Silica dust and disease
What is crystalline silica?
Silica is a naturally occurring and abundant mineral found in most rocks and soils. There are non-crystalline and crystalline forms of silica. Crystalline silica is found in stone, sand, gravel, concrete and mortar. It is also used to make a variety of products including engineered stone (used to fabricate kitchen and bathroom benchtops), bricks and tiles. The proportion of crystalline silica in engineered materials may be much higher than in natural stone.
Silica dust is generated by processes such as cutting, polishing, drilling, or grinding natural stone or engineered products that contain crystalline silica. ‘Respirable crystalline silica’ refers to silica dust particles that are small enough to penetrate deep into the lungs when inhaled.
Why is silica dust dangerous?
The inhalation of silica dust is associated with silicosis (irreversible scarring and stiffening of the lungs) and other diseases such as lung cancer, kidney disease and chronic obstructive pulmonary disease.
Silicosis can develop after short or long-term exposure to silica dust. Preventing or minimising exposure to silica dust are the only ways to avoid the risk of disease developing.
Activities that generate silica dust
It is estimated that up to 600,000 Australian workers are currently exposed to silica dust in the course of their employment (Source – Lung Foundation Australia). The types of work activities that can generate silica dust include:
- using power tools to cut, grind or polish natural and 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 and demolition
- brick, concrete or stone cutting; especially using dry methods
- abrasive blasting (blasting agent must not contain more 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
- pottery making
- crushing, loading, hauling and dumping of rock, and
- clean-up activities such as sweeping.
Information and resources
The Work Health and Safety (WHS) laws in each jurisdiction have requirements for persons conducting a business or undertaking to manage the risks relating to silica dust. This includes ensuring the workplace exposure standard for crystalline silica is not exceeded and to provide health monitoring to workers.
Although the WHS regulations dealing with silica are broadly similar around Australia, there are some differences which makes it necessary to check the laws in your state or territory. More information is available from your local WHS regulator.