Oncogenicity testing animal type

In a carcinogenicity study, rats and mice were given the liquid orally at two different dose levels, 5 days a week for 78 weeks." Both female and male test animals exhibited early mortality compared with untreated controls, and a variety of neoplasms were found in both treated animals and controls. Although rats of both sexes demonstrated a positive dose-related trend, no relationship was established between the dosage groups and the species, sex, type of neoplasm, or sites of occurrence. The lARC concluded that an evaluation of the carcinogenicity of 1,1,1-trichloroethane could not be made. In a subsequent study, rats exposed at 15 00 ppm 6 hours/day, 5 days/week for 2 years showed no oncogenic effects. ... 

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