By Michael Bartlett on October 24th, 2025 in Ethylene Oxide
EtO has a wide range of uses, including the sterilization of medical equipment. Even though it serves critical functions in modern healthcare and industry, mounting evidence indicates that it may pose a serious health threat. The IARC and the EPA classify EtO as a human carcinogen, with research suggesting it may be linked to liver cancer.
EtO has fundamental chemical properties that make it a potential cancer-causing agent. EtO directly interacts with human DNA to create what scientists call DNA adducts. As a result of the gas bonding with the genetic material of cells, these abnormal chemical structures form, triggering a cascade of harmful effects.
There are several dangers associated with the reaction between EtO molecules and DNA:
Since the liver is responsible for metabolizing chemicals and toxins, it is particularly vulnerable to these carcinogenic processes. The continual division and replication of damaged cells result in mutations, creating conditions that facilitate the development of cancer.
Animal studies strongly support the hypothesis that EtO causes liver cancer. Toxicology studies were conducted by the National Toxicology Program on rodents exposed to EtO inhalation. These studies revealed dose-related increases in hepatocellular adenomas and carcinomas in animals exposed to EtO at concentrations relevant to human occupational and environmental exposures.
Upon exposure to EtO, researchers observed preneoplastic foci in rat livers. Carcinogen exposure results in altered liver cells that serve as precursors to tumor development. A sustained inhalation of EtO can lead to hepatocellular carcinoma, or primary liver cancer, in animals. There is sufficient evidence for liver carcinogenesis in animals exposed to airborne EtO, according to the IARC.
The epidemiological study of EtO exposure in humans provides direct insights into the real-world health effects of exposure to EtO. The majority of human data comes from occupational studies tracking workers in EtO production facilities and sterilization plants. Hogstedt's landmark 1979 study reported an elevated rate of liver cancer mortality among EtO-exposed workers.
EtO-exposed populations have been reported to have a higher risk of liver cancer. Studies have found significant changes in liver enzyme levels in populations exposed to EtO, as well as other indicators of hepatic stress.
Community exposure to EtO-emitting facilities has emerged as a major concern for public health. There is constant exposure to fumes emanating from sterilization plants by residents living near them. The EPA says this ambient exposure pattern may increase liver cancer risk in local communities.
EtO is classified as a human carcinogen by the EPA in its 2016 assessment, which specifically cites evidence that inhalation exposure causes liver tumors. EPA regulations have been implemented to reduce EtO emissions from commercial sterilization facilities following this assessment, requiring drastic reductions in allowable emissions to reduce cancer risk.
If you developed liver cancer after living near a facility that uses EtO or after regularly working with the sterilizing agent, you may be eligible to file a claim. We at Environmental Litigation Group have decades of experience handling toxic exposure cases and remain on top of scientific developments. With the help of our compassionate legal team, you may be able to pursue compensation for medical costs, lost wages, and emotional suffering. Learn more about your legal options with a free consultation today.