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Occupational Disease in Mines

Safe At Work Ontario
  • Issued: January 28, 2016
  • Content last reviewed: September 2018

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.


Occupational disease continues to be a leading cause of illness and death to workers in the mining industry.

Between 2011 and 2015, there were 106 occupational disease fatalities in Ontario’s mining sector, based on Workplace Safety and Insurance Board (WSIB) data.

Employers must ensure measure and controls are in place to protect workers from exposure to hazards that can lead to immediate (acute) or long-term (latency) health effects. The risk of worker exposure to these hazards must be determined before work is performed.

Some examples of occupational disease in mining include:

  • asbestosis, mesothelioma
  • silicosis
  • cancers
    • lung (gold mining, coke oven)
    • nasal (nickel)
    • gastro-intestinal
  • chronic obstructive lung disease (sulfur dioxide)
  • emphysema
  • skin diseases
  • hearing loss (noise)

Some examples of exposure that can lead to occupational disease in mining include:

  • blasting gases: carbon dioxide, carbon monoxide, oxides of nitrogen, ammonia, and sulfur dioxide
  • diesel emissions: elemental/organic carbon, carbon monoxide, nitrogen dioxide, sulfur dioxide
  • drilling, mucking, rockbreaking: silica, general dust
  • refining: metals, sulfur dioxide, dust, chemical reagents
  • welding fumes, from the heating and burning of metal surfaces

Hazard controls may include:

  • engineering controls that prevent worker exposure to chemical, or biological hazards in underground and surface mines
  • safe work practices that include providing adequate ventilation or controls that eliminate or reduce exposure to safe limits
  • prescribed personal protective equipment (PPE) for tasks
  • training to enable workers to recognize occupational disease hazards
  • training workers on the prescribed use of PPE

Employers must:

  • complete a workplace audit to identify designated substances set out in the Designated Substances Regulation (Reg. 490) and Control of Exposure to Biological or Chemical Agents Regulations (Reg. 833)
  • conduct an assessment of those designated substances
  • establish a control program, including medical surveillance based on the workplace assessment, if needed
  • provide information and instruction to workers for hazards associated with occupational disease
  • encourage workers to report occurrences of suspected exposure to hazards related to occupational disease
  • identify and assess the risk of job-specific tasks that may expose workers to physical, chemical or biological exposures in underground and surface mines
  • establish controls to eliminate or reduce workers’ exposure to hazards
  • ensure control measures are in place to adequately protect workers from exposure

Some general duties of workplace parties


Below are some examples of employers’ duties under the Occupational Health and Safety Act (OHSA):

  • provide information, instruction and supervision to workers to protect their health and safety, including providing information on safe work policies and procedures specific to the workplace and type of work the workers will perform [Section 25(2)(a)]
  • take every precaution reasonable in the circumstances for workers’ protection [Section 25(2)(h)]
  • ensure prescribed measures and procedures are carried out at the workplace [Section 25(1)(c)]
  • ensure equipment, materials and protective devices required by the regulations are provided and maintained in good condition [Section 25(1)(a) and (b)]
  • provide assistance to, and co-operate with, the mine’s Joint Health and Safety Committee and/or a health and safety representative [Section 25(2)(e)]
  • prepare and review, at least annually, a written occupational health and safety policy for the workplace, and develop and maintain a program to implement that policy [Section 25 (2)(j)]
  • post an OHSA copy in the workplace [Section 25(2)(k)]
  • establish an occupational health service and surveillance program for workers as prescribed [Section 26]


Below are some examples of supervisors’ OHSA duties:

  • ensure workers comply with the OHSA and its regulations [Section 27(1)(a)]
  • ensure any equipment, protective devices or clothing required by the employer is used and/or worn by workers [Section 27(1)(b)]
  • advise workers of any potential or actual health or safety dangers known by the supervisor [Section 27(2)(a)]
  • if prescribed, provide workers with written instructions on the measures and procedures to be taken for workers’ protection [Section 27(2)(b)]
  • take every precaution reasonable in the circumstances for the protection of workers [Section 27(2)(c)]


Below are some examples of workers’ OHSA duties:

  • use or operate equipment in a safe manner [Section 28(2)(b)]
  • report defects in equipment to your supervisor or employer [Section 28(1)(c)]
  • work in compliance with the OHSA and its regulations [Section 28(1)(a)]
  • report any known workplace hazards or OHSA violations to your supervisor or employer
    [Section 28(1)(d)]

Workers should be aware of their OHSA rights, including the right to refuse unsafe work and the right to know about any potential hazards they may be exposed to in mines.

Protecting workers

Employers, supervisors and trainers should encourage workers to communicate any questions or concerns they may have about occupational disease. Supervisors or others involved in training workers should be familiar with any health and safety concerns faced by workers.

Compliance information

Ministry of Labour Health & Safety Contact Centre

Call toll-free 1-877-202-0008 anytime to report workplace health and safety incidents. Call 8:30 a.m. to 5 p.m. Monday to Friday for general inquiries about workplace health and safety.

Always call 911 in an emergency.

Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.