Notice of Incident
At approximately 4:05 p.m. on Saturday, May 2, 2026 ArcelorMittal Dofasco experienced a malfunction in the Utilities boiler system. As a result, Cokemaking operations were impacted with visible emissions at the flue stacks and flaring of gasses. The incident lasted a total of just under six hours.
The visible emission was the result of incomplete combustion of fuels, while flaring of gasses is required in these situations for the safety of the plant and personnel. Under normal conditions gasses and steam are used in coke, iron, steel and hot rolling closed loop processes.
Cokemaking stack and flaring emissions are mostly composed of nitrogen, carbon monoxide, carbon dioxide, and moisture. There are typically minor amounts of particulate in these types of emissions.
The Ontario Ministry of Environment, Parks and Conservation’s Spills Action Centre was notified, the operations are now stable, and our teams are investigating the cause of the failure.
About ArcelorMittal Dofasco
About ArcelorMittal Dofasco ArcelorMittal Dofasco is Canada’s largest producer of flat carbon steel and is part of the world’s largest steel and mining company. Headquartered in Hamilton, ON, with more than 4,500 employees each year we ship 4.5 million net tons of high-quality flat carbon steel to partners in automotive, energy, packaging and construction which are used in increasingly lighter, stronger and more sustainable products – from cans to cars. Our purpose is to produce ever smarter steels that have a positive benefit for people and planet. High performance steels made using innovative processes which use less energy, emit significantly less carbon and reduce costs. Steels that are cleaner, stronger and reusable. With steel at our core, our inventive people and an entrepreneurial culture at heart, we will support the world in making that change. This is what we believe it takes to be the steel company of the future. For more information about ArcelorMittal Dofasco, please visit: http://dofasco.arcelormittal.com/