granted EPA’s request to stay the litigation while the agency, now under the Trump administration, reconsiders its 2024 rule. While the litigation is now paused, the court denied EPA’s request to remand the 2024 rule without explanation.

EPA’s motion to stay the litigation followed its recent announcement that it will reconsider multiple NESHAPs, including the 2024 rule. EPA announced in its March 12, 2025, press release that:

While accomplishing EPA’s core mission of protecting the environment, the agency is committed to fulfilling President Trump’s promise to unleash American energy, lower costs for Americans, revitalize the American auto industry, restore the rule of law, and give power back to states to make their own decisions.

On March 21, 2025, EPA sent a letter to the Ethylene Oxide Sterilization Association (EOSA), a petitioner in the litigation, confirming that the Trump EPA is reconsidering the 2024 rule and, more specifically, the following issues:

• EPA’s authority to and decision to undertake a second residual risk review under Clean Air Act Section 112(f)(2), the analysis and determinations made in that review and the resulting risk standards;
• The standards promulgated pursuant to Clean Air Act Section 112(d)(6); and
• The requirement to demonstrate compliance using a continuous emission monitoring system.

Additionally, EPA stated that it intends to issue a proposed rule seeking public comment on those issues and any related proposed changes. The March 21 letter to EOSA also states that EPA expects to take final action by March 2026, which is one month before the current compliance deadline for the 2024 rule of April 2026.

As a result, on March 25, 2025, EPA again sought a stay of the case and to voluntarily remand the 2024 rule while EPA reconsiders it, despite the federal court having already denied EPA’s attempt to stay the case in February 2025. EPA attached its March 21 letter to EOSA to its motion, claiming that when EPA filed its previous abeyance motion, EPA had merely commenced review and not decided what action to take, if any. In its motion, EPA stated that its March 21 letter demonstrates that the agency has decided it wishes to reconsider the 2024 rule through rulemaking. EPA’s motion requests that the court remand the 2024 rule to EPA, suspend oral argument currently scheduled for April 15, 2025, and place the case in abeyance while EPA completes its action to avoid prejudice to petitioners.

On March 31, environmental organization and community group petitioners opposed EPA’s motion, arguing that their petition challenging the 2024 rule should proceed to argument on April 15, 2025, and be decided on its merits because otherwise alleged EtO emissions will continue. On the other hand, EOSA responded in favor of EPA’s motion to further highlight why EOSA believes remand and abeyance is the proper course given EPA’s decision to reconsider the 2024 rule within one year. EOSA argued that EPA’s motion should be granted in accordance with the court’s “consistent practice both before and after Loper Bright” to grant an abeyance where EPA has announced that it will review its prior decision and take further action.

On April 1, 2025, the court granted EPA’s motion to hold the case in abeyance without explanation, directing EPA to file a status report on June 30, 2025, and at 90-day intervals. The court also cancelled the oral argument scheduled for April 15, 2025. The court denied, however, EPA’s request for voluntarily remand of the 2024 rule to the EPA. Thus, while litigation to review the 2024 rule is paused, the court has retained jurisdiction of review.

For More Information

If you have any questions about this Alert, please contact Sharon L. Caffrey, Jeffrey S. Pollack, Coleen W. Hill, any of the attorneys in our Life Sciences and Medical Technologies Industry Group or the attorney in the firm with whom you are regularly in contact.

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