At a Glance
- In 2024, EPA finalized significant tightening of EtO emissions standards for commercial sterilizers, including new fugitive emissions controls, continuous monitoring requirements, and more stringent point-source standards.
- The Trump administration has since proposed rescinding key provisions of the 2024 rule, and has granted two-year presidential exemptions to 41 sterilization facilities. Those exemptions are currently being challenged in court.
- The public comment period on the proposed rollback closed May 15, 2026, drawing over 30,000 comments. A final rule on the proposed rollback is expected later this year, though the timeline could extend.
- At this time, the 2024 rule remains technically in effect, and state-level EtO requirements continue to apply regardless of federal action. Manufacturers and sterilizers should therefore be planning for multiple regulatory scenarios.
The regulatory landscape for ethylene oxide (EtO) emissions from commercial sterilization facilities is in the midst of a significant transition. The Trump administration has moved aggressively to unwind the US Environmental Protection Agency’s (EPA) 2024 EtO emissions standards for commercial sterilizers, including proposing a substantial rollback of the rule’s core provisions.
The 2024 EtO Rule and the Push to Roll It Back
On April 5, 2024, the EPA published the National Emission Standards for Hazardous Air Pollutants (NESHAP): Ethylene Oxide Emissions Standards for Sterilization Facilities Residual Risk and Technology Review (the “2024 Final Rule”). The 2024 Final Rule significantly strengthened emissions standards, adding new regulations for fugitive emissions (unintended releases of EtO that escape from equipment, valves, or building openings) from chemical sterilizers, requiring continuous emissions monitoring systems, imposing more stringent point-source standards for larger facilities (up to 99.99% reduction), and extending emissions reduction requirements for lower-emitting facilities. EPA projected it would cut annual EtO emissions from commercial sterilizers by approximately 90% across roughly 90 sterilization facilities, with compliance deadlines of April 2026 and April 2027.
The 2024 Final Rule raised concerns in the medical-device and sterilization industries regarding technical feasibility, implementation costs, and potential effects on the medical device supply chain and sterilization capacity. The Trump administration moved quickly to chart a different course.
On March 12, 2025, EPA announced its intent to reconsider the 2024 Final Rule as part of a broader initiative to revisit Biden-era NESHAP regulations, raising concerns that the Biden-era EtO emission standards “actively threaten facilities’ ability to sterilize equipment” and questioning whether Section 112(f)(2) of the Clean Air Act (CAA) authorized EPA to conduct the second residual risk review on which portions of the 2024 Final Rule were based.
On July 17, 2025, President Trump also granted two-year compliance exemptions to 41 commercial sterilization facilities under Section 112(i)(4) of the CAA, which permits the president to exempt a stationary source from compliance if the technology to comply is unavailable and the exemption serves the national security interest. The exempted facilities now have compliance deadlines extended to April 2028 or April 2029, depending on the applicable standard. During the exemption period, these facilities remain subject to the emissions standards that were in effect prior to the 2024 Final Rule.
But the presidential exemptions have not gone unchallenged. Public health and environmental advocates filed lawsuits in the US District Court for the District of Columbia alleging that President Trump exceeded his authority under the CAA. See Texas Environmental Justice Advocacy Services v. Trump, Case No. 1:25-cv-03745 (Oct 22, 2025); CleanAIRE NC v. Trump, Case No. 1:26-cv-00233 (Jan 28, 2026); Greater Birmingham Alliance to Stop Pollution v. Trump, Case No. 1:25-cv-04469 (Dec 22, 2025); and Minnesota Center for Environmental Advocacy v. Trump, Case No. 1:26-cv-00287 (Feb 2, 2026). These cases have been consolidated with Case No. 1:25-cv-03745, and they remain pending.
The March 2026 Proposed Rollback
On March 17, 2026, EPA published a proposed rule that would permanently rescind or significantly amend several core provisions of the 2024 Final Rule. 91 Fed. Reg. 12700.
EPA’s proposal rests on four main pillars:
- Rescission of all residual risk-based standards. EPA proposes to rescind every emissions standard set under the “residual risk” authority of Section 112(f)(2) of the CAA as part of the 2024 Final Rule. EPA now contends that Section 112(f)(2) authorizes only one residual risk review per source category (which was completed for commercial sterilizers in 2006), and that the second, “discretionary” risk review conducted for the 2024 Final Rule was unauthorized.
- Relaxation of technology-based standards for new aeration room vents. The 2024 Final Rule set different emissions standards for existing and new aeration room vents (ARVs) at larger facilities, requiring new ARVs to achieve a 99.9% reduction compared to 99.6% for existing ARVs. EPA proposes to equalize these standards at 99.6%, arguing this will allow facilities to share infrastructure and reduce costs.
- Rescission of the continuous emissions monitoring systems (CEMS) requirement. EPA proposes to eliminate the requirement that most facilities use continuous emissions monitoring systems, instead allowing all facilities to choose between CEMS and parametric monitoring, an approach that measures indirect indicators like temperature and pressure rather than actual emissions levels.
- Rescission of the permanent total enclosure (PTE) requirement. EPA proposes to eliminate the nationwide mandate that facilities use PTEs to capture fugitive emissions, asserting that such determinations are better left to state permitting authorities on a case-by-case basis.
EPA received over 30,000 public comments and held a virtual public hearing on April 1, 2026. A final rule is expected later this year, though the volume and complexity of the comments received could extend that timeline.
What Comes Next?
The regulatory uncertainty creates a challenging compliance environment for stakeholders across the EtO value chain. The 2024 Final Rule remains technically in effect, and facilities with presidential exemptions have deadlines through 2028 or 2029. If finalized, the proposed rollback could shift compliance obligations again.
Even if EPA relaxes federal standards, state regulators are not required to follow suit. For example, Illinois commercial sterilizers are already meeting a state-mandated 99.9% emissions reduction requirement and are implementing state-level continuous monitoring. California, Georgia, and other states have their own EtO-related requirements that remain in force regardless of federal action.
Until EPA issues a final reconsideration rule and any resulting litigation is resolved, manufacturers and sterilizers should plan for multiple scenarios rather than assume a single outcome, while assessing obligations under the existing NESHAP and monitoring pending regulations and applicable state requirements.
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