Ethylene Oxide: Invisible Threat, Inequitable Impact

Mapping communities impacted by cancer-causing ethylene oxide pollution

How to use this map

This interactive map shows 104 facilities that use and release ethylene oxide (EtO)—a known cancer-causing chemical—into the surrounding air. You can move the map, zoom in and out, and click on any facility for more details.

Two types of facilities are identified: Most are Commercial Sterilizers (circles on the map), which primarily use EtO to sterilize medical equipment; the remainder are Miscellaneous Organic Chemical Manufacturing (MON) facilities (diamonds), which emit EtO and other chemicals from a range of uses.

Information for each facility includes the number of people, schools, and childcare centers located within five miles—the area where elevated levels of EtO are most likely to occur. Nationwide, roughly 14.2 million people live within a five-mile radius of these facilities, as well as more than 10,000 schools and childcare centers.

Also highlighted is the percent of the population near each facility that are people of color, low-income, and with limited English-language proficiency. In most cases, these percentages are higher—sometimes much higher—than in the surrounding county, a stark example of environmental injustice and inequity. The data clearly show that people of color bear a disproportionate burden of ethylene oxide emissions.

Blue circles highlight the 23 commercial sterilizers that emit ethylene oxide at levels that definitively contribute to an  elevated cancer risk  for surrounding communities, as determined by the Environmental Protection Agency (EPA) in 2022. This may still underestimate overall risk, given that ethylene oxide is often just one of several toxic air pollutants that affected communities may be exposed to. Where possible, the excess cancer risk specifically attributable to EtO emissions is identified.

It is important to note that other EtO-emitting facilities exist; the sites on this map are highlighted because the Environmental Protection Agency (EPA) is currently working on establishing stronger emissions standards for these facilities (see below).

What is ethylene oxide?

 Ethylene oxide  is a flammable, colorless gas that is used to sterilize medical equipment and other plastics that are sensitive to heat or moisture, and as an antimicrobial treatment for spices, among other uses.

Its chemical properties make it especially good at killing viruses, bacteria, and human cells by reacting with proteins, DNA, and other essential cellular components. While EtO is widely used, safer alternatives exist.

How dangerous is it?

Ethylene oxide is a known cancer-causing chemical. Chronic exposure to EtO—inhaled throughout a person’s life—is associated with the development of cancers of the white blood cells, such as non-Hodgkin's lymphoma, myeloma, and lymphocytic leukemia. Studies have also shown a relationship between EtO exposure and breast cancer in women.

Also, because EtO is mutagenic—meaning it can change a cell’s DNA—children may be especially susceptible to its effects because their cells divide more rapidly as they grow. People who live, work, and attend school near facilities that release EtO into the air are at risk of unsafe exposures even when the facilities are using the best available technologies to handle and contain it.

Acute inhalation of EtO can also contribute to headaches, gastrointestinal issues, fatigue, and eye and skin burns.

Hazardous hotspots

The map also identifies twelve sterilizer hotspots, locations where two or more commercial sterilizers are located within 10 miles of each other. These hotspots include:

Additionally, there are several regions of high population density with a significant number of EtO facilities. These include places like:

Puerto Rico in particular bears a significant burden of EtO emissions, with a population one-tenth and land area one percent the size of Texas, but with more commercial sterilizers than all US states, behind only California and Texas.

Roughly 13 percent of Puerto Rico's population lives within five miles of a commercial sterilizer, and four of the 23 facilities identified by EPA as contributing to elevated cancer risks are in Puerto Rico.

About this analysis

Scroll down below the map for additional resources and information about these facilities and surrounding communities, including a downloadable spreadsheet with facility locations, compliance and enforcement data, and more details on the affected communities.

You'll also find information below on how you can take action to call on EPA to limit ethylene oxide emissions from commercial sterilizers and other facilities that emit EtO.

 Click here  to see this map in Spanish.

Take action

As of February 2023, the US Environmental Protection Agency is working on a rule to better protect the health of people living near commercial sterilizers that release ethylene oxide (EtO) into the surrounding air.

This long-delayed rulemaking would strengthen ethylene oxide emissions controls from commercial sterilizers using the best available science. Current EPA regulations for most EtO-emitting facilities do not account for the cancer risks posed by this toxic chemical, and without updated standards, the people that live, work, and attend school near these facilities may be exposed to harmful levels.

Fortunately, the EPA plans to update ethylene oxide regulations for facilities in the coming years, starting with commercial sterilizers. However, to ensure communities are no longer exposed to hazardous levels of ethylene oxide, the EPA must ultimately update standards for all facilities that use and emit ethylene oxide, including MON facilities, hospital sterilizers, and those that use EtO in the manufacturing of polymers and resins (neoprene), synthetic organic chemical manufacturing, polyether polyols production, and "chemical manufacturing area sources" (known as CMAS).

Raise your voice. Make a difference.

You can submit a public comment once the EPA releases its proposed rule for commercial sterilizers. It's especially important that the EPA hears from the people and communities most affected by ethylene oxide pollution, so make sure your voice is heard!

 Visit our activist resource webpage  for the latest information and timing on the EPA's proposed rule, plus resources to help you write a powerful public comment.

Get involved in your community

You can also join or support these grassroots organizations and coalitions working to protect their communities from ethylene oxide emissions:

Clean Air Laredo Coalition in Laredo, Texas:  https://cleanairlaredo.org/ 

Clean Air Now in Kansas City, Kansas & Missouri:  http://cankc.org/maxi 

Clean Power Lake County in Waukegan, Illinois:  https://cleanpowerlakecounty.org 

Mallory Heights Community Development Corporation in Memphis, Tennessee:  https://www.facebook.com/MalloryHeightsCDC/ 

Memphis Community Against Pollution in Memphis, Tennessee:  https://www.memphiscap.org/ 

Stop Sterigenics - Georgia in Georgia:  https://www.facebook.com/StopSterigenicsGA  

Learn more

Data and supporting materials for this map are drawn from the UCS report,  Invisible Threat, Inequitable Impact: Communities Impacted by Cancer-Causing Ethylene Oxide Pollution .

 Download additional data  on the facilities and communities featured in this analysis, including compliance and enforcement data, and more details on the affected communities.

Union of Concerned Scientists