When and why were PCBs made?

When and why were PCBs made?

Polychlorinated biphenyls (PCBs) are a group of persistent, dangerous man-made chemicals. Developed in 1929, PCBs were used widely across the world in flame retardants of everyday goods, the insulating material in electrical equipment; such as transformers and capacitors, and also in heat transfer liquids, dielectric fluids, caulks, paints, and in lubricants.

PCBs were finally banned in the U.S.A in 1979, but the irreversible damage was done to U.S and global waterways. Over 100 nations in the world still use PCBs, finding its way into land and water.