Polychlorinated biphenyls (PCBs) are chemicals that may be found in large transformers and capacitors. What term describes these chemicals?

• A. Polychlorinated biphenyls (PCBs)
• B. Nitrosamines
• C. Chlorofluorocarbons
• D. Pesticides

Answer: (A)

These chemicals are polychlorinated biphenyls, a family of man-made organic compounds made of two connected benzene rings with chlorine atoms attached. They were used in large transformers and capacitors because they resist heat, stay stable, and serve well as dielectric fluids. But they persist in the environment and can accumulate in living tissue, leading to health and ecological concerns. The other options point to different classes—nitrosamines are nitrogen-containing carcinogens found in some foods and tobacco smoke, chlorofluorocarbons are refrigerants and propellants, and pesticides are substances used to control pests. The term that describes these electrical-insulation chemicals is polychlorinated biphenyls (PCBs).