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PUBLIC HEALTH STATEMENT 

ETHYLENE OXIDE 

CAS#: 75-21-8 

Division of Toxicology December 1990 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for Ethylene 

oxide. It is one in a series of Public Health 

Statements about hazardous substances and their 

health effects. A shorter version, the ToxFAQsTM is 

also available. This information is important 

because this substance may harm you. The effects 

of exposure to any hazardous substance depend on 

the dose, the duration, how you are exposed, 

personal traits and habits, and whether other 

chemicals are present. For more information, call 

the ATSDR Information Center at 1-888-422-8737. 

This Statement was prepared to give you 

information about ethylene oxide and to emphasize 

the human health effects that may result from 

exposure to it. The Environmental Protection 

Agency (EPA) has identified 1,177 sites on its 

National Priorities List (NPL). Ethylene oxide has 

not been definitely identified at any NPL site. 

However, it has been tentatively identified at three 

of these sites. As EPA evaluates more sites, the 

number of sites at which ethylene oxide is found 

may change. This information is important for you 

to know because ethylene oxide may cause harmful 

health effects and because these sites are potential 

or actual sources of human exposure to ethylene 

oxide. 

When a chemical is released from a large area, such 

as an industrial plant, or from a container, such as a 

drum or bottle, it enters the environment as a 

chemical emission. This emission, which is also 

called a release, does not always lead to exposure. 

You can be exposed to a chemical only when you 

come into contact with the chemical. You may be 

exposed to it in the environment by breathing, 

eating, or drinking substances containing the 

chemical or from skin contact with it. 

If you are exposed to a hazardous substance such as 

ethylene oxide, several factors will determine 

whether harmful health effects will occur and what 

the type and severity of those health effects will be. 

These factors include the dose (how much), the 

duration (how long), the route or pathway by which 

you are exposed (breathing, eating, drinking, or skin 

contact the other chemicals to which you are 

exposed, and your individual characteristics such as 

age, sex, nutritional status, family traits, life style, 

and state of health. 

1.1 WHAT IS ETHYLENE OXIDE? 

Ethylene oxide (also known as ETO or oxirane) is a 

flammable gas with a somewhat sweet odor. It 

dissolves easily in water, alcohol, and most organic 

solvents. Ethylene oxide is produced in large 

volumes and is used to make other chemicals, 

especially ethylene glycol, a chemical used to make 

antifreeze and polyester. Most ethylene oxide is 

used up in the factories where it is produced. A very 

small amount (less than 1%) is used to control 

insects on stored agricultural products such as nuts 

and spices. 

Ethylene oxide is also used in very small amounts 

in hospitals to sterilize medical equipment and 

supplies. 

When ethylene oxide is produced or used, some of 

the gas is released to air and water. If it is released 

into the air, humidity and sunlight cause it to break 

down within a few days. In water, ethylene oxide 

will either break down or be destroyed by bacteria 

within a few days. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

ETHYLENE OXIDE 

CAS#: 75-21-8 

Division of Toxicology December 1990 

1.2 HOW MIGHT I BE EXPOSED TO 

ETHYLENE OXIDE? 

You are not likely to be exposed to ethylene in the 

general environment. In studies of the air quality in 

Texas and California, no ethylene oxide was found. 

There is also no evidence that ethylene oxide is 

commonly found in water. Because of the limited 

information about ethylene oxide in air, water, or 

soil at hazardous waste sites, we do not know how 

likely it is that you might be exposed to ethylene 

oxide at or near these sites. 

You may be exposed to ethylene oxide if you work 

where it is produced or used. Health care workers, 

such as technicians, nurses, and physicians in 

hospitals and clinics, may have contact with 

ethylene oxide because it is used to sterilize medical 

equipment and supplies. Since ethylene oxide is 

used as a fumigant to spray agricultural products, if 

you are a farmer or work on a farm where ethylene 

oxide is used, you may also be exposed to this 

substance. 

It is not known if food crops are a source of 

exposure to ethylene oxide for the general public. 

Ethylene oxide has been found at levels up to 3.5 

parts of ethylene oxide per one million parts of food 

(3.5 ppm) in some foods shortly after being sprayed 

with pesticide that contains it. These levels decrease 

with time as ethylene oxide evaporates or breaks 

down into other substances, and thus little or none 

may remain when the food is eaten. 

1.3 HOW CAN ETHYLENE OXIDE ENTER 

AND LEAVE MY BODY? 

Ethylene oxide can enter your body when air 

containing this substance is breathed into your 

lungs. Because ethylene oxide evaporates very 

easily, it is unlikely that it remains in or on food or 

remains dissolved in water long enough to be eaten 

or swallowed, although this is not known for 

certain. It is not known if ethylene oxide can enter 

the body through the skin. 

