Induction of carcinomas in the nasal cavity of rats by dioxane

Six out of 120 rats fed dioxane in drinking water at levels of 0.75, 1.0, 1.4 or 1.8% developed carcinomas in the nasal cavity. Spontaneous tumors at this tissue localization have not been reported to occur in laboratory animals. The carcinomas were pre-eminently of epidermoid type with few adenocarcinomatous areas and epithelial papillomas. Four rats with carcinoma of the nasal cavity had hepatocellular carcinoma in addition.