COSHH Training UK — What Tradespeople Need to Know About Hazardous Substances in 2026

What COSHH Is and Why It Applies to You

COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. Made under the Health and Safety at Work etc. Act 1974 and enforced by the Health and Safety Executive (HSE), the regulations impose a legal duty on employers and the self-employed to prevent or adequately control exposure to substances that can harm health. There is no minimum business size — a sole trader working alone is in scope, as is a national contractor with 500 operatives.

A 'substance hazardous to health' is defined broadly. It covers chemical products with hazard pictograms on the label, but equally it covers dusts, fumes, vapours, mists, and biological agents generated by the work process itself — things that appear on no safety data sheet because they didn't exist until your angle grinder met the concrete. If it can cause ill-health by being inhaled, absorbed through the skin, swallowed, or injected, COSHH almost certainly applies.

Two important carve-outs: lead and asbestos each have their own dedicated regulations (Control of Lead at Work Regulations 2002 and Control of Asbestos Regulations 2012 respectively) and are generally excluded from COSHH. However, incidental asbestos disturbance during minor works — drilling through artex, disturbing lagging on a pipe run — falls under COSHH for non-licensed work. The overlap matters in practice.

Hazardous Substances by Trade — Quick Reference

The following table covers the most common COSHH-relevant exposures by trade. This is not exhaustive — always check the safety data sheet (SDS) for any product you use.

The COSHH Assessment — Step by Step

COSHH does not prescribe a single form. What it requires is a structured, documented evaluation of every significant hazardous substance or process. Work through the following steps for each one.

1. Identify the substances

Walk through the job and list everything workers will use or be exposed to — bought-in products (check the label for GHS hazard pictograms and request the SDS from the supplier), and substances generated by the process itself such as silica dust from cutting masonry or fumes from welding. Don't overlook substances already present on site that your work might disturb.

2. Identify who could be harmed and how

Consider the operative directly using the substance, apprentices and labourers working nearby, other contractors on site, and clients or members of the public in adjacent areas. Note the route of exposure: inhalation is most common in construction, but skin contact (wet cement, epoxy resins) and ingestion (eating without washing contaminated hands) are also relevant.

3. Evaluate existing controls

Record what controls are currently in place — whether that is LEV already on site, existing PPE, a wet cutting method, or nothing at all. Be honest. The HSE's COSHH Essentials tool can help estimate exposure levels for common trade tasks without requiring full air monitoring.

4. Evaluate the risk

Compare the likely exposure against the relevant Workplace Exposure Limit (WEL) where one exists. Consider the toxicity of the substance, frequency and duration of exposure, the concentration generated, and whether the health effect is reversible (irritant dermatitis) or permanent and progressive (silicosis, occupational asthma once sensitised). Carcinogenic and sensitising substances require the most rigorous control regardless of measured exposure levels.

5. Decide and implement controls

Apply the hierarchy of control in strict order — covered in detail in the next section. Document specifically what controls you will use and confirm they are in place before the work starts. Brief all workers. Ensure PPE is correctly fitted and available on site.

6. Record the assessment

Write it down. For employers with five or more employees this is legally required; for smaller businesses a written record is strongly advisable as evidence of compliance. Keep assessments for at least five years after they are superseded. For substances causing long-latency diseases (silica, asbestos-related incidental disturbance, certain chemicals listed in COSHH Schedule 6), health surveillance records must be kept for 40 years — lung cancer and mesothelioma can take three to four decades to appear after exposure.

7. Monitor effectiveness

Check that the controls actually work. For local exhaust ventilation (LEV), this means thorough examination and testing at intervals not exceeding 14 months. For RPE, it means regular fit checks and filter inspection. Air monitoring may be needed for higher-risk substances to confirm exposure stays below WELs.

8. Review and update

Review the assessment whenever the process changes, a new substance is introduced, health surveillance reveals a concern, or an incident occurs. Annual review is a sensible baseline for assessments covering regularly performed tasks. A COSHH assessment is a living document, not a one-time checkbox.

