EPA Finalizes Rule to Reduce Ethylene Oxide Emissions

Last week, EPA issued a final rule that adopts stricter standards for air toxics emissions from commercial facilities that use ethylene oxide (EtO) as a sterilization agent. According to the agency, the rule will cut EtO emissions from commercial sterilizer facilities by more than 90 percent and reduce the number of people with a potential lifetime cancer risk of at least 1 in 1 million by 92 percent.

EtO is a flammable gas that is used primarily to produce other chemicals. Some EtO is used to sterilize medical instruments. There are currently 88 commercial sterilization facilities in the United States, according to EPA, with two additional facilities under construction. These facilities will be required to implement controls to bring their emissions of EtO into compliance with the rule. Compliance dates vary depending on the amount of EtO in use. Facilities that use more than 60 tons per year will need to comply within two years of the rule’s publication in the Federal Register. Facilities with an annual EtO usage of less than 1 ton have three years to comply.

EPA regulates emissions that are known or suspected to cause cancer through the national emission standards for hazardous pollutants, or NESHAP. The rule will amend NESHAP to address emissions from building leaks and sterilization chamber vents, require facilities to use continuous emissions monitoring systems, and ensure that emissions standards apply to sterilization processes when they start up, when they shut down, and when they malfunction.

EPA’s scrutiny of sterilization facilities stems from 2018 when the agency revised its risk basis for EtO in the agency’s Integrated Risk Information System, a change that indicated a thirtyfold increase in EtO’s cancer potency. This information galvanized residents of Willowbrook, Illinois, to call for an investigation of community exposures from a medical sterilization facility owned by Sterigenics, which eventually led to the facility’s closure. Industrial hygiene sampling found background levels of EtO greater than the EPA risk criteria up to three miles from the facility.

The rule has not yet been published in the Federal Register. A copy of the rule and other information about EtO is available from the EPA website.