Polycyclic Aromatic Hydrocarbons (PAHs)

PAHs come from both natural and human-made sources, and are formed during the incomplete burning of coal, oil, gas, garbage, or other organic substances; some PAHs are manufactured. Forest fires are the largest natural source of PAHs in Canada. The greatest human-made sources of PAHs are aluminum smelters, coking plants, creosote-treated products, spills of petroleum products and transportation. PAHs have been identified as probably cancer-causing, and are suspected reproductive and respiratory toxins.