Substance fact sheet
The background information page contains information and concepts that will be useful in understanding some of the issues surrounding the NPI. It is strongly recommended that you read this before reading the information presented below.
For an explanation of some of the terms used in this page, see the Glossary
| 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 |
Physical and chemical properties Physical properties: A colourless gas Melting Point (°C): -113 Boiling Point (°C): 10.5 Specific Gravity: 0.9 Chemical properties: |
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Common uses 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. |
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Sources of emissions Point sources Chemical manufacture, manufacturing industries may release to air. Diffuse sources, and point sources included in aggregated emissions data Release to air from some agricultural fumigation. Natural sources Ethylene oxide is unlikely to be found in the general environment. No significant natural sources of ethylene oxide are known. Mobile sources Car exhaust. Consumer products which may contain Ethylene oxide Spices at extremely low levels |
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Health effects How might I be exposed to Ethylene oxide? 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. By what pathways might Ethylene oxide enter my 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. Relative health hazard On a health hazard spectrum of 0 - 3 Ethylene oxide registers 2.8. A score of 3 represents a very high hazard to health, 2 represents a medium hazard and 1 is harmful to health. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the evaluation of its tendency to cause, or not cause cancer and/or birth defects. It does not take into account exposure to the substance. Human exposure is reflected in the NPI rank given to this substance (see comparative data below). A substance that scores highly as a health hazard is arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.  Health guidelines Worksafe Australia allows a worker to be exposed to no more than 1part per million of ethylene oxide on a time weighted average basis. See the Additional Information page for current health information. The Australian NOHSC National Exposure Standards Database link is probably the most useful source of information. Note that the emissions data in the NPI database is not directly comparable with these guidelines. What effect might Ethylene oxide have on my health? 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. |
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Environmental effects Environmental Fate 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. Environmental Transport 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. Relative hazard to the environment On an environmental spectrum of 0 - 3 Ethylene oxide registers 1. A score of 3 represents a very high hazard to the environment and 0 a negligible hazard. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the measure of its ability to remain active in the environment and whether it accumulates in living organisms. It does not take into exposure to the substance. Environmental exposure is reflected in the NPI rank for this substance (see comparative data below). A substance that scores highly as an environmental hazard is oxides of nitrogen at 3.0 and one of the lower scores is carbon monoxide at 0.8.  Environmental guidelines See the Additional Information page for current environmental guidelines. No national guidelines. What effect might Ethylene oxide have on the environment? 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. |
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Comparative data NPI Rank Approximately 400 substances were considered for inclusion on the NPI reporting list. A risk ranking was given based on health and environmental hazard identification and human and environmental exposure to the substance. Some substances were grouped together at the same rank with 208 ranks in total. Ethylene oxide was ranked as 46 out of the 208 ranks. Total hazard score (human health + environmental criteria) = 3.8.  |
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Sources of information used in preparing this article
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