1.6. Where are we exposed to respirable crystalline silica?
Exposure to respirable crystalline silica can occur anywhere that fine particles of silica dust are present in the air. Everyone is exposed to very low levels of respirable crystalline silica dust on a day to day basis because this naturally occurring substance is so abundant on the planet. However, experience indicates that environmental exposures to silica dust (even for people living in the vicinity of quarries) are not sufficiently high to cause any disease, so we will concentrate here on exposure to respirable crystalline silica in the workplace.
Occupational exposure to respirable crystalline silica can occur in any workplace situation where airborne dust, containing a proportion of respirable crystalline silica, is generated. Industries where respirable crystalline silica is present include quarrying, mining, mineral processing, foundry, brick and tiles, and construction works.
Respirable dust particles are so small that they cannot be seen with the naked eye.
Once airborne, respirable dust takes a very long time to settle. A single release of dust into the workplace air can lead to significant occupational exposure. In fact, in situations where the air is constantly stirred-up and where no fresh air is being introduced, respirable dust may remain airborne in the workplace for days.
Occupational exposure to respirable crystalline silica occurs in many industries including quarrying, mining, mineral processing (eg drying, grinding, bagging and handling), slate working, stone crushing and dressing, foundry work, brick and tile making, some refractory processes, construction work, including work with stone, concrete, brick and some insulation boards, tunnelling, building restoration and in the pottery and ceramic industries.