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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.
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.
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.
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.
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.
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 OK.
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.
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.
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.
- The 2014 National Air Toxic Assessment identified cancer risks from air toxics by census tract. Why did we not find about this until August of 2018?
- In August of 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.
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.
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 submitted an application to Illinois EPA for a permit to construct these controls. After discussion with Illinois EPA, Medline withdrew the application in order to revise it. A revised application is expected in April 2019.
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).
Why have estimated emissions from Vantage changed?
Vantage, until recently, used an unsupported emissions factor to estimate fugitive EtO emissions; this factor was based on a percentage of ethylene oxide use. Recently, Vantage began to utilize information available through the facility’s leak detection and repair (LDAR) program to develop a better estimate of fugitive emissions. They submitted an improved estimate of emissions to the Toxics Release Inventory (TRI) for 2017 emissions, after having already submitted a 2017 estimate. The updated estimate should appear in the TRI update in April 2019. Vantage has updated their fugitive emissions estimates back to 2010, when their LDAR program began. They have also updated their TRI estimates of point source emissions for emissions for 2012 and beyond based on the emissions control device efficiency demonstrated during a stack test conducted in late 2016.
Can Vantage reduce these emissions?
Yes. Vantage is installing enhanced controls, which are expected to significantly reduce the emissions from controlled emissions stacks. These controls are expected to be operational in April 2019.
Illinois EPA expects that Vantage will apply for a permit modification after installing the controls.
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 in their development of an ambient air monitoring plan. Vantage has indicated that they intend to monitor emissions at the facility boundary, after installing additional emissions controls.
Is EPA Planning to model ethylene oxide concentrations in the air near facilities in Lake County?
EPA will assist Illinois EPA in reviewing modeling required of sources to determine the impact of emissions controls. In addition, EPA will conduct modeling to help determine optimal locations for siting of EtO monitors.