Although only key references essential for the evaluation of the risks for human health and the environment are cited, this document is based on a comprehensive search of the available, original scientific literature, while valuable information has also been obtained from various reviews. A detailed data profile on ethylene oxide can be obtained from the International Register of Potentially Toxic Chemicals (UNEP/IRPTC, Palais des Nations, CH-1211 Geneva 10, Switzerland, telephone number 988400 - 985850). The document focuses on describing and evaluating the risks of ethylene oxide for human health and the environment.