To manage risks of silica dust, you must first identify whether silica dust is being generated and released into the air at your workplace. Workers are exposed to silica dust whenever it is airborne and they can breathe it in.
Different types of rock and rock products can contain different amounts of silica, for example:
|Type||Amount of silica (%)|
|Granite||25 to 40|
|Engineered stone||> 90|
|Aggregates, mortar and concrete||various|
Silica dust is generated in workplace processes such as crushing, cutting, drilling, grinding, sanding, sawing or polishing of natural stone or man-made silica containing products. Silica dust can be generated and found:
- during manufacturing and construction
- when mining or tunnelling
- in waste or sand-based products, and
- in materials brought to your workplace.
Some dust particles can be so small that they are not visible; these are referred to as respirable particles. Respirable silica dust particles are those that are small enough to breathe in and penetrate deep into the lungs causing permanent damage that can lead to serious illness or death. Silica dust is also linked to the development of auto-immune disorders and chronic renal (kidney) disease.
A label or safety data sheet (SDS) may not always be available at a workplace or with a product that contains silica. If you do not have an information sheet or SDS for a product, you might need to talk to your supplier to find out how much silica is present. However, you can assume that all engineered stone products contain very high amounts of silica.
Common silica containing materials and products include:
- stone products (natural and engineered)
- composite dental fillings
- manufactured timber
- drywall and some plasterboards
- tiles, and
- even some plastic material.
Activities that release silica dust into the air include:
- fabrication, installation, maintenance and removal of engineered stone countertops
- excavation, earth moving and drilling plant operations
- clay and stone processing machine operations
- paving and surfacing
- mining, quarrying and mineral ore treating processes
- road construction and tunnelling
- construction labouring and demolition
- brick, concrete or stone cutting; especially using dry methods
- abrasive blasting (blasting agent must not contain greater than 1 per cent of crystalline silica)
- foundry casting
- angle grinding, jack hammering and chiselling of concrete or masonry
- hydraulic fracturing of gas and oil wells
- crushing, loading, hauling and dumping of rock or muck, and
- clean-up activities such as sweeping or pressurised air blowing of dust.
Examples of work with potentially harmful exposures to silica
Manufacturing silica containing products
The use of engineered stone materials for benchtops in domestic and commercial premises has significantly increased in the last 10-15 years. Manufacturing stone items can result in a risk of dust exposure.
Fabricating, installing, maintaining and removing silica containing products
Silica dust can be made when cutting, grinding, trimming, removing or blasting silica containing products or from storing or disposing of dusty waste from these processes.
Engineered stone products can contain up to 97 per cent silica. The high amount of silica means that there is a very high risk of workers developing breathing problems and silicosis if they breathe in dust made from these products. An increase in the number of workers diagnosed with silicosis and progressive massive fibrosis has been linked to working with engineered stone.
Mining, quarrying, tunnelling and extractive minerals
Exposure to silica dust is a known issue, with high risks of worker exposure during rock crushing activities.
Construction, building and demolition
Silica dust can be formed on site from concrete cutting and using power tools on stone.