Commercial production of PCBs began in the U.S. in 1929 to meet the electrical industry’s need for safer cooling and insulating fluids, which became their primary use in Canada. Until banned in 1977 and 1980, PCBs were also used in hydraulic fluids, coatings, plasticizers, sealants, and as flame retardants, with most capacitors manufactured between 1930 and 1980 containing PCB dielectric liquids. In 1985, a major spill near Kenora, Ontario, raised public concern over the transport and disposal of PCBs when approximately 40 litres of transformer oil containing 56% PCBs leaked during transport, contaminating a 100-kilometre stretch of the Trans-Canada Highway and nearby vehicles. The transformer, being shipped from Quebec to Alberta for storage, highlighted ongoing risks associated with this hazardous material.