National Emission Standards for Hazardous Air Pollutants: Ethylene Oxide Emissions Standards for Sterilization Facilities Residual Risk and Technology Review

This action finalizes the residual risk and technology review (RTR) conducted for the Commercial Sterilization Facilities source category regulated under national emission standards for hazardous air pollutants (NESHAP) under the Clean Air Act. The EPA is finalizing decisions concerning the RTR, including definitions for affected sources, emission standards for previously unregulated sources, amendments pursuant to the risk review to address ethylene oxide (EtO) emissions from certain sterilization chamber vents (SCVs), aeration room vents (ARVs), chamber exhaust vents (CEVs), and room air emissions, and amendments pursuant to the technology review for certain SCVs and ARVs. In addition, we are taking final action to correct and clarify regulatory provisions related to emissions during periods of startup, shutdown, and malfunction (SSM), including removing exemptions for periods of SSM. We are also taking final action to require owners and operators to demonstrate compliance through the use of EtO continuous emissions monitoring systems (CEMS), with exceptions for very small users of EtO; add provisions for electronic reporting of performance test results and other reports; and include other technical revisions to improve consistency and clarity. We estimate that these final amendments will reduce EtO emissions from this source category by approximately 21 tons per year (tpy).