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Crystalline silica exposure

What is the potential risk?

Crystalline silica is a naturally occurring mineral most commonly found as quartz. It is found in substantial quantities in sand, sandstone, granite, stone and rock aggregates, clay, shale and slate. When crystalline silica is released in the air as a fine dust, workers may inhale the dust, which puts them at risk for illness. Workers exposed to crystalline silica dust are at risk of developing respiratory diseases such as silicosis and lung cancer.

Silica is used in a wide variety of materials including concrete, cement, asphalt, bricks, and stone (granite) countertops. Workers may be exposed to crystalline silica dust through activities such as sanding, cutting, drilling, grinding, crushing, demolition, and the cleanup of silica-based materials. Workers may also be exposed to the dust during abrasive blasting or during the manufacturing of products containing silica.

Construction, mining, and manufacturing workers who may be exposed to crystalline silica dust are at risk of developing adverse health effects.

What industries may be at risk?

  • Road construction and maintenance
  • Concrete cutting or coring
  • Concrete placing, finishing, surfacing, or repair
  • Concrete product manufacturing
  • Stone or marble cutting and product manufacture
  • Structural concrete product manufacturing
  • Clay digging or processing
  • Quarry
  • Diamond, seismic, or shot hole drilling
  • Stone crushing

How can I reduce the risk in my workplace?

As an employer, you need to know if there is the potential for the risk identified in this advisory to be present in your workplace. It’s your responsibility to regularly inspect your workplace, and to ensure that your safety procedures and practices control the risk. The following information highlights some of the sections of the Occupational Health and Safety (OHS) Regulation and Guidelines that are most relevant to this risk.

Section 5.54 of the OHS Regulation requires that the employer implement an exposure control plan (ECP) when:

  1. exposure monitoring under section 5.53(3) indicates that a worker is or may be exposed to an air contaminant in excess of 50% of its exposure limit,
  2. measurement is not possible at 50% of the applicable exposure limit, or
  3. otherwise required by this Regulation.

Section 5.57 of the Regulation requires that worker exposure to carcinogens and sensitizers must be maintained at levels as low as reasonably achievable below the exposure limit. These substances must be replaced, if practicable, with a material that reduces the risk to workers.

Additional ECP requirements are also specified in sections 5.55–5.59.

Where can I find resources?

You can access the following resources on

Guidelines covering work associated with rock dust:

Publication Date: Jan 2015 Asset type: Risk Advisory Reference: RA 2015-06