EPA proposes limits on carcinogenic gas used to sterilize medical devices

On Tuesday, the Environmental Protection Agency proposed new limits on the use of a carcinogenic gas called ethylene oxide. The hope is to reduce ethylene oxide emissions by 80%, which the agency said is part of the Biden administration’s Cancer Moonshot and its “commitment to securing environmental justice and protecting public health.”

The actions consist of two rules: one aimed at forcing sterilizing facilities that use ethylene oxide to cut down on their emissions, and another aimed at protecting workers and communities who are most vulnerable to exposure.

Ethylene oxide is currently the only way to sterilize medical devices that can’t be exposed to steam. It’s used to sanitize 20 billion devices in the U.S. per year, such as pacemakers, catheters, and ventilators, and is also used to sterilize spices. But the gas is also known to induce gene mutations and break chromosomes. Long-term exposure to this gas causes breast cancer, non-Hodgkin’s lymphoma, myeloma, and lymphocytic leukemia. The new rules would affect 86 sterilizing facilities nationwide.


The new EPA proposal would also require real-time monitoring of ethylene oxide inside the sterilizing factories that use it. Commercial sterilizers will have to extensively monitor their pollution controls and submit results to the EPA twice a year. If concentrations exceed the 10 parts per billion limit, workers would be required to wear personal protective equipment. The rules prohibit the use of ethylene oxide in settings where alternatives exist, like sterilizing musical instruments or objects in museums.

In the medical device setting, companies would need to set up technology to capture emissions and bring their ethylene oxide concentration down to 500 milligrams per liter of sterilizing solution.


“Based on our conversations with industry, we know that some of these measures are already in place at some of the larger sterilization facilities,” said Michal Freedhoff, assistant administrator for the Office of Chemical Safety and Pollution Prevention, referencing talks with sterilizing companies. “We know that some can be quickly implemented and also that some will take longer to put into place.”

While workers at medical device sterilization plants are at a higher occupational risk to exposure to the gas, including short-term effects, communities near sterilization plants — sometimes disproportionately made up of low-income individuals and people of color — are also at elevated risk for cancer because of ethylene oxide air pollution. A 2021 ProPublica investigation found that ethylene oxide was the largest contributor to excess industrial cancer risk from air pollutants in the U.S.

Last year, the EPA released a list of 23 communities at elevated risk. Puerto Rico, with four sites on the list and seven total sterilizers, had the most at-risk communities of any state or territory.

The Food and Drug Administration has tried to encourage the development of alternative, safer sterilization methods for medical devices. In 2019, the agency selected four companies to identify and develop alternatives, and has also backed efforts to reduce ethylene oxide emissions more broadly. In an August 2022 update, the FDA suggested that some sterilizing facilities have been able to cut emissions by 20% to 35% — but no clear alternative sterilization methods have emerged.

EPA Deputy Administrator Janet McCabe said Tuesday that researchers are working toward alternatives, but that the science isn’t quite there yet.

Device makers, meanwhile, seem less focused on trying to find ethylene oxide alternatives and have instead urged the EPA to continue allowing them to use the chemical while giving concrete targets on reducing emissions. Device lobbyist AdvaMed made protecting the industry’s use of ethylene oxide one of its major policy priorities this year. “We’ve said for four-plus years now we support a federal rule in this space,” Greg Crist, chief advocacy officer at AdvaMed, told STAT in March. “We know we can hit it as an industry.”

In a statement issued after the EPA’s announcement Tuesday, AdvaMed CEO Scott Whitaker said many medical devices “simply cannot” be sterilized by another method. He also said 18 months, the time period devicemakers would have to comply with the finalized rules, is “much too short.”

“Medtech companies want to continue serving patients without interruption,” Whitaker wrote. “We hope the EPA will take our comments into account and work with us on final regulations that ensure continued infection control while achieving the EPA’s goals, which we share, of protecting community members and employees.”

Despite the EPA’s list of communities disproportionately affected by ethylene oxide pollution and a 2016 risk assessment that classified the gas as carcinogenic, the EPA did not update its ethylene oxide emission rules in 2022, as required by the Clean Air Act. In fact, the nonprofit Earthjustice sued the EPA in December 2022 for missing its deadline to update ethylene oxide emission rules for the second time. The agency is required by law to revisit the rules every eight years, but hadn’t updated them since 2006.

Last week, the agency also proposed updates to six Clean Air Act rules called the Hazardous Organic National Emissions Standards for Hazardous Air Pollutants, which includes ethylene oxide. The proposed rule tightened standards and would require chemical plants that emit the chemicals to perform “fenceline monitoring” for the pollutants. Plants would have to find the source of the emission and make repairs if the amount of a chemical in the air at the facility’s fence exceeds a certain level.

As part of the proposal, the EPA conducted for the first time a community risk assessment, which showed that the new rules would decrease the number of people living within 6 miles of a plant who have an elevated air toxics-related cancer risk by 96%. This is especially important for people in Louisiana and Texas who live near multiple pollutant-emitting plants.

The agency will receive public comments on the rules over the next 60 days, and plans to finalize them in 2024. It will hold a public webinar on the topic on May 1.

This piece has been updated to include a reaction from device lobbyist AdvaMed. 

Source: STAT