COSHH Assessment for Tradespeople UK — A Practical Guide (2026)

Most tradespeople know they need to wear PPE around certain materials. Fewer know they're legally required to assess the risk before they pick up a tool. That's COSHH in a nutshell — and the HSE takes it seriously. This guide explains what COSHH means for tradespeople, which substances trigger an assessment, how to write one, and where people typically go wrong.

What is COSHH?

COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. The regulations were made under the Health and Safety at Work etc. Act 1974 and are enforced by the Health and Safety Executive (HSE). They place a legal duty on employers — and in many cases self-employed tradespeople — to prevent or adequately control their workers' exposure to substances that are hazardous to health.

A "substance hazardous to health" under COSHH is any substance, mixture, or process-generated material that can harm people when inhaled, swallowed, absorbed through the skin, or injected. This covers dusts, fumes, gases, vapours, biological agents, and chemical products. If it can hurt someone, COSHH probably applies.

The regulations do not cover lead (covered by the Control of Lead at Work Regulations 2002), asbestos in its own right (covered by the Control of Asbestos Regulations 2012), or ionising radiation. That said, COSHH does apply when you disturb asbestos incidentally during minor works — for example, drilling through an artex ceiling that contains chrysotile. Licensed asbestos removal work has its own separate regime.

Who needs to do COSHH assessments?

If you employ anyone — even one apprentice — you are an employer and COSHH applies in full. You must assess the risk from every hazardous substance your workers might be exposed to and put adequate controls in place.

Self-employed tradespeople are also in scope. If you work alone but use hazardous substances that could expose other people — clients, members of the public on the job site, subcontractors — you have a duty under both COSHH and the general duties in the Health and Safety at Work Act. Practically speaking, this means a sole trader cutting concrete in a customer's kitchen should still have a COSHH assessment for silica dust. The HSE can inspect your work and issue improvement notices regardless of your company size.

Which substances do tradespeople need to assess?

The list is longer than most people expect. Common hazardous substances encountered on construction and maintenance work include:

• Respirable crystalline silica (RCS). Generated when cutting, grinding, drilling, or chasing concrete, bricks, blocks, mortar, and natural stone. Silica dust causes silicosis — a permanent, progressive, and potentially fatal lung disease. The Workplace Exposure Limit (WEL) for RCS is 0.1 mg/m³ (8-hour TWA).
• Wood dust. Hardwood dust is a known carcinogen (Group 1, IARC). Softwood dust is a probable carcinogen. Both are heavily regulated. The WEL for hardwood dust is 3 mg/m³; for softwood and mixed wood dust it is 5 mg/m³.
• Lead paint. Sanding, burning off, or cutting surfaces coated with lead-based paint generates lead dust and fumes. This is covered by the Control of Lead at Work Regulations, but the assessment process is broadly similar to COSHH.
• Solvents and adhesives. Paint thinners, contact adhesives, primers, and cleaning agents often contain volatile organic compounds (VOCs) including toluene, xylene, and acetone. These can cause narcosis, dermatitis, and long-term organ damage.
• Cement and wet concrete. Portland cement contains hexavalent chromium, which causes allergic contact dermatitis (cement burns). Prolonged skin contact without barrier protection is a common cause of occupational dermatitis in construction.
• Isocyanates. Found in two-pack spray paints, spray foam insulation, and some adhesives. Isocyanates are the single largest cause of occupational asthma in the UK. Even brief overexposure can cause life-long sensitisation.
• Cleaning chemicals. Drain cleaners, mould treatments, descalers, and biocides can be corrosive, irritant, or toxic. Even products sold as "consumer" items may have significant hazards in trade quantities.
• Diesel exhaust emissions. Using diesel-powered plant, generators, or vehicles in enclosed spaces generates diesel particulate matter, which is a Group 1 carcinogen.
• Asbestos (disturbance during minor works). Where non-licensed work involves limited, short-duration disturbance of asbestos-containing materials (ACMs) — such as drilling through an artex ceiling or removing an old floor tile — COSHH assessments and the notifiable non-licensed work (NNLW) rules apply. Licensed ACM removal has its own framework under CAR 2012.

