The short answer
A COSHH (Control of Substances Hazardous to Health) assessment is a written document identifying: what hazardous substance is used, how it's used, who is exposed, what the health risks are, and what controls prevent harm. Under the COSHH Regulations 2002, UK employers are legally required to hold a COSHH assessment before allowing employees to work with any hazardous substance.
Who legally needs a COSHH assessment in the UK?
Every employer whose staff work with hazardous substances. In practice, this means basically every UK business with employees. Common examples:
Sole traders and micro-businesses without employeesare technically outside COSHH's employer scope, but they still have to comply with the general Health and Safety at Work Act 1974, which effectively requires the same paperwork. Most insurers also demand it.
What must a COSHH assessment cover?
A "suitable and sufficient" COSHH assessment (the legal wording from the 2002 Regulations) must cover:
- Identification of the hazardous substance(s) present
- The hazards those substances present (GHS classification)
- Who could be exposed and how (routes: skin, eyes, inhalation, ingestion)
- The circumstances of exposure (how it's used, frequency, quantities)
- An estimate of the risk level (Low / Medium / High)
- Existing control measures and their adequacy
- Additional controls required to reduce risk to acceptable levels
- PPE requirements
- Emergency procedures
- Health monitoring where required (e.g. for sensitisers)
- Review date
See our COSHH assessment template guide for the full 14-section breakdown of what a compliant document actually contains.
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The COSHH Regulations 2002, key legal points
The full regulation title is the Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677). It came into force on 21 November 2002 and has been amended several times since. Key points for UK small businesses:
- Regulation 6 requires the risk assessment itself, this is what a COSHH assessment satisfies
- Regulation 7 requires control measures based on the assessment findings
- Regulation 8 requires those controls to be used and maintained
- Regulation 9 requires monitoring where necessary (e.g. air sampling for WEL compliance)
- Regulation 10 requires health surveillance for certain substances (e.g. isocyanates, sensitisers)
- Regulation 11 requires employee information and training
- Assessments must be reviewed at least annually, and immediately if circumstances change
Penalties for non-compliance
The Health and Safety Executive enforces COSHH. If an inspection finds no assessment, or an inadequate one:
- Improvement notice, a formal order to fix the gap within a specified period (usually 21 days)
- Prohibition notice, an order stopping the activity immediately until fixed
- Fixed penalty notice (Fee for Intervention), £174/hour of inspector time, backdated to the point they identified the breach
- Prosecution, magistrates' court fines up to £20,000; Crown Court fines are unlimited. Directors can be personally liable.
Related COSHH resources
References
- Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677), UK legislation.gov.uk
- HSE EH40/2005 Workplace Exposure Limits, Health and Safety Executive
- COSHH basics: What you need to know, HSE
- COSHH essentials, control guidance for employers, HSE
- L5, Approved Code of Practice and guidance, HSE