Additional Questions about Ethylene Oxide (EtO)
Is EtO produced by the human body?
Yes, our bodies produce EtO when metabolizing ethylene. Ethylene is produced naturally in the body. The amount of ethylene converted to EtO in the body is unknown. However, ethylene is easily removed from the body through exhalation, which limits the amount of EtO produced.
Did EtO from the commercial sterilizer in our town cause my cancer?
We don’t know. Our risk assessment cannot tell us if a person’s cancer is attributable to a facility’s EtO emissions. The development of cancer is a complex process and there are many factors that can impact an individual’s cancer risk, including their genetics and overall health.
How far away from the facility do I have to be so that I am not at risk?
There is not a simple answer to how far away is far enough, because many factors impact how far EtO can travel and how long it stays concentrated in outdoor air. As EtO moves through the air, it becomes less concentrated. How much and how quickly depends on weather conditions, such as wind speed. How much a facility emits, exactly where the emissions leave the facility, and the amount of dispersion all impact how far EtO travels and whether it will remain at high enough concentrations to pose long-term risks.
Why is EtO use on medical equipment necessary? Are there alternatives?
As of now, EtO is the only method available to sterilize some medical devices that cannot be sterilized using heat or radiation — its use is critical for ensuring that sterile medical devices are available to prevent the transmission of infectious diseases to patients, especially during surgery.
EPA is committed to reducing the risks of EtO and supporting the development and use of alternatives. EPA continues to collaborate with FDA on innovation challenges to find alternatives to EtO.
Why is EtO use on spices necessary? Are there alternatives?
EtO is used to sterilize certain commodities to prevent serious food-borne illnesses such as those caused by Salmonella and Escherichia coli (E. coli). Eating foods treated with EtO does not present risks of concern. Some spices can be treated with alternatives to EtO including heat, steam, and irradiation. For other spices, there may not currently be any viable alternatives to EtO.
The Interim Decision on EtO calls for immediate cancellation of the use of EtO for specific dried herbs and spices for which its use is not considered critical for food safety, and phased cancellation for specific dried herbs and spices for which EtO use is considered critical for food safety but have potential alternatives to EtO.
Why did you use computer modeling to assess residential risk around these facilities? Wouldn't air monitoring be better?
Air monitoring data tells us about EtO only in the area where the monitor is located. But computer models let us look at EtO across an entire community—not just at the monitor location. In addition, current monitoring methods cannot detect EtO down to all risk levels. For calculating residential risk across every part of a community, our experts believe that computer modeling gives us the best estimate possible of EtO concentrations in the air and the risks from breathing that air over many decades. Modeling also allows us to quickly examine how risks are expected to change when emission controls are installed, for example.
Is EPA going to monitor for EtO in my community?
EPA believes that air modeling is a better tool for assessing risk, because it lets us look at EtO across an entire community—not just at a monitor location. In addition, EPA’s current method for measuring EtO cannot detect when levels in the air are very low, meaning we cannot measure it at all levels of risk. Modeling does allow us to estimate risk at all levels.
While we are not planning to conduct monitoring in communities, we will continue to provide technical assistance for state and local agencies that want to conduct monitoring. Air monitoring in the U.S. is typically done by state and local air agencies, with support from EPA. In addition, EPA is conducting research to improve air monitoring techniques and technologies to better detect EtO at lower levels.
Has EPA measured EtO in mobile source exhaust (such as from vehicles)?
No, EPA has not confirmed that EtO is present in mobile source exhaust. We are working diligently to develop test methods that will allow us to carefully evaluate mobile sources to determine the extent to which EtO may be emitted.
Studies from the 1980s reported EtO in emissions from mobile sources. Why isn't EPA relying on these studies?
While some preliminary studies from 50 to 60 years ago suggested that EtO may be formed when fuels are burned in an engine or in other combustion conditions, this work used methods that are outdated, and have significant uncertainties. It is not clear that the investigators identified EtO as an emission. Because of the lack of quality measurement techniques, robust data, and current research into the potential for formation of EtO in mobile sources, EPA is working to develop methods that will allow us to carefully evaluate combustion sources, including mobile sources, to determine if EtO is being emitted.