Dinitrotoluene (DNT) and toluene diamine (TDA) are intermediates in the production of toluene diisocyanate and polyurethane plastics. Some reproductive effects in rodents have been reported; and the National Institute for Occupational Safety and Health reported probable reproductive toxic effect to humans after a preliminary survey. Accordingly, 84 workers exposed to DNT/TDA (classified by intensity and recency of exposure) and 119 nonexposed workers were studied at Olin's chemical complex at Lake Charles, La. Each worker was the subject of a physician's urogenital examination, a reproductive and fertility questionnaire, an estimation of testicular volume, an assessment of serum follicle-stimulating hormone, and an analysis of semen for sperm count and morphology. No differences were found between the exposed and control groups among any of these variables. Although both TDA and DNT are readily absorbed (percutaneous, inhalation, ingestion), they did not present detectable reproductive hazard to the workers.