The Trump administration is on a crusade to deregulate toxic chemicals. These substances are so harmful that they landed on a list of 188 substances EPA was mandated to regulate by the 1990 Clean Air Act amendments. An earlier issue of Confined Space reported on EPA’s efforts to liberate formaldehyde from strict requirements. This piece considers the down-regulation of ethylene oxide (EtO), a chemical used to sterilize medical equipment such as heart valves, pacemakers, surgical kits, gowns, drapes, ventilators, syringes, and catheters without harming the equipment.
In 2024, the Biden administration issued a final rule toughening controls at 88 independent commercial facilities that use EtO. The rule was tough because EPA discovered that previous analyses of the dangers to public health caused by exposure to EtO understated the risk by orders of magnitude. The Trump EPA has issued a final rule drastically weakening those controls without considering the new science.
Exposure to EtO causes irritation of the eyes, skin, nose, throat, and lungs and, when a person is exposed for too long, damages the brain and nervous systems and causes lymphoid or breast cancer. The 88 facilities rescued by the Trump rule sterilize 50% of the 20 billion medical devices (!) used annually. Many are located in communities disadvantaged by low incomes and racism.
Of course, readers tune in to Confined Space because they are concerned about worker safety and health. While the mission of EPA is generally to oversee environmental hazards to the public, its work is also important for workplace safety. OSHA is authorized to issue “Permissible Exposure Limits” and back in the early seventies, it set limits for about 500 toxics based on science from the 1950s and 1960s. In 2026, these limits are outdated and defunct and OSHA is unable to update them in any reasonable timeframe. For workers in facilities where toxic chemicals are used, EPA is their last hope.
Regulating Toxic Air Pollutants
The 1963 Clean Air Act was the first, and many would say, the most important national environmental law. The House passed it 273 to 102 and the Senate confirmed it by voice vote. Congress has amended the law many times, making it stronger and more comprehensive, with the last round of amendments passed in 1990 under George H.W. Bush, who self-identified as an “environmental president.”
In the 1970 amendments, Congress authorized EPA to set National Emissions Standards for Hazardous Air Pollutants (NESHAPs). But that program faltered in a welter of inconclusive debates over the science.
Representative Henry Waxman (D-CA), who was the most effective champion of the Clean Air Act, had a stroke of genius when work began on the 1990 amendments. The best way to extricate the agency from endless brawls over the scientific findings about toxics was to adopt a technological approach as the first step. The 1990 amendments required EPA to identify the best available pollution controls to limit human exposure. This Maximum Achievable Control Technology was defined as equipment or manufacturing processes used successfully by the best-performing facilities in an industry.
To make sure EPA implemented the new technology regime quickly, the 1990 amendments included a list of 189 substances, including formaldehyde and ethylene oxide, in an effort to short circuit any debate over which chemicals were the worst. The 1990 amendments required EPA to write rules on tight schedules. Fearing that EPA would miss those deadlines, a constant problem for an agency with many mandates and insufficient staff, Congress added citizen suit provisions authorizing private parties to sue the agency into compliance. (Both provisions sound miraculous from today’s perspective, don’t they?) Eventually, the agency wrote technology requirements for the specific industries that emitted 187 listed chemicals, removing hydrogen sulfide and ammonia from the original list of 189 for idiosyncratic reasons.
Within eight years after first requiring pollution controls, the law instructed EPA to review the performance of covered facilities to ensure that public health was adequately protected. If “residual risk” was still present, the agency must report those conclusions to Congress. If Congress did not respond, the law required EPA to tighten regulatory controls to ensure that exposed people are protected with an “ample margin of safety.”
This standard meant that EPA’s rules must be protective of public health and not curtailed by concerns about how much the technology might cost. In another eight years, the agency must repeat the assessment, this time focusing on whether a better technology was available. Residual risk analysis was only required explicitly during the first evaluation.
An Agency Embattled
From its inception, EPA has been pulled in two opposing directions: regulated industries demand the moderation of regulations to reduce their cost and equally determined public health and environmental groups advocate keeping rules strong. The rules the agency wrote were expansive, expensive and worthwhile.
Yet as a restless electorate chose presidents from opposing parties in rapid succession, the agency’s budget was cut, existing laws were not adjusted to respond to new developments, and the courts took it upon themselves to reevaluate every aspect of rulemakings including the science (known in the legal trade as “hard look review”). Compounding the fear of being overturned by the courts, EPA was obliged to respond to a slew of burdensome procedural requirements imposed by Congress.
