Ethylene oxide is a cancer-causing hazardous air pollutant that is used to sterilize medical products, among other things – we’ve blogged about ethylene oxide pollution several times .    Because the U.S. Environmental Protection Agency (EPA) has moved the sticks on regulating ethylene oxide pollution yet again , it’s time for another update.   EPA on March 17 published a proposed rule and reconsideration of its April 5, 2024 Final Rule that revised the National Emission Standards for Hazardous Air Pollutants (NESHAPs) for facilities that use ethylene oxide to sterilize medical and other products.    The 2026 proposed rule would undo some, but not all, of the stricter emission standards imposed by the 2024 rule, mostly having to do with facilities that use 10 or more tons per year of ethylene oxide.    There are no such facilities in our region, although one facility in Erie uses smaller quantities of ethylene oxide. It appears that the emission limitations that apply to that facility will not change as a result of EPA’s latest proposed revisions to the NESHAPS.   What makes the latest proposed rule interesting is the basis that EPA asserts for promulgating it: specifically, that EPA lacked the authority to perform the residual risk review on which it based the revisions it made in 2024 and proposes to rescind now, because that was the second residual risk review it performed for the NESHAPs for ethylene oxide.    In other words, EPA is now claiming that some of the revisions that it made in 2024 to the NESHAPs for ethylene oxide broke the law. Did they?  Maybe. Some background on what the Clean Air Act says (and does not say) about revising NESHAPs will be helpful to understanding why (or why not):   The Act requires that within eight years after promulgating a NESHAPs, EPA must revisit it to determine whether it is sufficiently stringent. First, EPA must perform a technology review to determine whether the standard incorporates what’s known as developments in practices, processes, and control technologies, and revise the standard to incorporate such developments if it does not.    The Act further requires that EPA perform an additional technology review every eight years thereafter.   The Act also requires that within eight years of promulgating a NESHAPs, EPA must perform a residual risk review to determine whether the NESHAPs should be revised to address any health risks that remain despite the NESHAPs.    The Act does not  expressly require that EPA perform further residual risk reviews every eight years as it does for technology reviews. In fact, it does not say anything about additional residual risk reviews.   EPA first promulgated a NESHAPs for sterilization facilities that use ethylene oxide in 1994 and finalized technology and residual risk reviews for it in 2006. When EPA proposed the 2024 revisions to the standards, it took the position that it was permitted to do a second residual risk review because the Clean Air Act did not expressly prohibit such a review (which was a novel position for it to take).    EPA now claims that it can only exercise authority that is provided by the statute (rather than authority that is not prohibited by the statute), and that the Clean Air Act does not provide it with the authority to do additional residual risk reviews for a NESHAPs.   “This is another question that will be determined by the federal courts,” said GASP Senior Attorney John Baillie. “It is unlikely that Congress will clarify what authority it intends for EPA to have, although it should. EPA does itself no favors by flip-flopping every several years.”   EPA has scheduled a virtual public hearing for its proposed revisions to the ethylene oxide NESHAPs for April 1, 2026, with details to be announced at this address:  https://www.epa.gov/ stationary-sources-air-pollution/ ethylene-oxide-emissions-standards- sterilization-facilities .    Further, EPA is accepting comments on the proposed revisions through May 1.  You may submit your comments at https://www.regulations.gov/ , under Docket ID No. EPA-HQ-OAR-2019-0178.

Some abysmal news to share: As of this week, the Mon Valley has experienced 34 hydrogen sulfide (H₂S) exceedances so far in 2026.  To put that into perspective, during this same period last year, we were looking at just 14.  For the uninitiated: Hydrogen sulfide is an air pollutant with an unmistakable rotten egg odor that all-too-often blankets the Mon Valley.  While the Allegheny County Health Department (ACHD) tracks it, the health and quality-of-life impacts are more than just a nuisance.  A quick look at CREATE Lab’s Smell Pittsburgh app shows residents are reporting: • Respiratory issues : Especially for those with asthma. • Neurological symptoms: Headaches, nausea, and "brain fog." • Quality of life issues: Sleep interruption and the inability to let your kids play outside. If you are now asking yourself, “But where does the stuff come from?” know that ACHD’s own study attributed H2S exceedances almost entirely to emissions from U.S. Steel’s Clairton Plant.  Yet here we are in 2026, still waking up to air that violates Pennsylvania state standards. ACHD has the data. They have the dashboard. But monitoring and understanding the pollutant’s origin are just the first steps - now we need action. That’s why we are hoping you’ll join us at the upcoming Board of Health meeting to demand we move beyond monitoring and start mandating real change. The only way to ensure our leaders feel that urgency is to show up - in person if possible - and tell our stories.  We need to look the members in the eye and describe what it's like to live in the stench zone and ask them to do what they can to identify strategies to stem this issue. GASP will be speaking out, and we hope you’ll join us. • Date : This Wednesday, March 18, 2026 • Time : 12:30 p.m. • Place : Greater Pittsburgh Community Food Bank (1 N. Linden Street, Duquesne, PA 15110) Please, if you have experienced headaches, sore throat, or had to keep your windows shut on a beautiful day, the board needs to hear it.  Note: Residents who wish to address the board must register 24-hours in advance by clicking here . Please be aware that you can choose to comment in-person or via Zoom.

The Pennsylvania Department of Environmental Protection (DEP) published notice of its intent to issue a Plan Approval to Shell Chemical Appalachia LLC for modifications to the company’s ethane cracker in Monaca, Beaver County - with plans for a public hearing April 7. Specifically, the Plan Approval would: authorize Shell to modify flares that it uses to control air pollution at the Facility, as required by new federal regulations authorize Shell to install new equipment in the Facility’s Waste Water Treatment Plant (this equipment will reduce the Facility’s water pollution but will increase its air pollution); and modify other Plan Approvals that DEP has already issued for the Facility. DEP has made the Plan Approval and materials related to it available to the public on its website (click the link for Proposed Plan Approval PA-04-00740D on   this webpage ). Here are some save-the-dates:   March 19  -  Shell Plan Approval Q+A Public Meeting  6 PM * Penn State Beaver Auditorium, 100 University Drive in Monaca from 6 to 8 p.m.   March 31  –  We Speak, They Listen: Shaping the Public Record , 6:30 PM (Zoom) April 7  –  Shell Plan Approval Permit Public Hearing  6 PM (Monaca)** DEP’s notice states: Anyone wishing to present testimony should contact Emily Green, Southwest Environmental Justice Coordinator, emgreen@pa.gov or 412-442-4042, no less than 24 hours in advance of the public hearing to reserve a time to present testimony. Individuals who do not register may also present testimony on the day of the hearing. Oral testimony will be limited to a maximum of three (3) minutes per individual, and two (2) written copies of the oral testimony are requested. Further , DEP will accept written comments on the Plan Approval through April 17.   You may submit written comments about the Plan Approval: via e-mail to asandy@pa.gov or in writing to Department of Environmental Protection, Attn: Alexander Sandy, Air Quality Engineering Specialist, Air Quality Program, 400 Waterfront Drive, Pittsburgh, PA 15222.  Each written comment must contain the name, address and telephone number of the person submitting the comments, identification of the proposed Air Quality Plan Approval (PA-04-00740D) and a concise statement regarding the relevancy of the information or objections to issuance of the plan approval. Editor’s Note: GASP is reviewing the Plan Approval and will update this blog with anything notable that we find. Stay tuned!