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

Logo of NIOSH Pocket Guide

The NIOSH Pocket Guide to Chemical Hazards (NPG) helps workers, employers, and occupational health professionals recognize and control workplace chemical hazards.

Logo of Manual of Analytical Methods.Cdc-pdf[PDF - 1 MB]

The NIOSH Manual of Analytical Methods (NMAM) is a collection of methods for sampling and analysis of contaminants in workplace air, and in the blood and urine of workers who are occupationally exposed.

Logo of Health Hazard Evaluations consisting of three letters: HHE

The Health Hazard Evaluation Program (HHE) conducts onsite investigations of possible worker exposure to chemicals. Search the HHE database for more information on ethylene oxide.

Related NIOSH Resources

Selected Publications

Related Resources

International Resources

Page last reviewed: November 2, 2018