Regulation of Ethylene Oxide (EtO) Under the Federal Insecticide, Fungicide, and Rodenticide Act

Certain products containing EtO are considered pesticides under federal law because they can be used to kill viruses and bacteria. Pesticide labels, which are part of a pesticide registration and are legally binding under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), carry directions and precautions that define who may use a pesticide, as well as where, how, how much, and how often it may be used. Failure to follow the label is a violation of federal law.

EtO can be used as a pesticide to sterilize certain equipment, including some medical devices (like implants and surgical equipment) which cannot be sterilized using alternative methods such as steam or radiation due to lack of compatibility with certain materials. EtO is also used to sterilize some spices, certain dried herbs, and dried vegetables at commercial sterilization facilities in order to control food-borne pathogens such as Salmonella and Escherichia coli. Other registered uses of EtO include the sterilization of some museum/library/archival materials, cosmetics, musical instruments, and beekeeping equipment (a use only in North Carolina). These uses are minimal, and in most cases, EtO is no longer used for these purposes.

Regular exposure to EtO over long periods of time can pose cancer risks. EPA is working to mitigate these risks by updating the registrations of EtO as a pesticide under FIFRA. This is part of registration review, a process EPA conducts for all currently registered pesticides every 15 years to ensure that products can carry out their intended function without creating unreasonable risks to human health and the environment. The actions below outline the steps EPA has taken to date.

Draft Human Health and Ecological Risk Assessment

In November 2020, EPA's Office of Pesticide Programs released the draft human health and ecological risk assessment for EtO. In April 2023, EPA released its response to public comments on the 2020 human health and ecological risk assessment.

• 2020 Draft Human Health and Ecological Risk Assessment
• EPA’s Response to Public Comments on the 2020 Human Health and Ecological Risk Assessment (pdf) (500.9 KB)

Draft Human Health Draft Risk Assessment Addendum

In April 2023, EPA released a draft risk assessment addendum that provides additional information on cancer risks from EtO. The addendum does not present any revisions to the human health dietary risk assessment or the ecological risk assessment.

• 2023 Draft Human Health Risk Assessment Addendum (pdf) (985.04 KB)
• More Information on Human Health Risks

Proposed Interim Decision

In April 2023, EPA also released the proposed interim decision (PID) for EtO. The PID proposes measures that would mitigate EtO's risk to human health as quickly as possible.

• 2023 Proposed Interim Decision (pdf) (1.25 MB)
• Fact Sheet: Proposed Actions under FIFRA to Reduce Ethylene Oxide Risk (pdf) (206.78 KB)
• Explanation of Risk Reduction Measures in Proposed Interim Decision

Comment Period for the Proposed Interim Decision

Upon publication in the Federal Register, EPA's proposed interim decision (PID) and draft risk assessment addendum was available for public comment for 75 days. Once closed, EPA reviewed comments and made necessary revisions to the proposed mitigation for the Interim Decision.

• To view all documents related to EtO’s registration review, visit docket EPA-HQ-OPP-2013-0244.

Interim Decision

In January 2025, EPA released the interim decision (ID) for EtO. As a result of the 75-day comment period for the PID and over 60 stakeholder meetings with industry, other federal agencies, and non-profit organizations, EPA is not including in the ID several mitigation measures proposed in the PID, such as automation and all-in-one sterilization systems, and instead the mitigation included in the ID focuses on a lowered occupational exposure limit compared to the current Occupational Safety and Health Administration (OSHA) standard. The ID additionally identifies mitigation measures related to the termination of certain minor uses, the phase-out of certain spice uses, a reduced concentration rate for new medical device sterilization cycles, respiratory protection for workers involved in high exposure tasks, monitoring, training, and recordkeeping, as well as venting and abatement devices for healthcare facilities.

2025 EtO Interim Decision (pdf) (1.5 MB)

Risk Reduction Measures in Interim Decision 

Termination of Certain Uses Where Alternatives Exist

EPA has finalized the ban of the following use sites of EtO as necessary for mitigating the risks from exposure to EtO:

• Museum materials
• Library materials
• Archival materials
• Cosmetics
• Musical instruments
• Beekeeping equipment (in North Carolina)

The agency anticipates no impacts from the termination of museum, library, and archival materials; musical instruments; and cosmetic uses. This is because EtO is no longer commonly used in these sites and there are alternatives that are widely available, such as freezing, anoxia (oxygen deprivation), and gamma irradiation.

Similarly, there is low to no impact expected from the termination of the beekeeping equipment sterilization use in North Carolina (the only state with this registered use). Chemical, cultural, and mechanical controls can be used as alternatives to EtO to manage American foulbrood, a contagious disease that affects honeybees.

Additionally, EPA has identified the need for a phased use cancellation for specific food commodities, such as dried herbs and spices, for which EtO use is considered critical for food safety but have potential alternatives for EtO.

