COSHH Regulations for Tradespeople

Quick Answer: The Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677) require employers and self-employed tradespeople to assess and control exposure to hazardous substances. Key Workplace Exposure Limits include respirable crystalline silica at 0.1 mg/m³ (8-hour TWA), wood dust at 3 mg/m³, and flour dust at 1 mg/m³. COSHH assessments must be retained for 5 years; health surveillance records for 40 years.

Summary

Construction and trade work involves daily contact with substances capable of causing serious long-term harm — cement dust that damages lungs, solvents that affect the liver, wood dust that causes nasal cancer, and isocyanates in spray paints and expanding foam that trigger occupational asthma. These risks are not theoretical: occupational lung disease kills around 12,000 people annually in the UK, and construction workers are disproportionately represented in that figure.

COSHH places a legal duty on employers and self-employed people who direct the work of others to assess those risks and put controls in place. The regulations follow a well-established hierarchy: eliminate the hazardous substance if possible, substitute it for a less hazardous alternative, enclose or extract at source, and only then consider respiratory protective equipment as a supplementary measure. PPE is explicitly the lowest tier of control — a COSHH assessment that jumps straight to "wear a mask" without addressing the source of exposure is not compliant.

The regulations apply across all trades. Groundworkers cutting concrete face silica risks. Joiners and furniture makers face wood dust exposure. Painters using two-pack systems face isocyanate exposure. Tilers using cement-based adhesives face both silica and alkaline skin exposure. Understanding what substances are present in a workplace, what the safe limits are, and how to control exposure below those limits is a legal baseline, not an optional extra.

Key Facts

Quick Reference Table

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Substance Source WEL (8-hr TWA) Minimum RPE
Respirable crystalline silica Concrete, brick, mortar, stone cutting 0.1 mg/m³ FFP3 / P3 half-face
Hardwood dust Cutting, sanding oak, ash, beech 1 mg/m³ FFP3 (carcinogen)
Softwood dust Cutting, sanding pine, spruce, MDF 3 mg/m³ FFP2 minimum
Flour dust Kitchen fitting in bakeries or food sites 1 mg/m³ FFP2 minimum
Cement dust Mixing, handling, dry cement powder 1 mg/m³ (inhalable) FFP2 + gloves/eye protection
Isocyanates (MDI/TDI) Two-pack paint, expanding foam, PU adhesives 0.02 mg/m³ NCO P3 half-face + organic vapour; supplied air for spraying
Bitumen fumes Flat roofing, road patching 1 mg/m³ P3 + adequate ventilation
Styrene GRP installation, fibreglass work 100 ppm Organic vapour cartridge
Mould spores Remediation, damp property work No WEL; health hazard FFP3 minimum
VOCs (solvent-based paints) Painting, adhesives, thinners Substance-specific Organic vapour cartridge to APF requirement

Detailed Guidance

The 8-Step COSHH Assessment

A COSHH assessment is not a form-filling exercise. It is a structured process that must reflect the actual work being carried out. Generic assessments downloaded from the internet are not compliant if they do not reflect the specific substances and tasks in your business.

Step 1 — Identify the substances. Walk the job and list every hazardous substance used or generated. Include substances generated by the work itself — dust from cutting masonry, fumes from welding — as well as products brought to site. Check Safety Data Sheets for all products; Section 8 of the SDS covers exposure controls and WELs.

Step 2 — Decide who is at risk. Consider not just your own workers but other trades on the same site, members of the public in occupied buildings, and neighbours affected by external dust-generating operations. Consider all exposure routes: inhalation, skin absorption, eye contact, and ingestion via contaminated hands.

Step 3 — Evaluate exposure risks. Consider frequency, duration, and likely airborne concentration relative to the WEL. A task done for 10 minutes once a month is very different from one performed for several hours daily. Use HSE guidance documents and the COSHH Essentials e-tool for preliminary estimates where full hygiene monitoring is not available.

Step 4 — Decide on control measures. Apply the hierarchy of control in sequence. Do not default to RPE without first determining whether engineering controls could adequately reduce the risk.

