The Silent Killer
Respirable crystalline silica (RCS) is one of the most dangerous substances in construction. It's found in common materials including concrete, morite, sandstone, brick, and many other construction products. When these materials are cut, drilled, ground, or demolished, they release tiny silica particles that can be inhaled deep into the lungs.
The consequences are devastating: silicosis (irreversible lung scarring), lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease. The HSE estimates that silica dust causes around 500 construction worker deaths each year—more than are killed in workplace accidents.
Understanding the Hazard
What is Respirable Crystalline Silica?
Crystalline silica is a natural mineral found in stone, rock, sand, and clay. When materials containing silica are worked on, fine dust particles are released. The most dangerous particles are "respirable"—small enough (less than 10 micrometres) to penetrate deep into the lungs where they cannot be cleared and cause permanent damage.
High-Risk Activities
Tasks that generate significant silica dust include:
- Cutting concrete, paving, kerbs with disc cutters
- Chasing walls for electrical or plumbing installation
- Drilling into concrete or masonry
- Grinding concrete floors
- Breaking out concrete
- Scabbling or needle gunning
- Sand blasting (abrasive blasting)
- Angle grinding stone or concrete
- Tunnelling and mining
- Demolition work
Exposure Limits
The UK Workplace Exposure Limit (WEL) for respirable crystalline silica is 0.1 mg/m³ (8-hour TWA). This is a very low limit—invisible amounts of dust can exceed it. There is no known safe level of exposure.
Health Effects
Silicosis
Silicosis is permanent scarring of the lungs caused by silica particles. Symptoms include:
- Progressive breathlessness
- Persistent cough
- Weakness and fatigue
- Chest pain
There is no cure. Severe cases require lung transplant or are fatal. Accelerated silicosis can develop within 5-10 years of heavy exposure.
Lung Cancer
Crystalline silica is classified as a Group 1 carcinogen (known to cause cancer in humans). The risk increases with cumulative exposure.
COPD
Chronic obstructive pulmonary disease causes progressive breathing difficulty and is not reversible.
Other Conditions
Silica exposure is also linked to:
- Kidney disease
- Increased susceptibility to tuberculosis
- Auto-immune conditions
Legal Requirements
COSHH Regulations
The Control of Substances Hazardous to Health Regulations 2002 require employers to:
- Assess the risks from silica exposure
- Prevent or adequately control exposure
- Maintain and test control measures
- Monitor exposure where necessary
- Provide health surveillance
- Inform, instruct, and train workers
Hierarchy of Controls
You must apply controls in this order:
- Elimination: Use silica-free materials where possible
- Substitution: Use lower-silica alternatives
- Engineering controls: Water suppression, on-tool extraction, LEV
- Administrative controls: Reduce exposure time, restrict access
- RPE: Respiratory protective equipment as last resort
Essential Control Measures
Water Suppression
Water is highly effective at controlling silica dust:
- Use water-suppressed cutting and drilling equipment
- Ensure water supply is adequate and continuous
- Maintain water attachments and check for blockages
- Manage wet slurry safely (it still contains silica)
On-Tool Extraction
Dust extraction at the source is the next most effective control:
- Use tools with integrated dust extraction
- Connect to suitable M-class or H-class vacuum
- Ensure extraction is working before starting
- Change filters regularly per manufacturer guidance
- Dispose of collected dust safely
Local Exhaust Ventilation (LEV)
For fixed operations or where on-tool extraction isn't practical:
- Position capture hood as close to source as possible
- Ensure adequate airflow
- Maintain and test LEV systems (every 14 months minimum)
- Keep LEV examination records
Respiratory Protective Equipment (RPE)
When other controls are insufficient, RPE is required:
- Minimum FFP3 filtering facepiece for silica dust
- Must be properly fitted (face-fit tested)
- Clean-shaven where mask meets skin
- Powered respirators for extended work
- RPE selected for the exposure level (APF appropriate)
- Workers trained in correct use, storage, maintenance
Health Surveillance
Workers regularly exposed to silica dust require health surveillance:
- Pre-employment baseline assessment
- Regular lung function testing (spirometry)
- Chest X-rays at intervals determined by occupational health
- Questionnaires about respiratory symptoms
Health surveillance detects early signs of disease, enabling intervention before serious damage occurs.
Good Practice Checklist
- Assess silica risks for all relevant tasks
- Specify silica controls in RAMS
- Use water suppression or extraction on all dusty tasks
- Never dry sweep silica dust—use vacuum or damp methods
- Provide suitable RPE and ensure it's face-fit tested
- Establish health surveillance programme
- Train workers on silica risks and controls
- Maintain and test control equipment
- Clean work clothing regularly—don't take contamination home
- Monitor exposure where there's doubt about control adequacy
Worker Responsibilities
As a worker exposed to silica, you should:
- Use control measures correctly every time
- Report defective equipment immediately
- Wear RPE properly when required
- Attend health surveillance appointments
- Report respiratory symptoms promptly
- Don't eat, drink, or smoke in dusty areas
- Wash hands and face before breaks
Conclusion
Silica dust disease is preventable—but only if exposure is properly controlled. Don't accept dusty working conditions as normal. Dust you can see contains dangerous particles you can't see.
Every RAMS for work involving silica-containing materials should address dust control specifically. When you generate RAMS with DocGen, the system identifies common silica exposure scenarios—but always verify that controls match your actual working methods.
Your lungs are irreplaceable. Protect them.