Quick answer: Respirable crystalline silica (RCS) is present in concrete, brick, sandstone, mortar, natural stone, ceramics and engineered stone. Cutting, grinding, drilling and sanding these materials generates RCS particles fine enough to reach the alveoli of the lungs. Silicosis -- the irreversible, progressive and potentially fatal lung disease caused by RCS exposure -- is on the increase in the UK, driven partly by the rapid growth of engineered stone worktops (quartz and porcelain) in kitchen fitting and stone fabrication workshops. The HSE WEL for RCS is 0.1 mg/m3 -- one of the lowest WELs of any regulated substance, reflecting how hazardous it is at very low concentrations. A brief burst of angle grinder work on concrete in an enclosed garage can exceed this limit many times over. On-tool M-Class extraction and water suppression are the correct controls.
Silica is the second most abundant mineral in the earth crust. It is present in concrete, brick, mortar, natural sandstone, granite, slate, some ceramics and -- at very high concentrations -- in engineered stone worktops made from compressed quartz. The same silica content that makes these materials hard and durable makes the dust generated by cutting and grinding them acutely hazardous to lung tissue.
Silicosis was historically associated with mining, quarrying and tunnelling. The modern cases that the HSE is tracking come from kitchen worktop fabrication (engineered stone), tile cutting (particularly large-format porcelain tiles with high silica content), concrete grinding in construction and refurbishment, and driveway and landscaping work involving cutting block paving, sandstone and concrete.
What silicosis does to the lung
RCS particles that reach the alveoli are engulfed by macrophages -- the immune cells that patrol the lung. The macrophages cannot break down crystalline silica. Instead, the silica damages the macrophage from the inside, causing it to release inflammatory signals that trigger fibrosis -- the formation of scar tissue in the lung. This fibrosis is progressive and irreversible. Silicosis continues to develop and worsen even after exposure stops.
There are three clinical forms:
- Chronic silicosis -- develops after 10 or more years of lower-level exposure. Progressive breathlessness, reduced lung function, susceptibility to tuberculosis and lung cancer.
- Accelerated silicosis -- develops within 5-10 years of higher-level exposure. More rapid progression than chronic form.
- Acute silicosis -- develops within weeks to 5 years of very high exposure. Rapid progression to respiratory failure. Associated specifically with engineered stone fabrication where RCS content can reach 90% by mass.
The HSE has identified engineered stone fabrication as a priority enforcement area following reports of acute silicosis cases in young stone fabricators -- some fatal -- in Australia and Spain. UK enforcement is increasing.
The workshop and DIY exposure routes
Outside professional stone fabrication, RCS exposure occurs in:
- Angle grinding concrete, brick and mortar -- chasing walls for cables and pipes, grinding back mortar joints, smoothing concrete, removing render. Short duration, potentially very high instantaneous concentration.
- Cutting paving, block paving and sandstone -- angle grinder or disc cutter. Driveway and landscaping contractors and serious DIYers doing their own driveway are both exposed. Water suppression on the disc dramatically reduces airborne dust generation.
- Tile cutting -- particularly porcelain -- large-format porcelain tiles have high silica content. Dry cutting generates very high RCS concentrations. A wet tile saw is the correct tool for porcelain -- dry cutting an angle grinder is not.
- Drilling into concrete and masonry -- SDS and rotary hammer drilling into concrete generates RCS at the point of drilling. On-tool extraction via a dust shroud attached to the drill chuck captures the dust at source.
- Sanding and preparing concrete floors -- floor grinding and preparation for coatings generates RCS across the floor area. Industrial floor grinders with on-tool extraction are the commercial standard. Belt sanders and orbital sanders used on concrete by DIYers and small contractors without extraction create sustained RCS exposure.
Water suppression -- the practical alternative to extraction for some operations
For angle grinding and disc cutting where on-tool extraction is not practical, water suppression -- wetting the cutting line continuously during the cut -- dramatically reduces airborne dust generation. Wet cutting keeps RCS particles bound to the water rather than airborne. The water must be continuous and flowing onto the cutting point, not just applied to the surface before cutting.
Water suppression is not a substitute for extraction in enclosed spaces where the wet slurry created by wet cutting still contains RCS and can dry out and become airborne later. In enclosed workshops, on-tool M-Class extraction is the correct control. Water suppression is most effective for outdoor cutting operations.
The correct extraction for RCS-generating operations
M-Class on-tool extraction -- connecting an M-Class extractor directly to the tool via a dust shroud -- is the standard for concrete grinding, drill work and floor preparation. H-Class extraction is specified for engineered stone fabrication given the exceptionally high RCS content and the acute silicosis cases associated with that specific material. See: M-Class extraction | H-Class extraction
Respiratory protection for RCS work: FFP3 face-fit tested dust mask as supplementary protection where extraction is in use. FFP3 as the primary protection only where extraction is genuinely not possible for a specific short-duration task -- not as a substitute for engineering control.
Part of the series: What is Really in the Air in Your Workshop
Series hub | Metal grinding and welding fume | Woodworking and timber dust | Resin and fibreglass | Spray painting and isocyanates
Related pages
M-Class extraction | H-Class extraction | COSHH Regulations 2002 | HSE EH40 | HSE silica dust enforcement 2026
