This action finalizes the residual risk and technology review (RTR) conducted for the Miscellaneous Organic Chemical Manufacturing source category regulated under national emission standards for hazardous air pollutants (NESHAP). The U.S. Environmental Protection Agency (EPA) is finalizing decisions concerning the RTR, including amendments pursuant to the technology review for equipment leaks and heat exchange systems, and also amendments pursuant to the risk review to specifically address ethylene oxide emissions from storage tanks, process vents, and equipment leaks. 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 general exemptions for periods of SSM, adding work practice standards for periods of SSM where appropriate, and clarifying regulatory provisions for certain vent control bypasses. The EPA is also taking final action to add monitoring and operational requirements for flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins; add provisions for electronic reporting of performance test results and other reports; and include other technical corrections to improve consistency and clarity. We estimate that these final amendments will reduce hazardous air pollutants (HAP) emissions from this source category by approximately 107 tons per year (tpy) and reduce ethylene oxide emissions from this source category by approximately 0.76 tpy. We also estimate that these final amendments will reduce excess emissions of HAP from flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins by an additional 263 tpy.