Vinyl chloride monomer and other contaminants in PVC welding fumes.

An investigation into the nature of fumes produced during thermal welding of plasticized PVC sheeting has been carried out with the objective of determining if the known carcinogen vinyl chloride monomer (VCM) is formed and to assess the level of exposure to the operator. The results show that the atmospheric concentrations of VCM are well below accepted occupational exposure limits. This finding is consistent with reports in the technical literature which suggest that VCM is produced during thermal degradation of PVC only at temperatures considerably higher than those encountered during plastic welding.