Biological monitoring of exposures to carcinogenic compounds in the workplace can be a valuable adjunct to environmental sampling and occupational medicine. Carcinogen-DNA adduct analysis has promise as a biomarker of effective dose if target organ samples can be obtained non-invasively. We have developed non-invasive techniques using exfoliated urothelial and bronchial cells collected in urine and sputum, respectively. First morning urine samples were collected from 33 workers exposed to benzidine or benzidine-based dyes and controls matched for age, education, and smoking status. Sufficient DNA for 32P-postlabelling analysis was obtained from every sample. Mean levels of a specific DNA adduct (which co-chromatographed with standard characterized by MS) were elevated significantly in the benzidine-exposed workers relative to controls. In addition, workers exposed to benzidine had higher adduct levels than those exposed to benzidine-based dyes. This study demonstrates the usefulness of these non-invasive techniques for exposure/effect assessment. To be useful in occupational studies, biomarkers must also be sensitive to exposure interventions. We have conducted topical application studies of used gasoline engine oils in mice and found that the levels of carcinogen-DNA adducts in skin and lung can be significantly lowered if skin cleaning is conducted in a timely manner. The combination of useful, non-invasive techniques to monitor exposure and effect and industrial hygiene interventions can be used to detect and prevent exposures to a wide range of carcinogens including those found in used gasoline engine oils and jet exhausts.