NIOSH recommends in this document that occupational exposure to workplace air concentrations of tetrachloroethylene (127184) shall not exceed 50 parts per million (ppm) determined as a time weighted average (TWA) concentration for up to a 10 hour workday, 40 hour workweek, or at greater than a ceiling concentration of 100ppm determined by 15 minute samples, twice daily. Standards for medical surveillance of workers occupationally exposed to this substance, warning signs, personal protective equipment and clothing, housekeeping and work practices were outlined. Studies on the biologic effects of exposure to tetrachloroethylene were reviewed; topics included the extent of exposure, historical reports, effects on humans, epidemiologic studies, animal toxicity, and correlation of exposure and effect. Information was provided on environmental concentrations, engineering controls, sampling, analytical methods and the biologic evaluation of exposure. The basis for the development of the standard was discussed.