Pulmonary response to perfluoropolymer fume and particles generated under various exposure conditions

Combustion-product toxicity of perfluorinated polymers in small-scale tests varied markedly under various exposure conditions. The toxicity of perfluoropolymer fumes is associated with submicron pyrolysis particles (0.03-0.15 microns) in the fumes. The toxicity of pyrolysis products was not observed in rats exposed to the fumes filtered to remove the particles. The particles in the fume were agglomerated by aging or a water-treatment process, and the toxicity of particles was markedly reduced when rats were exposed to aged or water-treated fumes. Some agglomerated particles showed chain-aggregation and ultimately attained nonrespirable size. The reduced toxicity of pyrolysis fume is believed to be due to a decreased number of toxic particles resulting from particle agglomeration. Aged particle agglomerate was not toxic when instilled intratracheally into the rats. However, the particle agglomerate became toxic when rats were exposed by the inhalation to fumes evolved from the reheated agglomerate. The fumes contained numerous toxic submicron particles evolved from thermal decomposition of agglomerates by reheating. Rats exposed to the pyrolysis fumes died with pulmonary edema and hemorrhage due to Type I pneymocyte damage. The edematous lungs revealed some agglomerated particles, but it was difficult to distinguish small pyrolysis particles from contaminating dust or cellular debris.