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EPA in Illinois

Ethylene Oxide Emissions: Frequent Questions

On this page:

Basic information about ethylene oxide

What is ethylene oxide and what are its uses?

Ethylene oxide, or EtO, is a gas at room temperature. There are two key uses for ethylene oxide: 1) It is used to make other chemicals that produce many everyday products and 2) It is used to sterilize devices that can’t be sterilized using steam, such as some medical and dental equipment.

Ethylene oxide is reacted to make ethylene glycol, which is a key ingredient in a variety of consumer household products. Ethylene oxide is an essential building block for synthetic fibers (e.g., upholstery, carpet), plastics, PVC pipe and cosmetics.

How long does ethylene oxide stay in the air and how does it leave?

Like all air pollutants, ethylene oxide disperses in the air, with the speed of dispersal depending on the strength of winds. Ethylene oxide is a volatile compound, meaning that it does not persist for a long time in the environment.

Its estimated half-life in the atmosphere is 69 days (during summer months) to 149 days (during winter months). Ethylene oxide reacts in the air to form formic acid, which is a naturally occurring chemical.

Does rain wash ethylene oxide from the air?

Rain will likely not wash ethylene oxide out of the air. While ethylene oxide does dissolve in water, it can also evaporate from water back to the air.

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I would like to know how exactly ethylene oxide travels in the air/through the wind, and on average, what is the distance/range for which surrounding communities should be concerned of cancer risks as well?

Ethylene oxide can last in the air for weeks and can be transported with prevailing winds. At higher temperatures, especially above 50 degrees Fahrenheit, and stronger winds, we would expect ethylene oxide to transport farther away from the emission source more effectively.

What should I do if I live near an ethylene oxide emissions source and I smell ethylene oxide?

People cannot smell ethylene oxide when it is in the air at concentrations that have been monitored or modeled near emissions sources.

Are there alternatives to ethylene oxide?

Ethylene oxide is necessary to assure that some types of medical equipment are sterilized for safe use. Ethylene oxide is used for items that are sensitive to moisture, heat, or radiation. It can penetrate various materials and safely sterilize the equipment without causing damage.

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Health information

When did EPA classify ethylene oxide as a carcinogen?

EPA classified ethylene oxide as a human carcinogen in December 2016. Studies of workers show that their exposures to ethylene oxide are associated with an increased risk of cancers of the white blood cells (the infection-fighting cells of the immune system). Studies also showed an increased risk of breast cancer in females.

What kinds of cancer does ethylene oxide cause?

Evidence in humans indicates that long-term exposure to ethylene oxide increases the risk of cancers of the white blood cells, including non-Hodgkin lymphoma, myeloma, and lymphocytic leukemia. Studies also show that long-term exposure to ethylene oxide increases the risk of breast cancer in females.

Can ethylene oxide cause immediate/acute health effects?

Acute (short-term) inhalation exposure to high concentrations of ethylene oxide can cause headache, dizziness, nausea, fatigue, respiratory irritation (e.g., coughing, shortness of breath, wheezing) and, in some cases, vomiting and other types of gastrointestinal distress.

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Are levels of ethylene oxide in my area high enough to cause immediate health effects?

Based on available data, we do not expect ethylene oxide levels in the air around facilities to be high enough to cause immediate health effects.

The short-term (one-hour) estimated levels in the air are well below levels that may immediately cause serious, long-lasting or irreversible noncancer health effects.

The mid-term estimated levels (two weeks to one year) and the long-term estimated levels in the air are also below levels that may cause noncancer health effects.

EPA is working with states to gather additional information from facilities that will help us better understand what the ethylene oxide levels are in the air.

How long does ethylene oxide remain in the body?

Ethylene oxide is eliminated from the body fairly quickly – with levels dropping by about 50% every 42 minutes. (The elimination half-life of ethylene oxide in humans is approximately 42 minutes (Filser et al., 1992)). At that rate, almost 90% of ethylene oxide would be eliminated from the body in two hours.

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Are there medical tests to see if I have ethylene oxide in my system?

According to the Agency for Toxic Substances and Disease Registry (ATSDR) there are two kinds of tests that can determine if you have been recently exposed to ethylene oxide. One test measures ethylene oxide in blood and the other test measures it in your breath. However, these tests are not intended for use on individuals that may have been exposed to very low levels of ethylene oxide (as these tests are not sensitive enough to detect it) nor can they be used to predict how it will affect a person’s health. Because special equipment is needed, these tests are not usually done in the doctor's office.

