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📋 Toolbox Talk  ·  Health & Safety

COSHH:
Hazardous Substances at Work

Control of Substances Hazardous to Health — identifying hazards, Safety Data Sheets, WELs, PPE and what to do if you're exposed.

✅ Verified July 2026📚 HSE · COSHH Regs 2002🇬🇧 Applies across the UKukworkrights.co.uk
What is COSHH

What substances does COSHH cover?

  • Chemicals — cleaning products, solvents, paints, adhesives
  • Dusts — wood dust, flour dust, silica, coal dust
  • Fumes — welding fumes, paint spray, exhaust emissions
  • Biological agents — bacteria, viruses, fungi (e.g. in healthcare or laboratories)
  • Nanomaterials — increasingly regulated
  • Substances do not have to be obviously dangerous — flour, wood and silica are all COSHH hazards
  • Employers must carry out a COSHH assessment for any hazardous substance used at work

💡 Safety Data Sheets (SDS)

Every hazardous substance must have an SDS — available from the supplier. It tells you the hazards, how to handle it safely, what PPE to use and what to do in an emergency. You have the right to see it.
Control hierarchy

COSHH control measures — in order

1
Eliminate

Remove the hazardous substance entirely. Use a non-hazardous alternative if one exists.

2
Substitute

Replace with a less hazardous substance or form (e.g. water-based instead of solvent-based paint).

3
Enclose

Contain the process so the substance cannot escape into the working environment.

4
Control — local exhaust ventilation (LEV)

Extract fumes or dust at source before they enter the breathing zone.

5
PPE — last resort

Respiratory protection, gloves, eye protection. Only after all other controls have been applied. Must be the right type for the substance.

Key facts

COSHH — the numbers

13,000
Deaths per year estimated from occupational lung disease in Great Britain (HSE)
500+
Workplace exposure limits (WELs) published by HSE — EH40
2002
Year COSHH Regulations were last consolidated — still current law
8hrs
Standard time period over which WELs are measured (TWA)
Silica
One of the most dangerous workplace dusts — kills construction workers every week
SDS
Safety Data Sheet — 16 sections, must be provided by suppliers, available on request
Common questions

Frequently asked questions

Does COSHH apply to cleaning products?
Yes. Many everyday cleaning products contain hazardous substances — bleach, disinfectants, descalers. A COSHH assessment is required, and workers must be trained in safe use and storage.
What is a Workplace Exposure Limit (WEL)?
A WEL is the maximum concentration of an airborne substance that a worker should be exposed to, averaged over a reference period (usually 8 hours). WELs are published in HSE document EH40. Employers must not exceed them and must aim below them.
What should I do if I'm accidentally exposed?
Follow the emergency procedures in the SDS immediately — this may involve flushing with water, fresh air, or emergency medical attention. Report the incident in the accident book. Seek medical advice even if you feel fine — some effects are delayed.
Can I refuse to work with a hazardous substance?
Yes — if you believe the risk is serious and imminent and adequate controls are not in place. Report it to your supervisor and, if necessary, to HSE. You cannot be dismissed for raising genuine safety concerns.
Free H&S guidance

COSHH
free guidance

Get plain-English guidance on your rights and your employer's legal duties.

HSE Infoline
0300 003 1747
hse.gov.uk
ACAS
0300 123 1100
acas.org.uk
Citizens Advice
0800 144 8848
citizensadvice.org.uk
UK Work Rights
COSHH
ukworkrights.co.uk/toolbox-coshh.html

General guidance only — not legal advice · Verified July 2026 · © UK Work Rights Ltd · Company No. 17228507