Review of the toxic effects of Teflon, a compound obtained by the polymerization of tetrafluoroethylene (9002840). Topics include background hazard information, health hazard information, environmental evaluation, medical evaluation through questionnaire and urine analysis. Case report is presented of a factory where NIOSH investigators have found no significant hazard. Attention is drawn to the toxic pyrolysis products which Teflon may give off at temperatures 300 degrees centigrade and higher and to the occurrence of polymer fume fever in the plant even after the introduction of engineering control methods. Recommendations include improved housekeeping, periodic maintenance, and provision of first aid and clinical testing facilities.