Carcinogenicity of kepone.

Five studies of the carcinogenicity of the chlorinated pesticide Kepone (chlordecone) in animals were reviewed. Examination of histological sections showed that Kepone is unmistakably carcinogenic in rats and mice. Kepone induced malignant tumors in the liver of rats and mice in the National Cancer Institute studies and in the liver in rats in the Medical College of Virginia study. Malignant tumors were also found in organs other than the liver rats, including those on the lowest dose, in both studies. Female rats given Kepone were more likely to develop malignant tumors than male rats. There also were toxic changes, particularly in male rats. These included interstitial fibrosis of the kidney; polyarteritis of the mesenteric, pancreatic, and other arteries; and atrophy of the testes. Such lesions generally interfere with the health of the rats and with the development of tumors. Atrophy of the testes also prevents reproduction.