What is the potential risk?

In 2012, there were two combustible dust-related sawmill explosions in northern B.C. These resulted in four fatalities and dozens of injured workers.

Since then, WorkSafeBC has been proactively identifying sawmills and other primary wood processing facilities at risk. Manufacturing processes in a number of other industries may also use or produce combustible dust, which poses a risk of explosion and/or fire should the combustible dust come into contact with an ignition source. A variety of materials may be combustible when they are in dust or powder form, including:

• Wood and paper
• Grain and other food products, such as flour, coffee, and spices
• Coal
• Metals, such as aluminum, chromium, and magnesium
• Plastic
• Chemicals, such as pharmaceuticals, lactose, and sulfur

Combustible dust can accumulate on horizontal surfaces and can be dispersed in the air when these accumulations are disturbed. This can form a dust cloud that, if ignited, can cause an explosion, potentially resulting in injuries to workers.

The risk of a combustible dust explosion depends on multiple factors, including:

• Properties of the dust itself
• Amount of dust in a work environment
• Potential amount and concentration of dust that may become suspended in air
• Availability of oxygen
• Presence of ignition sources
• Confinement of the work area

Workers in industries where this dust is handled or produced are at the most risk of injury should an explosion or fire occur.

What industries may be at risk?

• Food and beverage product manufacturing
• Metal product manufacturing
• Petroleum, coal, rubber, plastic, and chemical product manufacturing
• Wood and paper product manufacturing
• Recycling

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 5.81 of the OHS Regulation requires the employer to ensure that if combustible dust collects in a building or structure or on machinery or equipment, it must be safely removed before accumulation of the dust could cause a fire or explosion.

Section 5.71 requires that a dust collector having an internal volume greater than 0.6 m3 (20 ft3) and being used to control combustible dusts must be located and constructed so that no worker will be endangered in the event of an explosion inside the collector.

The BC Fire Code also places specific duties on employers with regard to the control of accumulation of combustible dust in the workplace.

Where can I find resources?

You can access the following resources on worksafebc.com:

• OHS Guideline 5.71(3): Location and construction of dust collectors
• WorkSafe Bulletin: Controlling the hazards of combustible dusts in manufacturing
• WorkSafeBC webpage: Combustible dust