Ethylene Oxide Emissions


Ethylene Oxide Emissions  (ETO-1) 
Guidance Document | December 2023

Supplemental Training:

EtO & What You Need to Know Training
February 2024 | Archived Training


About the Resources

ITRC's Ethylene Oxide (EtO) Team began their work in January 2022. The Team focused on exploring background EtO, to better differentiate between point and nonpoint source emissions, and the various methods used to analyze EtO to create comprehensive and consistent resources on where, when, and how to analyze and manage EtO. The EtO team is currently wrapping up the development of fact sheets and informational videos that will be published on ITRC’s website.


Ethylene oxide (EtO) is a flammable, colorless gas used to make other chemicals for a range of products, including antifreeze, textiles, plastics, detergents, and adhesives (EPA, 2020). It is also used to sterilize medical equipment and spices. EtO in the environment is a result of emissions from the production of industrial chemicals, agricultural processes, medical sterilization, and mobile sources such as tailpipes and tobacco smoke. Currently, there are questions about how background EtO should be defined because of mobile source emissions causing disparate levels of EtO in the environment. There are also various analytical methods available and employed to measure EtO, which yields inconsistency in measurement and management. In 2016, the U.S. EPA updated the risk value for EtO, ultimately changing EtO's descriptor from 'probably carcinogenic to humans' to 'carcinogenic to humans.' Nationally, there are 58 'hot spots' with levels of EtO 100x the threshold that triggers the Clean Air Act (CAA). To better manage and effectively communicate risk to communities living near EtO-generating facilities, it is key to differentiate between point or nonpoint source emissions and to establish a consensus on how to measure and analyze EtO in the environment.

Team Lifespan: 

January 2022 - December 2023

Team Leaders

Keisha Long

April Lazzaro

Program Advisor