Why Dust Matters
Construction dust is one of the most serious health hazards in the industry. Unlike injuries which are immediately apparent, lung disease develops over years of exposure—but once established, it's irreversible.
The Scale of the Problem
- Over 500 construction workers die each year from silica-related diseases
- Thousands more develop COPD, asthma, and other lung conditions
- Silica exposure is the biggest occupational cancer risk in construction
- Many cases go undiagnosed or are attributed to smoking
The dust you can see is actually the least dangerous—it's the fine particles you can't see that penetrate deep into the lungs and cause the most harm. If you can see a dust cloud, you're almost certainly overexposed.
Types of Construction Dust
Construction generates various types of dust, each with different health risks. Understanding what you're dealing with is essential for selecting controls.
Silica Dust (RCS)
Respirable Crystalline Silica from cutting, grinding, or drilling concrete, brick, sandstone, and some artificial stone. Causes silicosis and lung cancer.
WEL: 0.1 mg/m³ - the strictest limit
Wood Dust
From sawing, sanding, and routing wood. Hardwood dust is carcinogenic (causes nasal cancer). Softwood dust is also hazardous.
WEL: 3 mg/m³ (hardwood 1 mg/m³)
Cement/Gypsum Dust
From mixing, cutting, and chasing. Causes respiratory irritation and may contain silica. Also causes skin irritation (cement dermatitis).
WEL: 10 mg/m³ (inhalable), 4 mg/m³ (respirable)
General Construction Dust
Mixed dust from demolition, sweeping, earthworks. May contain various hazardous components depending on source.
WEL: 10 mg/m³ (inhalable), 4 mg/m³ (respirable)
Silica Dust
Silica is the Biggest Killer
Silica is found in most construction materials: concrete, morite, brick, stone, and sand. Cutting, grinding, or drilling these releases respirable crystalline silica (RCS), which causes:
High-Silica Activities
Very High Risk
- Cutting concrete with a disc cutter
- Grinding concrete floors
- Chasing walls
- Breaking concrete with breaker
High Risk
- Drilling into masonry
- Scabbling concrete
- Mortar raking
- Dry sweeping dusty areas
Exposure Limit
The UK Workplace Exposure Limit for RCS is 0.1 mg/m³—one of the lowest limits for any substance. Uncontrolled cutting can produce exposures hundreds of times above this limit in seconds.
Legal Requirements
COSHH 2002
The Control of Substances Hazardous to Health Regulations require employers to assess risks from hazardous substances, prevent or control exposure, provide health surveillance where appropriate, and train workers.
Health and Safety at Work Act 1974
General duty to ensure the health and safety of employees so far as reasonably practicable. Includes protection from dust exposure.
PPE Regulations 2022
Where RPE is required, it must be suitable, properly fitted (face-fit tested for tight-fitting masks), maintained, and workers trained in its use.
HSE Enforcement
HSE has made construction dust a priority. Inspectors will check for dust controls and can issue enforcement notices for visible dust clouds, lack of controls, or improper RPE use. Companies face prosecution for serious failures.
Workplace Exposure Limits
WELs set the maximum concentration of a hazardous substance in workplace air, averaged over 8 hours (TWA) or 15 minutes (STEL).
| Substance | WEL (8hr TWA) | Notes |
|---|---|---|
| Silica (RCS) | 0.1 mg/m³ | Carcinogen - ALARP |
| Hardwood dust | 1 mg/m³ | Carcinogen - ALARP |
| Softwood dust | 3 mg/m³ | Respiratory sensitiser |
| Cement (Portland) | 10/4 mg/m³ | Inhalable/respirable |
| Gypsum | 10/4 mg/m³ | Inhalable/respirable |
ALARP Principle
For carcinogens like silica and hardwood dust, exposure must be reduced to As Low As Reasonably Practicable (ALARP)—not just below the WEL. You cannot rely on RPE to achieve the WEL; engineering controls must come first.
Control Hierarchy
COSHH requires controls to be applied in order of effectiveness. RPE should never be the first choice—it's a last resort.
Eliminate
Can you avoid creating dust? Buy pre-cut materials, use different methods, use silica-free materials where possible.
