The Baie-Comeau Smelter has both a prebake anode plant and a Söderberg plant. Söderberg anodes, a mixture of tar pitch and coke, bake during the electrolysis process rather than in a dedicated oven like at the other plants. This results in polycyclic aromatic hydrocarbons (PAH) emissions. In the Söderberg potrooms, approximately 85% of emissions are captured at the source to be treated by dry scrubbers. The remainder is emitted through the roof vents.
Total emissions decreased in 2011 and 2012 following improvements in the quality of the raw materials and pot operation. Since the Règlement sur l’assainissement de l’atmosphère clean air regulations went into effect in June 2011, the PAH target of 0.25 kg/t established for the Söderberg potroom has become a regulatory standard.