 Use Rate Reduction for Medical Equipment Sterilization

EPA has identified that lowering the amount of EtO used per sterilization cycle for medical devices is a necessary mitigation measure for new medical device sterilization cycles to reduce levels of exposure to EtO for workers while continuing to meet FDA requirements for sterility assurance. It is the agency’s understanding that many sterilization facilities sterilize medical devices using much higher concentrations of EtO than what is required for sterility assurance, often times double the necessary concentration.

In order to reduce risks posed by EtO, EPA has determined it necessary to implement a maximum EtO concentration limit of 600 mg/L for new sterilization cycles by the year 2035, taking into account the sensitivity of the medical device supply chain for currently approved rates. EtO use rate above this amount for sterility assurance in new sterilization cycles would no longer be permitted based on the risks associated with such use. Where a higher EtO use rate is necessary to ensure sterility based on the design of a device, recordkeeping is required to justify this higher rate.

EPA is aware of some medical device manufacturers who have been able to reduce the amount of EtO needed to sterilize certain medical devices. This mitigation measure will, once implemented, make this reduced EtO concentration for new cycles a nationwide standard to ensure reduced exposure to workers at commercial sterilization and healthcare facilities and to nearby communities.

Worker Exposure Limits

EPA has identified a need for worker exposure limits for EtO that are lower, and thus more protective, than the current OSHA Permissible Exposure Limit (PEL) of 1 ppm.

The phased timeframe contained in the ID for implementation of these lowered worker exposure limit is as follows:

• Limit of 0.5 ppm after 3 years
• Limit of 0.25 after 5 years
• Limit of 0.1 ppm after 10 years

Exceedance of the new lower worker exposure limit would trigger the same requirements as have historically been triggered by exceedance of the OSHA PEL, including respirators and a written compliance program.

Engineering Controls for Worker Protection in Commercial Sterilization Facilities

EPA has identified a need for separated HVAC systems in commercial sterilization facilities for EtO processing areas (i.e., sterilization, aeration) and non-processing areas (i.e., office spaces, storage areas) in order to reduce worker exposure throughout facilities. Commercial sterilization facilities may additionally implement any variety of engineering and process controls in order to meet lowered occupational exposure limits.

Engineering Controls for Healthcare Facilities

EPA has identified as necessary engineering controls to reduce exposure to EtO in healthcare facilities, including: 

• Separating EtO sterilization spaces from other work areas to reduce the broader circulation of EtO;
• Implementing negative air pressure in rooms containing EtO sterilization devices to ensure that air will not flow from the room with a higher EtO concentration through the rest of the healthcare facility;
• Discharging exhaust from all-in-one EtO healthcare facility sterilization devices through exterior ventilation stacks to ensure that there is minimal EtO exposure for workers within healthcare facilities;
• Using abatement devices (i.e., equipment used to capture polluting substances) that will remove EtO from the exhaust air and reduce discharge to the environment;
• Requiring abatement devices for healthcare facilities that use more than 10 lbs. of EtO/year by comparison, commercial sterilizers typically release tons of EtO annually; and
• Ventilation of EtO through exterior ventilation stacks to reduce exposure to healthcare facility workers. Exposure to communities from EtO used in healthcare facilities is expected to be minimal because the amount of EtO used at healthcare facilities is orders of magnitude lower than at commercial sterilization facilities.

Additional Personal Protective Equipment in Commercial Sterilization Facilities

EPA has identified as necessary that a self-contained breathing apparatus or a supplied airline respirator be worn by workers for any tasks where there may be high levels of EtO exposure. This will mitigate potential inhalation exposure risks to workers involved in the EtO sterilization process.

New Data Requirements for Commercial Sterilization Facilities

In order to quantify worker exposure in commercial sterilizers and warehouses, EPA expects to issue a data call-in (DCI) to understand the impacts of complying with EPA’s Clean Air Act (CAA) NESHAP for EtO and implementing mitigation measures identified in the ID issued under FIFRA, and to better understand how to further lower the occupational exposure limit. The data will include personal breathing zone (PBZ) monitoring of workers specifically involved in activities related to sterilization, documentation of the activities each worker performed while monitored, and whether they were wearing a respirator. For others in the facility, such as office workers or warehouse workers, EPA also intends to require the data to include personal breathing zone monitoring data to monitor their exposures.

Additionally, EPA will issue a DCI for a special study for monitoring data on fumigated commodities for medical devices to better understand exposure to EtO in warehouses. Through these data, EPA is seeking information on the exposure scenario from emissions from treated medical device commodities and materials and the potential for occupational exposure due to those emissions in the channels of trade after sterilization activities are complete. EPA will consider the worker exposure data submitted as part of the DCI to further inform the lowest worker exposure limit of 0.1 ppm and will re-evaluate within 8 years issuance of the ID (as compared to the normal 15 year registration review cycle).

Stationary Continuous Monitoring in Commercial Sterilization Facilities

EPA has identified as necessary stationary continuous indoor air monitoring using systems that can reliably measure to 0.1 ppm or lower, and recordkeeping of the room air levels of EtO.

For More Information

Learn more about EtO by visiting www.epa.gov/hazardous-air-pollutants-ethylene-oxide.