PCBs: these toxic pollutants were banned decades ago but still pose a huge threat

Historic landfills contain high levels of toxic synthetic chemicals known as PCBs which continue to pollute the environment and pose a health hazard. Jenya Smyk/Shutterstock

Toxic synthetic chemicals called polychlorinated biphenyls (PCBs) were banned more than 40 years ago but still threaten human health and the environment today.

PCBs were used to make industrial products such as coolants and electrical components until they were banned in the 1980s. They were popular because of their insulation properties, non-flammability and resistance to thermal and biological degradation. But that results in persistence and once released in the environment, these pollutants can remain in soil, water and air for decades or longer.