 Manufacturing of PBBs in the United States stopped in 1976, however because they do not degrade easily PBBs continue to be found in soil, water and air.PCBs (Polychlorinated biphenyls) are man made organic chemicals known as chlorinated hydrocarbons.PCBs were manufactured primarily for use as insulating fluids and coolants given their chemical stability, low flammability and electrical insulating properties.