Toolbox Talks · Mandatory · Construction

Toolbox Talk — Silica Dust

A dedicated silica dust toolbox talk for construction workers. RCS is a Group 1 carcinogen causing silicosis, lung cancer, and COPD. WEL 0.05 mg/m³ (halved in 2020). Dry cutting concrete or stone without controls generates 100x the WEL. Controls in hierarchy: wet cutting, on-tool extraction, FFP3 RPE (fit-tested), exclusion zones, H-class vacuum only. HSE’s most enforced construction health standard. Must be delivered at induction and when silica-risk tasks commence.

Last reviewed: 2 April 2026 — This guide reflects UK law as of this date. CDM 2015 / COSHH 2002 / MHSWR 1999 remains current with no amendments enacted as of 2 April 2026. Next scheduled review: 2 April 2027.

1. The Construction Dust That Causes Cancer

Silica dust is one of the biggest occupational health hazards in construction — and it is invisible. Workers spend years cutting concrete, brick, and stone without realising the damage being done to their lungs with every uncontrolled cut. Respirable crystalline silica (RCS) particles are so fine they penetrate deep into lung tissue, causing scarring that cannot be repaired. Silicosis is irreversible and fatal.

Silica dust is classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen — the same category as asbestos and tobacco smoke — meaning there is sufficient evidence that it causes lung cancer in humans. In addition to lung cancer, prolonged exposure causes silicosis and chronic obstructive pulmonary disease (COPD). The HSE estimates that approximately 500 construction workers die each year from silica-related lung disease.

The workplace exposure limit (WEL) for respirable crystalline silica is 0.05 mg/m³ — this limit was halved in 2020 to reflect the increased understanding of how dangerous even low-level exposure is. Dry cutting of concrete, brick, or stone cannot achieve this limit without controls. Water suppression and on-tool extraction are not optional extras — they are the minimum standard required by law.

Dry cutting concrete, brick, or stone is never acceptable

Water suppression or on-tool extraction must always be used when cutting silica-containing materials. This is the HSE's most enforced construction health standard — there are no exceptions. A single 300mm cut through a concrete block without controls can expose the operator to 100 times the workplace exposure limit. Every cut without water or extraction is an uncontrolled release of a Group 1 carcinogen.

2. Discussion Points and Record

The following discussion points must be covered during the toolbox talk. Each point should be discussed with reference to the specific work activities and materials on this site. Workers must understand what silica dust is, what it does to the body, and what controls are required on every task that generates it.

Discussion point	What to cover
What is silica dust?	Silica (silicon dioxide) is found in concrete, morite, brick, sandstone, granite, and many other construction materials. When these materials are cut, drilled, ground, or chased, respirable crystalline silica (RCS) dust is released. The particles are so small they are invisible to the naked eye — you cannot see, smell, or taste them. They penetrate deep into the lungs and cause permanent scarring of lung tissue.
What can it do to you?	Prolonged or high-level exposure to silica dust causes three serious conditions: silicosis (irreversible scarring and stiffening of the lungs, which progressively reduces breathing capacity and is fatal in severe cases), lung cancer (silica is a Group 1 carcinogen — the same classification as asbestos), and COPD (chronic obstructive pulmonary disease, causing permanent breathing difficulty). These conditions develop over years and are irreversible once established.
Where is the risk on this site?	Identify the specific tasks on this site that generate silica dust: cutting concrete blocks, chasing walls for services, drilling into masonry, grinding concrete floors, cutting paving slabs, demolition of masonry or concrete structures, and any other activity that cuts, grinds, or disturbs silica-containing materials. Discuss which trades and areas are affected and where controls must be applied.
What you must do	Always use wet cutting with water suppression when cutting concrete, brick, or stone. Where wet cutting is not practicable, use on-tool dust extraction connected to an M-class or H-class vacuum with a HEPA filter. Wear RPE (minimum FFP3, fit-tested) as additional protection — RPE supplements engineering controls, it does not replace them. Maintain an exclusion zone around dust-generating work to protect other workers. Never dry sweep silica dust — use a vacuum with HEPA filtration or damp down before sweeping.
What you must not do	Never dry cut concrete, brick, or stone without water suppression or on-tool extraction. Never use compressed air to blow dust off surfaces or clothing. Never dry sweep silica dust with a broom. Never remove or bypass dust extraction equipment. Never remove your RPE while dust is being generated or before the area has been adequately ventilated. Never assume that because you cannot see dust, the air is safe.
Symptoms to report	Report any of the following symptoms to your supervisor immediately: persistent cough, shortness of breath (especially during physical exertion), wheezing, chest tightness, or unusual fatigue. Early symptoms of silicosis can be subtle and easily dismissed as general unfitness. Early detection through health surveillance and prompt symptom reporting can prevent progression to severe disease.
Attendance record	All workers attending this toolbox talk must sign the attendance record. The record must include the date, topic, presenter name, and signatures of all attendees. This record provides evidence that workers have been informed about silica dust hazards and the controls required. Retain attendance records as part of the site health and safety file.

3. Common Mistakes

Relying on an FFP3 mask as the sole control for silica dust

RPE is the last line of defence in the hierarchy of controls, not the first. An FFP3 mask should never be the only measure used to protect a worker from silica dust. Water suppression and on-tool extraction must be used first to reduce dust at source. RPE is then worn as additional protection to deal with any residual dust that the engineering controls do not capture. Relying solely on a mask means the worker is breathing contaminated air with only a single layer of protection — and if the mask does not fit properly, does not seal correctly, or is removed even briefly, the worker is fully exposed to a Group 1 carcinogen.

Delivering this briefing once at induction and never again

A silica dust toolbox talk is not a one-time event. It should be delivered at induction so that all workers understand the hazard before starting work on site. It must then be repeated when silica-risk work starts on site (such as block cutting, concrete grinding, or chasing), and again when new workers or subcontractors arrive who will be carrying out or working near silica-generating tasks. Regular reinforcement ensures that the message is not forgotten and that controls are maintained throughout the project.

4. Frequently Asked Questions

What RPE is required for silica dust — can workers use a disposable FFP2 mask?▾

No. FFP2 is not adequate for silica dust. The minimum standard is FFP3, which provides 99% filtration efficiency compared to 94% for FFP2. Given that silica is a Group 1 carcinogen and even low-level exposure causes irreversible lung disease, the higher filtration standard is essential. All FFP3 masks must be fit-tested to the individual wearer to ensure an adequate seal — an untested mask may not protect the worker regardless of its filtration rating. Workers with facial hair (beards or stubble) cannot achieve an adequate seal with any disposable tight-fitting respirator, including FFP3. These workers should use a powered air purifying respirator (PAPR) with a loose-fitting hood, which does not rely on a facial seal and provides a continuous supply of filtered air.

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