Silica and Construction Dust — Protecting Your Lungs on Site (2026)

The Three Main Types of Construction Dust

The Health and Safety Executive (HSE) groups construction dust into three broad types. They differ in where they come from and how harmful they are, but all three can damage your lungs and all three must be controlled under COSHH.

• Silica dust (RCS): created when you work on materials containing crystalline silica — concrete, brick, block, stone, mortar, tiles and screed. This is the most dangerous of the three and the focus of this guide.
• Wood dust: from cutting and sanding softwood, hardwood and wood-based products like MDF. Hardwood dust is a known cause of nasal cancer; all wood dust can cause asthma and other respiratory disease.
• Lower-toxicity general dust: from materials containing little or no silica, such as gypsum plaster, limestone and marble. Lower risk does not mean no risk — heavy exposure still harms the lungs.

Why Respirable Crystalline Silica Is So Dangerous

Silica is one of the most common minerals on earth, and crystalline silica is bound up in the everyday materials trades handle constantly: concrete, brick, block, stone, mortar, tiles and sand-cement screed. When you cut, grind, drill, chase or even dry sweep these materials, you release a cloud of extremely fine particles — far too small to see in normal light. The fraction small enough to be drawn deep into the lungs is called respirable crystalline silica, or RCS.

Once those particles reach the deepest part of your lungs, your body cannot clear them. They cause scarring and inflammation that builds up over years. The result is a group of incurable diseases: silicosis (irreversible scarring of the lung tissue that leaves you increasingly breathless), chronic obstructive pulmonary disease (COPD), and lung cancer. After asbestos, silica dust is the biggest cause of occupational lung disease deaths in UK construction.

The cruellest part is the delay. You usually feel nothing at the time and nothing for years afterwards. The damage accumulates quietly — the equivalent of a teaspoon of dust spread over a working lifetime is enough to do serious harm — and by the time you notice the breathlessness, the damage is already done and it is permanent. That is exactly why control matters today, on every job, not when symptoms appear. The disease is preventable; the damage is not curable.

Your Legal Duties Under COSHH

Construction dust is covered by the Control of Substances Hazardous to Health Regulations (COSHH). If you employ anyone, or you are self-employed and your work creates dust, the law requires you to assess the risk and control exposure. In practice this means:

• Carry out a COSHH assessment for the dusty tasks you do — identify the material, the dust it produces and how you will control it.
• Put controls in place that are proportionate to the risk, following the control hierarchy below.
• Make sure controls are used correctly and kept in good working order.
• Provide information, instruction and training so workers understand the risk and how to protect themselves.
• Provide health surveillance where exposure is significant, so early signs of disease can be picked up.

This is not optional paperwork. HSE inspectors actively target dust on site, and failure to control silica is one of the most common reasons for enforcement notices in construction.

The Workplace Exposure Limit for Silica

RCS has a Workplace Exposure Limit (WEL) of 0.1 mg/m³ averaged over an 8-hour working day. That is a tiny amount — a single uncontrolled task such as cutting paving slabs or chasing out a wall with a grinder can put you many times over that limit within minutes. The WEL is a legal ceiling you must not exceed, not a target to aim for; your duty under COSHH is to reduce exposure as low as is reasonably practicable, well below the limit.

It is also worth knowing that there are ongoing proposals and pressure to lower the silica WEL further, in line with moves seen in other countries. The safest approach is not to chase the legal number but to control dust so effectively that exposure is minimal regardless of where the limit sits.

The Control Hierarchy — Where RPE Really Sits

The single biggest mistake in dust control is reaching for a mask first. A mask is the last line of defence, not the first. The right order — the control hierarchy — is to stop the dust getting into the air in the first place, then capture what is created, and only then protect the worker with respiratory protective equipment (RPE).

1. Eliminate the dust

The best dust is the dust you never create. Plan jobs to cut materials to size off site, order pre-cut blocks, bricks and slabs, or use products designed to be fixed without cutting. If the dusty task never happens on site, there is no exposure to control.

2. Water suppression (wet cutting)

Feeding a steady supply of water to the cutting point damps the dust down before it can become airborne. Properly applied, wet cutting dramatically reduces RCS — but it has to be a continuous, adequate flow at the blade, not a quick splash. A trickle that runs out halfway through the cut offers little protection, and the resulting slurry must be cleaned up by wet methods, not left to dry and become dust again.

3. On-tool extraction

On-tool extraction captures dust at the point it is created, using a shroud or hood fitted to the tool connected to a suitable vacuum. The vacuum must be an M-class or H-class industrial unit — an ordinary workshop vac or domestic hoover will not capture fine respirable dust and will simply blow it back into the air. The tool shroud must match the tool and be in good condition, and the whole system needs the right filters, kept clean and checked regularly.

4. Ventilation

Working in the open air, or providing good general and local ventilation indoors, helps disperse any dust that does escape. Never carry out heavy dusty work in an enclosed, unventilated space without serious additional controls.

5. RPE — the last line, done properly

Only after the steps above have reduced dust as far as possible should you rely on RPE to deal with what remains. For silica that means a properly rated mask: a disposable or half mask to at least FFP3 standard, or a powered respirator for longer or heavier work. Crucially, RPE only works if it seals to the face. That means:

• Face-fit testing: tight-fitting masks must be face-fit tested to the individual wearer, because no single mask fits every face.
• Clean-shaven: stubble or a beard breaks the seal and lets dust straight in. Wearers of tight-fitting masks must be clean-shaven at the seal, or use a powered loose-fitting hood instead.
• Worn correctly, every time: a mask hanging round the neck or pulled down to talk protects no one.

A flimsy paper "nuisance" or comfort mask is useless against silica. It is not rated to filter respirable dust, does not seal to the face, and gives a dangerous false sense of safety. If it is not at least FFP3 and fitted properly, it is not protecting your lungs.

Health Surveillance and Housekeeping

Where workers are significantly exposed to silica, COSHH requires health surveillance — typically a lung-function and respiratory questionnaire programme that can spot early signs of disease while something can still be done about the work. Take it seriously; it is there to catch problems before they become disabling.

Housekeeping matters just as much as the cutting itself. Never dry sweep and never use compressed air or a leaf blower to clear settled dust — both throw enormous quantities of fine silica straight back into the air you breathe. Use an M-class or H-class vacuum, or wet methods, to clean up. Clean as you go rather than letting dust build up, and dispose of slurry and waste before it dries out.

Quick Reference: Dusty Tasks and Controls

The Bottom Line

Silicosis, COPD and lung cancer from construction dust are entirely preventable — but the damage they cause is permanent. You cannot undo it, and you usually won't feel it coming until it is far too late. Control the dust at source with off-site cutting, water suppression and on-tool extraction, ventilate the work, keep the site clean with vacuums and wet methods, and treat a properly fitted FFP3 mask as the last line rather than the first. Your lungs have to last a whole career, and then a whole retirement. Protect them on every job.