What is COSHH and Why Does It Matter?

COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. It's the law that requires employers to control substances that are hazardous to health in the workplace. For construction professionals, this isn't just bureaucracy—it's about preventing serious illnesses that can develop from exposure to common site materials.

Many construction workers don't realise that everyday materials can cause lasting health problems. Wet cement can cause chemical burns and dermatitis. Silica dust from cutting concrete can cause silicosis—an incurable lung disease. Even common cleaning products can be hazardous if used incorrectly.

The Legal Requirements

Under COSHH, employers must:

• Assess the risks: Identify which hazardous substances are present and who might be exposed
• Decide on controls: Implement measures to prevent or adequately control exposure
• Use controls: Ensure control measures are properly used and maintained
• Monitor exposure: Where necessary, monitor workers' exposure levels
• Carry out health surveillance: For workers exposed to certain substances
• Provide information and training: Ensure workers understand the risks and controls

If you employ five or more people, you must record the significant findings of your COSHH assessment in writing.

Common Hazardous Substances on Construction Sites

Cement and Concrete Products

Cement is alkaline and can cause serious chemical burns on contact with skin. Prolonged contact with wet cement is a major cause of occupational dermatitis in construction workers. Always wear appropriate gloves and wash off cement immediately if skin contact occurs.

Silica Dust

Respirable crystalline silica (RCS) is released when cutting, grinding, or drilling concrete, brick, or stone. It's one of the most serious health hazards on construction sites, causing silicosis and increasing the risk of lung cancer. The HSE estimates that 500 construction workers die each year from silica-related diseases.

Wood Dust

Hardwood dust is a known carcinogen, and softwood dust can cause respiratory sensitisation. Joiners, carpenters, and anyone cutting wood products need proper dust extraction and respiratory protection.

Solvents and Adhesives

Many paints, adhesives, and cleaning products contain volatile organic compounds (VOCs) that can cause headaches, dizziness, and long-term health effects. Always check Safety Data Sheets (SDS) and ensure adequate ventilation.

Isocyanates

Found in two-pack paints, spray foam insulation, and some adhesives. Isocyanates are a leading cause of occupational asthma in the UK. Once sensitised, even tiny exposures can trigger severe reactions.

How to Conduct a COSHH Assessment

Step 1: Identify Hazardous Substances

Start by listing all substances used or created on site:

• Check product labels for hazard symbols and warning phrases
• Request Safety Data Sheets (SDS) from suppliers—they're legally required to provide them
• Consider substances created by work processes (e.g., dust from cutting, fumes from welding)
• Don't forget substances that might already be present (e.g., asbestos in older buildings)

Step 2: Assess Who Might Be Harmed

Think about everyone who could be exposed:

• Workers directly using the substance
• Other workers nearby
• Cleaners and maintenance staff
• Visitors and members of the public
• People who might be more vulnerable (pregnant workers, those with existing conditions)

Step 3: Evaluate the Risks

Consider:

• How hazardous is the substance? (Check the SDS hazard classification)
• How much will people be exposed to?
• How often and for how long?
• What route of exposure? (Breathing in, skin contact, ingestion)
• What controls are already in place?

Step 4: Decide on Control Measures

Follow the hierarchy of control:

1. Eliminate: Can you avoid using the hazardous substance altogether?
2. Substitute: Can you use a less hazardous alternative?
3. Engineering controls: Can you use dust extraction, local exhaust ventilation, or enclosure?
4. Administrative controls: Limit exposure time, rotate workers, improve procedures
5. PPE: As a last resort, provide appropriate respiratory protection, gloves, etc.

Step 5: Record and Communicate

Document your findings, including:

• What hazardous substances are present
• Who might be exposed and how
• What control measures are in place
• What PPE is required
• Emergency procedures

Share this information with all workers through toolbox talks and site inductions.

Using the HSE's COSHH Essentials

The HSE provides a free online tool called COSHH Essentials that generates control guidance based on the hazard classification and amount of substance used. It's particularly useful for common construction tasks and can give you practical advice sheets to share with workers.

Common COSHH Mistakes to Avoid

• Relying solely on PPE: PPE should be the last resort, not the first response
• Not reading Safety Data Sheets: These contain vital information about handling and emergencies
• Ignoring process-generated substances: Dust and fumes from work activities are often overlooked
• Generic assessments: COSHH assessments need to be specific to your site and activities
• No health surveillance: Some exposures require ongoing health monitoring of workers
• Forgetting to review: Assessments should be updated when substances, processes, or conditions change

Practical Tips for Construction Sites

• Keep a file of Safety Data Sheets on site and make sure workers know where to find them
• Include COSHH information in toolbox talks before work involving hazardous substances
• Use water suppression or on-tool extraction when cutting concrete or masonry
• Provide skin care products—barrier creams and moisturisers can help prevent dermatitis
• Ensure PPE fits properly—respiratory protection only works if it seals correctly
• Store chemicals properly—segregate incompatible substances and secure flammable materials

Conclusion

COSHH assessments don't need to be complicated, but they do need to be done properly. The health effects of chemical exposure often develop slowly and may not appear until years after exposure—by which point, damage may be irreversible.

Taking COSHH seriously protects your workers from serious illness, keeps you legally compliant, and demonstrates to clients that you take health and safety seriously. With tools like DocGen, you can integrate COSHH considerations into your overall safety documentation, ensuring nothing gets overlooked.