A gas chromatographic method is described for determining traces of 13 carcinogens and related compounds (aromatic amines and estrogens) in admixture in wastewater and human urine. This method was developed for use in toxicological research for monitoring the safe disposal of wastewater and to signal any accidental exposure of personnel to hazardous test substances. Salient elements of the procedure are: extraction of phenolic and neutral residues from the acidified sample, liquid--liquid partitioning cleanup and separation of neutral from phenolic residues at pH 14 and 10.2, acid hydrolysis of the neutral component, subsequent alkalinization of the sample and extraction of the basic residues as the free amines, conversion of all residues to the corresponding pentafluoropropionyl (PFP) derivatives and quantification by electron-capture gas chromatography. Residues were detectable in wastewater and urine at the 0.1 and 1 ppb levels, respectively. Additional information is provided concerning partition values for all PFP derivatives in five solvent systems, structure verification of the derivatives by mass spectrometry and the adaption of this method to the monitoring of surfaces and air in potentially contaminated work areas.