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.