National environmental laws are organized by the target that is polluted: for example, the Clean Air Act, the Clean Water Act, and the Resource Conservation and Recovery Act (land). EPA’s statutory mandates focus first and foremost on whether a proposed rule will provide sufficient protection for public health and the environment and embrace the precautionary principle—hazards should be eliminated even where the science is not iron-clad, because it is always better to be safe than sorry. For really important efforts to eliminate the worst air pollution, the law says the rules must provide either an “adequate” or “ample” margin of safety. In a landmark Supreme Court case, this language was read to prohibit consideration of remedial costs when EPA decided what level of pollution was acceptable.[1]
In sharp contrast, the Occupational Safety and Health Act imposes an economic feasibility standard for each standard OSHA issues. The standards may not threaten to put industries out of business. The restraints in OSHA’s authorizing statute remain the same that Congress adopted in 1970, while EPA’s numerous authorizing statutes have been updated several times.
The White House Office of Management and Budget (OMB) requires both OSHA and EPA to undertake cost-benefit analyses. OMB often demands changes in proposed regulations to reduce their costs, and the agencies must either convince OMB that the requirements are needed or accept their decisions.
The first Trump administration undermined EPA’s ability to function, eliminating work on climate change and producing a brain drain of staff. And then Trump was elected for a second term.
The Science of Risk
Like so many other efforts to control toxics, regulation of EtO has a troubled history. OSHA issued an EtO permissible exposure limit (PEL) in 1984 that provided important protections for workers in EtO manufacturing facilities and hospitals where the sterilant was used.
Its requirements focused primarily on keeping exposures to workers below a Permissible Exposure Limit (PPM) of 1 part per million over an eight-hour average and also included a short-term exposure limit. Public health experts reviewed hospital compliance with the OSHA rule in 1993 and concluded that “overexposures continued to occur widely.”
In 1994, following passage of the 1990 Clean Air Act Amendments, EPA reviewed its requirements for EtO and concluded that the required technology was working and there was no significant residual risk. The second review was done in 2006, but focused only on the technology used to control exposures and releases into the air. The Biden administration began the third review in 2023 and issued a final rule in April 2024. By then, the science had developed to the point that EPA staff realized that the 2006 rule was severely under-protective. EPA acknowledged that even though the law did not require a residual risk analysis, the agency still retained “discretion or authority” to conduct one if “such a review is warranted.”
Integrated Risk Information System
Regulators usually need to know the “reference dose” (RfD) of a chemical before they can find a way to control it through mandates for industry. The RfD is the amount that cannot be safely taken in by the human body before adverse health effects are triggered. The body absorbs chemicals by inhalation, ingestion, or dermal exposure.
EPA’s Integrated Risk and Information System (IRIS) is generally in charge of determining RfDs. Regulatory action should be triggered when EPA develops an RfD for a specific chemical for the first time or new science is developed showing the chemical is more dangerous than originally thought. Because IRIS was in the business of developing RfDs, the chemical industry has done everything in its power t0undermine the program and has generally been quite successful. Nevertheless, EPA’s most ambitious programs, from reducing toxic air emissions to the cleanup of Superfund sites, rely on IRIS findings.
In 2016, IRIS concluded that exposure to EtO was far more dangerous than EPA thought. Based on that analysis, the 2024 Biden rule required facilities to cut their emissions by about 90% to 0.1 ppm, ten times stricter than the 1984 OSHA standard. This stark difference illustrates that unless the Occupational Safety and Health Act is amended – and OSHA receives the resources — to enable OSHA to update its PELS more efficiently, the worker protection agency will never adequately protect workers from most hazardous chemicals.
The 2024 Biden rule accepted the IRIS findings and was written on the assumption that EtO emissions from those 88 commercial EtO production facilities could result in 8,000 deaths in a population of one million people, a fatality rate generally considered far too high. The Biden rule required the installation of equipment and adoption of manufacturing practices that reduced the risk to 100 deaths in one million.
The problem of excess emissions at commercial sterilization plants was also perceived as an environmental justice issue, especially in Texas and Louisiana where many of such facilities are located in the midst of poor black communities. The Trump administration considers the concept of “environmental justice” as a prime example of “wokeness” and has scoured the government to eliminate such efforts.
Trump 2.0 Interventions on EtO and IRIS
The Trump 2.0 EPA has decided to kill the Biden rule and dismantle the IRIS program, decisions that were as predictable as they are controversial and terrifically unfortunate. To get its way, the Trump EPA has invoked fear-mongering based on inaccurate claims.
In the agency’s announcement of its decision to kill the Biden rule, EPA administrator Lee Zeldin claimed that the Biden rule would “threaten facilities’ ability to sterilize equipment and … put countless lives at risk.”
Zeldin that “the medical community, industry stakeholders and other federal agencies” were concerned that the Biden rule would threaten the “feasibility of complying with the more stringent EtO emission standards and the significant impacts the requirements would have on maintaining a strong domestic supply chain for sterilized medical equipment essential to saving American lives.”
The Trump administration’s allegation that the Biden rule will force the entire commercial industry for medical equipment sterilization to go out of business has no credible evidentiary support in either the Biden or the Trump rules.
