Carcinogenicity of single and multiple intratracheal instillations of cadmium oxide in the rat.

The carcinogenic effects of single or multiple exposures to intratracheally instilled cadmium oxide, resulting in total doses of 0, 25, 50, and 75 micrograms, were studied in groups of 41 to 48 male Fischer rats. Pulmonary-deposited cadmium oxide did not result in increased numbers of tumors, except in the mammary gland or in rats that had three or more tumor types. Cadmium oxide was not carcinogenic in the lung, liver, kidney, or prostate gland of rats.