Most rocks, sands, clays and also products such as bricks, tiles and concrete
contain crystalline silica.
When these materials are worked, eg cut, sanded, carved, ground etc, dust is
created, part of which is sufficiently fine to be termed Respirable Crystalline
Silica (RCS) which can lead to serious health conditions.
Employers have a range of actions presented in a revised publication "Stone
dust and you", that need to be carried out in different situations when
employees are exposed.
In general the publication reminds:
Stone dust can damage your health!
Remember keep the dust down, don't breathe it in!
AplusA-online.de - Source: Health and safety executive