Decades of research linking ethylene oxide and cancer: Early discoveries and late regulations

The public health risks of ethylene oxide exposure are an emerging issue among the American population today, but most scientists and health experts have already been aware of this problem for decades. EtO is a colorless gas that is widely known for its use in sterilizing medical equipment, dried food supplies, herbs, and many other products. However, its effectiveness in killing microorganisms also makes it dangerous for the healthy cells and the DNA of people exposed to it. Despite many research studies connecting EtO and an increased risk of cancer, there are still many facilities emitting EtO each year.

Decades of ethylene oxide research: a timeline of ignored warnings

The scientific community has been aware of EtO's properties as an alkylating agent for decades. The first studies revealing the potential effects of ethylene oxide can be traced back up to six decades. Here are some of the key events in the history of ethylene oxide and cancer research:

• 1950s
• As early as 1948, a study already found that ethylene oxide can alter genetic material in cells, which means it has the potential to make cells cancerous.
• 1980s
• In 1977, the National Institute for Occupational Safety and Health observed changes in the cell's genetic materials following EtO exposure and the covalent bonding between EtO and DNA. They concluded that occupational exposure to ethylene oxide may increase the frequency of mutations in the population. The first few epidemiological studies that linked ethylene oxide to cancer started getting published as early as 1979. These links to ethylene oxide were concerning with the rise of leukemia and stomach cancer among people exposed to low levels of EtO.
• 1985
• The World Health Organization (WHO) released a report concluding that ethylene oxide was a probable human carcinogen. The report also said that its levels in the environment should be kept 'as low as feasible'.
• 1994
• In 1994, ethylene oxide was reclassified as carcinogenic to humans. This was based on EtO's effects found in human and animal studies. The chemical, depending on dose, can increase the frequency of chromosomal aberrations in exposed workers, induce gene mutations in animal studies, and is a powerful mutagen and clastogen (which means it can disturb DNA processes).

In 1989, some alternatives to ethylene oxide sterilization had already been invented. However, around 50 percent of sterile medical devices in the U.S. are still produced from EtO sterilization to this day.

2016: US EPA finally acknowledges the danger of EtO

In 2016, the Environmental Protection Agency (EPA) finally released the results of a 10-year-long toxicological assessment. They found that EtO is carcinogenic by inhalation exposure, and settled on a new health value for EtO. The 2016 health value indicated that EtO is 30 times more toxic to adults than was previously estimated, and 60 times more toxic to children. This decision by the EPA was met with contrasting opinions by experts and sterilization companies. While sterilization companies claim that ethylene oxide is essential to sterilizing sensitive medical devices, some groups like the American Lung Association acknowledge the short-term and long-term effects of EtO exposure in the air and welcome the reduction in emissions.

In 2024, nearly seven decades after the first study on EtO's effect on cell genetic material, the US EPA announced a new rule to reduce toxic air pollution from chemical plants. EtO is one of the toxic air pollutants targeted by the new rules, which aim to reduce the number of people with increased risks for cancer from toxic chemicals in the air.

File your ethylene oxide claim for cancer with ELG Law

While the industrial regulations regarding EtO are just being finalized, there are decades of research to support ethylene oxide claims of workers and residents who developed cancer from toxic air exposure. If you worked at an EtO sterilization facility or lived near one, your exposure may have affected your risks of developing cancer. If you developed any of the EtO-associated cancers after your exposure, do not hesitate to contact ELG Law to file a claim. We only need your proof of exposure (employment records or proof of residence) and medical documents (showing a cancer diagnosis) to evaluate your claim.