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Silica – the everywhere danger
By Stephen Gleeson
The dangers of silica are best described as a serious, often fatal and entirely preventable occupational health hazard. It is a potent, invisible and carcinogenic dust that causes irreversible lung damage and other severe illnesses when inhaled. Reference: Safe Work Australia. Silica falls into two types, naturally formed crystalline silica and amorphous silica (human made), which generally is not deemed to be hazardous – not life threatening.
Crystalline Silica characteristics:
- Particles are extremely small, microscopic in fact – a silica particle is approximately 100 times smaller than a grain of sand
- Silica particles can be suspended in the air for hours, long after the dust (carrier) has disappeared
- Due to their size, can be present even though they can’t be seen with the naked eye
- Once damage is done to lung tissue, unfortunately it is irreversible
- Silica comes from quartz and is found virtually everywhere from sand at the beach, sandstone, cement, tiles, rocks, granites to engineered stone – the worst offender.
Exposure can result from drilling, cutting and / or sanding a material containing silica, creating dust which in turn can be inhaled, known as Respirable Crystalline Silica / RCS.
If working in a high risk industry to silica exposure, it is mandatory that workers have regular lung function checks. Under OHS Regulations, 2017, the employer has a duty to create and maintain a safe working environment this includes identifying and reducing exposure to silica.
1 in every 100 workers are exposed to unsafe levels silica in Australia that will develop into a debilitating disease over time. In another context, around 600,000 workers are exposed to dust containing silica yearly in Australia. Reference: Australian Workers’ Union (AWU) and Lung Foundation Australia
The most common and characteristic disease caused by exposure to RCS is silicosis / scarring of the lungs which is a progressive, incurable lung disease caused by inhaling tiny / microscopic silica dust particles.
Apart from silicosis, inhalation of RCS particles can also cause or lead to:
- susceptibility to a range of infections, in particular TB
- chronic bronchitis
- lung cancer
- emphysema
- development of a range of auto immune diseases, such as scleroderma, often fatal
- arthritis
- joint pain
- kidney damage.
Industries typically where exposure to RCS can be expected:
- Construction, Building and Demolition
- Mining and Quarrying
- Tunnelling and Civil Engineering
- Manufacturing
- Stone Fabrication (Natural Stone)
- Abrasive Blasting and Surface Treatment
Other impacted industries include;
- Agriculture: Working in very dusty, dry, sandy soils
- Engineering/Surveying: Soil testing and drilling
- Dental Work: Fabricating and adjusting prosthetics using materials with silica.
Did you know that:
- Exposure to silica is often made without the impacted person knowing it
- There are thousands of cases silica exposure in Australia yearly
- Current estimates indicate a rising epidemic of silica-related deaths in Australia, with projections suggesting that over 10,000 future cases of lung cancer and up to 100,000 cases of silicosis could result from current workplace exposure to Respirable Crystalline Silica (RCS). Reference: WorkSafe ACT.
The crystalline silica content varies significantly, depending on the material, for example:
High Concentration (Generally > 50%)
- Engineered Stone (reconstituted stone): Often up to 95-97%
- Sandstone: 70–90% or up to 95%
- Quartzite: 20% to 95%
- Sand: Up to 70–100%
- Calcium-silicate bricks: 50-55%
Moderate to High Concentration (20% – 60%)
- Granite: 20% to 60% (typically 30-40%)
- Slate: 20% to 40%
- Autoclaved Aerated Concrete (AAC): 20% to 40%
- Shale: 20% to 40%
- Concrete & Mortar: 25% to 70% or less than 30%
- Ceramic Tiles: 5% to 45%
Low to Moderate Concentration (< 30%)
- Brick: 5% to 15% or up to 30%
- Porcelain: 14% to 18%
- Bluestone / basalt: less than 10%
- Marble: Less than 5%
- Limestone: Less than 5%
- Demolition dust: 3 to 4%
Employers responsibilities:
Employers must protect workers from silica dust by ensuring exposure stays below the 0.05 (8-hour TWA) standard, with a recommended 0.02 precautionary limit. Key duties include applying the hierarchy of controls (eliminating, substituting, or engineering out dust), providing respirators (PPE), conducting atmospheric monitoring and providing health monitoring for employees. Reference: WorkSafe Victoria.
To assist an employer comply with their WorkSafe obligations and ethical responsibilities, in relation to RCS, Hazcon provides a range of services including;
- Dust & Silica Monitoring & Services
- Dangerous Goods & Hazardous Substances
- HSE Specific Hazard Program
- Indoor Air Quality (IAQ), and
- Silica Awareness Training (2 hour or 4 hour – non accredited).
