Ethylene Oxide (EtO) Risks and Your Health
EPA, the Occupational Safety and Health Administration (OSHA), state and local agencies, and the companies that use ethylene oxide (EtO) share responsibility for reducing the amount of EtO people are exposed to at work and in their communities. EPA completes this work in two primary ways: by providing clear directions on pesticide labels, including measures that protect workers' health; and, in partnership with state and local air agencies, by limiting the amount of EtO that comes out of facilities.
On this page:
- What EPA Knows About Risk from EtO
- Recent Risk Analyses
- Learn More About EtO and Your Health
- Additional Resources About EtO and Health
What EPA Knows About Risk from EtO
As a part of EPA’s work to set new requirements to reduce risk and protect public health, EPA completes scientific analyses to understand details about this risk, including:
- How dangerous air toxics like EtO are when people breathe them in;
- Where EtO emissions come from; and
- Who is more at risk from EtO exposure.
Who is More at Risk from EtO Exposure and Where
There are potential health risks associated with the use of EtO. Specifically, if a person breathes in EtO in concentrations that might be found inside or nearby facilities where EtO is used over the course of many years (either a career or a lifetime), it can increase the risk of certain types of cancer, including breast cancer and cancer of the white blood cells, including non-Hodgkin lymphoma, myeloma, and lymphocytic leukemia. Three main factors affect the risk level that EPA calculates:
- the amount of EtO in the air in or near the facility,
- how far away a person is from the facility; and
- how much time a person is in or near the facility.
Recent Risk Analyses
EPA scientists recently completed two separate risk assessments:
- To understand the impact of EtO emissions from commercial sterilization facilities on residential risk in communities near those facilities; and
- To understand risk to workers who use EtO to sterilize things and others who work, live, and go to school or daycare near places where EtO is used to sterilize things.
As part of the first risk assessment, we collected and used the best and most recently available science about how much EtO each commercial sterilization facility uses, the control systems they have in place, details about the design of the building, and information about the community, including weather and wind patterns and information about where people live. We used this information to predict, or model, how much EtO comes out of the facility and where it goes. We used this to predict cancer risk for people who live near these facilities. EPA risk estimates for people who live near facilities assume that people breathe in the EtO 24 hours a day, 7 days a week, for the entirety of 70 years.
In the second risk assessment, EPA scientists considered risks to those who apply EtO and to those who live, work, or attend school or daycare near facilities where EtO is used to sterilize things.
Neither of these analyses found any indication of acute or short-term health risks associated with the routine use of EtO as facilities where it is used to sterilize things.
EPA predicts the highest cancer risk is for workers who directly handle EtO over the course of an entire 35-year career in either commercial sterilization facilities or healthcare settings. EPA has also found that there are potentially elevated cancer risks for people who work over the course of an entire 35-year career inside commercial sterilization facilities but who do not directly handle EtO. These workers might include administrative or management workers in other parts of these facilities. In addition, EPA has found potentially elevated cancer risk from long-term exposure for people who work, go to school or daycare, or live nearby commercial sterilization facilities. Risk decreases with distance from a facility.
For these risk assessments, we looked at excess cancer risk attributable to a single chemical, EtO. This estimated risk is in addition to the risk of developing cancer from other causes.
Risk for Workers Who Handle EtO
- Without the new, proposed practices or engineering controls in place to protect them, we would expect that if 17 workers who apply EtO to medical devices in commercial sterilization facilities are exposed to EtO over the course of their entire career (8 hours per day, for 240 days a year, for 35 years) then one of those 17 workers would develop cancer from this work.
- Without the proposed practices or engineering controls in place to protect them, we would expect that if 25 workers who apply EtO in healthcare facilities are exposed to EtO over the course of their entire career (8 hours per day, for 240 days a year, for 35 years) then one of those 25 workers would develop cancer from this work.
- Without the new, proposed practices or engineering controls in place to protect them, we would expect that if 36 workers who apply EtO to spices in commercial sterilization facilities are exposed to EtO over the course of their entire career (8 hours per day, for 240 days a year, for 35 years) then one of those 36 workers would develop cancer from this work.
The above represent the most likely estimates for elevated cancer risk, assuming that no voluntary risk reduction measures are in place to protect workers and that exposure is constant over an extended period of time.
Actual risks could vary significantly from these estimates based on the levels of EtO in the air inside or near the facility, the length of time someone actually spends breathing in air with these levels of EtO, and any voluntary control or protective measures in place at the facility. For example, risks can be reduced through measures that have already been taken or can be implemented by increasing access to personal protective equipment, adequate ventilation, and safety protocols to avoid direct contact with EtO. Many facilities have already successfully implemented these measures, reducing risks.
