Document N2z1No10EQv9abz84kRgevMVy

/ Executive Summary 1. Gjus-L-lIT Sources of xpo^u-t'-e ^ ^*j . *' `J PC3s have been widely used in electrical equipnent such as capacitors and transforners. These are considered to be completely closed systems, although minor amounts of PCBs can be found on the outer metal surface. The substitution of PCBs in electrical equipment for non-PC3 liquids could possibly result in an increased environments, contamination. Smaller volumes of PCBs have frequently been used as fire resistant liquid in nominally closed systems like hydraulic and heat exchange systems. Earlier there have been many uses of PCBs in open ended systems like plasticizer, paint, inks and adhesives. I A* * ' PCDDs and PCDFs are ubiquitous in the environment. , They do not occur naturally, nor are they intentionally produced. Rather these compounds are formed as trace amounts of undesired impurities in the manufacturing of chlorinated phenols and their derivatives and PCBs. The production of these chemicals has decreased during the 1980s. PCDDs and PCDFs have also been identified in various combustion processes like the incineration of municipal