Control of Substances Hazardous to Health Regulations 2002

COSHH explained: LEV testing and certification for safe air at work

If your work creates dust, fume, mist or vapour, COSHH is the law that says you must control it. Where extraction is the control, that local exhaust ventilation has to be tested on a strict schedule to prove it still works.

We are an independent, P601-qualified examiner: we test and certify your LEV, we do not sell or install it, so the report we leave you is impartial and stands up to an HSE inspection.

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14 months
Maximum gap between LEV thorough examination and tests
Reg 9
Maintain, examine and test control measures
5 years
How long every LEV test record is kept
P601
BOHS qualification for the competent examiner
The regulation

What is COSHH, and why does it exist?

COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. It is enforced by the Health and Safety Executive and supported by the Approved Code of Practice L5, the LEV guide HSG258, and the workplace exposure limits in EH40.

COSHH treats harm from dust, fume, mist, vapour, gas and biological agents as something to be controlled, not accepted as part of the job. Breathing in these contaminants is one of the biggest causes of long-term occupational ill health: the HSE estimates that around 12,000 deaths a year in Britain are linked to past exposures at work, from cancers to asthma and lung disease.

The duty is not advisory. It falls on the employer to prevent exposure or, where that is not reasonably practicable, to control it and prove the controls keep working. Local exhaust ventilation is the most common engineering control, which is why LEV testing sits at the heart of COSHH compliance.

At a glance

  • Full name: Control of Substances Hazardous to Health Regulations 2002
  • First introduced 1988, current version 2002
  • Enforced by the HSE; ACOP L5, LEV guide HSG258
  • Covers dust, fume, mist, vapour, gas and biological agents
  • Excludes asbestos, lead and radioactive substances (own regulations)
  • LEV testing duty sits in Regulation 9
Scope

What substances does COSHH cover?

COSHH applies to almost any substance that can harm health through the way it is used at work, whether it arrives in a labelled container or is created by the process itself. The contaminants you generate are as much in scope as the ones you buy in.

Dust

Wood dust, flour, silica and metal dust from cutting, sanding and grinding.

Fume

Welding fume, solder fume and fumes from hot processes and furnaces.

Mist & vapour

Paint and oil mist from spraying and machining, and solvent vapours.

Chemicals & gases

Cleaning chemicals, adhesives, process gases and biological agents.

Covered by COSHH

  • Substances labelled hazardous, and those a process generates
  • Dust at high concentration, even nuisance dust like flour or wood
  • Biological agents such as bacteria and other micro-organisms
  • Fume, mist and vapour that workers can breathe in

Has its own separate law

  • Asbestos, under the Control of Asbestos Regulations
  • Lead, under the Control of Lead at Work Regulations
  • Radioactive substances, under the Ionising Radiations Regulations
  • Substances hazardous only as flammable or explosive sit elsewhere
Good control practice

The eight principles COSHH is built on

Schedule 2A of COSHH sets out eight principles of good control practice. Skip them and the HSE takes it that you are not properly protecting your people, whether or not a substance has a set exposure limit.

1

Design out emissions

Design the process so it releases and spreads as little contaminant as possible.

2

Cover every route

Account for inhalation, skin absorption and ingestion when choosing controls.

3

Control in proportion

Match the strength of the control to the size of the health risk.

4

Choose effective controls

Pick measures that reliably contain the substance at source, such as LEV.

5

PPE as a last resort

Use protective equipment only where other controls cannot achieve adequate control.

6

Check and review

Maintain, examine and test the controls, and review them over time.

7

Inform and train

Tell people the risks and train them to use the controls properly.

8

Do not add new risk

Make sure a control does not create a bigger hazard than the one it solves.

Where this lands for most businesses: once you decide extraction is the right control, principle six is the one with teeth. It is the legal duty to keep the LEV working and to prove it, through the thorough examination and test that Regulation 9 requires.
LEV testing & certification

How often must LEV be tested?

Regulation 9 requires a Thorough Examination and Test, the TExT, of every LEV system by a competent person at least every 14 months. That is a maximum, not a target. The interval shortens where the process is higher risk or the system degrades faster.

ProcessMaximum interval
Most LEVAt least every 14 months (not 12)
Schedule 4Specified high-risk processes: every 1 or 6 months
Wood & weldingOften 6 months on a risk basis, given the known cancer and lung risk

A TExT is far more than a glance at the fan. It measures airflow and capture at the hood against the system’s design or commissioning data, checks ducting, filters and hoods, and confirms the LEV still controls exposure as intended. Records are kept for five years.

Why 14 months, not 12?

The regulation says 14, and the extra two months let a fixed test date drift forward each year without ever breaching the limit, so the same week never clashes with a shutdown. Many businesses still test annually for simplicity, which is fine: 14 months is the ceiling, not the recommendation.

What sets the real interval is the risk: a Schedule 4 process can need testing every one or six months.

Is there an “LEV certificate”?

The proof of compliance is the TExT report required by Regulation 9, kept in the LEV logbook for five years. People call it an “LEV certificate”, and a clean report does certify the system as compliant, so the term is fair here, unlike with some other regimes.

We issue the full report digitally, with the airflow readings and any actions clearly set out.

