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If you were asked to list the hazards found on construction sites, would you think to include the dust that is created from chipping, grinding, drilling or cutting stone, concrete, bricks or any other material that could contain silica?
Silica, in its crystalline form, is naturally found in soil, sand, granite, and many other minerals. Quartz, the most common form of silica, is commonly used in the construction trades and found in building materials such as sand, asphalt, stone, rock, concrete, brick, block, and mortar.
The most common way workers get exposed to silica is by inhaling the dust when they chip, cut, drill, or grind objects that contain crystalline silica. If this dust is inhaled it can cause serious respiratory tract diseases.
Health impacts of exposure
When very small (respirable) silica dust particles are inhaled they can penetrate deep into the lungs and cause disabling and sometimes fatal diseases of the lung and kidney. When a person inhales crystalline silica, the lungs react and develop scarring and hardening around the trapped silica particles, resulting in a disease called silicosis. Silicosis is a disabling, irreversible, and sometimes fatal lung disease for which there is no cure. Since silicosis affects lung function, it makes you susceptible to lung infections such as tuberculosis. For smokers this is more hazardous, as smoking damages the lungs and adds to the damage caused by breathing silica dust. The other bad news is that crystalline silica is also a known carcinogen which means it can cause lung cancer.
CAREX Canada reports that approximately 380,000 Canadians are exposed to silica at work, primarily in the construction sector. According to 2011 cancer statistics from the Occupational Cancer Research Centre (OCRC)'s Burden of Occupational Cancer Study, 570 lung cancer cases (2.4% overall) were attributed to occupational exposure to crystalline silica in Canada.
Construction trades labourers, heavy equipment operators, and plasterers and drywallers are most at risk to be exposed to silica, according to CAREX Canada. A variety of construction activities can expose construction workers to crystalline silica. The most severe exposures generally occur during abrasive blasting with sand to remove paint and rust from bridges, tanks, concrete structures, and other surfaces. Other construction activities that may cause severe exposure include: crushing and unloading rocks, jack hammering, rock/well drilling, concrete mixing, concrete drilling, brick and concrete block cutting and sawing, and tunneling operations.
Crystalline silica, especially quartz, is widely used in many different ways and therefore exposure may also occur in other industries and occupations such as mining, roofing, agriculture, manufacturing, and stone or artificial stone countertop cutting.
Eliminating the hazardous process or material, where possible, is the most effective way to protect the worker. This involves looking at ways to substitute crystalline silica containing materials with safer alternatives, whenever possible. In some work situations, garnet, a less hazardous material, can be used instead of silica for sand-blasting.
If eliminating the process that is creating hazardous dust isn’t possible, there are other hazard control measures available. Reducing the amount of concrete finishing where possible can mean less grinding. Splitting concrete pavers rather than sawing them will generate less dust. Incorporating engineering controls such as spraying water and local exhaust ventilation integrated into the tools greatly reduce the concentration of crystalline silica dust in the air. Engineering controls may require physically modifying the facilities, equipment, and processes to reduce exposure but are effective measures.
Administrative controls that involve changing the way the work is done can limit the risk of silica dust exposure. For example, providing workers with necessary education and supervision; developing a written exposure control plan for silica; posting warning signs in the work area; scheduling crews to work as far away from silica-dust generating activities as possible; providing adequate washing facilities on site; developing safe work procedures for dealing with silica dust; and monitoring worker exposure to silica.
Personal protective equipment, although the least effective control, may also be necessary. Properly fitted, tested and certified respirators, eye wear, and protective clothing should be worn when required.
Employers and workers alike need to be aware of the hazards of the work activity and the job site. Know the operations and job tasks that generate crystalline silica dust, understand the related health hazards and protect against exposure to this hazardous dust. Together you can save your breath and maybe even a life.
On March 24, 2016, the Occupational Safety and Health Administration (OSHA) issued a crystalline silica standard for the construction industry in the United States to protect workers from exposure to respirable crystalline silica.
Tips & Tools
Chainsaws are essential tools for arborists, landscapers, hydro maintenance workers and lumberjacks. They are powerful tools that have the potential to be extremely dangerous. Improper handling and use of a chainsaw can result in very serious injuries and even death. Whether you use your chainsaw every day or once a month, here are some safety tips for using your chainsaw safely.
Tips for handling:
General tips to know when using chainsaws
Resources from CCOHS:
On Friday May 19, 2017, Health Canada announced that they are delaying two of the WHMIS 2015 transition timelines. The two new deadline dates affect suppliers who are manufacturers and importers and suppliers who are distributors and those who import for their own use.
For information on employer WHMIS requirements set out by federal, provincial and territorial occupational health and safety agencies, contact the agency in your jurisdiction. Specific WHMIS requirements for any jurisdiction can also be found at WHMIS.org.
This month’s Health and Safety To Go! podcasts feature the new episode Keeping Both Young and New Workers Safe this Summer and an encore presentation of Talking About Lyme Disease.
Feature Podcast: Keeping Both Young and New Workers Safe This Summer
The Canadian Centre for Occupational Health and Safety (CCOHS) offers advice and tips about keeping young and new workers safe on the job.
The podcast runs 8:13 minutes. Listen to the podcast now.
Encore Podcast: Talking About Lyme Disease
The distribution area of Lyme disease carrying ticks in Canada is expanding. CCOHS explains why it's important to be on the lookout for ticks and how to recognize the signs and symptoms of this disease.
The podcast runs 4:37 minutes. Listen to the podcast now.
CCOHS produces free monthly podcasts on a wide variety of topics designed to keep you current with information, tips, and insights into the health, safety, and well-being of working Canadians. You can download the audio segment to your computer or MP3 player and listen to it at your own convenience... or on the go!
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The Health and Safety Report, a free monthly newsletter produced by the Canadian Centre for Occupational Health and Safety (CCOHS), provides information, advice, and resources that help support a safe and healthy work environment and the total well being of workers.
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