Ethylene Oxide

CAS RN:75-21-8

Toxicity Summary

IDENTIFICATION: Ethylene oxide is a colorless, high reactive gas at room temperature and pressure. It used in the manufacture of ethylene glycol and surfactants. It used in the manufacture of surfactants. Ethylene oxide is also used as a sterilant for health care materials and other heat-sensitive products. HUMAN EXPOSURE: Ethylene oxide is rapidly taken up via the lungs, distributed, and metabolized to ethylene glycol and to glutathione conjugates. Ethylene oxide can be absorbed though the skin from the gas phase or from aqueous solutions and is uniformly distributed throughout the body. Ethylene oxide is an alkylating agent and forms protein and DNA adducts. Hemoglobin adducts have been used for biomonitoring. Based on studies primarily in occupationally exposed populations, ethylene oxide is an ocular, respiratory, and dermal irritant and a sensitizing agent. Neurological effects (primarily sensorimotor polyneuropathy) have been observed in workers exposed to relatively high concentrations. The route of likely greatest exposure and focus of the human health is inhalation from air. There is some evidence of an association between exposure to ethylene oxide and the development of haematological cancers in epidemiological studies of occupationally exposed populations, limitations of the data preclude definitive conclusions. There is consistent evidence that ethylene oxide has induced clastogenic changes in exposed workers. ANIMAL/PLANT STUDIES: The acute inhalation toxicity of ethylene oxide in rodents and dogs is low. In inhalation studies, ethylene oxide has induced a wide range of tumours (e.g., leukaemia, lymohoma, brain, lung). Ethylene oxide induces gene mutations at all phylogenetic levels tested in vitro and in vivo. It also induces germ cell mutations and clastogenic effects in experimental animals. In experimental animals, ethylene oxide is fetotoxic in the presence and absence of maternal toxicity at concentrations higher than those associated with cancer and other non-cancer (i.e., neurological) effects; it is teratogenic only at very high concentrations (above about 1600 mg/m3). Evidence from epidemiological studies of reproductive effects (primarily spontaneous abortions) of ethylene oxide in humans is limited. In experimental animals, among non-neoplastic effects, reproductive effects occur at lowest concentration (>90 mg/m3). These include reductions in litter size, increased post-implantation losses, alterations in sperm morphology, and changes in sperm count and motility. Available data on the non-neoplastic effects of repeated exposure to ethylene oxide in studies are limited, with past focus being primarily on the carcinogenicity of the compound. Reported effects in studies in animals were restricted primarily to those on the hematological and nervous systems.
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