TCC Regulatory Alert: EPA Proposes Hazardous Organic National Emissions Standard for Hazardous Air Pollutants including Ethylene Oxide

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Regulatory Alert

April 10, 2023

 EPA Proposes Hazardous Organic National Emissions Standard for Hazardous Air Pollutants including Ethylene Oxide 

On April 6, 2023, The U.S. Environmental Protection Agency (EPA) has proposed a new Hazardous Organic National emissions standard (HON). The proposal would require a significant reduction in the emissions of hazardous air pollutants including ethylene oxide (EtO) and chloroprene from chemical plants. EPA’s proposal targets a variety of equipment and processes used to make synthetic organic chemicals and a variety of processes used in polymers and resins production, including neoprene production (affecting approximately 200 plants across the country). EPA’s proposal would impose dramatic reductions in EtO emissions from eight plants in Texas, Louisiana, and the Ohio River Valley.

EPA’s proposed rules would require chemical plants to conduct fence-line monitoring if they use, produce, store, or emit any of six “air toxics” including EtO, chloroprene, benzene, 1,3-butadiene, ethylene dichloride and vinyl chloride. If annual average air concentrations of the chemicals are higher than an “action level” at the fence-line, owners and operators would have to find the source and make repairs or implement reductions. The proposed action levels vary depending on the chemical. For EtO, EPA is proposing an action level of 0.2 micrograms per cubic meter of air. Starting one year after monitoring begins, facilities would be required to submit quarterly data to EPA, which would be due within 45 days of the end of each quarter. EPA would make the monitoring data available to the public through its WebFIRE database. EPA is also proposing more protective standards for other equipment and processes that emit air toxics, including EtO. These include more stringent and updated standards for process vents, heat exchange systems, equipment leaks, and storage tanks.

EPA alleges that EtO is harmful to children. Furthermore, using its community risk assessment, EPA states that it intends to propose a rule to reduce emissions of EtO from commercial sterilization facilities and other industries that emit EtO, including polyether polyols production, hospital sterilizers, and chemical manufacturing area sources.

EPA will hold a webinar on the proposal for communities and tribes April 13, 2023, to provide information about the proposed rules and answer questions. Link to register to attend the webinar ( The Agency will take written comments for 60 days after the proposal is published in the Federal Register. EPA will hold a virtual public hearing 21 days after publication. EPA has a consent decree deadline to issue a final rule by March 29, 2024.

TCC will continue to monitor these developments regarding the EPA’s HON proposal and notify members as changes are made.


If you have any questions about this update, please contact Shea Pearson, TCC General Counsel at or 512-646-6403.

Sent by EHCMA on behalf of:

Texas Chemical Council