Diesel Exhaust Exposure Awareness

For most Canadian workplaces, no. The federal COHSR adopts ACGIH exposure limits by reference, but ACGIH formally withdrew its proposed diesel particulate limit in 2003 and has never finalized one, so no federal numeric limit exists. The main exception is mining: Ontario's Regulation 854 sets the most protective limit in Canada at 0.12 mg/m3 elemental carbon as an 8-hour average, effective September 1, 2023, but it applies only in Ontario mines.

Diesel engine exhaust is classified as an IARC Group 1 carcinogen, the same category as asbestos and crystalline silica. Unlike those substances, most Canadian workers exposed to diesel exhaust have no numeric exposure limit protecting them, which means hazard recognition, engineering controls, and disciplined work practices carry more of the protective weight. CAREX Canada estimates more than 900,000 Canadian workers are occupationally exposed, making it one of the most widespread carcinogen exposures in the country.

Truck and transit drivers, forklift operators, miners, mechanics who run engines indoors, construction and tunnelling crews, warehouse and port workers, firefighters exposed in apparatus bays, and farm equipment operators working in enclosed barns. Because exposure cuts across so many sectors, most exposed workers fall outside any mining-specific regulation with a numeric limit, and their protection depends on the general duty clause, hazard communication, and the controls this course teaches.

In federally regulated workplaces, yes, where exposure is likely: diesel exhaust falls under COHSR Part X as a hazardous substance, which requires a hazard investigation, controls applied in hierarchy order, and employee education and training under section 10.14 for any worker who is or may be exposed. Training records must be kept for two years after exposure ends. Provincially, the general duty to inform and instruct workers about workplace hazards covers the same ground.

No. Mining has the most developed rules, such as Ontario's numeric limit and Quebec's carbon monoxide testing regime requiring engine checks every 300 operating hours or six months, but the hazard is far broader. Depot, garage, loading dock, and idling-zone exposures in trucking, transit, warehousing, and emergency services are covered by general hazardous-substance and duty-of-care provisions instead. Working near diesel equipment in an enclosed space with no functioning ventilation could reasonably support a work refusal.