ABSTRACT
Polychlorinated biphenyls (PCBs) have been used widely in industrial applications because of their thermal stability, excellent dielectric (electrically insulating) properties, and resistance to oxidation, acids, bases, and other chemical agents. PCBs therefore have found use in capacitors and transformers as dielectric fluids, in hydraulic systems, gas turbines and vacuum pumps, and as fire retardants and plasticizers (215). In 1971, however, Monsanto Company, the sole U.S. producer, voluntarily restricted the use of PCBs to closed systems (capacitors, transformers, vacuum pumps, gas-transmission turbines) and discontinued production entirely in 1978 (281). These applications use complex mixtures of PCBs marketed under the trade names Aroclor (Monsanto Company, USA), Clophen (Germany), Phenoclor and Pyralene (France), Kaneclor and Santotherm (Japan), and Fenclor (Italy). Askarels are synthetic mixtures of chlorinated biphenyls and trichlorobenzenes.
