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west virginia department of environmental protection
west virginia department of environmental protection
west virginia department of environmental protection

Ethylene Oxide (EtO)

Overview

The U.S. Environmental Protection Agency (EPA) conducted a study of air toxic emissions across the United States using data from 2014. That data was compiled and released by the EPA in 2018 in a report called the National Air Toxics Assessment (NATA). The NATA was a broad overview of air emissions across the country – commonly referred to as a screening tool – and is designed to identify areas that may need further investigation.

The 2018 assessment based on 2014 data identified four census tracts in West Virginia, all of which are nearby EtO-emitting facilities in Institute and South Charleston.

While the assessment released in 2018 was being conducted, the EPA made a finding related to EtO and reclassified it from a probable human carcinogen to a known human carcinogen.

The potentially elevated risk is not due to new emission sources or increased emissions from permit holders, but rather to the EPA's finding that long-term exposure to EtO may be more harmful than previously thought.

Since the release of the 2018 report, the EPA has replaced the NATA with a new screening tool - AirToxScreen. This assessment estimates air toxics using emissions data from the most recent year of complete data available.

The WVDEP has entered into voluntary collaborative agreements with each of the EtO-emitting facilities in Institute and South Charleston, which implemented additional measures and requirements to further reduce EtO emissions. As a result of WVDEP’s more in depth analysis and the Voluntary Agreements with the four facilities, EtO emissions have decreased by 76% in South Charleston and 67% in Institute since 2014.

 
Ethylene Oxide in the Institute and South Charleston Areas


The WVDEP is committed to staying engaged nationally as the EPA works to update regulations to reduce impacts from hazardous air pollutant emissions like EtO. The WVDEP is continuing to work with West Virginia facilities and communities to reduce the potential health risks associated with air toxic emissions.

Stay Informed

Collaborative Agreement

The WVDEP has entered into Collaborative Agreements with the four EtO-emitting facilities in South Charleston and Institute: Union Carbide and Covestro in South Charleston, and Union Carbide and Specialty Products in Institute.

These agreements implement additional, site-specific requirements designed to reduce EtO emissions, including:

  • Significantly reducing allowable emission limits for EtO

  • Identifying and fixing leaks at levels 50 to 1,000 times lower that what is required by current regulations

  • Developing a site-specific screening program for rail cars containing EtO in its service (UCC- Institute)

  • Continuing to work with WVDEP and the U.S. Environmental Protection Agency (EPA) to develop improved monitoring for EtO emissions

Documents

Notice of Comment Period for Covestro LLC’s Title V Operating Permit Renewal

A public notice for the Draft/Proposed Title V Permit Renewal for Covestro LLC’s South Charleston Plant will be published in the Charleston Gazette-Mail on January 28, 2025, with a 30-day comment period ending February 27, 2025.

The renewal includes stricter ethylene oxide emission limits, reducing the facility-wide limit from 0.71 to 0.25 tons per year, with reported actual emissions of 0.12 tons in 2023. Additionally, provisions for constructing an ethylene oxide distribution system were removed. If new EPA requirements under 40 C.F.R. 63, Subpart PPP are finalized, Covestro LLC must comply, and the permit will be updated accordingly.

DAQ Title V Permits

Subscribe to EtO Updates

The WVDEP is committed to staying engaged with the public as the EPA works to update regulations to reduce impacts from EtO. To receive updates from the WVDEP regarding its monitoring project, upcoming public meetings, and other matters related to EtO in the Kanawha Valley, please sign up for our EtO Mailing List.

Subscribe to DEP's EtO Mailing List

AirToxScreen

The U.S. EPA developed AirToxScreen as a screening tool for state, local and tribal air agencies. AirToxScreen’s results help these agencies identify which pollutants, emission sources and places they may wish to study further to better understand any possible risks to public health from air toxics.

Currently, emissions data from 2017, 2018, and 2019 are available.

