Ethylene Oxide


CAS No. 75-21-8

Ethylene oxide (C₂H₄O) is a flammable gas with a somewhat sweet odor. Exposure to ethylene oxide may cause headache, nausea, vomiting, diarrhea, breathing difficulty, drowsiness, weakness, exhaustion, eye and skin burns, frostbite, and reproductive effects. Workers may be harmed from exposure to ethylene oxide. The level of exposure depends upon the dose, duration, and work being done.

Ethylene oxide is used in many industries. It’s used to make ethylene glycol, a product used in antifreeze and polyester.  Some examples of workers at risk of being exposed to ethylene oxide include the following:

  • Factory workers in plants that use it to produce solvents, antifreeze, textiles, detergents, adhesives, and polyurethane foam
  • Factory workers who work in plants that manufacture ethylene oxide
  • Agricultural workers who use it to control insects in grain bins
  • Hospital workers who use it to sterilize medical equipment and supplies

NIOSH recommends that employers use Hierarchy of Controls to prevent injuries. If you work in an industry that uses ethylene oxide, please read chemical labels and the accompanying Safety Data Sheets for hazard information. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.

The following resources provide information about occupational exposure to ethylene oxide. Useful search terms for ethylene oxide include “dimethylene oxide,” “1,2-epoxy ethane,” and “oxirane.”

NIOSH Chemical Resources

Related NIOSH Resources

Selected Publications

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International Resources

Page last reviewed: June 21, 2019