Illinois EPA information on Ethylene Oxide


​The Illinois EPA has issued a construction permit to Sterigenics U.S., LLC.  The issuance follows a comprehensive review of application materials and applicable requirements, including requirements of the new Matt Haller Act.  The construction permit authorizes the installation of a suite of enhancements at the Willowbrook I sterilization facility.  Additionally, the permit establishes a cap on emissions at the facility. The issued construction permit and responsiveness summary may be found in the documents section below.

Illinois EPA Issues Construction Permit to Comply with General Assembly’s Toughest-in-Nation Restrictions

​Ethylene oxide (C2H4O)

Ethylene oxide is a flammable, colorless gas.  It is produced and used to make a range of products, including antifreeze, textiles, plastics, detergents and adhesives. Ethylene oxide also is used to sterilize some medical equipment that cannot otherwise be sterilized by steam, ultraviolet light or other means, such as certain plastic and electronic devices.  Ethylene oxide is also emitted in extremely small amounts from combustion of fuels.

The Clean Air Act lists ethylene oxide as a hazardous air pollutant (HAP). The Clean Air Act requires the USEPA to regulate hazardous air pollutants from categories of industrial facilities. In December 2016, U.S. EPA updated its Integrated Risk Information System (IRIS) value for ethylene oxide.


Sterilization of medical devices is an essential aspect of modern medicine. There are several technologies to sterilize medical products and devices; however, many medical devices are sterilized using ethylene oxide because they have plastic parts or instrumentation that can be damaged by the steam, high heat or radiation of alternatives.  The Food and Drug Administration (FDA) regulates the sterilization of medical devices such that medical providers have a supply of sterilized medical devices.  While the FDA has stated that it will be studying alternatives to ethylene oxide sterilization, it has not identified potential alternatives for near term approval. 

Statutory and Regulatory Background

Since passage of the federal Clean Air Act (CAA) in 1970, there have been enormous reductions in emissions and corresponding improvements to ambient air quality.  The original CAA focused on common air pollutants, some of which, such as ozone and particulate matter, were potentially causing acute health problems in certain parts of the country. 

With passage of the 1990 Amendments to the CAA, USEPA began to set emission standards for hazardous air pollutants (HAP).  Since that time, total emissions of hazardous air pollutants have declined. These National Emission Standards for Hazardous Air Pollutants (NESHAP) are technology-based standards to reduce HAP emissions from specific industries.  The NESHAP for commercial sterilization plants was adopted in 1994, requiring control equipment to be added to commercial sterilizers reducing ethylene oxide emissions.  NESHAPs are meant to be revisited by USEPA on a periodic basis to incorporate new science on hazardous air pollutants.

USEPA revisited the public health science and has published a new Integrated Risk Information System (IRIS) value for ethylene oxide in December 2016. IRIS data is a used by USEPA in evaluating risk of HAPs.  With the new IRIS value for ethylene oxide, the USEPA began to review sources of ethylene oxide emissions including commercial sterilization facilities and performed dispersion modeling of the facilities nationwide.  In reviewing the modeling and comparing to the IRIS value, certain facilities showed a higher than acceptable risk value at which further control of emissions is appropriate.  USEPA typically regards a chronic risk (lifetime) of more the 1 in 10,000 to be higher than acceptable. 

The USEPA released this information to states and the public in August 2018 with the release of the most recent National Air Toxics Assessment.  USEPA is moving forward with revising the NESHAP for commercial sterilization facilities in light of this information.

Permitting and Regulation of Stationary Sources

Among other things, the Illinois EPA enforces federal and state air pollution control laws and rules including   NESHAP standards. One way Illinois EPA does so is with permitting of emitting facilities.  This includes permitting of commercial sterilization facilities such as the Medline facility in Waukegan and the Sterigenics facility in Willowbrook. The Illinois EPA takes seriously its statutory mandate to protect ambient air quality.

Since the release by USEPA of the National Air Toxics Assessment and subsequent ambient monitoring data for Willowbrook, the Illinois EPA has been evaluating sources of ethylene oxide emissions including those in Lake County.  The Agency has devoted a great deal of time and resources to understanding the issues around ethylene oxide including the location, emissions, air quality contribution, and existing and potential additional control measures for sources of ethylene oxide.    

Although revised federal standards (NESHAPs) for ethylene oxide have not yet been proposed by the USEPA; at this time, the USEPA is working to that end.

Separately, the Illinois EPA is requiring facilities to take actions to reduce their ethylene oxide emissions to be protective of ambient air quality.   

​On May 30, 2019, the Illinois General Assembly passed Senate Bills 1854 and 1852 addressing sources of ethylene oxide emissions.  Governor Pritzker signed these two bills into law, as Public Act 101-0022 and Public Act 101-0023 respectively, on June 21, 2019 with an immediate effective date.

