The objective of this research project is to uncover presently unrecognized chemicals and drugs in the environment which are involved in the induction of bladder cancer in humans. Our approach is to attempt to utilize the knowledge gained concerning the induction of bladder cancer in dogs by the aromatic amines, in which our results have demonstrated that the responsible etiological agent is N-hydroxy and nitroso metabolites. Consequently, we are examining the urine of human volunteers given various proprietary and prescription drugs which chemical considerations indicate may produce N-hydroxylated metabolites. In order to accomplish these analyses, it has been first necessary to synthesize these metabolites. The first group of drugs we have attempted to study has been the analgesic-antipyretics related to phenacetin, including phenacetin itself, acetaminophen, and acetanilin. N-hydroxy and nitroso metabolites of these substances have been prepared and mass spectral data obtained. The next step will be to examine the urine of volunteers given these drugs utilizing GC Mass Spectrometry to determine their presence. We are also analyzing the urine of heavy smokers with this technique to determine the presence in urine of N-hydroxy or nitroso metabolites of the aromatic amines present in tobacco smoke.