Who is responsible

Responsibilities and the competent person

COSHH puts the legal duty firmly on the employer. You can outsource the test, but you cannot outsource the responsibility, and the examiner you choose has to be genuinely qualified to do it.

Employers & duty holders

  • Carry out a COSHH assessment of every hazardous substance
  • Prevent exposure, or control it with measures like LEV
  • Keep controls maintained and arrange the LEV test
  • Hold a logbook and keep test records for five years
  • Inform, train and health-surveil where needed
  • The Reg 9 duty stays with you even when the test is outsourced

The competent examiner

  • Holds the BOHS P601 qualification for LEV examination and testing
  • Works to HSG258, the HSE guide to LEV
  • Is independent and impartial, with no stake in the result
  • Measures airflow and capture against the design data
  • Issues a clear report with readings and any actions to take

Operators & employees

  • Use the LEV as trained, with the hood in the right place
  • Carry out daily and weekly checks on airflow and condition
  • Report damage, blockages or weak extraction at once
  • Wear the RPE provided where it is required
  • Do not bypass or switch off the extraction to work faster
Common confusion

COSHH vs PUWER: which one covers your extraction?

An extraction unit sits in both worlds at once, which is where the confusion starts. The clean way to separate them is by what each law is actually protecting.

COSHH

Control of the substance

The law about protecting health from hazardous substances. It is why the LEV exists and why its capture performance is tested.

Protects
People’s health from dust, fume, mist and vapour
Test
LEV thorough examination and test, at least every 14 months
Output
TExT report kept in the logbook for five years
PUWER

Safety of the equipment

The law about the extraction unit as a piece of work equipment: that it is suitable, maintained and mechanically safe to run.

Protects
People from the equipment itself, moving parts and electrics
Test
Risk-based inspection under Regulation 6, no fixed interval
Output
Inspection record, not a statutory certificate

For a fume or dust extraction system, both apply at once. COSHH asks whether it still captures the contaminant and protects health, which is the LEV test. PUWER asks whether the unit itself is safe and maintained work equipment. The COSHH LEV test is the one with the fixed legal clock, so it is usually the deadline that drives the booking.

Why it matters

What happens if you do not comply?

COSHH is enforced under criminal law. When an HSE inspector visits, they typically ask for the LEV logbook before they look at the system, because the records are the evidence that exposure is being controlled. A missing or out-of-date TExT is a clear breach, even if the extraction is switched on.

Inspectors can issue improvement and prohibition notices, and serious or repeated failings lead to prosecution and fines tied to the harm risked. The deeper cost is human: occupational lung disease and cancers develop quietly over years, long after the exposure that caused them.

  • Improvement notices requiring the controls to be put right
  • Prohibition notices that stop a process until exposure is controlled
  • Prosecution of the company and, in serious cases, of individuals
  • Fines set against the harm risked and the size of the business
  • Occupational disease, the asthma, lung damage and cancers COSHH exists to prevent

Five habits that keep you compliant

  1. Keep a live LEV logbook with the commissioning data and every TExT report
  2. Book the thorough examination and test before the 14-month date, sooner if risk demands
  3. Run daily and weekly checks on airflow, hoods and filters
  4. Replace loaded filters on condition, not just at the annual test
  5. Use an independent, P601-qualified examiner and keep records for five years
FAQs

COSHH and LEV questions, answered

What does COSHH stand for?
COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. It is the UK law that requires employers to prevent or control workers’ exposure to hazardous substances such as dust, fume, mist, vapour, gas and biological agents.
How often does LEV need testing under COSHH?
Regulation 9 requires a thorough examination and test at least every 14 months for most LEV. Higher-risk Schedule 4 processes need testing every 1 or 6 months, and many wood and welding systems are tested 6-monthly on a risk basis.
What is an LEV thorough examination and test (TExT)?
It is a detailed check that the local exhaust ventilation still captures contaminants as designed. The competent person measures airflow and capture against the system’s design data, inspects hoods, ducting and filters, and records the result.
How long must LEV test records be kept?
Every LEV thorough examination and test report must be kept for at least five years, in the LEV logbook. An HSE inspector will usually ask to see the logbook before inspecting the system itself.
Who is qualified to test LEV?
A competent person, which for LEV means an examiner holding the BOHS P601 qualification and working to HSG258. They should be independent of whoever supplied or installed the system, so there is no commercial reason to pass a failing one.
Who is responsible for COSHH compliance?
The employer. You can outsource the LEV test to a competent person, but the Regulation 9 duty to keep controls working stays with you. If your people are exposed, you are responsible for controlling it and proving the controls work.
Does COSHH apply to dust like wood or flour?
Yes. Wood dust and flour dust are hazardous to health and are covered by COSHH. Wood dust is linked to nasal cancer, which is why wood and welding extraction is often tested every 6 months rather than annually.
Is COSHH the same as a PUWER inspection?
No. COSHH tests whether the LEV still controls exposure to the substance, through the 14-monthly TExT. PUWER covers the unit as safe work equipment. An extraction system needs both, but the COSHH LEV test is the one with the fixed legal deadline.

Book your LEV test

We carry out independent, P601-qualified LEV testing and certification across the UK, with your TExT report and airflow readings on file the moment we leave site. No onboarding delay, no thirty-day wait, no red tape.

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