EPA reaches out to communities exposed to ethylene oxide emissions from commercial sterilizers


Aug. 22, 2022

The Environmental Protection Agency made an announcement on August 3, 2022, of its plans to address the risks posed by ethylene oxide (EtO) emissions from commercial sterilizers and to engage with the communities most affected by these emissions due to their proximity to the facilities. EPA will hold a webinar on August 10, 2022, to provide current information on risks and plans to reduce exposure followed by meetings in affected communities. EPA also announced a proposed air pollution regulation addressing EtO emissions from commercial sterilizers will be issued later this year.

What is ethylene oxide and why is it a problem?

  • According to the EPA, ethylene oxide or EtO (CAS RN 75-21-8) is a colorless gas used to sterilize 50% of medical devices and dental equipment that cannot be sterilized using steam or radiation. It is also used to sterilize some food products and spices, and as a pesticide. [ For more on how EtO is used in medical applications, read AgencyIQ Life Science’s analysis here or POLITICO Pro’s analysis here .]
  • EtO is also produced in large volumes for use in the manufacture of other chemicals and products including antifreeze, textiles, plastics, detergents, and adhesives.
  • EPA explained in its announcement that EtO is known to cause cancer (blood and breast) when it is breathed in over the course of many years. Although the emissions from these facilities manufacturing or using ethylene oxide do not exceed short-term health benchmarks, the problem is with exposure over a lifetime. Consequently, the surrounding communities, referred to as “fenceline communities” are exposed to these emissions at levels much higher than residents not living in proximity to the 23 medical sterilizing facilities or these other sterilizing facilities throughout the U.S.

How is ethylene oxide evaluated and regulated?

  • Sterilizing facilities using EtO must comply with Section 112 of the Clean Air Act (CAA) which identifies EtO as a hazardous air pollutant because it is suspected to cause cancer in humans, is highly mutagenic and teratogenic, and has significant acute and subchronic exposure health effects.
  • In 1994, the EPA promulgated the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for EtO commercial sterilization and fumigation operations which was last updated in 2006. EtO is listed as a substance used in miscellaneous organic chemical manufacturing called the MON under NESHAP. NESHAP establishes emission standards for both major and area sources that use at least 1 ton of EtO in sterilization or fumigation operations in any 12-month period.
  • The standards require existing and new major sources to control emissions to the level achievable by the maximum achievable control technology (MACT) which are performance criteria designed to significantly reduce air toxics emissions, and by requiring existing and new area sources to control emissions using generally available control technology (GACT) which are less stringent standards.
  • In 2016, the EPA released its updated Integrated Risk Information System (IRIS) unit risk estimate for EtO , which indicated that cancer risks from EtO were significantly higher than previously understood.
  • Subsequently, the EPA released the National Air Toxics Assessment (NATA) in August 2018, identifying EtO emissions from commercial sterilization that contribute to health risks across the U.S.
  • In an effort to determine if the EtO emissions should be further restricted, the EPA published an advanced notice of proposed rulemaking (ANPRM) in December 2019 to obtain information from industry and the public to potentially revise the existing standards for sterilization facilities utilizing EtO. The ANPRM sought information including, the calculation, capture, and control of fugitive emissions, and practices to reduce them; existing and new types of control devices and process equipment and improvements to efficiency; and improvements to EtO monitoring technologies. This is referred to as the Risk and Technology Review for MON.
  • Two information collection requests were proposed in 2020 and 2021, with the goal of better understanding emission sources, measurement and monitoring techniques, available control technologies and efficiencies. The EPA broadened its data collection efforts to include all facilities subject to ethylene oxide emission standards for sterilization facilities (40 CFR part 63, subpart O) that were not involved in a December 2019 questionnaire.
  • EPA also issued a final rule on August 12, 2020, finalizing the residual risk and technology review conducted for the MON source category regulated under NESHAP. With this rule, the EPA finalized amendments to the technology review for equipment leaks and heat exchange systems, and to the risk review for EtO emissions from storage tanks, process vents, and equipment leaks. The EPA also added monitoring and operational requirements for flares that control ethylene oxide emissions and provisions for electronic reporting of performance test results among other changes.
  • The EPA then published a rule on February 4, 2022 proposing to reconsider the August 2020 final rule due to the use of the 2016 IRIS inhalation unit risk estimate for EtO in assessing cancer risk for the source category. The risk review determined that the risks for this source category under the current MACT provisions were unacceptable due to ethylene oxide emissions. This led to the EPA promulgating the 2020 final amendments to the MON that require control of ethylene oxide emissions for process vents, storage tanks, and equipment. The EPA declared the 2020 MON final rule reduced risks to an acceptable level with an ample margin of safety to protect public health.
  • Following promulgation of the 2020 final rule, EPA received five petitions, four of which requested EPA to reconsider the rule to reassess the risk assessment for the 2020 MON using a different alternative risk value for EtO rather than the IRIS value. The Texas Commission on Environmental Quality (TCEQ) risk value for EtO which was finalized after the comment period for the proposed MON rulemaking closed, was proposed to be used. Since the 2020 MON final rule preamble stated that the EPA remains open to new and updated scientific information, such as the TCEQ value, EPA reviewed the TCEQ.
  • EPA found the TCEQ estimated risk value for EtO is 2000-fold lower than the IRIS risk value. It does not include women in its assessment, nor does it provide new studies or other information suggesting TCEQ’s unit risk estimate (URE) provides a better estimate of risk exposure from EtO. Consequently, EPA proposed to reaffirm its decision to use the IRIS URE in the 2020 MON final rule.
  • This rule, Reconsideration of the 2020 National Emission Standards for Hazardous Air Pollutants (NESHAP): Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review has been submitted for review and is in the final stage of rulemaking which should be finalized this year.
  • Under the Emergency Planning and Community Right-to-Know Act (EPCRA), the EPA has the discretionary authority to extend reporting requirements to specific facilities based on a chemical’s toxicity, the facility’s proximity to other facilities that release the chemical or to population centers, any history of chemical releases at the facility, or other factors the EPA deems appropriate. Consequently, In December 2021, EPA extended Toxics Release Reporting requirements on EtO to include 29 contract sterilization facilities that use EtO but are not required to report to EPA. These facilities were required to start tracking their chemical activities and releases and other waste management quantities beginning in January 2022 and, if appropriate, submit TRI data beginning in 2023.

