Ethylene oxide, also called oxirane, is a chemical primarily used in the production of other chemicals.

The International Agency for Research on Cancer (IARC) and the United States Protection Agency (EPA) classify it as a known human carcinogen. Carcinogens are chemicals that can cause cancer.

According to the National Cancer Institute, leukemia and lymphoma are the cancers most frequently associated with chronic ethylene oxide exposure. Weaker evidence suggests that it might also be linked to stomach and breast cancer.

The main way people are exposed to ethylene oxide is by inhaling it. People who work in or live near facilities that contain ethylene oxide seem to be at the highest risk of chronic exposure.

Keep reading to learn more about the link between ethylene oxide and cancer.

Ethylene oxide is a colorless gas at room temperature with a sweet odor. It’s used to make chemicals that are used in products such as:

  • antifreeze
  • detergents
  • adhesives
  • pharmaceuticals
  • polyurethane foam
  • cosmetics and shampoos
  • household cleaners

Ethylene oxide is also used as a pesticide and as a sterilizing agent for medical equipment that can’t be sterilized with high-temperature steam.

It’s estimated that ethylene oxide is used to sterilize over 20 billion medical devices per year to prevent infection. This is equivalent to about half the medical supplies used in the United States. The gas is removed from medical devices before they’re used on humans.

The risk of chronic exposure to ethylene oxide is very low for people in the general population. People at the highest risk of chronic exposure include:

  • factory workers who make products made with ethylene oxide
  • workers in factories that make ethylene oxide
  • farm workers who use ethylene oxide in grain bins
  • hospital workers who use it on medical equipment

People in the general population may be exposed via breathing in tobacco smoke, which also contains ethylate oxide.

Some people who live near facilities that use ethylene oxide may be exposed to factory emissions.

The EPA and IARC both classify ethylene oxide as a cancer-causing chemical when it’s inhaled.

It’s a genotoxic substance, which means it can damage your DNA. Damage to your DNA can turn off signals that tell cells when to undergo cellular death and cause them to become cancerous.

Cancerous cells replicate out of control and can create tumors in solid organ cancers or crowd out healthy cells in blood cancers.

Research suggests that ethylene oxide may only cause DNA damage in concentrations over a certain threshold.

Chronic exposure to ethylene oxide may increase your chances of developing some types of cancers.

The cancers most associated with ethylene oxide exposure are leukemia and lymphoma. It may also be related to stomach and breast cancer, but the evidence is weaker.

Researchers are still trying to understand the link between ethylene oxide exposure and cancer. Research has been conflicting up to this point. According to the EPA, studies have shown workers exposed to ethylene have higher rates of leukemia and lymphoma. Female workers also have higher rates of breast cancer.

The EPA also recently completed an analysis that showed that ethylene oxide emissions in the United States contributed to elevated cancer risk for people living in some communities near factories that use the chemical. They specifically looked at 24 hours a day of exposure for 70 years.

However, in a 2022 review of studies analyzing all the available scientific literature, researchers found evidence suggesting no association between ethylene oxide and cancer at human-relevant exposure levels.

The results of this study were consistent with a 2019 review of studies where researchers concluded that the IARC and EPA classification may overestimate ethylene’s cancer risk.

Sudden inhalation of very high amounts of ethylene oxide can cause symptoms such as:

If ethylene oxide gas contacts your skin or eyes, it can cause irritation or frostbite. Permanent eye damage and blindness are possible.

Workers exposed to low doses for years may experience:

Some evidence suggests ethylene oxide exposure can increase the risk of miscarriage in women.

Doctors can test if you’ve been exposed to ethylene oxide by running tests to look for the chemical in your blood or breath.

However, ethylene oxide leaves your body within hours or days so these tests may not show exposure beyond this time.

Almost everybody is exposed to low levels of ethylene oxide in their daily life. Breathing in high levels of ethylene oxide fumes or coming into contact with it can cause permanent injuries.

If you’re exposed to ethylene oxide, it’s a good idea to:

  • move yourself to fresh air as soon as possible if you inhale ethylene oxide
  • remove yourself from the source of ethylene oxide
  • remove any contaminated clothes as soon as possible
  • if your eyes are exposed, immediately flush them with lukewarm water for at least 15 minutes
  • if ethylene oxide is spilled on your skin, wash thoroughly with soap and water
  • seek emergency medical attention if you develop concerning symptoms

Does living near a commercial sterilizer plant put you at risk for cancer?

Living near a plant that uses ethyl oxide may increase your risk.

An EPA analysis found exposure for 24 hours a day for 70 years can increase cancer risk in people living in communities near factories that use ethylene oxide.

How far do you need to be from a factory that uses ethylene oxide to lower cancer risk?

It’s not clear how far from a factory that uses ethylene oxide you need to be to lower your cancer risk. The farther away you are, the less concentrated chemicals are in the air.

Factors like how much is emitted from the factory, wind speeds, and weather can all influence ethylene oxide concentration.

Are children at greater risk?

Children may be at a higher risk of the harmful effects of ethylene oxide and other chemicals. They’re more susceptible to DNA damage because their bodies are still growing.

Is there ethylene oxide in tobacco smoke?

Tobacco smoke contains ethylene oxide. Avoiding or quitting smoking can help reduce your and your family’s exposure to ethylene oxide and many other harmful chemicals.

Ethylene oxide is a chemical that’s classified as a carcinogenic substance by the EPA and IARC. It’s been most linked to leukemia and lymphoma.

Research has been conflicting on how much chronic ethylene oxide exposure increases your cancer risk. Sudden exposure to high amounts of ethylene oxide can cause potentially serious symptoms like blindness or respiratory failure.

It’s important to seek immediate medical attention if you experience concerning symptoms after coming into contact with high concentrations of ethylene oxide.