Vancouver, BC — WorkSafeBC has released a bulletin warning of the risks involved in breathing crystalline silica dust.
Silica is the second most common mineral in the earth’s crust and a major component of sand, rock and mineral ores. Silica exists in both crystalline and non-crystalline (amorphous) form. It is the crystalline form of silica that is the main concern when considering potential health effects. The most common type of crystalline silica is quartz.
Breathing in crystalline silica dust over a prolonged period of time can cause silicosis — a disease in which fine particles deposited in the lungs scar the lung tissue. Exposure has also been linked to lung cancer.
Silicosis is one of the oldest occupational diseases and still kills thousands of people every year, everywhere in the world. Initially, workers with silicosis may have no symptoms. However, as the disease progresses, the affected worker may experience shortness of breath, a severe cough and weakness. These symptoms can worsen over time and eventually cause death.
Crystalline silica is found in common materials such as concrete, cement, and mortar, masonry, tiles, brick, granite, sand, fill dirt, top soil, asphalt-containing rock or stone and abrasive used for blasting. Silica dust is released when rocks, sand, concrete and some ores are crushed or broken.
Work in mines, quarries, foundries, and construction sites, in the manufacture of glass, ceramics, and abrasive powders, and in masonry workshops can be particularly risky. Sandblasting as well as any abrasive blasting — even if the abrasive does not contain silica — may pose a silicosis hazard when it is used to remove materials that contain crystalline silica, such as remains of sand moulds from metal castings. Activities such as dry sweeping, clearing sand or concrete or cleaning masonry with pressurized air can create large dust clouds that can be equally as hazardous, even in the open air.
The WorkSafeBC Bulletin includes a list of work activities that put you at risk for crystalline silica dust exposure.
Steps employers can take to protect workers
– Establish and implement an exposure control plan that provides a detailed approach to protecting workers from harmful exposure to crystalline silica dust. The plan should include purpose and responsibilities, risk assessment, health hazard information, engineering controls, written safe work procedures, worker training, washing or decontamination facilities, health monitoring, and record keeping.
– Substitute glass beads, olivine, or other material for silica sand in abrasive blasting.
– Change the process. Design buildings with pre-built recesses for plumbing, gas, and electric wiring so there is less need to cut or drill masonry and concrete.
– Provide engineering controls. Use local exhaust ventilation or water spray systems to reduce dust levels and use barriers to prevent access to the area by unprotected workers.
– Provide appropriate personal protective equipment (PPE) such as respirators and protective clothing if engineering controls and work practices are not effective in controlling exposure.
– Train workers on the dangers of silica exposure, and how to use dust controls and PPE.
What workers can do to protect themselves
– Learn about the control methods that can protect you.
– Ask your supervisor how you will be protected when performing dusty work.
– Follow safe work procedures, and use respiratory protection.
For more information, view the WorkSafeBC Bulletin on the dangers of breathing silica dust and see The dangers of silica and how to prevent exposure, also published by WorkSafeBC. Read more information about the health effects of quartz silica from OSH Answers. Find information on silica substitutes from Occupational & Environmental Medicine, Michigan State University, and refer to the Crystalline Silica in the Workplace Bulletin from Work Safe Alberta.