After a person has been exposed to ethylene oxide, 

it leaves the body through the urine or feces or by 

breathing it out through the lungs. This probably 

occurs very rapidly, perhaps within 2 or 3 days. 

1.4 HOW CAN ETHYLENE OXIDE AFFECT 

MY HEALTH? 

Ethylene oxide can cause a wide variety of harmful 

health effects in exposed persons. In general, with 

higher levels of exposure to the chemical, more 

severe effects will occur. The major effects seen in 

workers exposed to ethylene oxide at low levels for 

several months or years are irritation of the eyes, 

skin, and mucous membranes and problems in the 

functioning of the brain and nerves. At higher levels 

of exposure to ethylene oxide, which may result 

from accidents or equipment breakdown, the types 

of effects are similar, but they are more severe and 

harmful. There is also some evidence that exposure 

to ethylene oxide can cause an increased rate of 

miscarriages in female workers exposed to ethylene 

oxide. Studies in animals have shown that breathing 

ethylene oxide at high levels can interfere with their 

ability to reproduce. Litter sizes have been smaller 

than usual, and the babies of exposed animals have 

weighed less than normal and have had delayed 

bone formation. 

Scale studies of workers exposed to ethylene oxide 

in ethylene oxide factories or hospital sterilizing 

rooms have shown an increased incidence of 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

ETHYLENE OXIDE 

CAS#: 75-21-8 

Division of Toxicology December 1990 

leukemia, stomach cancer, cancer of the pancreas 

and Hodgkin's disease. Ethylene oxide has also 

been shown to cause cancer in laboratory animals. 

Leukemia, brain tumors, lung tumors and tumors of 

the tear glands of the eye have been found. 

1.5 WHAT LEVELS OF EXPOSURE HAVE 

RESULTED IN HARMFUL HEALTH 

EFFECTS? 

Skin contact with ethylene oxide can result in 

blisters and burns that may appear to be similar to 

frostbite. With longer times of contact, there is a 

more severe reaction. Eye damage can also result 

from ethylene oxide contact. 

It is possible to smell ethylene oxide if it is present 

in water at or above 140 mg per liter (about one 

quart) of water. It can also be smelled in air if it is 

present at or above 430 ppm (430 parts of ethylene 

oxide per million parts of air). 

Exposure to high levels (700 ppm) of ethylene 

oxide in air has resulted in seizures and cataracts in 

people. Exposure to lower levels has resulted in 

problems with hand/eye coordination and eye and 

nose irritation. In animals, kidney damage has been 

seen at levels of 100 ppm, while lower levels (50 

ppm) have resulted in decreased physical activity. 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO ETHYLENE OXIDE? 

There are two kinds of tests that can determine if 

you have been exposed to ethylene oxide within the 

last couple of days. These tests are not routinely 

done in a doctor's office, but can be done in a 

special laboratory. One test measures this substance 

in blood, the other measures it in air that you 

breathe out of your lungs. If you were exposed to 

ethylene oxide more than two or three days ago, 

there may be no ethylene oxide remaining in your 

body. In addition, if you have been exposed to very 

low levels of ethylene oxide, these tests may not 

detect it. The results of these tests cannot be used to 

predict the type or severity of health effects 

resulting from exposure. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The Food and Drug Administration (FDA) has set a 

tolerance limit of 50 ppm of ethylene oxide in 

ground spices. Any release to the environment 

greater than 10 pounds must be reported to the EPA. 

The Occupational Safety and Health Administration 

(OSHA) has set a limit of 1 ppm over an 8-hour 

workday, 40-hour workweek with a short-term 

exposure limit (not to exceed 15 minutes) of 5 ppm. 

The National Institute of Occupational Safety and 

Health (NIOSH) recommends that average 

workplace air should contain less than 0.1 ppm 

ethylene oxide averaged over a 10-hour workday, 

40-hour workweek. 

The federal recommendations have been updated as 

of July 1999. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

ETHYLENE OXIDE 

CAS#: 75-21-8 

Division of Toxicology December 1990 

1.8 WHERE CAN I GET MORE 

INFORMATION? 

If you have any more questions or concerns, 

please contact your community or state health or 

environmental quality department or: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology 

1600 Clifton Road NE, Mailstop F-32 

Atlanta, GA 30333 

Information line and technical assistance: 

Phone: 888-422-8737 

FAX: (770)-488-4178 

ATSDR can also tell you the location of 

occupational and environmental health clinics. 

These clinics specialize in recognizing, evaluating, 

and treating illnesses resulting from exposure to 

hazardous substances. 

To order toxicological profiles, contact: 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

Phone: 800-553-6847 or 703-605-6000 

Reference 

Agency for Toxic Substances and Disease Registry 

(ATSDR). 1990. Toxicological profile for ethylene 

oxide. Atlanta, GA: U.S. Department of Health and 

Human Services, Public Health Service. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov