What is crystalline silica?
Crystalline silica is a natural mineral found mostly as quartz in sand and sandstone which are used in building products. Workers will also come across silica when excavating or tunnelling through sandstone.
Typical crystalline silica levels in different materials are:
- sand and sandstone: 70-100%
- manufactured stone: 93% or higher
- granite: 20-45% (typically 30%)
- concrete and mortar: 25-70%
- calcium-silicate bricks: 50-55%
- slate: 20-40%
- brick: up to 30%
- fibre cement sheets: 10-30%
- demolition dust: 3-4%
- marble: 2%
- limestone: 2%