Risk to Residents and Others Who Spend Time Near Commercial Sterilizers
While workers who directly handle EtO are likely to have the highest risks, EPA found that there may also be risks for people who live or work near these facilities.
For the following groups of people, if one million of them were exposed to EtO in that air at expected levels, 100 or more of them would be expected to get cancer from that exposure:
- Workers who spend their entire career (8 hours per day, for 240 days a year, for 35 years) working in commercial sterilization facilities, but not directly handling EtO.
- Workers who work close to the commercial sterilization facility for their entire career (8 hours per day, for 240 days a year, for 35 years).
- Certain residents who live near commercial sterilizations facilities and spend their entire lives (24 hours a day, 7 days a week, for 70 years) near these facilities. Learn more about potential residential risk.
These risks can be reduced through measures that have already been taken or can be implemented by increasing access to personal protective equipment, adequate ventilation, and safety protocols to avoid direct contact with EtO. EPA is proposing these protective measures and control requirements to reduce risk for all people who are exposed to EtO when it is used to sterilize things. Learn more.
Risk to Children Who Go to School or Daycare Near Commercial Sterilizers
This assessment found that there may be risk for children who go to school or daycare near commercial sterilizers. Risk levels for certain children may be over one in one million. If one million of these children were exposed for the entirety of the time they spend in a school or daycare, at least one of them would be expected to get cancer from that exposure.
If someone is in multiple categories (for example a worker who also lives very close to a facility), that person may have a higher risk than what would be expected from one category alone.
Little to No Anticipated Risk for Patients and Medical Staff
EPA expects risks to be much lower to those near hospital sterilization settings than those near commercial sterilization facilities. The amount of EtO applied in healthcare facilities is significantly less than the amount of EtO applied in commercial sterilizing facilities.
No Indication of Risk for Typical Users of Products That Have Been Sterilized with EtO
There is no indication of risk for people who purchase or consume spices that have been sterilized with EtO or for patients or healthcare staff that use products or devices that have been sterilized with EtO.
Learn More About EtO and Your Health
Keeping up with routine health screenings and doctor’s visits is one of the best things you can do for your health. Taking care of your health is always important. If you think you are being exposed to ethylene oxide in the outdoor air or through your work and you are concerned about how this might impact your health, start by contacting a healthcare provider. In addition, the Agency for Toxic Substances and Disease Registry (ATSDR) can help answer general questions about associations between EtO exposure and health conditions based on health study findings. You can reach ATSDR at: EtO@cdc.gov. ATSDR also developed a resource that you can share with your doctor so that they can learn more about this issue as well: Clinician Brief: Ethylene Oxide.
If you are concerned about EtO and your child’s health, contacting your health care provider is a good place to start. If your provider is not familiar with EtO, they can work with you to contact the Pediatric Environmental Health Specialty Unit (PEHSU) that serves your area. EPA and the ATSDR support the PEHSUs, which are a national network of medical and public health experts on environmental health issues that can impact reproductive or children’s health. If you don’t have a doctor, you can contact the PEHSU for your area directly.
Additional Resources About EtO and Health
These federal resources may also be helpful:
- EPA’s Health Effects Notebook for Hazardous Air Pollutants includes a summary fact sheet on EtO: Ethylene Oxide - CAS 75-21-8 (pdf) (320.07 KB, 12/20/2018)
- Questions and answers related to health and ethylene oxide in the air.
- Information about EPA’s ongoing reevaluation of how EtO is used as a pesticide.
- EPA’s 2016 updated final Integrated Risk Information System (IRIS) assessment concluded that EtO is carcinogenic to humans by the inhalation route of exposure. Read the technical documents for this assessment.
- The National Cancer Institute's summary of the health effects linked to ethylene oxide exposure.
- The Agency for Toxic Substances and Disease Registry's (ATSDR) Clinician Brief: Ethylene Oxide. This tool is part of a series that aims to educate healthcare providers on hazardous environmental exposures.
- The Agency for Toxic Substances and Disease Registry's (ATSDR) Chemicals Cancer and You. This booklet explains cancer risk factors, how cancer develops, and how toxic substances like EtO can affect your body.
If you have concerns about EtO exposure, you should contact your local Department of Health, your state environmental authority, or EPA. You also can learn more about this pollutant in your community.