New York State Real Estate Salesperson Licensing Exam

Which hazardous component was historically used as insulation in electric transformers?

1. Asbestos

2. Lead

3. PCB's or polychlorinated biphenyls

4. Mercury

The correct answer is: PCB's or polychlorinated biphenyls

The correct answer is polychlorinated biphenyls (PCBs), which were historically used in electric transformers due to their insulating properties and chemical stability. PCBs are a group of man-made organic chemicals that were widely utilized in electrical equipment, hydraulic systems, and other industrial applications because they do not easily break down and are effective at preventing electrical fires. Using PCBs in transformers helped in managing heat and maintaining electrical performance; however, it was later discovered that they posed significant environmental and health risks. This led to their prohibition in many countries due to concerns about their persistence in the environment and potential for bioaccumulation, as well as their negative effects on human health, including cancer and immune system damage. Asbestos, while also associated with insulation, was primarily used in other building materials and has a different set of health risks, such as lung diseases. Lead has a long history in many electrical applications too, but it was not predominantly used as an insulator in transformers. Mercury is another hazardous material, but its primary use in electrical systems was in switches and lighting, rather than as an insulating component.