Silica Dust (RCS)
By the Riskora Editorial Team · Last reviewed
Respirable crystalline silica (RCS) is the fine, lung-penetrating dust released when materials containing silica — concrete, brick, stone, mortar, tile — are cut, ground or drilled.
The UK workplace exposure limit (WEL) for RCS is 0.1 mg/m³ measured as an 8-hour time-weighted average. It is enforceable under COSHH.
Long-term exposure causes silicosis, lung cancer and chronic obstructive pulmonary disease. The HSE estimates around 500 UK construction workers die each year from past silica exposure.
Effective controls — water suppression, on-tool extraction, RPE rated FFP3 — are well-established. The failure mode is almost always cutting indoors or in ill-ventilated spaces without water or extraction.
Why it matters
Silica is the second-biggest occupational cancer risk to UK construction workers after asbestos. Risk assessments that mention 'wear a dust mask' for cutting blockwork are not adequate.