10 facts about silica and why it is bad for you
What is silica?
Silica is a naturally occurring and common mineral called silicon dioxide. Silicon dioxide has both a crystalline and non-crystalline form. The crystalline form is known as quartz, and it is present in sand, stone, concrete and mortar.
Crystalline silica occurs in varying amounts in different rock and construction products. For example, granite contains 25 to 40% silica, while engineered composite stone contains over 90%.
The silica content of concrete aggregates could be around 30%.
Why is silica dangerous?
Silica becomes hazardous if we inhale very small particles of it in dust.
Construction industry processes such as dry drilling, grinding, sanding, crushing and sweeping release particles that can become airborne.
A proportion of dust can have a particle size small enough to be inhaled into our lungs. This proportion is called respirable silica dust and is usually less than seven microns (millionths of a metre) in diameter.
It’s so tiny that you might breathe it in and not know.
What diseases can silica dust cause?
According to SafeWork Australia, people who breathe in respirable silica dust can develop several serious or life-threatening diseases, such as:
- chronic bronchitis
- emphysema
- acute silicosis
- accelerated silicosis
- chronic silicosis
- lung cancer
- kidney damage, or
- scleroderma
Acute silicosis has been associated with an increased risk of developing lung cancer.
The Cancer Council estimates that each year 230 people will develop lung cancer due to past exposure to silica dust.
Who is most at risk?
Workers in industries exposed to silica-containing dust are at most risk. Typically, this includes construction workers, miners, farmers or engineers.
While not everybody who is exposed will develop cancer, the risk of disease increases with long term exposure or high-level dust exposure.
How can you reduce silica dust exposure?
Australian workplaces must comply with work health and safety laws. Although there may be some minor difference across the states and territories, the best approach is to eliminate a risk if possible.
We cannot avoid silica as it is a common mineral in many construction products. However, we can take some measures to avoid generating dust.
Eliminate drilling when installing temporary and permanent edge protection handrails
The traditional installation of edge protection handrails has involved drilling holes for each post into pre-cast concrete, Jersey Barriers, Gawk Screens and RE Walls. The drilling generates large volumes of potentially hazardous dust, as each steel post requires multiple fixing bolts.
Clearing dust debris from the drilled holes with blowers is another potential source of airborne silica.
Non-Drill developed and patented a system that eliminates the need for drilling by utilising existing anchor points in pre-cast concrete.
The Non-Drill system reduces the exposure risk to construction workers by removing a dust-generating task.
Apart from improving on-site work health and safety, the Non-Drill system gives significant productivity improvements because of its fast installation speed.
7 Key Messages
- Crystalline silica is a naturally occurring mineral found in many construction products.
- Breathing dust containing very fine silica particles can increase the risk of several serious diseases, including lung cancer.
- Processes such as drilling and grinding can generate dust containing respirable silica.
- Construction workers can be regularly exposed to silica-containing dust.
- The traditional installation of edge protection barriers in pre-cast creates significant amounts of dust through drilling.
- Safety legislation recommends eliminating an identified risk if possible.
- Non-Drill permanent or temporary handrails can be fixed to pre-cast concrete, Jersey Barriers, Gawk Screens and RE Walls without any need for drilling.