Silica Dust: it can take your breath away

Silica is one of the most common minerals on earth and is a basic component of soil, sand and many rocks. It exists in several forms—including crystalline, which is the most abundant and used extensively in industrial applications because of its unique physical and chemical properties. When dormant, silica is harmless, but when disturbed, airborne and inhaled it can become a genuine health risk. Long-term or heavy short-term exposures to airborne crystalline silica dust can cause a disabling, sometimes fatal, lung disease called silicosis. It occurs when fine silica particles deposited in the lungs cause thickening and scarring of tissue that restricts the lungs’ ability to extract oxygen from air. The damage is permanent. Exposure to crystalline silica has also been linked to bronchitis, tuberculosis and lung cancer.

Airborne hazards, such as invert drilling fluid exposure, have been a safety focus in recent years. Most recently, industry’s efforts have centered on silica dust exposure.  Silica is not a new workplace hazard, but growth in operations such as hydraulic fracturing has prompted companies in Canada’s oilpatch to redouble efforts to prevent worker (and environmental) exposure.

“Occupational disease in all industries is a serious issue,” says Robert Waterhouse, a Certified Industrial Hygienist (CIH) and Program Manager for Industry Development at Enform. “If we want to prevent these diseases we need to increase awareness and ensure that workers and supervisors are setup for success in the management of these risks.”

 

Possible Sources of Silica Exposure Recommended Actions/Controls
#1 Source

Drilling fluid dry product additive handling, either at the mixing shack hopper or on the mud tanks

 

  1. Use local exhaust ventilation
  2. Prevent adjacent exposure and reduce waste
    • Discharge exhaust silica dust into the drilling mud
  3.  Follow standard procedures
  4. Add the product slowly to:
    • Add as little energy to the product as possible
    • Maximize the incorporation of the additive into the fluid system
    • Avoid deposits at the bottom of the mud tank and overflowing the shaker
    • Lower energy » lower exposure, more efficient and lower costs
  5. Use a respirator equipped with P100 filters
#2 Source

Cement silo in-loading

  1. Understand silica concentration in both the cement and the additives
  2. Use a dust filter on the cement in-loading exhaust port
  3. Avoid any visible airborne cement dust
  4. Wear a respirator equipped with P100 filters when in airborne dust
#3 Source

Operation or maintenance of cutting dryers

  1. Be aware of rock composition and potential silica exposure
  2. Wear a respirator equipped with P100 filters when in airborne dust
#4 Source

Oil-based drilling fluid “Invert” mist

  1. Follow Invert exposure control plan

 

Dealing with silica exposure comes with its own set of challenges. Many drilling product fluid additives that are naturally sourced, such as barite, lime, and graphite, may contain silica. One challenge is that some products may not indicate that crystalline silica (such as quartz) is present, even though it is. If silica is present as 0.1% or more, it is required to be disclosed on a Safety Data Sheet (SDS). Unfortunately, there is no legislative requirement for suppliers to test products when preparing SDSs, even with recent changes in WHMIS 2015 (GHS). If you are not confident in the level of silica in your product, take a bulk sample and have it tested at a laboratory.

Working with association partners and members of industry, Enform has developed key resources and guidelines for controlling silica dust exposures. These resources provide detailed information on health hazards posed by silica, including: exposure factors, limits and symptoms. They also prescribe processes for risk identification, assessment and control, and outline clear responsibilities for employers, prime contractors, supervisors and workers.

You can find it all by visiting www.enform.ca.