What are PCBs?

Once widely used, PCBs are a very stable, non-corrosive and relatively nonflammable chemical substance.  They are insoluble in water and act as excellent dielectric insulators and heat conductors.

These properties made PCBs a valuable industrial chemical used in a variety of products you could find all around you.  PCBs were used most often in electrical transformers, capacitors and lamp ballasts. They were also used in caulking, carbonless paper, hydraulic fluids, printing inks, rubber, paint, sealants, adhesive and asphalt.

Yet few hazardous wastes cause greater concern than PCBs, or polychlorinated biphenyls.  First manufactured in 1929, PCBs first caused misgivings in the 1960s when the chemical was discovered in remote and otherwise unpolluted areas. Brief exposure to PCBs poses a minimal health risk to humans and long-term effects are unknown, although it is known that PCBs accumulate in body tissues and are passed up the food chain.

So what exactly makes PCBs so bad?

When burned between 250° Celsius and 750° Celsius, PCBs convert to PCDFs (polychlorinated dibenzofurans, or furans), or PCDDs (polychlorinated dibenzo-p-dioxins, or dioxins), both of which pose serious risks to human and environmental health. In 1977, PCBs were voluntarily banned by North America manufactures and importers, although PCBs are still found in electrical equipment still in use.

 Because the natural breakdown of PCBs occurs very slowly over decades or even centuries, and its chemical stability makes it resistant to chemical or biological breakdown, disposing of PCBs has been a challenge to both governments and industries.  For several decades, PCBs were stored in special storage facilities.

PCBs are treated in the Swan Hills Treatment Centre's Incineration Facility, which is BADT (Best Available Demonstrated Technology) for organic waste.  The PCB waste is treated at the FBD Kiln, with a capacity of 35,000 tonnes per year.  This high-temperature incineration system operates at temperatures up to 1,200° Celsius with secondary combustion chambers equipped with dual-fire burners. (Reaching this temperature is essential in the destruction of PCBs, as burning at temperatures between 250° Celsius and 750° Celsius creates dioxins and furans.)