The objective of this contract is to examine the carcinogenicity of p-nitrophenol administered dermally to swiss mice. This is being accomplished by exposing groups of male swiss mice to p-nitrophenol by the dermal route of administration for 103 weeks. At the end of the exposure period, all surviving animals will be given a complete gross necropsy, the required tissues collected and processed histologically, and subjected to histopathological analysis. The results will be analyzed for possible carcinogenic effects of the chemical.