Health Canada evaluated the toxicity data for NDMA and concluded that cancer is the critical endpoint for quantitation of exposure-response for risk characterization. TD05s were calculated for hepatic biliary cystadenomas, hepatic carcinomas, and hepatic hemangiosarcomas. The panel agreed with Health Canada's conclusions. For ethylene oxide, Health Canada concluded that there is clear evidence of carcinogenicity in laboratory animals and that human studies provide suggestive, but inconclusive, evidence of increased risk for hematological cancers. Ethylene oxide is clearly genotoxic in in vitro assays, and in vivo assays have also been consistently positive, providing clear evidence of somatic and germ cell genotoxicity.
Cancer is considered to be the critical effect for ethylene oxide.
The panel agreed with Health Canada's characterization of the human and animal data and agreed that the animal data are the appropriate basis for deriving TC05s. The meeting was open to the public. The peer review panel was made up of experts from government, consulting, environmental groups, and industry, creating a balanced panel, while carefully managing potential conflict of interest issues. This site also provides more information about TERA and the peer review program. Posted August 24, 1999.