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EPA in Illinois

Sterigenics Willowbrook Facility: What We Know

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About the initial air monitoring

U.S. EPA conducted initial short-term canister air sampling for three days in mid-May 2018 near the Willowbrook facility to determine whether ethylene oxide could be detected using U.S. EPA’s Method TO-15 and what levels of ethylene oxide, if any, were present in the outdoor air.  While this method was capable of measuring ethylene oxide at the concentrations observed during the short-term sampling period, this technique is not sensitive enough to measure levels of ethylene oxide at all levels that may present a long-term public health risk.  U.S. EPA began additional outdoor air quality monitoring on November 13, 2018. Learn more.

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Initial air monitoring data and map

The link below provides a summary of ethylene oxide air samples collected during the initial short-term sampling in Willowbrook in May 2018. It also includes a map of each monitoring location.

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Health information

Ethylene oxide is a flammable, colorless gas used to make other chemicals that are used in making a range of products, including antifreeze, textiles, plastics, detergents and adhesives. Ethylene oxide also is used to sterilize equipment and plastic devices that cannot be sterilized by steam, such as medical equipment. EPA recently updated its risk value for ethylene oxide and is working with industry, and state, local and tribal air agencies to address this chemical.

Long-term exposure to ethylene oxide can irritate the eyes, skin, nose, throat, and lungs, and harm the brain and nervous system (causing effects such as headaches, memory loss, numbness). Studies show that breathing air containing elevated ethylene oxide levels over many years increases the risk of some types of cancers, including cancers of the white blood cells (such as non-Hodgkin’s lymphoma, myeloma and lymphocytic leukemia); and breast cancer in females.

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ATSDR analysis

U.S. EPA asked the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate whether ethylene oxide air concentrations near Sterigenics pose a public health problem for people living and working in Willowbrook. ATDSR provided a response in a letter dated July 26, 2018; this evaluation was based not on current conditions, but rather on modeled and monitored ethylene oxide levels prior to the installation of additional controls. ATSDR concluded: “if measured and modeled data represent typical ethylene oxide ambient concentrations in ambient air, an elevated cancer risk exists for residents and offsite workers in the Willowbrook community surrounding the Sterigenics facility. These elevated risks present a public health hazard to these populations.”

ATSDR also concluded that “measured and modeled ethylene oxide concentrations in ambient air indicate that noncancer health effects are unlikely for residents and off-site workers in the Willowbrook community surrounding the Sterigenics facility.”

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