Polychlorinated biphenyls (PCBs) are a group of synthetic organic chemicals that consist of two linked benzene rings with chlorine atoms attached. They were widely used in industrial applications, such as electrical equipment, hydraulic fluids, and as coolants, due to their chemical stability and insulating properties. However, their production was banned in many countries in the late 1970s because of their harmful environmental and health effects. PCBs are persistent in the environment and can accumulate in the food chain, leading to exposure in humans and wildlife. They are associated with various health risks, including cancer and immune system issues. Cleanup and management of PCB-contaminated sites remain a significant environmental challenge, often involving regulatory agencies like the Environmental Protection Agency (EPA).