The Five Specific Hazards Every Tradesperson Must Know

Silica dust (RCS)

Respirable crystalline silica is the most serious occupational lung hazard in UK construction. Cutting, grinding, drilling, or chasing concrete, brick, block, mortar, natural stone, and porcelain tiles generates fine silica particles small enough to reach the deep lung. Over time this causes silicosis — a progressive, irreversible lung disease — and significantly increases the risk of lung cancer. There is no cure for silicosis.

The WEL for RCS is 0.1 mg/m³ as an 8-hour TWA. Uncontrolled cutting operations routinely generate concentrations 10 to 100 times this limit. You cannot see or smell silica dust at hazardous concentrations. Required controls are on-tool water suppression or H-class (HEPA) vacuum extraction connected directly to the tool, and respiratory protective equipment at a minimum of FFP3. Standard disposable blue or white dust masks (FFP1 or FFP2) offer no meaningful protection against RCS and must not be used as the sole control.

Wood dust

Hardwood dust is classified as a Group 1 carcinogen by the International Agency for Research on Cancer — the same category as tobacco. Regular exposure causes adenocarcinoma of the nasal cavity and paranasal sinuses. Softwood dust causes occupational asthma and rhinitis. MDF contains formaldehyde-based resin which releases vapour and fine particles when cut; formaldehyde is a known human carcinogen.

The WEL for hardwood dust is 3 mg/m³; for softwood and mixed wood dust it is 5 mg/m³ (both 8-hour TWA). Local exhaust ventilation at the tool and FFP3 respiratory protection are required for hardwood work. Cutting MDF in an enclosed space without extraction — a kitchen, a cupboard, a van with the back doors shut — will exceed the WEL rapidly.

Wet cement and skin hazards

Wet cement contains hexavalent chromium (chromium VI), a skin sensitiser and carcinogen. Prolonged or repeated skin contact causes cement burns — a chemical burn that can be slow to appear but severe — and occupational contact dermatitis. Once sensitised, a worker may be unable to work with cement products again. Controls: impermeable gloves (nitrile or equivalent), barrier cream on exposed skin, and prompt washing after contact. Do not kneel in wet cement or tuck trouser legs into boots.

Isocyanates

Isocyanates are found in two-pack spray paints (common in vehicle refinishing, metal coating, and high-end joinery), spray polyurethane foam insulation, and some adhesives. They are a leading cause of occupational asthma in the UK. The critical clinical fact: once a person is sensitised to isocyanates, they are sensitised for life. Even very low subsequent exposure will trigger asthma attacks. There is no cure and no desensitisation treatment. Workers must be removed from any further isocyanate exposure. Spraying two-pack paint without supplied-air respiratory protection is one of the most dangerous things a decorator can do.

Isocyanates cannot be adequately controlled by air-purifying respirators (including FFP3 disposables) when spraying. Supplied-air or powered air-purifying respirator (PAPR) equipment with appropriate filters is required. Health surveillance — pre-employment respiratory baseline and ongoing lung function checks — is required for any worker regularly exposed to isocyanates.

Bitumen fumes

Hot bitumen used in roofing, waterproofing, and road surfacing produces complex hydrocarbon fumes classified as probably carcinogenic to humans (Group 2A, IARC). Skin exposure to hot bitumen causes burns; repeated skin contact with bituminous materials is associated with skin cancer. Controls include LEV where practicable (enclosed kettles with extraction), working upwind where possible, RPE at minimum FFP3 (though powered air-purifying units are preferable for sustained hot-melt work), and impermeable gloves and coveralls. Never use petrol or other solvents to remove bitumen from skin — use barrier cream before work and a proprietary skin cleanser after.

The Controls Hierarchy — Applied in Plain English

COSHH Regulation 7 requires employers to prevent exposure, or where prevention is not reasonably practicable, adequately control it. Control must follow a strict hierarchy. PPE is at the bottom — it protects only the wearer, it fails if it does not fit, and it relies entirely on the worker using it correctly every time. Engineering controls at the source protect everyone without relying on individual behaviour.

