COSHH Assessment Template: Free Guide with Examples

COSHH assessments are a legal requirement on every UK construction site where hazardous substances are used. Yet they are one of the most commonly failed elements during HSE inspections. This guide walks you through exactly what COSHH requires, how to complete an assessment properly, the most common substances you will encounter on construction sites, and practical examples you can follow.

What COSHH Requires

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) requires every employer to assess the risks from hazardous substances used or created during work activities. On construction sites, this covers everything from cement and silica dust to solvents, adhesives, diesel fumes, and wood dust.

The law is clear: you must carry out a COSHH assessment before any work involving hazardous substances begins. You cannot start work and then write the assessment afterwards. HSE inspectors specifically look for dated assessments that predate the work activity.

COSHH applies to substances that are:

• Classified as very toxic, toxic, harmful, irritant, or corrosive under the CLP Regulation
• Assigned a workplace exposure limit (WEL)
• Biological agents connected to the work
• Dust of any kind in substantial concentrations
• Any substance that, because of the way it is used, creates a health risk

The Eight Steps of a COSHH Assessment

HSE outlines eight essential steps for a proper COSHH assessment. Following these in order ensures nothing is missed:

1. Identify hazardous substances. Gather safety data sheets (SDS) for every product used. Also identify substances created by the work -- cutting concrete creates silica dust; welding creates metal fumes.
2. Identify who might be harmed and how. Consider operatives, other trades nearby, visitors, and members of the public. Think about both immediate effects (burns, irritation) and long-term health effects (occupational asthma, cancer).
3. Assess the level of exposure. How much of the substance is present? How long are people exposed? Is it inhaled, ingested, or absorbed through the skin? What is the workplace exposure limit?
4. Decide on control measures. Follow the hierarchy: eliminate the substance, substitute with a less hazardous alternative, enclose the process, use local exhaust ventilation, improve general ventilation, reduce the number of people exposed, reduce the duration of exposure, and finally specify PPE.
5. Record the assessment. Document everything: the substance, the hazards, the people exposed, the controls, and the residual risk.
6. Implement the controls. Make sure the control measures you have specified are actually put in place on site. An assessment sitting in a folder is useless.
7. Monitor and review. Check that controls are working. If air monitoring is required (e.g. for silica dust), arrange it. Review assessments when circumstances change -- new substances, different methods, new information from suppliers.
8. Provide information, instruction, and training. Every worker exposed to a hazardous substance must know what it is, what harm it can cause, what controls are in place, and what to do if something goes wrong.

Common Hazardous Substances on Construction Sites

Here are the substances you will encounter most frequently and need COSHH assessments for:

Silica Dust (Respirable Crystalline Silica)

Created when cutting, grinding, or drilling concrete, brick, sandstone, and morite. The workplace exposure limit is 0.1 mg/m3. Long-term exposure causes silicosis, an incurable lung disease. This is the single biggest health risk on most construction sites.

Cement and Wet Concrete

Contains hexavalent chromium and is highly alkaline (pH 12-13). Causes cement burns, dermatitis, and allergic contact dermatitis. Skin contact is the primary route of exposure.

Wood Dust

Both hardwood and softwood dust are hazardous. Hardwood dust is a known carcinogen (causes nasal cancer). The WEL is 3 mg/m3 for softwood and 3 mg/m3 for hardwood (previously 5 mg/m3, reduced in 2020).

Solvents and Adhesives

Thinners, primers, resin adhesives, contact adhesives, and PU sealants all release volatile organic compounds (VOCs). Effects include headaches, dizziness, nausea, and long-term liver and kidney damage.

Diesel Exhaust Emissions (DEE)

From generators, plant, and vehicles on site. Classified as a Group 1 carcinogen by the IARC. Particularly dangerous in enclosed or semi-enclosed areas such as basements and tunnels.

Isocyanates

Found in spray foam insulation, some paints, and adhesives. The most common cause of occupational asthma in the UK. Once sensitised, even tiny exposures can trigger severe reactions.