Questions about this assessment should be directed to EPA at airtoxics@epa.gov.

AirToxScreen

Learn More

More information about EtO and the steps the WVDEP and EPA have taken to address the issue can be found below.

About

The WVDEP conducted a fence line monitoring project at EtO-emitting sites in the Kanawha Valley in January 2022. The project used EPA’s most recently approved method designed to measure low concentrations of EtO and consisted of four rounds of sampling at eight different sites: Three (3) around the South Charleston facility, four (4) around the Institute facility, and one (1) background site – Guthrie, WV. A background site is an area with no known sources of EtO. Each round represents one 24-hour period.

The primary purpose of the monitoring was to determine the presence and concentration of EtO in the air.

Collectively, the results of the four (4) rounds of sampling, along with emissions and weather data from the days sampled, were reviewed by both the WVDEP and EPA and compiled into a final report .


Results

The WVDEP has received results from all four rounds of sampling.

The concentrations were measured in parts per billion (ppb) by volume. For comparison purposes, 1 ppb is equivalent to one second in a 32-year time span or one drop of water in an Olympic-sized swimming pool.

These concentrations are influenced by many factors, including wind and weather data, operations at the facilities, and background levels, which is why multiple rounds of sampling were being conducted.

These single data points, on their own, cannot be used to draw conclusions regarding the lifetime health risk associated with EtO.

Sample Location Results (ppbv)* Predominant Wind Direction
Guthrie WV Background Site ** 0.0361 Not Available
#0 South Charleston, WV NonDetect From the Northwest
#3 North Charleston, WV 0.0165 From the Northwest
#4 North Chareston, WV 0.0121 From the Northwest
#10 Institute, WV 0.0821 From the West/Northwest
#13 Institute, WV 0.0375 From the West/Northwest
#14 Institute, WV 0.0376 From the West/Northwest
#15 Institute, WV 0.0505 From the West/Northwest

* Concentrations measured in parts per billion by volume (ppbv)
** Background site: This is an area with no known emitters of Ethylene Oxide
Method Detect Level (MDL) for the sampling = 0.0261 ppbv.

MDL is the minimum concentration of a substance that can be measured and reported with 99% confidence that the concentration is greater than zero.


Sample Location Results (ppbv)* Predominant Wind Direction
Guthrie WV Background Site ** 0.0884 Not Available
#0 South Charleston, WV VOID Intake regulator not working
#3 North Charleston, WV 0.0227 From the Northeast
#4 North Chareston, WV 0.088 From the Northeast
#10 Institute, WV 0.0996 From the Northeast and Southeast
#13 Institute, WV 0.204 From the Northeast and Southeast
#14 Institute, WV 0.0958 From the Northeast and Southeast
#15 Institute, WV 1.3 From the Northeast and Southeast

* Concentrations measured in parts per billion by volume (ppbv)
** Background site: This is an area with no known emitters of Ethylene Oxide
Method Detect Level (MDL) for the sampling = 0.0261 ppbv.

MDL is the minimum concentration of a substance that can be measured and reported with 99% confidence that the concentration is greater than zero.


Sample Location Results (ppbv)* Predominant Wind Direction
Guthrie WV Background Site ** 0.0321 Not Available
#0 South Charleston, WV 0.08 From West & South
#3 North Charleston, WV 0.155 From West & South
#4 North Chareston, WV 0.0794 From West & South
#10 Institute, WV 0.182 From Southeast and West
#13 Institute, WV Invalidated Canister developed leak during exposure
#13 Institute, WV (Collocated) 0.0714 From Southeast and West
#14 Institute, WV 0.119 From Southeast and West
#15 Institute, WV 0.447 From Southeast and West

* Concentrations measured in parts per billion by volume (ppbv)
** Background site: This is an area with no known emitters of Ethylene Oxide
Method Detect Level (MDL) for the sampling = 0.0261 ppbv.

