Wood Dust COSHH Assessment: Risks, Controls, and What the HSE Expects

Wood Dust Is Not a Minor Hazard

Wood is natural. That makes it easy to underestimate the risk. But wood dust is one of the better-documented occupational carcinogens in UK health and safety law, and carpenters and joiners have significantly elevated rates of both asthma and sinonasal cancer compared to the general working population.

The HSE's own data shows that carpenters and joiners are four times more likely to develop occupational asthma than workers in most other trades. For hardwood dust specifically — oak, beech, ash, walnut — the link to nasal cancer is well-established. Hardwood dust is classified as a Group 1 carcinogen (known to cause cancer in humans).

This is not a risk that can be managed with a line in a toolbox talk and a dust mask. A proper COSHH assessment, proper engineering controls, and health surveillance are legal requirements.

Who Is Affected?

Wood dust COSHH obligations apply wherever workers are regularly exposed to airborne wood dust. That includes:

Joinery shops and timber yards — saw benches, planers, sanders, routers, CNC machinery
On-site carpentry — cutting timber, boards, and sheet materials on construction sites
Kitchen and furniture manufacturing — panel-cutting, edge-banding, CNC routing
Shopfitting and interior fit-out — on-site cutting and finishing
Woodturning and craft workshops
School design and technology departments — often overlooked, but the same obligations apply

The duty arises from the work activity, not the business type. A sole-trader carpenter cutting MDF boards in a client's kitchen has the same COSHH obligations as a large joinery manufacturer.

The Workplace Exposure Limits for Wood Dust

There are two separate WELs for wood dust, depending on the type of timber:

Hardwood dust: 3 mg/m³ (8-hour time-weighted average)
Softwood dust: 5 mg/m³ (8-hour time-weighted average)

Where a workplace generates mixed dust — hardwood and softwood in the same space — the hardwood limit of 3 mg/m³ applies to the entire mixture.

These figures come from the EH40 Workplace Exposure Limits document. Because hardwood dust is classified as a carcinogen, the higher standard under COSHH Regulation 7 applies: exposure must be reduced to "as low as is reasonably practicable" — not just below the WEL, but as low as achievable with reasonable effort.

In practice, this means engineering controls (local exhaust ventilation) should be running whenever dust-generating machinery is in use, regardless of whether exposure is likely to be below the WEL on a given day.

Conducting the COSHH Assessment

A wood dust COSHH assessment needs to be task-specific and workplace-specific. A generic "wood dust — wear a mask" entry is not adequate.

Step 1: Map the dust-generating tasks

List every machine and hand tool in use that generates wood dust, and every task where cutting, sanding, routing, or turning takes place. For each:

What type of timber is being worked (hardwood or softwood — or a mixture)?
How long is the task and how frequently is it performed?
What is the ventilation arrangement in the workspace?
What controls are currently in place?

Different tasks generate very different exposures. Drum sanding generates fine airborne dust at a rate that can exceed the WEL within minutes in a poorly-controlled space. A single crosscut with a hand saw produces far less. The assessment needs to reflect these differences.

Step 2: Assess the exposure level

For small workshops, the HSE's COSHH Essentials control guidance sheets for woodworking provide task-by-task exposure estimates and prescribe the appropriate control approach. These sheets are freely available and tell you which LEV type, air velocity, and capture method is appropriate for each machine.

For larger operations, or where there is any doubt about compliance, personal air monitoring using a calibrated sampling pump is the only way to confirm that exposures are within the WEL. Occupational hygienists carry out this monitoring.

Step 3: Apply the control hierarchy

Elimination and substitution. Where hardwood can be replaced by softwood or a sheet product for a given application, that substitution reduces carcinogen exposure. Consider whether MDF products with lower free-formaldehyde content (a separate COSHH concern) are specified, since MDF dust carries its own exposure considerations.

Engineering controls — LEV. Local exhaust ventilation is the primary control for wood dust. Every fixed woodworking machine — saw bench, planer, thicknesser, sander, router table — should have on-machine LEV fitted and running during use. The LEV system captures dust at source, before it becomes airborne in the workspace.

LEV requirements under COSHH include:

The system must be adequate for the task — not just any extraction hood, but a capture system designed to handle the volume and velocity of dust generated by that specific machine
Ducting, fans, and filters must be maintained in efficient working order
COSHH Regulation 9 requires that LEV systems used for wood dust are examined and tested by a competent person at least every 14 months, with a written report issued after each examination — see our full guide to LEV testing for what that involves

Cleaning. Dust must not be allowed to accumulate on surfaces. A build-up of fine wood dust on beams, ledges, and equipment eventually becomes airborne when disturbed. Compressed air blowdown must not be used — HSE specifically advises against it as it disperses settled dust back into the breathing zone. Use H-class (HEPA-rated) industrial vacuum cleaners for all dust removal. M-class vacuums do not provide adequate filtration for the finest wood dust particles.

