The production of polychlorinated biphenyls (PCBs) has been widely restricted, as they are

Polychlorinated biphenyls (PCBs) are carcinogens that bioaccumulate in the environment. PCBs are a group of synthetic organic chemicals that were widely used in electrical equipment, paints, plastics, and other industrial products until their production was banned or restricted in many countries in the late 1970s and early 1980s. PCBs are persistent, meaning they do not break down easily in the environment, and bioaccumulative, meaning they build up in the fatty tissues of animals and humans. Exposure to PCBs can cause various adverse health effects, such as cancer, liver damage, immune system impairment, reproductive and developmental disorders, and neurobehavioral effects12.

References: = WELL v2 Feature 11: Fundamental Material Safety, Polychlorinated Biphenyls (PCBs): Sources, Exposures, Toxicities