PCBs and the precautionary principle

Polychlorinated biphenyls (PCBs) are chlorinated organic compounds that were first synthesised in the laboratory in 1881. By 1899 a pathological condition named chloracne had been identified, a painful disfiguring skin disease that affected people employed in the chlorinated organic industry. Mass production of PCBs for commercial use started in 1929. Thirty-seven years elapsed before PCBs became a major public issue, recognised as environmental pollutants, and a danger to animals and humans. Large-scale production worldwide, and in particular in some eastern European countries, continued until the mid-1980s. PCBs are the first obvious example of a substance that was not intentionally spread into the environment, but nevertheless became widespread and bioaccumulated to high concentrations.