How to Fill In a COSHH Assessment

A COSHH assessment form should capture the following information clearly:

Section 1: Substance Information

• Product name (exactly as on the label)
• Manufacturer or supplier
• CAS number (from the safety data sheet)
• Hazard classification (GHS pictograms and signal words)
• Workplace exposure limit (if one exists)

Section 2: Work Activity

• Describe the task: what is being done, where, and how
• How is the substance used or created?
• What quantity is used per shift?
• How long does the task take?
• How often is this task carried out?

Section 3: Exposure Assessment

• Route of exposure: inhalation, skin contact, ingestion, or injection
• Who is exposed: operatives doing the work, people working nearby, public
• Duration and frequency of exposure
• Level of exposure compared to the WEL

Section 4: Control Measures

• Elimination or substitution options tried or considered
• Engineering controls (LEV, water suppression, enclosure)
• Administrative controls (restricted access, reduced exposure time, supervision)
• PPE required (type, standard, replacement frequency)

Section 5: Emergency Procedures

• First aid measures for each route of exposure
• Spill procedures
• Fire-fighting media
• Waste disposal requirements

COSHH Assessment Example: Cement Dust

Here is a worked example of how to assess cement dust exposure during concrete cutting:

Hazards identified: Inhalation of respirable dust (WEL 10 mg/m3 inhalable, 4 mg/m3 respirable). Skin contact causing irritant dermatitis. Eye irritation. Respirable crystalline silica content (WEL 0.1 mg/m3).

Control measures:

• Use water suppression on all cutting equipment to reduce airborne dust by up to 90%
• Position cutting area downwind of other workers where possible
• Provide RPE (FFP3 disposable masks, face-fit tested) for the cutting operative
• Provide barrier cream and suitable gloves (nitrile, minimum 0.4mm thickness)
• Safety goggles to EN 166 for the cutting operative
• Welfare facilities for washing before eating, drinking, or smoking
• Damp down cut materials and sweep with water, never dry sweep
• Health surveillance: baseline lung function test, annual review for workers regularly exposed

Residual risk: Low, provided all controls are implemented and maintained.

Common COSHH Mistakes on Construction Sites

These are the errors that HSE inspectors find most frequently:

• No safety data sheets on site. You must have the SDS for every chemical product. If a product arrives without one, do not use it until you have obtained it from the supplier.
• Assessments written after the work. COSHH assessments must be completed before exposure begins. Backdating is a compliance failure.
• Jumping straight to PPE. The hierarchy of control requires you to consider elimination, substitution, and engineering controls before specifying PPE. Inspectors look for evidence that you have considered alternatives.
• Generic assessments not linked to specific tasks. "Cement -- wear gloves" is not a COSHH assessment. You need substance-specific, task-specific detail.
• No health surveillance. If workers are regularly exposed to silica, isocyanates, solvents, or other substances with long-term health effects, you must provide health surveillance. This is not optional.
• Failing to review when products change. If you switch from one adhesive to another, the old COSHH assessment no longer applies. Every product change triggers a new assessment.
• No training records. Workers must be trained on the hazards and controls for the substances they work with. You need a record of this training.

Using AI for COSHH Assessments

AI tools like Site Manager AI can generate COSHH assessments based on the substance name and work activity. The AI cross-references the safety data sheet information, applicable WELs, and recommended control measures to produce a comprehensive assessment in minutes.

This is particularly useful when:

• A new product arrives on site and you need a COSHH assessment quickly
• You are tendering for work and need to demonstrate your COSHH competence
• You manage multiple sites with different substances and need consistent, thorough documentation
• You want to ensure you have not missed any hazards or regulatory requirements

The AI generates the assessment, you review it against your site knowledge and the actual SDS, and you have a compliant document in a fraction of the time.

Related Reading

• Construction COSHH Assessment with AI
• Health and Safety Documentation in Construction
• AI Risk Assessment for Construction