COSHH Training — What You Actually Need

There is no single mandatory COSHH certificate. The regulations require that workers are provided with suitable and sufficient information, instruction, and training — but they do not specify a particular qualification or course length. What the HSE expects is that every worker understands the hazardous substances they work with, the health risks those substances pose, the controls in place, how to use PPE correctly, and what to do if something goes wrong.

In practice, acceptable COSHH training takes several forms:

• Online COSHH awareness courses — typically 2 to 3 hours, cost £15 to £40, provide a certificate of completion. Suitable for most trade operatives to demonstrate basic awareness. Providers include CITB eLearning, IOSH, and a range of CPD-accredited platforms.
• Toolbox talks — documented, job-specific briefings covering the substances used on a particular site or project. These are often the most practically useful form of COSHH training because they are specific to the actual hazards the worker will encounter that week.
• NEBOSH Unit NGC3 (or the full NEBOSH General Certificate) — appropriate for supervisors, safety officers, and anyone with COSHH management responsibilities. This level of qualification demonstrates competence in carrying out and reviewing COSHH assessments.
• CITB Health, Safety and Environment (HS&E) test — the operatives' card test covers COSHH awareness at a basic level as part of the CSCS card scheme. Not a substitute for job-specific COSHH training, but demonstrates baseline knowledge.

Keep training records. If an HSE inspector visits — or if a former employee later develops an occupational disease — your records are the evidence that you discharged your duty. A signed toolbox talk attendance sheet is worth considerably more than a verbal assurance that workers were told.

COSHH and RIDDOR — When You Must Report

RIDDOR (Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013) requires employers and the self-employed to report certain work-related ill-health conditions to the HSE. COSHH substances are directly linked to several RIDDOR-reportable occupational diseases. The trigger is a diagnosis by a doctor confirming the condition is work-related — not the exposure itself, which may have occurred years or decades earlier.

The COSHH-linked conditions you must report under RIDDOR include:

• Occupational asthma — triggered by sensitising substances including isocyanates, wood dust, flux fumes, and reactive dyes. Report when a doctor confirms the diagnosis and work exposure is identified as a cause.
• Occupational dermatitis — work-related skin disease caused by substances including wet cement (chromium VI), epoxy resins, cutting fluids, and rubber chemicals.
• Silicosis — any confirmed diagnosis in a worker with occupational silica exposure must be reported.
• Pneumoconiosis — including coal workers' pneumoconiosis and other dust-related lung fibrosis.
• Tendinitis or tenosynovitis from hand/arm vibration — not strictly a chemical COSHH issue, but arises from similar tool use patterns and is RIDDOR-reportable.

Reports are made to the HSE online via the RIDDOR reporting portal at riddor.gov.uk. There is no charge and the process is straightforward. Failure to report a RIDDOR-reportable condition is itself a criminal offence under the regulations.

COSHH Compliance as a Business Asset

The HSE is clear that COSHH compliance is not optional, and enforcement is real. An improvement notice requires you to fix identified failures within a set period. A prohibition notice stops the activity immediately. Prosecution for serious failures — particularly where workers have been harmed — can result in unlimited fines and, in cases involving gross negligence, imprisonment. The HSE publishes enforcement action details publicly; COSHH failures featuring silica dust and welding fume appear regularly.

But beyond the legal baseline, a well-run, COSHH-compliant business is a more professional and more marketable business. Commercial clients, housing associations, and local authorities increasingly require evidence of health and safety competence — COSHH assessments, training records, method statements, and health surveillance records — as part of their supplier qualification process. Being able to produce these documents on request puts you ahead of competitors who treat safety paperwork as an afterthought.

Clients and principal contractors operating under CDM 2015 must satisfy themselves that the contractors they appoint are competent in health and safety. Demonstrable COSHH compliance — a proper assessment process, trained operatives, correct controls, and documented records — is evidence of that competence. It can be the difference between winning and losing a commercial tender. It also reduces your exposure to civil claims if a worker develops an occupational disease traced back to your jobs.

The tradespeople who treat COSHH seriously are not doing it purely to avoid HSE visits. They are doing it because it protects their workers, protects their business, and positions them as the kind of contractor serious clients want on site.