The University of Illinois at Chicago’s School of Public Health recently conducted monitoring of ethylene oxide adducts in hemoglobin of residents of Lake County, IL who live near ethylene oxide emissions sources. This is a form of medical testing available to some researchers, but not currently available to the medical community broadly.

Are children at risk?

EPA is taking steps to reduce ethylene oxide in the air to reduce risk. The greatest risk is for people who have lived near a facility releasing ethylene oxide into the air for their entire lifetime. For a single year of exposure to ethylene oxide, the cancer risk is greater for children than for adults. This is because ethylene oxide can damage DNA. For everyone, including children, risks would decrease with decreased exposure.

What ambient air concentrations of ethylene oxide are acceptable/safe?

Ethylene oxide is one of 187 pollutants that Congress classified as “hazardous air pollutants,” also called “air toxics.” The Clean Air Act instructs the U.S. EPA to regulate air toxics by setting limits on the amount of pollution that industrial sources can emit to the air, rather than by setting ambient standards, which are limits on the amount of a pollutant that is allowed in the outdoor air. So the Agency does not have a “bright line,” or a level for ethylene oxide below which air quality is considered okay.

EPA considers any exposure, however small, to a carcinogen to create some cancer risk. EPA has typically not attempted to address estimated cancer risks caused by emissions from an individual facility if the risks to the most exposed person are the are below 1 in a million, or in some cases, if they are below 100 in a million.

The concentration of ethylene oxide associated with a 1-in-a-million cancer risk, for a lifetime of continuous exposure, is 0.0002 ug/m3. The concentration of ethylene oxide associated with a 100-in-a-million cancer risk, for a lifetime of continuous exposure, is 0.02 ug/m3.

Is there information suggesting ethylene oxide causes birth defects and autism?

We are not aware of data suggesting that ethylene oxide is associated with effects such as birth defects or autism.

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Can food sold or served near a large source of emissions become contaminated with ethylene oxide?

It is unlikely that ethylene oxide would remain in or on food or remain dissolved in water long enough to be eaten or swallowed.

Is ethylene oxide produced by the human body?

Yes, our bodies produce ethylene oxide when metabolizing ethylene, which is produced naturally in the body. The percentage of ethylene converted to ethylene oxide in the body is unknown, but expected to be low.

Is my breast cancer caused by ethylene oxide?

There is no single cause of, or risk factor for, breast cancer. Studies show that long-term, occupational exposure to high levels of ethylene oxide increases the risk of breast cancer in women. It is very difficult, however, to attribute specific instances of breast cancer to one risk factor.

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National Air Toxics Assessment (NATA)

What is the National Air Toxics Assessment?

  • EPA’s National Air Toxics Assessment, or NATA, is a nationwide screening tool. Its purpose is to help air quality agencies determine if they need to look closer at particular areas, pollutants, or types of pollution sources to better understand risks to public health.
  • NATA estimates potential risk from long-term exposure to 180 different pollutants called “air toxics.” It estimates potential risk across the entire U.S., at the census tract level.
  • NATA is not considered a full risk assessment, and cannot tell any one person if they are going to get cancer or the cause of cancer that they did get. But it did identify ethylene oxide in some parts of the country as an issue that needs to be addressed. 
  • In August 2018, EPA released its 2014 NATA. It is called the 2014 NATA because it is based on 2014 air emission levels.
  • For the 2014 NATA, EPA used new estimates of the cancer potency of ethylene oxide that were issued in December of 2016 and not available for the previous version of NATA (2011). This means that in the 2014 NATA, more areas show elevated risks caused by ethylene oxide than in the 2011 NATA. This does not necessarily mean there is more of this compound in the air in these places than before.

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Does NATA reflect up-to-date conditions?

No. The current NATA released in 2018 is based on estimates of emissions in 2014. Changes in actual emissions, as well as corrections to the emissions inventory, will change our understanding of risks. For instance, emissions from Vantage were not included in the 2018 NATA due to an error in the National Emissions Inventory.

What does NATA estimate is the cancer risk from exposure to air toxics?

NATA is a screening tool, intended to help U.S. EPA and state, local and tribal air agencies determine if areas, pollutants or types of pollution sources need to be examined further to better understand risks to public health. NATA provides broad estimates of the risk of developing cancer and other serious health effects over census tracts across the country. It does not estimate any person’s individual risk.  Based on NATA, the U.S. EPA estimates that the average cancer risk across the U.S. population, specifically due to air toxics, to be 30 in a million.

