Ethylene oxide is primarily used in the manufacture of other chemicals. Most ethylene oxide is used to manufacture ethylene glycol (used in automotive antifreeze/coolant) and polyester. Ethylene oxide is also used for the sterilisation of equipment in hospitals and veterinary institutions. A small amount is also used to control pests on stored agricultural products.
Substance name: Ethylene oxide
CASR number: 75-21-8
Molecular formula: C2H40
Synonyms: 1,2-Epoxyethane, ETO, EtO, E.O., Ethene oxide, Alpha,beta-oxidoethane, oxirane, Dimethylene Oxide, oxacyclopropane, dihydrooxirene, oxane, oxyfume, oxyfume 12 fema no.2433, amprolene, amproline.
A colourless gas.
Melting Point: -113°C
Boiling Point: 10.5°C
Specific Gravity: 0.9
Flammable. Ethylene oxide is irritating, yet has a sweet etherlike odour. It is highly reactive and will completely dissolve in water.
The National Pollutant Inventory (NPI) holds data for all sources of ethylene oxide emissions in Australia.
Short term exposure will cause irritation of the eyes and mucous membranes (mouth, nose, throat). Increasing levels of exposure can cause dizziness, nausea, difficulty in breathing, depression of the central nervous system, burns, eye damage, convulsions and death. Long term exposure may cause irritation of the eyes, skin, and mucous membranes, problems with brain and nerve functions and cataracts. Shoes and clothing contaminated with ethylene oxide may cause burns at a later time. Both short term and long term exposure may result in increased rates of miscarriages. Ethylene oxide is classified as a probable carcinogen by Worksafe Australia. There may be no safe level of exposure to a carcinogen.
Entering the body
Ethylene oxide can enter your body when air containing ethylene oxide is breathed into your lungs. Because it evaporates very quickly it is very unlikely for it to remain in food products or water. If you have been exposed to ethylene oxide it leaves your body through exhaling it from your lungs or through urine and faeces.
You are not likely to be exposed to ethylene oxide in the general environment. You may be exposed to ethylene oxide if you work where it is manufactured or used. Examples: the chemical industry, health care, fumigating agricultural products.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for ethylene oxide through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 1 parts per million (1.8 mg/m3)
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
There is no guideline for ethylene oxide in the Australian Drinking Water Guidelines.
The immediate effects of exposure to high concentrations of ethylene oxide can mean death of animals, birds or fish and death or low growth rate in plants. Long-term effects on animal life may include shortened lifespan, reproductive problems, lower fertility, and changes in appearance or behaviour. Ethylene oxide has moderate long term toxicity to aquatic life.
Entering the environment
If spilled in water ethylene oxide will spread on the surface, vaporise, and mix with the water. Ethylene oxide can also be dispersed by the wind.
Where it ends up
Because it is so reactive ethylene oxide will not stay in the environment very long. Ethylene oxide is converted to ethylene glycol when released. Ethylene oxide is not persistent in air due to washout by rain and degradation by chemical processes. Short term ecological effects of larger contaminations are: death of animals including birds and fish, death of plants or low growth rates in plants. Ethylene oxide has moderate acute (short term) toxicity to aquatic life. Long term effects may include shortened lifespan, reproductive problems and lower fertility rates.
No national guidelines.
Chemical manufacture, manufacturing industries may release to air.
Diffuse sources, and industry sources included in diffuse emissions data
Release to air from some agricultural fumigation.
Ethylene oxide is unlikely to be found in the general environment. No significant natural sources of ethylene oxide are known.
Spices at extremely low levels.
Sources used in preparing this information
- Agency for Toxic Substances and Disease Registry (1989), Public Health Statement (accessed, March, 1999)
- Australian and New Zealand Environment and Conservation Council (ANZECC) (1992), Australian Water Quality Guidelines for Fresh and Marine Waters.
- ChemFinder WebServer Project (1995), Ethylene oxide (accessed, March, 1999)
- Environmental Defense Fund (1998), Ethylene Oxide: The Chemical Scorecard: (accessed, March, 1999)
- Environmental Health Center, A division of the National Safety Council, Environment Writer – Chemical Backgrounders (February, 1999) (accessed, March, 1999)
- Meagher, D (1991), The Macmillan Dictionary of The Australian Environment, Macmillan Education Australia Pty Ltd.
- National Environment Protection Council (1997), Information Bulletin On air Pollutants (accessed, March, 1999)
- National Environment Protection Council (1998), National Environment Protection Measure for the National Pollutant Inventory (accessed, March, 1999)
- New Jersey Department of Health and Senior Services (1995), Hazardous Substance Fact Sheet, PO Box 368, Trenton, NJ.
- New Jersey Department of Health, Right to Know Program (1986), TRIFacts (accessed, March, 1999)
- Richardson, M (1992), Dictionary of Substances and their Effects, Royal Society of Chemistry, Clays Ltd, England.
- Sittig, M (1991), Handbook of Toxic and Hazardous Chemicals and Carcinogens, 3rd edition, Noyes Publications, USA.
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- US Department of Health and Human Services (1990), NIOSH Pocket Guide to Chemical Hazards, Publication No. 90-117.
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed June 2021.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018