Zeldin then attempted to reassure the public that the repeal would ensure that “lifesaving medical devices remain available for the critical care of America’s children, elderly and all patients without unnecessary exposure to communities.” The press release added that the new rule would save $630 million in costs to the medical equipment sterilization industry.
The Trump administration’s allegation that the Biden rule will force the entire commercial industry for medical equipment sterilization to go out of business has no credible evidentiary support in either the Biden or the Trump rules. It also claimed that the Biden rule, if implemented, would actually kill people: “countless lives would be saved from lethal of significantly debilitat[ing] infections” that would occur over twenty years “without properly sterilized medical equipment.”
These statements implying that the Biden rule would leave sensitive medical equipment dangerously unsterilized ignore that the Clean Air Act requires EPA to base its technology requirements on equipment that is already being used. In other words, when the Biden EPA wrote its 2024 rule curbing emissions of EtO at commercial facilities, it was required to find sterilization facilities that were already successfully delivering the lower levels of pollution the rule required.
Accusations that EPA (or OSHA) regulations will put entire industries out of business and kill people as a result is a frequent refrain of regulated industries. Yet these allegations are never supported by any rules ever issued in the agencies’ past. Evidence shows that industry’s cost predictions are almost always wildly exaggerated. And regulated industries, facing new rules that may potentially increase costs, either find less expensive and more efficient ways to reduce exposures, or move on to cheaper alternatives.
Meanwhile, the abolition of IRIS means that EPA will lose the function of calculating reference doses for chemicals its programs regulate. In fact, the IRIS analysis showing the increased danger caused by exposure to EtO is no longer available on the EPA website.
In a strange twist, unhappy with the IRIS assessment of the residual hazard of EtO exposure, the Trump 2.0 EPA tried to use an alternative assessment of the toxicity of EtO prepared by the Texas Commission of Environmental Quality (TCEQ). That analysis concluded that the chemical was significantly less toxic than the analysis done by IRIS. TCEQ has a reputation for leaning toward the industry side of regulatory issues. Someone on the EPA professional staff managed to get the TCEQ EtO document in front of an ad hoc committee assembled by the National Academies of Science, Engineering, and Medicine (NAS). Its conclusions in March 2025 were bristling: “The lack of application of systematic review methods, the exclusion of critical epidemiological data, the limitations in the modeling approach and use of unpublished validation data all contribute to a lack of confidence in TCEQ’s risk assessment of ethylene oxide.”
The Trump Supreme Court
Environmental groups and state attorney generals have sued the agency over the rollback of the Biden EtO rule and several other deregulatory decisions. The main issue in this fight is whether EPA can use its expertise to evaluate human health effects to conduct an additional residual risk review if new scientific evidence becomes available while doing its required eight-year technological review.
The Trump EPA says no, invoking a recent Supreme Court decision to justify its final action. Two months after the Biden rule came out, the Supreme Court decided Loper Bright Enterprises et al. v. Raimondo, a landmark decision that gives federal judges exclusive authority to interpret what any ambiguous parts of a statute mean instead of deferring to what the experts at the implementing agency say it means.[2] Using the Loper decision as its defense, EPA is arguing that the Biden rule is “inconsistent with the best reading of the statute,” because the Clean Air Act clearly “authorizes a single residual risk review… within eight years,” even if new science is found. In a misreading of Loper, EPA argues that the decision prohibits the agency from considering new science or conducting residual risk assessments except during the first eight-year review of installed controls. Because that authority is not specifically provided, they argue, the agency has no “discretion” to go ahead and evaluate residual risk, even if new evidence is found.
This argument that the agency is prohibited from doing more to develop a rule than is specifically mentioned by the Clean Air Act is extreme. If taken literally, it will mean that factfinding during a rulemaking becomes trapped in the narrowest reading of an authorizing statute and EPA will be free to ignore readily available science showing greater risk. The use of Loper as a crutch for opportunistic interpretations by agency staff is growing more frequent. In the end, the judges, not the agency, are supposed to be in charge.
The Upshot
The second Trump administration has launched a concerted attack on science produced inside and outside the government. It will take years to understand fully the implications of cancelling billions of dollars in research grants to the nation’s universities and undermining EPA’s expertise and destroying IRIS.
As the EtO rollback demonstrates, many of the Trump administration’s deregulatory activities will end up in the courts. District court and appellate judges could face a series of complex disputes over science, technology, and the law. If the lower courts reverse Trump 2 rollbacks, the conservative Supreme Court may intervene to reverse those decisions and reinstate deregulation with decisions that will have long-lasting implications for public health.
The good news in this scenario of woe is that California is refusing to accept these attacks on public health and has pledged to regulate on its own. As one of the largest economies in the world, this development is encouraging. Hopefully other states will follow.
[1] The case is Whitman v. American Trucking Associations, 121 S. Ct. 903 (2001). The majority opinion was written by none other than Justice Antonin Scalia.
[2] 603 U.S. 369 (2024).