How can I find the estimated cancer risk for where I live?

To see NATA results for specific areas, go to the 2014 NATA map application map. The colors in the NATA map are based on estimates of risks, which are a combination of emissions, how those emissions spread in the air, and exposure to people.

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What is EPA doing to reduce ethylene oxide in my area and across the country?

We are taking a two-pronged approach to finding opportunities to reduce ethylene oxide emissions:

EPA is reviewing Clean Air Act regulations for facilities that emit ethylene oxide:

  • EPA has begun reviewing its air toxics emissions standards for miscellaneous organic chemical manufacturing facilities, some of which emit ethylene oxide.
  • EPA also plans to take a closer look at its rules for other types of facilities, beginning with its emissions standards for commercial sterilizers. 

EPA is also getting additional information on ethylene oxide emissions:

  • EPA also is gathering additional information on industrial emissions of ethylene oxide, which may include data from testing at facilities.
  • This information will help EPA as it looks for opportunities to reduce ethylene oxide emissions as part of its regulations review.
  • It also will help us determine whether more immediate emission reduction steps are necessary in any particular locations.

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Does EPA have emissions standards for facilities that emit ethylene oxide?

EPA has existing National Emissions Standards for Hazardous Air Pollutants (NESHAPs) for industries that emit ethylene oxide, and we have begun to review and update those.  In particular:

Chemical industry: EPA is currently conducting a Risk and Technology Review (RTR) for the Miscellaneous Organic NESHAP (also known as the MON). The agency has a court-ordered deadline that requires the MON RTR be finalized by March 13, 2020.  Status of this rulemaking.

Commercial Sterilizers: EPA is also conducting an RTR for the Ethylene Oxide Emissions Standards for Sterilization Facilities NESHAP. This standard applies to commercial sterilization facilities, but not to small sterilizers used by hospitals.  Status of this rulemaking.

Why haven't permissible standards in emissions at the federal/state/local level conformed to align with this acknowledgement of environmental pollutant and public endangerment? When will this conform and affect permitting, etc. as is the case when a law changes?

The Clean Air Act requires EPA to protect air quality and directs different approaches to address different types of air pollution. Ethylene oxide is a hazardous air pollutant, also referred to as a toxic air pollutant or air toxic. There are 187 different toxic air pollutants regulated by EPA. They are known to cause cancer and other serious health impacts such as reproductive effects or birth defects. EPA does not set air quality standards for these pollutants, but rather develops emission standards specifically for those industrial facilities that emit them in two phases.

  • The first phase is “technology-based.” EPA develops emissions standards for controlling air toxics from sources in an industry group (or “source category”). These emissions standards, called maximum achievable control technology (MACT) standards, are based on emissions levels that are already being achieved by the best-controlled and lowest-emitting sources in an industry.
  • The second phase is “risk-based.” Within eight years of setting the MACT standards, the Clean Air Act directs EPA to assess the remaining health risks from each source category to determine whether the MACT standards protect public health with an ample margin of safety and protect against adverse environmental effects. In this phase, EPA must determine whether more health-protective standards are necessary.

Also, every eight years after setting the MACT standards, the Clean Air Act requires that the EPA review and revise the MACT standards, if necessary, to account for improvements in air pollution controls and/or pollution prevention.

EPA is currently reviewing Clean Air Act regulations for facilities that emit ethylene oxide including commercial sterilizers and miscellaneous organic chemical manufacturing facilities.

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EPA is influenced by the entities they regulate. This is clear from the record and self-evident in reviewing comment periods and the time elapsed from initial findings to adoptions of new rules. What can be done to eliminate the influence industry has on EPA?

For regulatory programs, EPA often has discussions early in the rulemaking process with government partners (federal, state, local and tribal) and with interested parties such as affected industries, environmental groups, and communities. After a rule is complete, EPA works with government partners and stakeholders to achieve effective implementation.

EPA's regulatory work under the Clean Air Act guarantees that every citizen has opportunities to provide comments on any air pollution rule proposed by EPA.

EPA publishes every proposed rule in the Federal Register. Any citizen can provide written comments on any proposed rule, and these comments are placed in an electronic docket. EPA must respond in writing to each substantive comment and must place its responses in the docket, the official rulemaking record.

