Crystalline silica is the crystalline form of silicon dioxide , a naturally occurring mineral that forms a major component of most rocks . It is found in natural stones like granite and sandstone and is used to create artificial products like engineered stone and tiles .
When dust is created through natural or artificial means it comes in a range of sizes , from very small ( less than 10 micrometres [µ m ] in diameter ) to larger particles that can be seen with the naked eye . Dust that is less than 10 µ m in diameter ( Figure 1 ) is known as respirable dust as , when inhaled , it travels deep into the lungs .
Figure 1 : Dust particle sizes ( original image from Mining and Quarrying Occupational Health and Safety Committee ).
In its solid form , such as the slab supplied to a workplace for fabrication , engineered stone does not have hazardous properties ; it is the dust that is generated from engineered stone that has the potential to cause harm when it is breathed in .
The fabrication stage involves using mechanical processes such as cutting , grinding , trimming , drilling , sanding and polishing of the engineered stone to create a specific product ready to be supplied for installation . For example , creating a kitchen benchtop to size and cutting holes for positioning a sink and tap .
Once the fabricated engineered stone product is installed , further mechanical processes may be required , for example , minor cutting to enable a custom fit , or for maintenance purposes .
Cutting , grinding , trimming , drilling , sanding and polishing engineered stone products generates respirable dust containing crystalline silica ( silica dust ). When breathed in over time , silica dust can cause fatal lung disease . The risks are much greater where the engineered stone contains high levels of crystalline silica .
Workers fabricating , processing , installing , maintaining or removing engineered stone products without appropriate control measures in place may be exposed to high levels of silica dust ( for example through dust or mist clouds ). Workers can also be exposed to silica dust from poor housekeeping methods that disturb accumulated dust , including dry sweeping , using compressed air or high-pressure water cleaners and general-purpose vacuum cleaners not designed for use with hazardous dusts .
Managing the risks of respirable crystalline silica from engineered stone in the workplace - Code of Practice 7 of 57