How to do a COSHH assessment — step by step

There is no single prescribed form, but the HSE expects you to work through a logical process. Here is how to do it properly.

Step 1 — Identify the substance

Walk through the job and list every substance workers will handle or be exposed to, including substances generated by the work process itself (dust, fumes, vapour). Do not forget substances that are already on site if you are working at a client's premises.

Step 2 — Get the Safety Data Sheet (SDS)

For any product you buy, the supplier is legally required to provide a Safety Data Sheet (also called an MSDS — Material Safety Data Sheet). The SDS contains 16 sections covering hazard identification, composition, first-aid measures, handling and storage, exposure controls, and more. Read sections 2, 8, and 11 carefully. Keep the SDS accessible on site. The HSE inspector will ask for it.

For process-generated substances like silica dust or wood dust, the SDS route does not directly apply. Instead, refer to HSE guidance documents such as EH40 (Workplace Exposure Limits) and the relevant COSHH essentials guidance sheets.

Step 3 — Identify who is exposed and how

Consider all the people who could be exposed: the operative using the substance, other workers nearby, apprentices and labourers in the vicinity, clients or members of the public in adjacent areas. Note the route of exposure (inhalation, skin contact, ingestion) and the likely duration and frequency of exposure.

Step 4 — Evaluate the risk

Compare the likely exposure against the Workplace Exposure Limit (WEL) where one exists. Consider the toxicity and hazard classification of the substance, the duration and frequency of exposure, and whether existing controls are adequate. The HSE's COSHH Essentials tool can help you estimate exposure levels without full air monitoring in many cases.

Step 5 — Decide on controls

Work through the hierarchy of control (see below). Document what controls you will use and why.

Step 6 — Record the assessment

If you employ five or more people, you must record your significant findings in writing. Even if you employ fewer, a written record is strongly advisable — it demonstrates compliance and protects you if there is ever an injury or enforcement action.

Step 7 — Review and update

Review the assessment whenever there is reason to believe it is no longer valid: new substances are introduced, the work process changes, a health surveillance result suggests a problem, or there has been an incident. As a minimum, review all assessments periodically — annually is a sensible default.

The hierarchy of control

COSHH regulation 7 requires you to apply the hierarchy of control in order. You cannot skip straight to PPE.

1. Elimination. Remove the hazardous substance entirely. Can you achieve the same result without using it? This is the most effective control and should always be considered first.
2. Substitution. Replace the hazardous substance with a less hazardous alternative. For example, switching from a solvent-based adhesive to a water-based one, or using pre-wetted silica-free abrasive instead of dry grinding.
3. Engineering controls. Use on-tool dust extraction (H-class vacuum), local exhaust ventilation (LEV), damping down with water, enclosed systems, or isolation to prevent the substance reaching workers. Engineering controls are preferred over administrative controls and PPE because they work independently of human behaviour.
4. Administrative controls. Restrict access to the area, rotate workers to limit exposure duration, use safe systems of work, and provide training. These reduce exposure but rely on people following procedures consistently.
5. Personal protective equipment (PPE). PPE is always the last resort, not the first response. If engineering and administrative controls cannot adequately control exposure, appropriate PPE must be provided, maintained, and used correctly.

One of the most common COSHH failures the HSE sees is jumping straight to PPE — handing a worker a dust mask and calling it done. A standard FFP1 or FFP2 dust mask offers no meaningful protection against RCS (respirable crystalline silica). Silica dust requires at minimum an FFP3 filtering facepiece or a half-face respirator with P3 filters, and only after engineering controls have been maximised.

