New diesel exposure limit for underground mines in Ontario

Tuesday, April 11, 2023

Law reduces exposure to harmful chemicals and allows robots to detect hazards

Hazard alert poster of Health Effects of Diesel Exhaust

New rules to improve ventilation requirements in underground mines and lower exposure to harmful diesel exhaust to the most protective levels in North America will come into effect in July. Long-term exposure to diesel exhaust can be a significant cause of lung cancer in miners.

Regulations will also allow for the use of track-mounted robots in mines to increase safety. These specialized machines with a high-definition camera will be controlled by an operator to identify loose rocks, misfired explosives and other safety hazards, while keeping workers out of danger.

These amendments respond to calls from unions for a reduction of how much diesel particulate miners can be exposed to underground and follow recommendations from the Mining Health, Safety and Prevention Review and recent coroner’s inquests.

Quick Facts

  • Regulatory amendments will come into force on July 1, 2023, and others in effect on September 1, 2023, to allow employers time to comply.

  • Effective September 1, 2023, the new exposure limit will be a time-weighted average exposure to elemental carbon of not more than 0.12 milligrams per cubic metre of air, instead of 0.4 milligrams per cubic metre of air based on total carbon.

  • Ontario has 37 underground mines. About 12,000 miners work below ground and Ontario mines employ approximately 29,000 workers in total.

Additional Resources

Health effects of diesel exhaust - Infographic Hazard Alert - Please download, print and share in your workplace

Mining regulation

Occupational Health and Safety Act                                                                                                    

Health effects of diesel exhaust in mines

Free training resources on diesel emission hazards for all industries

Hazards Associated with Diesel Exhaust Emissions

Mining safety guideline for reducing diesel emissions underground

Reducing diesel particulate matter in underground mines: Two successful examples