MDL is the minimum concentration of a substance that can be measured and reported with 99% confidence that the concentration is greater than zero.


Sample Location Results (ppbv)* Predominant Wind Direction
Guthrie, WV Background Site ** 0.271 Not Available
Buffalo, WV Background Site ** 0.365 Not Available
#0 South Charleston, WV 0.146 From West
#3 North Charleston, WV 0.221 From West
#4 North Chareston, WV 0.277 From West
#10 Institute, WV 0.674 From West
#13 Institute, WV 0.124 From West
#14 Institute, WV 0.514 From West
#15 Institute, WV 0.183 From West

* Concentrations measured in parts per billion by volume (ppbv)
** Background site: This is an area with no known emitters of Ethylene Oxide
Method Detect Level (MDL) for the sampling = 0.048 ppbv.

MDL is the minimum concentration of a substance that can be measured and reported with 99% confidence that the concentration is greater than zero.


Documents and Resources

Additional Monitoring

Union Carbide Corporation (UCC) conducted an EtO sampling project for its South Charleston and Institute facilities that started in May 2022. The EPA-approved project sampled seven locations around both the South Charleston and Institute sites for seven weeks. Each round consisted of one 24-hour period.

In an effort to compare site-specific data, the WVDEP sampled at one similar location at each site for seven weeks, as well as two background locations (Guthrie, WV and Buffalo, WV). The WVDEP's Field Sampling Plan and Standard Operating Procedure for its additional monitoring is available on this page.

The samples collected by UCC were provided directly to the EPA.

The WVDEP's sampling results are available on this page. The MDL for the additional sampling was 0.0480 ppbv.

Please note the additional sampling is separate from the WVDEP's initial monitoring project and will not be factored into the agency's final report mentioned above.

2022 Ethylene Oxide Additional Monitoring Results

Concentrations measured in parts per billion by volume (ppbv)

Sample Location May 24-25 May 31 - June 1 June 7-8 June 14-15 June 22-23 June 28-29 July 5-6
Guthrie Background** 0.0733 0.296 0.636 0.95 0.817 0.495 0.552
#3 North Charleston, WV 0.184 0.257 0.762 2.48 0.979 1.23 ***
#15 Institute, WV 1.23 1.93 0.571 1.76 1.65 2.36 ***
#16 Buffalo, WV Background** 0.169 0.109 0.714 0.122 0.354 0.151 0.486

* Concentrations measured in parts per billion by volume (ppbv)
** Background site: This is an area with no known emitters of Ethylene Oxide
*** Results voided/invalidated by the lab
Method Detection Level (MDL) for the sampling = 0.048 ppb
MDL is the minimum concentration of a substance that can be measured and reported with 99% confidence that the concentration is greater than zero.


2025 Monitoring

As part of the Collaborative Agreement with WVDEP, Union Carbide Corporation (UCC) conducted an EtO sampling project that started in January 2025. The DEP-approved project sampled two locations: the western fenceline of the Institute Industrial Site, and a background location in Buffalo WV, not near any known sources of EtO. Three rounds of sampling were performed, consisting of 24-hour periods each.

The EPA approved new Method 327 for the fenceline detection of EtO.  At the time of the sampling, WVDEP was unaware of any commercial laboratory that could perform this method.  After consulting with the EPA, they identified that Enthalpy Analytical, LLC was one of the laboratories that was closest to being able to perform the method.  UCC used this laboratory for the project.

The goal of the project was to place six canisters side-by-side at the western fenceline to determine the precision of multiple canisters measuring concentrations down to parts per trillion using as close to Method 327 as possible.  In addition to the six canisters, a field blank and a field spike were placed next to the six canisters.  Additionally, two canisters were placed in a rural location in Buffalo, WV to compare the concentrations on-site at the fenceline against a background location.

The sampling results, Quality Assurance Protection Plan (QAPP), and Standard Operating Procedure (SOP) are available on this page. The Method Detection Limit (MDL) for the six canisters varied from 9 to 18 parts per trillion by volume (pptv).

