Action Needed to Protect Americans from Toxic EtO Pollution

Ethylene oxide (EtO) is a common, highly hazardous industrial chemical linked to breast cancer and immune system cancers like non-Hodgkin lymphoma and lymphocytic leukemia (see EPA IRIS Exec Summary, Dec 2016). Concerned community members in Illinois made it a 2018 campaign issue after two federal agencies released studies showing elevated cancer risks outside Chicago. Thanks to the effort and organizing of their constituents, members of Congress are now taking action to combat the threat this colorless and highly explosive toxic gas poses to neighborhoods across the country.

EtO is made from ethylene, a petrochemical, and is used primarily to make ethylene glycol, a highly toxic chemical used in antifreeze and as a coolant for cars, gas compressors, and air conditioning systems. It is also commonly used as a sterilizer for medical equipment, and industrial sterilizing facilities around the country vent it, poisoning the air of nearby communities. The U.S. Environmental Protection Agency (EPA) considers EtO emissions from sterilization facilities to be among the most hazardous air pollutants posing the greatest health risks in the largest number of urban areas.

State and federal agencies monitor EtO air emissions, but monitoring is far behind where it should be. Local, publicly-available data is either outdated or nonexistent. The EPA released its most recent National Air Toxics Assessment (NATA) in 2018, but the data is from 2014. The NATA is used as a screening tool to identify places of interest for more detailed study, so comprehensive local monitoring is still needed to pinpoint risk at specific places, like homes or schools, or to compare risks and exposures at local levels, like between neighborhoods, but the NATA is supposed to be the starting point.

Since 2014, EPA updated its Integrated Risk Information System (IRIS), estimating cancer risks from EtO exposure are 30 times worse than previously thought. This was based on a 2016 assessment of all available scientific studies including laboratory animal studies, cellular mechanistic studies, and workplace epidemiologic studies (see Jinot et al 2018). EPA’s updated risk assessment confirms that EtO is carcinogenic to humans by inhalation (stronger than its previous classification of ‘probably carcinogenic to humans’).

In August 2018, the Agency for Toxic Substances and Disease Registry (ATSDR) within the U.S. Department for Health and Human Services (HHS) issued its final Health Consultation report on health risks posed by EtO air emissions from the Sterigenics facility in Willowbrook, a Chicago suburb. But the problem isn’t limited to this one facility.

Screenshot of EPA NATA map around Willowbrook, Illinois, released in 2018 with data from 2014.

Alarmingly, the 2014 NATA already shows 58 EPA monitoring tracts in 18 different counties across 12 states that have EtO air emissions at levels that pose cancer risks higher than 1 in 10 thousand people (see ATSDR 2018 Health Consultation report). This is far higher than the 1 in 1 million that EPA considers an acceptable risk, which triggers federal regulators to notify polluters.

Over 288,000 people live in the monitoring tracts across the country that EPA identified to be at elevated risk of EtO exposure, and nine counties have facilities that are emitting more EtO than the Sterigenics Willowbrook facility. This is not a singular issue affecting one suburb of Chicago, it’s a national issue that begs EPA action in how it monitors and regulates air toxics in general.

U.S. Counties with High EtO Cancer Risk

(>1:10,000 people, Source: EPA NATA)




Total EtO Emissions (Tons/Year)

St. Charles


Union Carbide




Port Neches Plant




Midwest Sterilization Corp




Texas Operations


Cape Girardeau


Midwest Sterilization Corp




B Braun




C R Bard



West Virginia

Union Carbide


Doña Ana

New Mexico









BCP Ingredients


St. John the Baptist


Air Products Performance Manufacturing




Medline Industries


New Castle










Channelview Plant



Puerto Rico

Edwards Lifesciences Corp



New Jersey



Successful efforts by community members and journalists in Illinois brought much needed public attention to EtO last year. Since then, Illinois Senators Durbin and Duckworth and Representatives Foster, Lipinski and Schneider introduced the Expanding Transparency Of Information and Safeguarding Toxics (ETO IS Toxic) Act, which directs EPA and ATSDR to modernize their pollution monitoring and chemical assessment programs. They’ve sent numerous letters already and plan to send more in the coming months.

EPA should update the National Air Toxics Assessment more frequently, coordinate more quickly and transparently with other agencies, and update and enforce stricter regulations on venting. Not only will it save lives if EPA takes these actions, it will help rebuild trust within local communities that the federal government really is trying to protect public health.

Unfortunately, EPA seems to be moving in the opposite direction. On February 4, EPA snuck a review of the health risk factor for EtO into its proposed amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Hydrochloric Acid (HCl) Production source category, even though it acknowledges EtO is not part of the HCl source category under review. This happened a day before EPA released updated data from Willowbrook confirming high levels of EtO in surrounding neighborhoods, and a day after allegations surfaced that Sterigenics was covering up its emissions and operating secret plants.

On February 11, NRDC joined 17 other environmental organizations on a letter to EPA stating the inappropriateness of opening the EtO health risk factor in this source-focused proposal. But since EPA has done so, it should hold at least one public hearing on this proposal as it relates to EtO to give the public a chance to comment. The letter also emphasizes that though most of the national attention generated by this issue is in the Chicago area, EtO is an issue affecting communities around the nation.

Local Illinoisans and the members of Congress who represent them are raising awareness about this issue. Members of the Illinois congressional delegation—Sens. Durbin and Duckworth and Reps. Schneider, Lipinski, Foster, and Casten— most recently re-introduced the ETO IS Toxic Act. The people of Illinois – and all around the country – must be protected from this dangerous toxin. Given EPA’s foot-dragging on this issue, members of Congress should join this effort to force the agency to do its job and protect our health and that of our children.

About the Authors

Dan West

Senior Advocate, Government Affairs

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