Polychlorinated Biphenyls (PCBs)

Chemical compounds produced by the chlorination of biphenyls which, thanks to exhibiting particular characteristics (non- combustible, thermally stable, viscous and a high boiling point), have found an application as coolants, hydraulicc fluid, Transformer Oil, plasticizers (softeners) and insulating materials, etc. PCBs are toxic and carcinogenic. PCBs posses a high Persistence with Half-lifes of up to several decades. Substitute materials with equally favourable characteristics have been discoverd (e.g. silicone oils, phthalic esters).