The Toxicity of Polytetrafluoroethylene Pyrolysis Products—Including Carbonyl Fluoride and a Reaction Product, Silicon Tetrafluoride

Abstract The toxicity of pyrolysis products (550°C) of polytetrafluoroethylene (PTFE) was evaluated by exposure of dogs, rabbits, guinea pigs, rats and mice. Carbonyl fluoride (COF2) was identified as the principal toxic component. One-hour exposures of rats showed a 24-hour LC50 of 370 ppm for the pyrolysis products and an LC50 of 360 ppm for COF2. When PTFE is pyrolyzed in the absence of silica, the products are less toxic to a slight degree. Pathology revealed changes in the lungs and livers of exposed animals. Irritation of the lungs may persist for some days.