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Ethylene Oxide


CAS No. 75-21-8

Ethylene oxide (C₂H₄O) is a flammable gas with a slightly sweet odor. People exposed to it may:

  • Have headaches
  • Feel sick to the stomach
  • Vomit
  • Have diarrhea
  • Have trouble breathing
  • Feel sleepy
  • Feel weak
  • Be very tired
  • Have eye and skin burns
  • Get frostbite
  • Have reproductive problems

Ethylene oxide may harm workers, and the harm it may cause varies depending on the situation. Possible harm can involve how much ethylene oxide a worker is exposed to, how long the worker is exposed, and what the worker is doing.

Many industries use ethylene oxide. Some use it to make ethylene glycol, which industries use to make antifreeze and polyester.

Here are examples of workers who may come into contact with ethylene oxide:

  • Factory workers in plants that use it to make solvents, antifreeze, textiles, detergents, adhesives, or polyurethane foam
  • Factory workers in plants that make ethylene oxide
  • Farm workers who use it to control insects in grain bins
  • Hospital workers who use it to kill germs on medical equipment and supplies

NIOSH recommends that employers use the Hierarchy of Controls to prevent injuries. If you work in an industry that uses ethylene oxide, please read chemical labels and review the Safety Data Sheets. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn ways to control chemicals in workplaces.

Other terms for ethylene oxide include “dimethylene oxide,” “1,2-epoxy ethane,” and “oxirane.” Learn more in the resources below about keeping workers safe from ethylene oxide.

NIOSH Chemical Resources

NIOSH Pocket Guide to Chemical Hazard
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The NIOSH Pocket Guide to Chemical Hazards helps workers, employers, and occupational health professionals to find and control workplace chemical hazards.

Manual of Analytical Methods

The NIOSH Manual of Analytical Methods presents methods for sampling and analyzing contaminants in workplace air and in the blood and urine of workers exposed to chemicals in the workplace.

Health Hazard Evaluations
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The Health Hazard Evaluation Program investigates workplaces where chemicals or other health hazards may be present. Use the search tool to learn more about chemical investigations.

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