Trichloroethylene is an organic solvent primarily used for the vapor degreasing of metals. Approximately 200,000 industrial workers are exposed to this solvent annually. Although the major physiological response in humans from acute or chronic exposure to trichloroethylene is central nervous system depression, damage to liver, kidney and heart have also been reported. Since the metabolic fate and toxic effects of trichloroethylene are similar in many mammalian species to those in man, the fact that this compound has recently been implicated as a potent liver carcinogen in mice may be of significance. Approximately 60% of the total world production of trichloroethylene is released to the environment each year. However, due to its low water solubility, high vapor pressure and high atmospheric photodegradation rate, trichloroethylene is not expected to persist in the environment. Ambient concentrations in the atmosphere of industrialized areas are only about 16 ppt. Proper use of local exhaust systems in conjunction with vapor condensation apparatus and good general ventilation should be sufficient to maintain levels of trichloroethylene in the workshop environment well below the recommended 100 ppm and to insure a minimum release to the ambient atmosphere.