Administrative controls. Restrict access to high-dust areas during machining; limit individual exposure duration where possible; keep doors and windows configured to maintain ventilation without creating cross-draughts that displace the LEV capture.

RPE. Respiratory protective equipment is required when engineering controls alone cannot achieve adequate control — typically for short-duration tasks without fixed LEV (site carpentry, hand sanding), or as a backup to LEV for tasks with very high dust generation. For wood dust, minimum P2-rated filtering facepiece for intermittent exposure; P3 and powered air-purifying respirators for heavy or prolonged exposure.

RPE must be fit-tested. A flat-fold P3 mask on a worker with a beard provides essentially no protection against fine wood dust.

Step 4: Record and review

The assessment record should document:

Each task assessed and the timber type involved
Estimated or measured exposure level
Controls in place (LEV details, cleaning regime, RPE)
Health surveillance arrangements
Next review date

Review whenever there is a change in materials, processes, or controls — and regularly as a matter of good practice, commonly at least every two years.

Health Surveillance for Wood Dust Exposure

Workers regularly exposed to wood dust — whether hardwood or softwood — require health surveillance under COSHH Regulation 11.

For wood dust, health surveillance typically includes:

Respiratory health surveillance:

Annual questionnaire covering respiratory symptoms (wheeze, persistent cough, chest tightness, breathlessness on exertion)
Periodic lung function testing (spirometry) to detect early-stage occupational asthma
Referral to occupational physician if symptoms are identified

Sinonasal surveillance (hardwood workers):

Because of the link between hardwood dust and nasal cancer, some occupational health programmes include periodic nose and sinus symptom questionnaires for workers with significant long-term hardwood exposure
This is less universally mandated than respiratory surveillance, but the HSE strongly encourages it for regular hardwood workers

Health records must be kept for 40 years after the exposure ends. The long latency period of occupational cancer means that records from today may be needed to support or defend a compensation claim decades from now.

LEV Maintenance and the 14-Month Examination

The 14-month thorough examination of LEV systems is one of the most frequently missed COSHH requirements in woodworking. The requirement comes from COSHH Regulation 9 and applies to any LEV system used for substances hazardous to health — which includes all wood dust extraction.

The examination must be carried out by a "competent person" — in practice, an occupational hygiene contractor or LEV engineer. It is not a visual check; it involves measuring capture velocities, checking duct integrity, testing filter efficiency, and confirming that the system is performing as designed. A written report is produced after each examination and must be kept for five years.

For more on what the LEV examination involves and how to prepare for it, see our LEV testing guide.

Linking Wood Dust to Your Wider COSHH Programme

A wood dust assessment does not stand alone. It connects to:

Your COSHH substance register — list each timber species in regular use with the applicable WEL and the relevant assessment reference
Your COSHH control measures programme — the hierarchy of control applied to wood dust is the same framework that governs all your substance controls
Your COSHH training — workers must understand the hazard, why the controls are in place, and how to use LEV correctly. Extraction that gets bypassed because it slows the cut is extraction that does not protect anyone
Your workplace exposure limits reference — wood dust has specific WELs that must be incorporated into assessments

If your workers also handle construction dust — silica, cement, general construction debris — see our silica dust COSHH assessment guide for the parallel assessment covering that hazard.

Making Wood Dust Compliance Manageable

For a small joinery workshop or a carpentry business with a handful of operatives, managing wood dust COSHH properly comes down to three things: a written task-by-task assessment, a maintained LEV system with its 14-month examination on the calendar, and basic health surveillance through an occupational health provider.

The paperwork burden is real but finite. A competent assessment of a joinery workshop with ten machines and two timber types can be produced in a day. The harder discipline is keeping it current — updating it when you add a new machine, buy a new species of timber, or change a process.

COSHHmate is being built to manage that ongoing work — keeping assessments, LEV records, health surveillance schedules, and substance registers connected and up to date without a filing system that only one person understands. Join the waitlist to hear when it launches.

This guide is for information only and does not constitute legal advice. COSHH obligations for wood dust depend on specific tasks, timber species, duration of exposure, and control measures in your workplace. The definitive sources are the Control of Substances Hazardous to Health Regulations 2002 and HSE woodworking health guidance.

Sources

HSE: Wood dust — health hazards and controls (hse.gov.uk)
COSHH Regulations 2002, Regulation 7 — Adequate control of exposure (legislation.gov.uk)
COSHH Regulations 2002, Regulation 9 — Maintenance, examination and testing of control measures (legislation.gov.uk)
COSHH Regulations 2002, Regulation 11 — Health surveillance (legislation.gov.uk)
Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677) (legislation.gov.uk)