Silica Identification, Quantitation & Control
Silica has been highlighted in recent times and everyone needs to understand the risks. Crystalline silica (silica) is found in sand, stone, concrete and mortar. It is also used to make a variety of products including composite stone used to fabricate kitchen and bathroom benchtops, bricks, tiles and some plastics. When workers cut, crush, drill, polish, saw or grind products that contain silica, dust particles are generated that are small enough to lodge deep in the lungs and cause illness or disease including silicosis. Silica is one of the most abundant minerals found in the earth’s crust and is used in many products across a variety of industries and workplaces. Crystalline silica is most dangerous to health when dust is generated, becomes airborne and is then inhaled by a worker/person.
Where Silica Dust Is Generated
Examples of work activities that can generate respirable silica dust particles include:
- During fabrication and installation of composite (engineered or manufactured) stone counter tops
- Excavation, earth moving and drilling plant operations
- Clay and stone processing machine operations
- Paving and surfacing
- Mining, quarrying and mineral ore treating processes
- Tunnelling
- Construction labouring activities
- 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, and
- Pottery making
FAQs
- What is respirable crystalline silica dust?
- Respirable crystalline silica dust is made up of particles small enough to be breathed deep into the lungs. It is released whenever silica-containing materials such as concrete, stone, brick, tile or engineered stone are cut, drilled, ground, polished or crushed. The particles are too fine to see in normal light, which is why airborne monitoring is used rather than a visual check.
- How is airborne silica measured on a worksite?
- Airborne silica is measured with personal air monitoring: a sampling pump and filter head worn in the worker's breathing zone for a representative part of the shift. The filter is then analysed by a laboratory and the result compared against the workplace exposure standard for respirable crystalline silica, giving an evidence-based picture of exposure rather than an estimate.
- What controls reduce silica exposure during cutting and grinding?
- The most effective controls come first: eliminate or substitute the task, then use engineering controls such as on-tool water suppression, local exhaust ventilation and enclosed cabins with filtered air. Administrative controls like exclusion zones, task rotation and housekeeping with H-class vacuums follow, with correctly fit-tested respiratory protection as the final layer, never the only one.