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Hazardous Air Pollutants: Ethylene Oxide

Agency Actions on Ethylene Oxide

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Regulations for Ethylene Oxide

The Clean Air Act requires the EPA to regulate emissions of hazardous air pollutants from industrial facilities, and to control these emissions by developing and implementing standards and guidelines. Ethylene oxide – a hazardous air pollutant – is emitted from several types of industrial facilities that are regulated by EPA, including:

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Strategy for Reviewing Ethylene Oxide Emissions

EPA will review Clean Air Act regulations for facilities that emit ethylene oxide to ensure that they protect the public from significant risk. The Agency has begun its review of its air toxics emissions standards for miscellaneous organic chemical manufacturing (often referred to as the “MON”). EPA last updated this rule in 2006 and is under a court order to complete review of the rule by March 2020. As part of this review, the Agency will consider risks to health and the environment, along with advances in work practices, processes or emission controls that can further reduce air toxics emissions.

The Agency also plans to take a closer look at air toxics emissions standards for other industries that emit ethylene oxide to determine whether a review of those rules is needed. EPA will start this closer look with its air toxics emissions standards for commercial sterilizers.

As part of its review of rules, EPA will gather additional information on industrial emissions of ethylene oxide, including where emissions occur, how those emissions can be controlled, and how current emission controls can be improved. The Agency also may seek information from emissions testing at facilities that emit ethylene oxide, focusing first on areas where NATA estimates elevated cancer risk.

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Gathering Emissions Information

For ethylene oxide, facility emissions testing, combined with air quality modeling, can provide a more complete picture of ethylene oxide in the air in an area than air quality monitoring can currently provide. Existing monitoring methods are not sensitive enough to detect ethylene oxide at all levels in the outdoor air. EPA is actively working to develop new techniques for measuring ethylene oxide in the outdoor air.

In addition, data from emissions testing can be used in the review and development of air toxics regulations; data from air quality monitoring cannot. Under the Clean Air Act, air toxics regulations focus on setting limits on the amount of a pollutant an industrial facility can emit to the air.

The information EPA obtains will help the Agency as it evaluates opportunities to reduce ethylene oxide emissions as part of its regulations review. It also will help EPA determine whether more immediate emission reduction steps are necessary in any locations.

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