WASHINGTON (Nov. 6, 2019) — Today, the U.S. Environmental Protection Agency (EPA) continued its progress on a suite of actions to address ethylene oxide by announcing proposed amendments to the Miscellaneous Organic Chemical Manufacturing National Emission Standards for Hazardous Air Pollutants (NESHAP), known as MON, to reduce hazardous air pollutants, including ethylene oxide. EPA is also continuing work to address ethylene oxide from commercial sterilizers; working closely with other federal partners such as the Food and Drug Administration (FDA) to address medical device supplies; and providing an update on its work to better understand ethylene oxide – in particular, work to characterize air concentrations of this chemical.
"EPA’s actions underscore the Trump Administration’s commitment to addressing and reducing hazardous air pollutants, including ethylene oxide emissions, across the country,” said EPA Administrator Andrew Wheeler. “The proposed MON amendments represent the first regulatory action that EPA is taking to address ethylene oxide under our two-pronged approach to reduce emissions. This proposal would reduce other hazardous air pollutants from our nation’s air, while providing improved compliance measures for industry.”
Proposed MON Amendments
The proposed MON amendments are expected to reduce emissions of hazardous air pollutants from the source category by 116 tons per year, which includes a 93 percent reduction in ethylene oxide emissions from covered facilities. The proposal addresses EPA’s obligation under the Clean Air Act to conduct the residual risk and technology (RTR) review for the miscellaneous organic chemical manufacturing source category. EPA has evaluated the risks posed by air toxics from this source category and has determined cancer risks for this source category to be unacceptable. To reduce risks to an acceptable level, EPA is proposing additional requirements for process vents, storage tanks, and equipment in ethylene oxide service. In addition to reducing ethylene oxide emissions, the MON amendments would include updates to requirements for flares, heat exchange systems, and equipment leaks. These proposed requirements would further reduce emission of air toxics for these covered facilities. EPA is taking comment on all aspects of this proposal and will hold public hearings in early December in Washington, DC and Houston, TX. A separate notice will provide details on the hearings shortly.
To further explain the uncertainties in the estimated cancer risks from ethylene oxide, EPA is also posting the Memorandum: Sensitivity of ethylene oxide risk estimates to dose-response model selection, which explores the various dose-response models evaluated in the ethylene oxide carcinogenicity assessment. This information provides important context for interpreting the risk results from the Residual Risk Assessment developed in support of this proposal.
EPA’s Two-Pronged Approach to Ethylene Oxide
EPA has been taking steps to address ethylene oxide emissions after EPA’s National Air Toxics Assessment, issued in 2018, found that ethylene oxide emissions may be contributing to potentially elevated cancer risk in some areas around the country. Since then, EPA has been taking a two-pronged approach to evaluate these emissions. First, the agency is reviewing existing Clean Air Act regulations for industrial facilities that emit ethylene oxide. Second, because the process for revising our regulations takes time, EPA is gathering additional information on ethylene oxide emissions and is working with state and local air agencies to determine whether more immediate emission reduction steps may be warranted. By working with our state and local partners, we seek to identify opportunities to achieve early emission reductions.
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