A class of organic chemical compounds called halogenated
aromatics includes polychlorinated biphenyls (PCB),
polybrominated biphenyls (PBB), naphthalenes, benzenes, and
diphenyl ethers (PCDE, PBDE), as well as a number of pesticides
such as DDT (see Poisoning: Chlorinated Hydrocarbon Compounds).
Triclosan is a PCDE commonly used in antibacterial household
products, and PBDE are used as flame retardants in plastics and
electronic components. Most PCB use has been discontinued, but
common PCB-containing products still in use include electrical
transformers and capacitors and fluorescent light ballasts.
These should be considered to contain PCB if manufactured before
1980 unless they are labeled otherwise. Other compounds
resulting in persistent PCB contamination around farms and other
facilities include hydraulic and heat transfer fluids, epoxy
paints, and construction adhesives. How long the poisoning
lasts, how much toxin builds up in the body, and the types of
toxic effects vary considerably among the many d