PCB include 209 congeners C6H5-nCln-C6H5-mClm (m+n=1-10) and their metabolites. They offer digestive, occupational and primarily environmental exposure hazards. The 1995 inventory covering 6 voivodships in South-West Poland disclosed 69 transformers and 11,600 condensers using (Polish and imported) dielectric PCB fluids. The data were too few to estimate all-Poland PCB hazards. Production of domestic Chlorofen (mostly heptachlorobiphenyl) and Tamol (higher chlorinated PCB), 1680 tons of the two together plus 2000 tons of by-products made over 1966-1976, was discontinued in mid-1970s; the two PCB were used as dielectric fluids in transformers. The former production sites and the places where imported PCB mixtures were applied must be (re)considered to evaluate potential domestic contamination areas and hazards. 22 refs.