OSHA "select carcinogen"; highly flammable; severe irritant.

Ethylene oxide is a severe irritant to the eyes, skin, and respiratory tract and exhibits moderate acute toxicity by all routes of exposure. Symptoms of overexposure by inhalation may be delayed and can include nausea, vomiting, headache, drowsiness, and difficulty breathing. Ethylene oxide can cause serious burns to the skin, which may only appear after a delay of 1 to 5 hours. This substance may also be absorbed through the skin to cause the systemic effects listed above. Eye contact can result in severe burns. Ethylene oxide is not considered to have adequate warning properties.

Ethylene oxide is listed by IARC in Group 2A ("probable human carcinogen") and is classified as a "select carcinogen" under the criteria of the OSHA Laboratory Standard. There is some evidence from animal studies that ethylene oxide may be a developmental and reproductive toxin in both males and females. Exposure to this substance may lead to sensitization.

Ethylene oxide is an extremely flammable substance (NFPA rating = 4). Ethylene oxide vapor may be ignited by hot surfaces such as hot plates and static electricity discharges, and since the vapor is heavier than air, it may travel a considerable distance to an