The possible carcinogenic hazard of exposure to trichloroethylene (79016) (TCE) was presented, and chemical properties and primary uses of TCE were described. Metal degreasing and dry cleaning trades were responsible for about 90 percent of TCE consumption. It was also used as an anesthetic in medical and dental procedures. Human toxicity was characterized primarily by central nervous system depression, especially after acute exposure. Skin contact could result in local irritation and blistering after prolonged exposure, and repetitive occupational hand immersion caused finger paralysis. Cardiac arrhythmias were common and diffusion across the placenta was rapid, while liver and kidney effects were rare. Human and animal exposure could result in respiratory failure or cardiac arrest. The state of euphoria which results from deliberate inhalation of TCE has resulted in addiction among adolescents sniffing commercial products. To date, there had been no reports linking TCE exposure to human cancer. A study was made by the National Cancer Institute in rats and mice. Osborne-Mendel-rats and B6C3F-mice were exposed five times per week to TCE by gastric intubation. Rats received 500 or 1000mg/kg doses, and male mice received 1200 or 2400mg/kg while female mice were given 900 or 1800mg/kg. In mice, 30.6 percent and 43.2 percent of animals receiving low and high doses, respectively, developed hepatocellular carcinoma. No such lesions were seen in rats. It was noted that the exposure standard set by the Occupational Safety and Health Administration is 100 parts per million. The largest estimated worker populations exposed to TCE were in electrical and transportation equipment industries. Among medical, dental, and hospital personnel, approximately 5000 workers were estimated to be exposed to TCE. Additional animal studies as well as detailed epidemiological investigations were anticipated.