EPA also must offer the opportunity for public hearings on proposed air quality rules.

Is the EPA planning on setting regulations for EtO and what is the expected timeframe? What regulations are they working on, handling as well as emissions?

EPA has existing rules for industries that emit ethylene oxide, and we have begun to review those.  We are starting with our air toxics emissions standards for miscellaneous organic chemical manufacturing facilities, some of which emit ethylene oxide. We also are beginning work to look at emissions standards for commercial sterilizers.

What does the EPA think of the Ontario Canada standards for ambient air concentration published in 2007 based upon their own work and review of various standards including North Carolina and California?

EPA’s 2016 unit risk estimate (URE) for ethylene oxide is based on the best available science and follows the EPA guidelines. Ontario’s 2007 air quality standards for ethylene oxide are based on animal carcinogenicity data and do not take into account data on occupational exposures to ethylene oxide. Ontario’s standards were being developed at the same time the U.S. EPA was conducting its revised toxicity assessment of ethylene oxide. EPA’s revised assessment concluded that ethylene oxide is a known human carcinogen and established a URE that is based on human data.

Does the U.S. EPA oversee the Illinois EPA? How does this oversight apply to operating permits issued by the state that fail to meet conditions of operating permits?

While Illinois EPA is the permitting authority, the U.S. EPA retains oversight of all state agencies that issue what are known as “Title V operating permits.” This oversight includes approving the state rules governing operating permits, periodically evaluating state programs to make sure they are working, and reviewing individual permits issued by states.

For individual permits, the Clean Air Act provides the EPA a 45-day period to review each operating permit before a state issues, renews or modifies a final permit (permits must be renewed every five years). During this review period, the U.S. EPA can object to an operating permit if it does not comply with the requirements of the Clean Air Act. If the U.S.EPA does not object to a permit during the 45-day period, citizens have 60 days to petition the U.S. EPA and request that the Agency object to the operating permit.

Sources of Ethylene Oxide Emissions in Lake County, IL

What are the largest sources of ethylene oxide emissions in Lake County, IL?

EPA believes that the largest sources of ethylene oxide emissions in Lake County are Medline, a commercial sterilizer located in Waukegan, and Vantage, a chemical production facility in Gurnee. 

What are the estimated emissions at Medline?

Medline had reported ethylene oxide emissions of 2,863 pounds from their controlled emission stacks in 2017.

Can Medline reduce these emissions?

Yes. Medline has developed a plan to enhance its control of emissions from both controlled emissions stacks and from fugitive emissions sources. The company has received a permit from Illinois EPA (the state agency) for a permit to construct improved controls at the facility. The permit limits total facility emissions of ethylene oxide to 150 pounds per year. The deadline for meeting the requirements of the state permit is December 18, 2019The construction permit is available on Illinois EPA’s website(PDF)EXIT (23 pp, 951K, About PDF)

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What are the estimated emissions at Vantage?

Vantage estimates that they emitted 1,547 pounds of emissions of ethylene oxide in 2017, including 737 pounds from controlled emissions stacks and 811 pounds from “fugitive” sources, such as leaking valves and other equipment. Vantage considers this estimate to be more accurate than what they previously reported to the Toxics Release Inventory (TRI).

Can Vantage reduce these emissions?

Yes. Vantage has installed an additional pollution control device at its facility and has committed to performing ambient air monitoring around its facility.  Illinois EPA has proposed a permit for this facility that limits total emissions of ethylene oxide from the facility to 110 pounds per year, starting in 2020. 

You can also check at for updated information at Illinois EPA information on Ethylene Oxide Exit

Is EPA Planning to monitor ethylene oxide concentrations in the air near Medline and Vantage?

EPA does not currently plan to monitor ethylene oxide concentrations in Lake County, although EPA is providing technical support to the Lake County Health Department, which is conducting ambient air monitoring. Vantage and Medline have also  conducted additional emissions monitoring.

Is EPA Planning to model ethylene oxide concentrations in the air near facilities in Lake County?

Illinois EPA required both facilities to model their post-control ethylene oxide emissions to verify that permitted controls would be protective of public health.

What are the levels of EtO in the air in Lake County?

Lake County Health Department is now posting EtO air concentrations from its summer 2019 air monitoring results: Lake County EtO Monitoring Results.  Air sampling location maps and wind roses showing wind speed, duration and direction are also included.

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