The results showed good consistency, with an overall average relative percent difference of 8.3% for the six canisters over the three sampling events, which is a noticeable improvement over the 2022 sampling performed by UCC. This data is available on this page.

Please note the additional 2025 sampling is separate from WVDEP's initial monitoring project in 2022, and will not be factored into the agency's final report mentioned above.

Resources


Public Meeting: EtO Monitoring Report

The WVDEP held an in-person public meeting on Thursday, March 2, 2023 at West Virginia State University. DAQ staff provided a presentation of the report and its findings and answered questions from citizens and media.

Public Meeting Materials

Update Meeting: August 18, 2022

The WVDEP, along with representatives from the West Virginia Department of Health and Human Resources' (DHHR) Bureau for Public Health (BPH) and the U.S. EPA's Region 3 Office, hosted an in-person update meeting at the Schoenbaum Center in North Charleston on Thursday, August 18, 2022.

WVDEP, BPH, and EPA staff each presented information related to Ethylene Oxide, answered questions, and met with citizens.

Questions related to BPH's presentation can be directed to DHHRCommunications@wv.gov.

Update Meeting Materials

Community Open House

On Saturday, March 26, 2022, the WVDEP, along with representatives from the West Virginia Department of Health and Human Resources' (DHHR) Bureau for Public Health (BPH) and the U.S. EPA's Region 3 Office, hosted an in-person community open house at the Dunbar Recreation Center in Dunbar.

WVDEP, BPH, and EPA staff set up stations and displays, answered questions, and met with citizens.

Questions related to BPH's presentation can be directed to DHHRCommunications@wv.gov.

WVDEP Open House Materials

Virtual Community Meeting About Ethylene Oxide

The U.S. Environmental Protection Agency (EPA) has determined that the chemical compound, ethylene oxide, poses significantly more risks to human health than previously thought. That compound is used at the Union Carbide, International Flavors and Fragrances/Specialty Products, and Covestro LLC chemical production facilities at Institute and South Charleston, WV. EPA and the WV Department of Environmental Protection (WVDEP) held a virtual meeting to provide members of the communities located near those facilities with information about ethylene oxide and its known health effects.

The WVDEP and U.S. EPA Region 3 held a virtual public meeting on Thursday, September 23, 2021 from 6 to 8 p.m. to provide provide details on EtO and the upcoming monitoring and modeling and to answer questions.

 

Documents and Resources

Meeting With State and Local Elected Officials and Higher Education Representatives

The WVDEP met with local mayors, Kanawha County Commissioners, members of the West Virginia Legislature, and representatives from West Virginia State University on August 10, 2021, to provide information and answer questions related to EtO.

Meeting Documents

Ongoing Outreach

Virtual Town Halls

The WVDEP's Environmental Advocate provides updates on EtO and other environmental issues involving the agency through quarterly virtual meetings.

These meetings are open to the public. For more information, contact DEPAdvocate@wv.gov.

Press Releases

Community Advisory Panels (CAPs)

The WVDEP has been participating in Community Advisory Panels for the South Charleston and Western Kanawha County areas since August 2021. CAPs are monthly meetings between citizens and industry representatives designed to increase communication and transparency.

To learn more about a CAP, contact Mary Green at mgreen@magc.info.

What is Ethylene Oxide (EtO)?

Ethylene oxide (EtO) is a flammable, colorless gas used to make a range of products, including antifreeze, textiles, plastics, detergents and adhesives. EtO also is used to sterilize equipment and plastic devices that cannot be sterilized by steam, such as medical and dental equipment.

According to the Centers for Disease Control and Prevention (CDC), environmental exposures to EtO may also include vehicle exhaust and tobacco smoke.

The Clean Air Act lists EtO as one of 187 hazardous air pollutants (HAP), commonly referred to as air toxics.

What is the National Air Toxics Assessment (NATA)?