Next steps

  • EPA Administrator, Michael Regan made this statement in the August 3, 2022, press release, “Today, EPA is taking action to ensure communities are informed and engaged in our efforts to address ethylene oxide, a potent air toxic posing serious health risks with long-term exposure. Under my watch, EPA will do everything we can to share critical information on exposure risk to the people who need and deserve this information, and to take action to protect communities from pollution.”
  • EPA is holding a national public webinar on the evening of August 10, 2022, from 8 p.m. to 9:30 p.m. to focus on the national scope of EtO risks. EPA will share details of the risk assessment for EtO, and efforts to reduce this risk. EPA will also listen to concerns and answer questions.
  • After this national webinar, EPA will host individual meetings in the upcoming weeks in each of the communities found to be at the highest risk. Information will be posted on the page for each community listed here. EPA has also provided a full list of all commercial sterilizers in the U.S. and has stated that later in 2022, it will release additional, national-level information about the risks that EtO creates to those who work in EtO facilities, as well as those who spend time near them.
  • Certain contract sterilization facilities utilizing EtO will now be required to report emissions in accordance with the Toxics Release Inventory (TRI) for data on chemical activities, releases, and other waste management quantities starting from January 1, 2022, to be reported In July 2023.
  • These sterilization facilities utilizing EtO are necessary to human health but also cause toxic emissions that are particularly dangerous to the residents of communities in close proximity to these facilities. It is expected that the new TRI reporting requirements will help EPA to better evaluate those emissions and discharges in order to mitigate the damage to the local residents.
  • EPA is moving ahead with actions under the Clean Air Act that will address air emissions of ethylene oxide. The EPA is currently reviewing the rule for commercial sterilizers and intends to use the 2016 IRIS values in the upcoming proposed rule.
  • The new rule for commercial sterilizers expected later this year, will impose new requirements to reduce emissions of EtO with additional requirements concerning process vents and storage tanks in EtO service. EPA has stated that these final amendments are expected to result in reductions of EtO emissions of approximately 0.76 tons per year.

To contact the author of this item, please email Patricia Iscaro.
To contact the editor of this item, please email Alexander Gaffney

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