Silica
Silica is one of the most common hazards on a worksite, particularly in the construction, oil and gas, manufacturing, and agriculture industries. Silica dust can cause silicosis, a serious and irreversible lung disease. It can also cause lung cancer. Cutting, breaking, crushing, drilling, grinding, or blasting concrete or stone releases the dust. As workers breathe in the dust the silica settles in their lungs.
For information on protecting workers from harmful exposure to silica dust, see the resources section below. In addition, the BC Construction Safety Alliance (BCCSA) has developed a silica control tool for use in the construction industry.
- How workers are exposed
- The risks
- How to reduce the risks
- Resources
How workers are exposed
Silica is the basic component in sand and rock. It’s in construction materials such as:
- Concrete, concrete block, cement, and mortar
- Masonry, tiles, brick, and refractory brick
- Granite, sand, fill dirt, and top soil
- Asphalt-containing rock or stone
- Abrasive used for blasting
Any activity with these materials can expose workers to respirable silica (RCS) dust. The most common ways silica dust is released in the workplace include:
- Chipping, sawing, grinding, hammering, or drilling
- Crushing, loading, hauling, or dumping
- Building demolition
- Power cutting or dressing stone
- Facade renovation, including tuck-point work
- Abrasive or hydro blasting
- Dry sweeping or pressurized air blowing
- Tunneling, excavating, or earth moving
The risks
Inhaling silica dust can cause silicosis, a serious and irreversible lung disease. It can be lethal. Silica damages the lung and causes scar tissue to form. This causes the lung tissue to become thicker. Silica exposure can also cause lung cancer.
It is possible to have silicosis without showing any symptoms at first. The longer workers have been exposed to silica dust, the worse the symptoms will become. As the disease progresses workers may show noticeable symptoms such as:
- Shortness of breath
- Severe coughing
- Body weakness
How to reduce the risks
The best way to reduce the risk of exposure to silica dust is to eliminate the source of exposure. If that's not possible, there are other risk controls to use. When choosing risk controls, start by asking the questions in the following steps. The steps are listed in order of effectiveness.
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1
Elimination or substitution
Eliminating the hazard by substituting a safer process or material, where possible, is the most effective control. Some questions to consider:
- Can a less hazardous material be used (for example, garnet instead of silica in sand-blasting operations)?
- Can formwork be designed more carefully to reduce the amount of concrete finishing required?
- Can a process that generates less dust be used (for example, splitting rather than sawing concrete pavers)?
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2
Engineering controls
Making physical modifications to facilities, equipment, and processes can reduce exposure. Some questions to consider:
- Can local exhaust ventilation be used on all equipment that generates silica dust?
- Can water be used to prevent dust from becoming airborne?
- Can the areas that generate large amounts of dust be enclosed, and have proper ventilation to clean the air?
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3
Administrative controls
These involve changing work practices and work policies. Providing awareness tools and training also count as administrative controls. All can limit the risk of silica dust exposure. Some questions to consider:
- Have you developed and implemented an exposure control plan (ECP) for silica?
- Can warning signs be posted in the work area?
- Can crews be scheduled to work away from silica dust-generating processes?
- Have you provided adequate washing facilities on site?
- Do you have a system for monitoring worker exposure to silica?
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4
Personal protective equipment (PPE)
PPE is the least effective control and should be used with at least one other control in place. Some questions to consider:
- Do workers have the proper respirators, eye wear, and protective clothing?
- Has personal protective equipment been tested to make sure it is working properly?
Resources
Title
Reducing the risk of exposure to crystalline silica dust for horse trainers and riding coaches
Exposure to crystalline silica dust in riding arenas presents health hazards for horse trainers and riding coaches. This bulletin explains the hazards, suggests options for preventing worker exposure,...
Title
Developing a Silica Exposure Control Plan
This guidance document is intended to assist employers to development an exposure control plan (ECP) that meets the requirements of the Occupational Health and Safety Regulation and protects workers from...
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Exposure Control Plan for Cutting Concrete
Cutting concrete without proper dust controls can generate high levels of silica-containing dust. Breathing in this fine dust can cause a serious lung disease called silicosis, which is characterized by...