The NATA is USEPA's ongoing review of air toxics in the United States. It serves as a screening tool for state, local and tribal air agencies to help identify which pollutants, emission sources, and/or localized areas should be studied further to better understand possible public health risks.

The NATA calculates air toxics concentrations and long-term health risks for identified areas called “census tracts.” The most recent NATA report, which used 2014 data, identified 106 census tracts in the United States with an estimated cancer risk greater than 100 in 1 million. This means there’s a likelihood that 100 in 1 million people (or 1 in 10,000 people) would develop cancer if they breathed air containing the same amount of the same air pollutant every day for 70 years. The primary risk in many of these census tracts is driven by emissions of EtO.

In West Virginia, the NATA identified four census tracts with a total cancer risk greater than 100 in 1 million. All four tracts were in the Institute and South Charleston areas.

For more information related to the 2014 NATA, please see USEPA’s 2014 NATA Fact Sheet.


What Are the Health Risks of EtO?

According to the USEPA, short-term inhalation exposure to high concentrations of EtO can cause headache, dizziness, nausea, fatigue, respiratory irritation and, in some cases, vomiting and other types of gastrointestinal distress. Long-term exposure can irritate the eyes, skin, throat, and lungs, and harm the brain and nervous system, causing headaches, memory loss, and numbness.

Studies show breathing air containing elevated levels of EtO over many years can increase the risk of some types of cancers. Workers exposed to EtO are associated with an increased risk of cancers of the white blood cells, as well as an increased risk of breast cancer in females.

It is important to recognize that each type of cancer has its own risk factors, some of which are better understood than others. It is very rare that a specific cause can be found for any particular case of cancer. More information is available on the CDC’s Agency for Toxic Substances and Disease Registry (ATSDR).

It should be noted that the West Virginia Department of Health and Human Resources’ Bureau for Public Health (BPH) conducted an initial assessment of the cancer registry for the areas of concern in Institute and South Charleston in December 2019 and did not identify elevated levels of the cancers associated with EtO in these areas.


What is DEP Doing to Address the Concerns of EtO?

The WVDEP is partnering with the USEPA, facilities that use EtO, communities, and other stakeholders to further identify and evaluate the sources of EtO emissions in West Virginia. The department’s efforts include:

  • Immediately contacted the State Department of Health and Human Resources' (DHHR) Bureau for Public Health (BPH) for a review of the cancer registry for the areas identified by the EPA. BPH has not found elevated levels of the cancers associated with EtO in these areas.

  • Gathered updated emissions data (2017) and weather data more representative of local conditions because the EPA's assessment used 2014 emissions data and weather data from Yeager Airport.

  • Performed significantly more detailed, site-specific emissions modeling than previously done by the EPA. Modeling is a mathematical simulation, like weather forecasting models, used to predict the way pollutants behave in the atmosphere under different emission rates, weather, and operating scenarios.

  • Requested the EPA to expedite their review of air regulations that govern EtO sources in West Virginia and across the country.

  • Requested the facilities that emit EtO to commit, in writing, to voluntary work practices that go above and beyond what is required by state and federal regulations. ​The facilities have all committed to these voluntary practices.

  • Conducted fence line monitoring around the EtO-emitting facilities in South Charleston and Institute in 2022.

  • Issued a press release in 2019 outlining the new findings related to EtO.

  • Created an EtO webpage and online mailing list to keep the public informed and provide updates.

  • Hosted meetings with state and local elected officials and the public in the fall of 2021.

  • Hosted in-person public meetings in March (Dunbar) and August (North Charleston) 2022.

  • Has and will continue to participate in Community Advisory Panels (CAPs) for the South Charleston and Institute areas. CAPs are monthly meetings between citizens and industry representatives designed to increase communication and transparency. To learn more about a CAP, contact Mary Green at mgreen@magc.info.