Step 5 — Put controls in place. Procure and commission LEV equipment before the job starts. Issue correct RPE matched to the WEL and the required Assigned Protection Factor. Train workers on correct use. A control measure that exists only on paper is not a control.

Step 6 — Maintain controls. LEV systems must be examined and tested every 14 months under COSHH Regulation 9 and records kept. RPE requires regular cleaning, filter replacement, and seal inspection. Record all maintenance activities.

Step 7 — Monitor exposure. For high-risk substances, air sampling by an occupational hygienist verifies that controls are working. Monitoring is particularly important when controls are first introduced, when exposure is suspected to be near the WEL, or where a legal requirement exists (isocyanates, certain carcinogens). Monitoring records should be kept for 5 years.

Step 8 — Health surveillance. Where required by COSHH Schedule 6, arrange regular medical checks. Silica: lung function tests (spirometry). Isocyanates: occupational asthma screening — any sensitised worker must be permanently removed from isocyanate exposure. Hardwood dust: nasal examination for sino-nasal cancer. Dermatitis: skin checks for cement, epoxy, and cutting fluid workers. Records must be kept for 40 years.

Hierarchy of Control

The hierarchy must be applied in order. Skipping steps is only permissible if a higher-order control is genuinely not reasonably practicable, and that conclusion must be documented.

Eliminate — Remove the hazardous substance entirely. Use a process that does not require it. Pre-formed components instead of site-cut masonry where the specification allows.

Substitute — Replace with a less hazardous substance. Water-based paint instead of solvent-based where performance allows. Pre-mixed wet render instead of dry cement powder. Vacuum-blasting instead of dry grit blasting on steel. Note: the replacement must itself be assessed — substitutes can introduce different hazards.

Enclose — Contain the substance or process to prevent release into the working environment. Enclosed mixing areas, sealed containers for waste solvent.

Local exhaust ventilation (LEV) — Capture dust, fume, or vapour at or near the point of generation before it disperses. On-tool extraction is the construction standard: dust-shrouded angle grinders, vacuum-attached drills and hammer drills, downdraught benches for timber machining. LEV is only effective if correctly matched to the task and maintained to the 14-month examination standard.

Administrative controls — Reduce exposure through work organisation: rotating workers to limit individual daily dose, scheduling high-dust tasks when fewer people are present, wet-cutting instead of dry-cutting masonry.

Respiratory Protective Equipment — The final layer of defence, not the first. RPE does not eliminate the hazard; it reduces the wearer's exposure only. Its effectiveness depends entirely on correct selection, correct fit, and consistent correct use.

Respiratory Protective Equipment: Selection and Fit Testing

RPE must be selected based on the Assigned Protection Factor (APF) required to reduce measured or estimated exposure down to below the WEL.

Example calculation: Silica exposure during dry angle-grinding without LEV is estimated at 1.0 mg/m³. WEL = 0.1 mg/m³. Required APF = 1.0 ÷ 0.1 = 10. An FFP3 disposable mask (APF 20) provides adequate protection; an FFP2 (APF 10) is at the limit and leaves no margin; an FFP1 (APF 4) is wholly inadequate.

Disposable filtering facepieces:

Reusable half-face masks with P3 filters — APF 20 for particles. Where both dust and vapour hazards coexist, an appropriate gas/vapour cartridge must be combined with the P3 particle filter.

Powered air-purifying respirators (PAPR) — APF 20 (half-face hood) or higher. No fit test required, making them suitable for workers with facial hair, facial scarring, or where prolonged FFP3 wear is impractical.

Fit testing is a legal requirement for all tight-fitting RPE under COSHH. Qualitative fit testing (saccharin or bitrex challenge) is acceptable for FFP2 and FFP3. Quantitative fit testing is required for APF above 20. Workers with significant facial hair cannot be adequately fit-tested for tight-fitting RPE — a loose-fitting PAPR must be provided instead.