Medline Industries

Medline Industries is a commercial sterilizer located at 1160 Northpoint Boulevard in Waukegan.  Medline uses ethylene oxide to sterilize medical equipment and devices. The facility currently operates under a federally enforceable state operating (FESOP) permit.  As required by the current NESHAP, Medline has emission control equipment that controls ethylene oxide from the chambers where sterilization occurs and the rooms where the sterilized devices are aerated.

To address its ethylene oxide emissions, Medline has applied for and the Illinois EPA has issued a construction permit to the facility.  The construction permit may be found in the Documents and Links section below.  Under the construction permit, Medline will install several new emission controls, place the building under 100% capture (negative air pressure) and route all emissions through control devices.  The construction permit includes performance requirements for the control devices and a limit on emissions from the facility of 150 pounds per year. Additionally, the permit requires a state of the art emissions monitor to be installed and a stack test to be performed to verify compliance.  The measures set forth in the permit go well beyond measures required under the current NESHAP Subpart O. 

These actions will significantly reduce the emissions and impact from Medline.  The annual emission limit being established in the permit is set at the current level of detection for monitoring but actual emissions from the facility are expected to be lower.  Dispersion modeling for Medline with these changes has been performed. The modelling has shown that with these changes, Medline's impact is far below USEPA’s reference 1 in 10,000 risk level. 

Public Outreach

The Illinois EPA held a public meeting in Waukegan to answer questions related to the planned issuance of the permit to Medline.  The meeting was held on May 23, 2019 at Whittier Elementary School in Waukegan. 

On May 30, 2019, the Illinois EPA issued construction permit 19020013 to Medline to install the controls and monitoring described above.

The Illinois EPA will continue to update this website to provide information on progress related to Medline. 

If you have questions about Medline, please submit them to

Vantage Industries

Vantage Industries is a chemical manufacturer.  The facility uses ethylene oxide in the manufacture of household and industrial products.  

Vantage has installed additional pollution control devices at its facility and has committed to performing ambient air monitoring around its facility. 

Public Outreach

The Illinois EPA will shortly be scheduling a meeting in Gurnee to discuss a permitting transaction addressing the above measures among other actions at the facility.  When a meeting is scheduled Illinois EPA will be making an announcement and reaching out locally to notify residents.  You can also check back here for updated information.


Sterigenics is a commercial sterilizer operating out of two buildings, Willowbrook I and Willowbrook II, located at 7775 Quincy Street and 830 Midway in Willowbrook.  The facilities are a single source for purposes of air permitting.  Sterigenics uses ethylene oxide to sterilize medical equipment and devices. The facility currently operates under a Clean Air Act Permit Program (CAAPP) permit.  As required by the current NESHAP, Sterigenics has emission control equipment that controls ethylene oxide from the chambers where sterilization occurs and the rooms where the sterilized devices are aerated. Additionally, Sterigenics previously received a construction permit from the Illinois EPA to control emissions from the facility backvents.

Following several months of consistently high monitoring data, on February 15, 2019, Illinois EPA Director John Kim issued a Seal Order to Sterigenics preventing the commencement of any new sterilization cycles using ethylene oxide at Willowbrook I & II as of the date and time of the Seal Order.

On June 24, 2019, Sterigenics submitted an application, see the Documents and Links section below, to the Illinois EPA for a construction permit for further enhancements at the Willowbrook I facility.  The Illinois has reviewed the application to ensure it satisfies among other things SB 1852/Public Act 101-0022 and has prepared a draft construction permit.

Public Outreach

The Illinois EPA has scheduled a formal public meeting in Willowbrook to accept oral comments on the draft construction permit for Sterigenics.   The meeting will be held on August 1, 2019 from 6:00 pm to 9:00 pm at
Ashton Place
341 75th Street
Willowbrook, IL 60527

The Illinois EPA will accept written comments concerning the draft permit until August 15, 2019.  Written comments should be submitted to by August 15, 2019.


Questions about the meetings, permitting or other issues related to these sources should be made to the appropriate mailbox above or to

Brad Frost
Office of Community Relations

Media Inquiries should be directed to

Kim Biggs
Public Information Officer

Documents and Links


Meeting Notice


Issued Construction Permit 19020013 


Issued Construction Permit

Responsiveness Summary


Memorandum in support of certification

Memorandum in support of dispersion modeling

Meeting Transcript

Meeting Guidelines

Meeting Notice


Draft Construction Permit

Sterigenics construction permit application - June 24, 2019

Consent Order Overview and Frequently Asked Questions

Proposed Consent Order

Memorandum in Support of Motion to Enter Consent Order

Joint Motion to Enter Consent Order

Sterigenics Entered Consent Order - September 6, 2019

Seal Order Removal