Environmental Protection


Ethylene Oxide (EtO) Sterilizers

For assistance with compliance regarding the following regulations, contact Occupational Safety and Environmental Health (OSEH) Environmental Protection and Permitting Program (EP3) at (734) 936-1920.

Ethylene Oxide (abbreviated EtO) Sterilizers are used to sterilize and fumigate equipment that cannot support traditional high-temperature steam sterilization. They are often used in hospitals to kill microorganisms on medical equipment and supplies. Contaminated material is placed inside an enclosed space with EtO gas for a certain period of time, then the space is emptied of the gas through several purges. Michigan Department of Environmental Quality (MDEQ) requires all exhaust gas to be vented to an acid-water scrubber or a catalytic oxidation unit that is guaranteed, by the manufacturer, to reduce EtO emissions to the atmosphere by at least 99.9%.

Ethylene oxide is considered a hazardous air pollutant (HAP) because it is mutagenic and teratogenic, and research has shown that it likely causes cancer in humans. To protect human health and the environment, each EtO sterilizer is required to obtain a permit before installation as well as continuously monitor emissions.

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