PCBs were once widely used as dielectric fluids in transformers and capacitors, with peak production in the United States in 1970. PCBs were also used as lubricants and in plastics, paints, inks, and carbonless copy paper. While the use of PCBs in existing equipment is allowed in both the United States and Canada, manufacture and new uses ceased in the late 1970s. Because the production of PCBs has been banned, efforts to estimate the potential PCB loadings have focused on inventories of capacitors and transformers containing PCBs. In 1991, a total of 1,026 tonnes of PCBs were estimated to be in use or storage in the Lake Superior watershed.
Estimates show that industries house more PCBs than do utilities in the watershed.
The destruction of PCBs will eliminate an estimated 41 kilograms per year released through spills. Provide incentives to remove mercury from fuel emissions. Eliminate nonessential uses of mercury. Remove PCBs at the end of the useful life span of equipment. Emphasize destruction of PCBs rather than storage.