Ethylene Oxide in Utah

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Ethylene Oxide Monitor on a pole in a neighborhood.

Ethylene Oxide Study & Risk Assessment Community Meeting–August 17, 2022

Ethylene Oxide Study

EPA’s latest National Air Toxics Assessment identified ethylene oxide as an air toxic pollutant of emerging concern, with potential to lead to elevated cancer risk. To determine any potential health risk from exposure to ethylene oxide in Utah communities, the Division of Air Quality and the University of Utah will measure ambient ethylene oxide in two communities located close to medical sterilization facilities, which are common sources of ethylene oxide. Measurements will be collected during winter and summer 2022, and will be complemented by a health risk assessment analysis. Funding for this study was awarded by EPA.

What is ethylene oxide and what are its uses?

Ethylene oxide is a gas used to sterilize equipment that cannot be sterilized by steam, such as medical and dental devices. It is also used to make chemicals for the manufacturing of everyday products, including antifreeze, textiles, plastics, detergents and adhesives.

Ethylene oxide in outdoor air can have various sources, including industrial facilities such as chemical manufacturers and sterilizers. It is also listed by the EPA as one of 187 “Hazardous Air Pollutants,” which are pollutants known or suspected to cause cancer or other serious health effects.

What is a safe level of ethylene oxide?

The Clean Air Act requires the EPA to regulate “Hazardous Air Pollutants” (HAPs), also known as air toxics. Rather than setting ambient air standards, which are limits on the amount of a pollutant that is allowed in outdoor air, HAPs emissions are capped for industrial sources directly. Conducting measurements along with a health risk assessment are the best approaches to assess if additional controls on ethylene oxide emissions are needed.

Where are the monitors located?

A total of 16 air monitors will be distributed throughout Salt Lake County with emphasis around medical sterilization facilities. This will allow us to determine the levels of ethylene oxide near these facilities and how they compare to levels at more distant locations.

How do the monitors work?

A sample of ambient air is pulled into an evacuated stainless steel canister, where the difference in pressure between the inside of the canister and outdoor air causes the sample air to flow into the canister. Air is drawn at a fixed rate over 24 hours, after which the canister is sent to a laboratory for measurement of ethylene oxide using an EPA-approved chemical analysis method.

When will results be available to the public?

The final study report will be released by September 2023, but intermittent results will be shared as they become available and are reviewed.


Contact Rachel Edie (, (385) 306-6502 or Nancy Daher (, (385) 377-6017 with questions.