Substitute
Use less hazardous materials or methods. Diamond blades produce less dust than abrasive discs. Wet methods reduce airborne dust.
Engineering Controls
Water suppression and on-tool extraction are the primary controls for most construction dust work. These should be used wherever possible.
Administrative Controls
Reduce exposure time, separate dusty work from other activities, good housekeeping (vacuum, don't sweep), restrict access.
RPE (Last Resort)
Only after higher controls are in place. May still be needed for residual exposure. Must be properly selected, face-fit tested, and maintained.
Water Suppression
Water suppression is highly effective at controlling dust. It captures dust at source before it becomes airborne. For silica work, it's often the best available control.
Water Suppression Applications
Floor saws, wall saws, and hand-held saws with water feed
All core drilling should use water—it also improves cutting performance
Wet grinding systems for floor preparation and surface finishing
Water spray on breaker work to suppress visible dust
Water spray or misting systems during demolition operations
Slurry Management
Water suppression creates slurry which must be managed. It still contains silica and should not be allowed to dry out (creating dust). Clean up wet, don't let it dry and sweep.
On-Tool Extraction
On-tool extraction (also called Local Exhaust Ventilation or LEV) captures dust at the point it's created. It's essential for dry cutting and drilling operations.
Equipment Requirements
- M-class or H-class vacuum minimum
- Dust-class appropriate to hazard
- Sufficient airflow for the tool
- Shroud or enclosure fitted to tool
- HEPA filter for silica work
- Regular maintenance and filter checks
Dust Class Ratings
- L-Class: Low hazard (>1% filter efficiency)
- M-Class: Medium hazard (>99% efficiency)
- H-Class: High hazard (>99.995% efficiency)
- Silica requires M-class minimum, H-class preferred
LEV Testing
COSHH requires LEV systems to be examined and tested at least every 14 months (or per manufacturer guidelines). Records must be kept for 5 years. This applies to on-tool extraction systems used to control substances hazardous to health.
Respiratory Protection
RPE is the last line of defence—not the first. It should supplement, not replace, other controls. When needed, it must be properly selected, fitted, and maintained.
RPE Selection for Construction
| Type | APF | Suitable For |
|---|---|---|
| FFP2 disposable | 10x | Low dust, NOT silica work |
| FFP3 disposable | 20x | Moderate dust, short silica tasks |
| Half-mask + P3 | 20x | Regular dust work |
| Full-face + P3 | 40x | Higher exposure, eye protection |
| Powered (TH3) | 40x | Long duration, hot work |
APF = Assigned Protection Factor
Face-Fit Testing
Tight-fitting RPE (disposables, half-masks, full-face masks) must be face-fit tested for each wearer. Without a proper seal, protection is drastically reduced. Facial hair prevents an effective seal—clean-shaven in the seal area is required.
RPE Programme Requirements
An effective RPE programme includes: selection based on hazard assessment, face-fit testing, user training, inspection before use, proper storage, filter replacement schedules, and record keeping.
Frequently Asked Questions
Can I just use a dust mask?
A basic "nuisance dust" mask provides almost no protection against silica and fine construction dust. At minimum, an FFP3 is needed for silica work, and only after engineering controls are in place. The mask must be face-fit tested.
If I can't see dust, is it safe?
No. The most dangerous particles are invisible—they're too small to see. If you can see a dust cloud, exposure is extremely high. Invisible doesn't mean safe.
Is wet cutting always better than dry?
Wet cutting with water suppression is generally preferred for silica work as it's highly effective at source. However, it creates slurry to manage and may not be suitable in all environments. On-tool extraction is an alternative for dry work.
How long can I work with silica exposure?
There is no safe level of silica exposure—it should be reduced to ALARP. With proper controls (water suppression or extraction) and appropriate RPE, workers can perform silica tasks. Without controls, even brief exposure can exceed limits.
Do I need health surveillance for dust?
Health surveillance is required where there is significant exposure to respiratory sensitisers (like wood dust) or where exposure to other dust types is likely to cause disease. For silica work, lung function testing and health questionnaires are appropriate.
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