Air quality standards – Washington State Department of Ecology

Ethylene oxide (EtO) is a colorless, flammable gas. At very high levels, it smells like ether. EPA has classified ethylene oxide as an air toxic. It is a chemical ingredient used in solvents, antifreeze, textiles, and glues. It is also used to sterilize surgical equipment — particularly plastics that are difficult to sterilize with steam.

EPA’s most recent National Air Toxics Assessment identified several locations that may have higher cancer risks from long-term exposure to ethylene oxide. Most of these places are close to where ethylene oxide is made or to industries that use the chemical.

Even though none of these locations are in Washington, Ecology’s air quality monitoring station near downtown Seattle has found ethylene oxide. Based on this and on studies from other areas, we are following this as an emerging health concern.