On January 14, 2025, the EPA announced it released the Interim Decision for Ethylene Oxide (EtO), which is a pesticide used on 50 percent of all sterilized medical devices in the United States and on approximately 30 percent of dried herbs and spices.

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“EtO is known to cause cancer, including lymphocytic leukemia, breast cancer, non-Hodgkin lymphoma and myeloma in people,” according to an Agency news release. “Workers who use EtO and people who work, live, or go to school or daycare near facilities that use EtO may breathe in emissions at levels that can increase cancer risk. The greatest risk is for people who work for their entire careers at facilities directly handling EtO with insufficient worker protections in place.”

“EPA continues to make important strides to protect people from dangerous chemicals like ethylene oxide,” Michal Freedhoff, assistant administrator for the Office of Chemical Safety and Pollution Prevention, says in the release. “These protections will reduce EtO exposures to workers and communities, while also ensuring that the chemical remains available to provide sterile life-saving medical supplies.”

The EPA regulates EtO’s use as a pesticide under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). In some cases, EtO is the only option available for sterilizing surgical kits, according to the EPA.

To review EtO’s registration, the EPA assessed the cancer risk from working in sterilization and healthcare facilities that use EtO, living in communities near EtO facilities, and consuming dried herbs and spices treated with EtO.

Highlights of the Interim Decision include:

Commercial sterilizers

• Lowered worker exposure limit of 0.5 parts per million (ppm) by 2028, 0.25 ppm by 2030, and 0.1 ppm by 2035 compared with the 1984 Occupational Safety and Health Administration (OSHA) limit of 1 ppm. Any workers who could be exposed to concentrations of EtO above these limits would need to wear additional respiratory protection.
• Finalizing the ban of use for museum, library, and archival materials; cosmetics; musical instruments; and beekeeping equipment.
• Immediate cancellation of uses of EtO for specific dried herbs and spices that aren’t considered critical uses for food safety, as well as phased cancellation of uses for specific dried herbs and spices that are considered critical uses for food safety but have potential alternatives to EtO use.
• Establishing a concentration limit of 600 milligrams per liter (mg/L) for new medical device sterilization cycles within 10 years. If a device requires a concentration of EtO greater than 600 mg/L due to the device design, the facility must maintain records to justify the increased application rate.
• Separation of heating, ventilation, and air conditioning (HVAC) systems for areas where EtO is used and areas where EtO isn’t used to reduce EtO exposure in areas like offices.
• Requiring respirators to protect workers involved in certain high-EtO-exposure tasks, such as connecting and disconnecting EtO containers from sterilization process equipment.
• Continuous EtO concentration monitoring throughout sterilization facilities, including on-site storage facilities.
• Data requirements to monitor breathing zone worker exposure to EtO within commercial sterilization facilities and warehouses that store sterilized materials both on- and off-site.

Healthcare facilities

• Require abatement devices for healthcare facilities that use more than 10 pounds of EtO per year by comparison. Commercial sterilizers typically release tons of EtO annually.
• Ventilation of EtO through exterior ventilation stacks to reduce healthcare facility workers’ exposure. Communities’ exposure to EtO used in healthcare facilities is expected to be minimal because the amount of EtO used at healthcare facilities is magnitudes lower than at commercial sterilization facilities.

“The Interim Decision includes mitigation measures that, in addition to the measures included in the 2024 EtO National Emissions Standards for Hazardous Air Pollutants (NESHAP), will reduce exposure to workers and nearby communities,” according to the EPA. “Together, these two EPA actions provide a comprehensive approach to addressing EtO pollution concerns, including cancer risk, that will increase safety in communities and for workers while supporting ongoing supply chain needs for sterilized medical equipment.”

Next steps

Registrants are expected to submit label amendments that include the changes outlined in the Interim Decision within 60 days after publication. The EPA plans to quickly review the label amendments so products sold and distributed by registrants will include the changes outlined in the Interim Decision.

“The timing for implementation for individual mitigation measures ranges from two years to 10 years, taking into consideration the costs, technology availability, potential impacts to the medical device supply chain and other logistical elements,” the EPA states. “Additionally, EPA will issue a Data Call-In (DCI) to gather information on worker exposure. Specifically, the DCI will require submission of worker exposure data for commercial sterilizers and warehouses in order to understand the worker exposure impacts of complying with EPA’s Clean Air Act EtO commercial sterilization NESHAP and implementing the mitigation measures identified in this Interim Decision.

“EPA will reevaluate this Interim Decision within eight years, earlier than the typical 15-year cycle, based on the submitted worker exposure data, in order to identify further opportunities to reduce EtO exposures.”

For more information, see Docket # EPA-HQ-OPP-2013-0244 and the EPA EtO webpage.