Common Trade Substances and Their Risks

Cement — Despite its ubiquity, cement is one of the most underestimated hazardous substances in construction. The alkaline pH (12–13) causes progressive burns that may not be painful initially, leading workers to tolerate prolonged skin contact. Repeated exposure causes chrome dermatitis and cement burns. Chrome-reduced cement (containing ferrous sulphate) is required where cement is mixed by hand. Waterproof gloves, eye protection, and barrier cream are the minimum controls.

Silica from cutting masonry — Angle grinding, disc cutting, core drilling, and breaking concrete and brick all release respirable crystalline silica. Even brief dry cutting without controls can generate airborne concentrations 20–100 times the WEL. On-tool water suppression (wet cutting) or vacuum-shrouded extraction is the standard control for construction. Silicosis is progressive, irreversible, and can develop within a few years of high-level exposure.

Isocyanates in expanding foam and two-pack coatings — MDI is present in one-component expanding foam used daily by plumbers, joiners, and window fitters. Even brief sensitising exposure can trigger a permanent occupational asthma response to any future isocyanate contact, however minimal. Sensitised workers cannot return to isocyanate work at any concentration. Adequate ventilation and P3 RPE with organic vapour cartridge are required; supplied-air breathing apparatus is mandatory for sprayed two-pack coatings.

Wood dust from hardwoods — Hardwood dust (oak, beech, ash, iroko, and others) is classified as a Group 1 human carcinogen by IARC for sino-nasal and nasopharyngeal cancer. The risk accumulates over a working lifetime. LEV at source is essential; FFP3 RPE covers residual exposure. The 2020 WEL revision brought softwood dust under the same 3 mg/m³ limit as mixed dust, and set hardwood at the more stringent 1 mg/m³.

Safety Data Sheets and Site Compliance

Suppliers are legally required under UK REACH to provide a Safety Data Sheet for any substance classified as hazardous. SDSs must be in English, follow the 16-section GHS format, and be accessible on site during use of the substance. Section 8 specifies the WEL and recommended PPE; Section 15 covers regulatory status.

A file of current SDSs for all site products — physical or digital — is a practical compliance baseline. When a product is reformulated, a new SDS is issued and the relevant COSHH assessment section should be reviewed before work continues.

Frequently Asked Questions

Do COSHH regulations apply to sole traders?

Yes. COSHH Regulation 3 covers self-employed people who may be exposed to hazardous substances in the course of their own work. A sole trader working alone has a duty to themselves; a sole trader employing or directing a labourer has a duty to that worker as well. The assessment can be simpler for a sole trader than for a large workforce, but it must exist and reflect actual working conditions.

Is a Safety Data Sheet the same as a COSHH assessment?

No. The SDS is a document provided by the manufacturer describing the substance's hazards and recommended controls. The COSHH assessment is a site-specific document produced by the employer that uses SDS information alongside actual task details, exposure duration, and workforce numbers to determine whether controls are adequate. Using a supplier's SDS as a COSHH assessment does not meet the legal requirement.

How often should COSHH assessments be reviewed?

COSHH Regulation 6(3) requires review whenever there is reason to believe the assessment is no longer valid: new substances, process changes, new health evidence, or following a health incident. A formal review every two years is reasonable practice for most trade activities. Any new product introduced to site should trigger an immediate review of the relevant section.

Does wearing an FFP2 mask satisfy COSHH for silica work?

Only if the estimated exposure does not require a higher APF. For dry cutting masonry without LEV, concentrations typically exceed 1 mg/m³, requiring an APF of at least 10. FFP2 (APF 10) provides no safety margin; FFP3 (APF 20) is the correct choice. HSE guidance on silica specifically recommends FFP3 as the minimum RPE for silica-generating tasks without adequate LEV.

What happens if the HSE finds no COSHH assessment?

Failure to carry out a COSHH assessment is a criminal offence under the Health and Safety at Work etc. Act 1974. The HSE can issue an Improvement Notice, a Prohibition Notice stopping work immediately, or prosecute. Crown Court prosecution can result in unlimited fines; persistent serious breaches can result in custodial sentences. Civil liability for occupational disease claims arising from inadequate controls can result in substantial compensation awards.

Regulations & Standards