New Information in Crystalline Silica Exposure!

New Information in Crystalline Silica Exposure!


Did you mention crystalline silica? What exactly is it and how could it affect me at work?

We’ve got some answers for you, and you’ll better understand why it’s important to keep up to date with Quebec’s regulatory changes.

What is crystalline silica?

The main form of crystalline silica is quartz. It is found in construction materials such as brick, concrete, ceramics, mortar and granite. Specific tasks are therefore highly conducive to exposure to crystalline silica:

  • Demolition
  • Drilling
  • Sawing
  • Grinding
  • Sanding
  • Dry sweeping
  • Crushing

What are the associated dangers?

Exposure to crystalline silica dust can cause silicosis. This is a type of pneumoconiosis, a group of lung diseases caused by the inhalation of certain dust particles.

When silica particles are inhaled, they can have the following effects on the human body:

  • Lung inflammation: Inhaled silica particles cause inflammation of the lungs, as the immune system reacts to their presence. This inflammation can lead to coughing, chest pain and breathing difficulties.
  • Scarring (fibrosis): Over time, ongoing inflammation triggers the formation of scar tissue in the lungs. This scarring reduces the elasticity of lung tissue, making it more difficult for the lungs to expand and contract.
  • Reduced lung function: As scarring progresses, lung function decreases, leading to symptoms such as shortness of breath and reduced exercise tolerance. Severe cases of silicosis can result in significant disability.
  • Increased susceptibility to infection: The damaged lung tissue of silicosis sufferers is more vulnerable to infections such as tuberculosis (TB) and other respiratory diseases.
  • Risk of complications: Silicosis increases the risk of developing other respiratory conditions, such as chronic obstructive pulmonary disease (COPD) and lung cancer.

*The severity of silicosis can vary according to factors such as the duration and intensity of exposure to silica dust.

How to reduce exposure to crystalline silica?

CNESST and IRSST have joined forces to provide you with a document containing the best practices for preventing worker exposure to silica.

Read the document here

For all other questions, our occupational hygiene specialists are available to help you!

What’s changing in Quebec?

As of April 28, 2024, new exposure limits for crystalline silica will officially come into effect. These changes to the regulation respecting occupational health and safety are designed to limit the occupational illnesses associated with this exposure.

One of the major changes to the regulation is the permissible exposure value applicable to crystalline silica, which will now be 0.05 mg/m3. This still represents a 50% reduction of the exposure levels previously accepted.

What has already changed for work with crystalline silica?

In the Safety Code for the Construction Industry, this subsection is added following article 3.24.22: §3.25 Work liable to produce crystalline silica dust emissions.

This subsection applies to all construction sites where materials containing or presumed to contain crystalline silica are present. These changes to the Construction Safety Code (CSTC) came into force on June 8, 2023, in Quebec. The CNESST is thus deploying several strategies to enforce its zero-tolerance rule regarding exposure to crystalline silica in the workplace.

The materials presumed to contain crystalline silica are listed below:

  • Slate
  • Asphalt
  • Concrete
  • Brick
  • Ceramic
  • Cement
  • Fibrocement
  • Granite
  • Aggregate
  • Stoneware
  • Mortar

It is also important to mention that an analysis must be carried out to demonstrate the absence of crystalline silica on the worksite. If the employer already has a safety data sheet (SDS) or an analysis carried out using a recognized method, there is no need to provide a further demonstration. This SDS or analysis must be available at all times on the construction site.

If you have to perform work involving a material that is presumed to contain or contain crystalline silica, and the material may emit dust, the employer must implement measures to control the emissions. Here are the 4 methods named in this regulation change (GAZETTE OFFICIELLE DU QUÉBEC, May 24, 2023, 155th year, #21):

  1. the use of an exhaust ventilation system fitted with a high-efficiency filter
  2. the use of a process to humidify dust emissions
  3. isolation of workers from the dust source
  4. containment of the dust source so as not to expose workers to it

Do you work in an enclosed operating cabin?

According to changes in regulations, this must have the following characteristics:

  • Air entering the cabin must be filtered using a high-efficiency filter.
  • Positive pressure must be maintained.
  • The cabin must be equipped with a heating and air-conditioning system.
  • Door and window seals must be maintained appropriately to ensure airtightness. 

Respiratory protection when working with crystalline silica

Where the employer is unable to offer exposure below the limit value to employees working with materials presumed to contain crystalline silica, the employer must require the use of respiratory protective equipment (RPE). The respirator supplied by the employer must offer a characteristic protection factor of 10. The filter must be a series 100 or HEPA filter.

Find out more about our protective masks and filters right here!

What about training? 

It’s essential to properly train workers who will be performing tasks involving the risk of exposure to crystalline silica. As a minimum, training should cover the following topics:

  • Materials that may contain crystalline silica
  • Jobs that expose workers to crystalline silica dust
  • Health effects of exposure
  • Safe work practices to be implemented
  • Use, maintenance and wearing of protective equipment and dust control tools

Delimiting the work area

It’s imperative to mark out work areas with danger signs. This will keep unequipped workers away from these hazardous areas. Only workers wearing respiratory protection that complies with these regulations can access these work areas.

Don’t forget to clean your work clothes!

Before leaving work, you should either put your clothes in a closed bag provided by your employer, or clean them with a damp cloth or a vacuum cleaner with a high-capacity filter. No other method of cleaning is permitted. Using a broom or jets of compressed air could suspend dust containing crystalline silica in the air.

Debris from materials used
If you are working with materials suspected of containing silica, they must be dampened or enclosed in a closed container to limit the amount of dust produced. This rule applies to both indoor and outdoor work.


Do you need respiratory protection?

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