A brief description is provided of the production, uses, toxicity, and metabolism of trichloroethylene (79016) (TCE), and a special occupational hazard review is given of TCE's potential as a workplace carcinogen. In addition, the results of a recent survey of industrial vapor degreasing operations, the primary source of occupational exposures to TCE, are presented along with data from other surveys or reviews to document the extent and nature of occupational exposures to TCE and existing control methods. TCE's acute toxicity is well known and is related mainly to central nervous system depression, cardiac arrhythmias, and dermal effects. In contrast, chronic effects are not so well documented under usual occupational exposure conditions. There is evidence, however, for latent effects, including those of the liver, kidneys, and nervous system. Based upon this special review of all these data, NIOSH concludes that TCE has a weak carcinogenic potential.