What to include in a written COSHH assessment

Your written assessment should cover, for each substance or process:

• The name of the substance or process-generated material
• The task or location where exposure occurs
• The route of exposure (inhalation, skin, ingestion)
• Who is at risk and how many people
• The relevant WEL or health-based exposure limit (if one exists)
• Existing controls already in place
• Additional controls needed to achieve adequate control
• Type, standard, and maintenance schedule for PPE required
• Emergency procedures (spill response, first aid, emergency contacts)
• Whether health surveillance is required
• Review date
• Assessor's name and date of assessment

Health surveillance

Health surveillance is required under COSHH regulation 11 where workers are exposed to substances with a recognised link to a specific disease, and where valid techniques exist to detect early signs of that disease. For tradespeople, the main triggers are:

• Respirable crystalline silica — lung function testing and respiratory health questionnaires for workers with regular exposure.
• Isocyanates — pre-employment and ongoing respiratory surveillance, carried out by an occupational health professional.
• Hardwood dust — lung function and nasal health checks for workers with regular exposure.
• Dermal sensitisers (e.g. wet cement, epoxy resins) — skin health checks for regular users.

Health surveillance must be carried out by, or under the supervision of, a suitably qualified person — typically an occupational health nurse or physician. A COSHH assessment is the trigger that tells you surveillance is needed; it does not replace the surveillance itself.

Keeping records

COSHH assessments should be kept for as long as they are valid, plus a reasonable period after. As a practical rule, keep all superseded assessments for at least three years after they are replaced.

Health surveillance records must be kept for a minimum of 40 years for substances that cause long-latency diseases (silica, asbestos-related work under COSHH, vinyl chloride monomer, and others listed in COSHH Schedule 6). This is not a typo — lung cancer and mesothelioma can take 30 to 40 years to develop after exposure. The records need to be available if a former employee later makes a claim.

Store health surveillance records confidentially. Individual records must not be disclosed to the employer without the worker's consent — only the fitness-for-work outcome is passed on.

COSHH for sole traders

If you work alone, you might assume COSHH does not apply to you. It does. As a self-employed person who works on other people's premises or alongside other contractors, you have a duty not to expose others to risk. And if your exposure to a hazardous substance could harm you personally, there is still a strong regulatory expectation that you have assessed and managed that risk.

The HSE does inspect sole traders and one-person limited companies. If you are cutting concrete in a domestic property without dust extraction and an FFP3 respirator, you are exposed, your client is exposed, and you are operating without a COSHH assessment. That is an enforcement risk and, more importantly, a genuine health risk.

The good news for sole traders is that COSHH assessments do not need to be complex. A one-page document covering the substances you regularly use, the controls you apply, and the PPE you wear is sufficient. Create it once, review it when your work changes, and keep it with your other site paperwork.

Common COSHH mistakes

• No SDS on site. If an inspector arrives or a worker has a reaction, you need to be able to show the Safety Data Sheet immediately. Keep digital copies accessible on your phone or van tablet.
• Wrong respiratory protection for silica. Standard dust masks (FFP1, FFP2, or the cheap disposable masks on most builder's merchants shelves) do not adequately filter respirable silica particles. FFP3 is the minimum; if you are doing heavy grinding work regularly, a half-face respirator with P3 cartridges provides better fit and protection.
• Treating PPE as the only control. PPE alone is not adequate control under COSHH. You must also consider engineering controls — on-tool extraction, water suppression, ventilation — before reaching for the respirator.
• Not reviewing after process changes. If you start using a new product, change your method, or take on a new type of work, the existing COSHH assessment may no longer be valid. Review it before the work starts, not after.
• Generic assessments with no site-specific detail. Downloading a template and filing it without completing it is not a COSHH assessment. The HSE expects assessments to reflect the actual substances, tasks, and controls at your specific jobs.
• Forgetting process-generated substances. Silica dust and wood dust are not products you buy — they are created by your work. Many tradespeople assess the chemicals they buy but overlook the dust generated by cutting and grinding.