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EPA in Illinois

Sterigenics Willowbrook Facility - Agency Response

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Willowbrook – Air Monitoring Plan for ethylene oxide

U.S. EPA and Illinois EPA are working with Sterigenics to obtain updated information, including the new stack test results and refined modeling parameters.

U.S. EPA has received a number of requests to conduct additional outdoor air quality air monitoring ethylene oxide in Willowbrook. While there are limitations to the ability of currently available monitoring instruments and techniques to measure ethylene oxide at all levels that may present a long-term public health risk, U.S. EPA intends to conduct additional outdoor air quality monitoring.  Read the Quality Assurance Project Plan for Field Sampling Plan for Ambient Air Ethylene Oxide Monitoring near Sterigenics Facility, Willowbrook, IL

EPA will be monitoring outdoor air near the Sterigenics facility to better understand the levels of ethylene oxide (EtO) in the air. The first monitors began collecting air samples on Nov. 13, 2018.  Learn more about U.S. EPA's plans for outdoor air monitoring in the Willowbrook Community.

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EPA and Illinois EPA Actions in Willowbrook

U.S. EPA and Illinois EPA have worked with Sterigenics to reduce emissions from the facility. In June, Sterigenics submitted a construction permit application to Illinois EPA to incorporate additional emission controls. After review from the U.S. EPA and Illinois EPA, Illinois EPA issued the permit on June 26, 2018. Sterigenics finished installing additional pollution controls to capture ethylene oxide emissions on July 27, 2018.

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What are the next steps?

Stack tests to measure current emissions have been conducted. Early indications from the stack testing suggest that emissions have been significantly reduced since Sterigenics began operating with the additional pollution controls. U.S. EPA and Illinois EPA will work with the company to evaluate the possible need for additional action.

To provide updated, comprehensive information to the public, U.S.EPA will analyze stack testing results, conduct additional risk and exposure modeling, and conduct outdoor air quality monitoring for ethylene oxide. See the test results from September 20, 2018 and September 21, 2018.

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