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Miscellaneous Organic Chemical Manufacturing National Emission Standards for Hazardous Air Pollutants Risk and Technology Review

EPA is proposing amendments to the 2003 Miscellaneous Organic Chemical Manufacturing National Emission Standards for Hazardous Air Pollutants (NESHAP), known as the MON.

After fully implementing the NESHAP, EPA has evaluated the risks remaining  and determined cancer risks from the miscellaneous organic chemical manufacturing 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. Once these requirements are implemented, EPA proposes that risks are acceptable and provide an ample margin of safety to protect public health and the environment.

EPA identified cost-effective developments in practices, processes or control technologies for heat exchange systems and equipment leaks that would further reduce emissions of hazardous air pollutants. In addition, EPA is proposing amendments for added monitoring and operational requirements for flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins, and is also allowing facilities to opt in to these flare requirements in lieu of complying with the current flare standards. The proposal includes clarifying language that the standards are applicable during periods of startup, shutdown and malfunction. This proposal also includes electronic reporting of performance test results and reports, performance evaluation reports and compliance reports.

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 range of models used 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 rule.

Read the summary fact sheet and memorandum below.

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