What were polychlorinated biphenyls used for in electrical equipment?

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organohalogen compound Vinyl chloride is an organohalogen compound that has important industrial applications. When treated with certain catalysts, vinyl chloride monomers undergo polymerization and form the larger compound known as polyvinyl chloride, or PVC. PVC is used in the manufacture of numerous products, including packaging films and water pipes.

Polychlorinated biphenyls (PCBs) were widely utilized in electrical equipment primarily because they are excellent dielectrics, or electrical insulators.1

Due to their stability at high temperatures and their resistance to fire, these organohalogen compounds served as effective insulating fluids in transformers and capacitors. Additionally, their chemical properties made them useful as heat-transfer fluids and lubricants within this equipment.1

While these characteristics provided significant industrial utility, the environmental and health risks associated with their persistence and toxicity eventually led to a ban on their production.1