  • Has and will continue to provide updates on EtO and other environmental topics via virtual town hall meetings with the agency’s Environmental Advocate. These meetings are open to all citizens.

  • Continuing to enforce existing state and federal regulations, and permits, including those relating to EtO emissions.

What is USEPA Doing to Reduce EtO Nationally?

The USEPA regularly reviews Clean Air Act regulations for facilities that emit hazardous air pollutants, including EtO, to ensure that they protect the public from significant risk. In addition, they are beginning work to review other regulations for facilities that emit EtO.

The following existing federal rules addressing industries using or producing EtO are under review for updates, with their anticipated final date:

  • Commercial sterilizers, 2022

  • Hospital sterilizers, 2023

  • Group 1 polymers and resins (neoprene), 2024

  • Synthetic organic chemicals manufacturing industry, 2024

  • Polyether polyols production, 2024

  • Chemical manufacturing area sources, 2024

Unknowns About EtO

There are still many unanswered questions regarding EtO, and the risk of exposure to low levels of EtO is not well understood. The USEPA is working to find answers to questions such as:

  • Why is EtO found in areas with no known sources and what are those sources?

  • How do the ambient levels of EtO vary nationally and seasonally across the country?

  • How long does EtO persist in the atmosphere?

  • What is its involvement of atmospheric chemistry and transport?

  • What are the best methods for measuring EtO in real-time and/or at the source?

  • How can methods used to monitor for EtO be improved?

  • What are the next steps if the presence of EtO is confirmed to be everywhere?

While the USEPA and State air agencies are working together to better understand emissions in areas identified by the 2014 NATA, national air quality data shows that total emissions of air toxics are declining, and the concentrations of many air toxics are trending downward.

For the latest information from the USEPA, please visit EPA’s Actions on Ethylene Oxide webpage.

Further Reading

Union Carbide Corporation

Union Carbide Corporation (UCC) is appreciative of the opportunity to communicate with the West Virginia Department of Environmental Protection (WVDEP) regarding its commitment to reducing ethylene oxide (EtO) emissions at our facilities at Institute and South Charleston. We understand our responsibility to the community in which we operate and use the best available science and technology, and advanced monitoring capabilities, to reduce EtO emissions. UCC is committed to high operational and safety practices that meet or exceed current federal and state regulations and align with our Company’s own aggressive sustainability goals. We have proactively worked to reduce fugitive EtO emissions by:

  1. Repairing components with detected leaks at detection levels lower than what is considered a leak by applicable regulation

  2. Voluntarily increasing monitoring frequency of potential leak points more than required by the regulation

  3. Reducing the number of fugitive components by replacing the components with welded connections.

UCC is very proud of our teams who safely operate our facilities and will continue to explore proactive measures to further reduce EtO emissions.

Covestro, LLC

Covestro is focused on the health and safety of our employees and the residents of the community surrounding our South Charleston facility. Our facility was designed to minimize potential emissions of ethylene oxide and we continually monitor our systems and equipment in accordance with the EPA and DEP management programs, and as such, operate well within the applicable regulations. We are closely following the developments surrounding ethylene oxide, including working with the EPA and DEP, and we are committed to operating our plant safely.

Covestro continuously reviews our emissions management protocols across our entire operation, including ethylene oxide, and actively surpasses EPA requirements with regard to our monitoring program. This includes monitoring potential leak points more often than the current EPA requirements as well as taking action to correct any detected leaks at levels below current EPA requirements. Covestro is committed to working with our industry partners and the WV DEP to appropriately respond to the DEP assessment in the best interest of our employees and our community.


Specialty Products US, LLC

Specialty Products US, LLC exceeds regulatory requirements by conducting monitoring more frequently than required, making proactive repairs and consistently evaluating opportunities for improvement.

Additional Links and Related Information

Contact Us

West Virginia Department of Environmental Protection
Division of Air Quality
601 57th Street SE
Charleston, WV 25304
Phone: (304) 926-0475​

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