Ethylene oxide is defined by the U.S. Department of Transportation as a flammable liquid. It vaporizes rapidly at atmospheric temperature and pressure forming an extremely flammable vapor which will explode if ignited. The vapor is moderately toxic by inhalation and is irritating to the eyes and mucous membranes. When in the liquid form it produces burns of the skin or eyes upon contact. Ethylene oxide may decompose or polymerize when in contact with active catalysts. The rapid decomposition or polymerization generates heat and may result in an explosion. The full text of this chemical safety data sheet should be consulted for details of the hazards of ethylene oxide and suggestions for their control.