A plain-English guide to the Control of Substances Hazardous to Health Regulations 2002 — what they cover, who they apply to, and what compliance looks like.

COSHH stands for Control of Substances Hazardous to Health. The COSHH Regulations 2002 set out duties in Great Britain to protect people from hazardous-substance exposure at work. Northern Ireland has its own COSHH Regulations 2003.

COSHH can apply to substances bought, stored or produced at work, including wood dust, salon chemicals, cleaning products, welding fume and biological agents. Identify the actual health risks and check whether a specific regime such as asbestos or lead regulation applies.

When the regulations came in

The first COSHH regulations were made in 1988. The current Great Britain regulations came into force on 21 November 2002 as SI 2002/2677 and have since been amended. Use the current legislation; an EH40 exposure-limit update is not a replacement set of COSHH regulations.

COSHH sits under the Health and Safety at Work etc. Act 1974 in Great Britain. HSE or the relevant local authority enforces it according to the premises and activity. HSE’s L5 Approved Code of Practice remains in its sixth edition, published in 2013.

What COSHH covers

Visual diagram showing the categories of substances covered by COSHH.

The regulations apply to “substances hazardous to health”. In practice that means:

  • Chemicals and products containing chemicals — cleaning agents, paints, adhesives, solvents, agricultural chemicals, fuel
  • Fumes, including welding fume, soldering fume and exhaust emissions
  • Dusts — wood dust, silica dust from cutting or grinding stone and concrete, flour, grain, cement
  • Vapours and mists from sprays, metalworking fluids and similar processes
  • Gases, including asphyxiating gases like CO₂ and nitrogen
  • Biological agents — bacteria, viruses, fungi and other microorganisms that cause disease

A substance may harm health without a warning label. Frequent or prolonged wet work, especially with soaps or cleaners, can cause dermatitis. Assess the actual exposure rather than treating a handwashing count as a universal legal threshold.

For the detailed scope, including the edge cases — nanomaterials, asphyxiating gases, and the awkward definition of “substance hazardous to health” in law — see our guide to what substances are covered by COSHH.

What COSHH does not cover

Specific regimes cover the following hazards; the detailed exclusions must be checked:

  • Asbestos risks are addressed by the Control of Asbestos Regulations 2012
  • Lead risks are addressed by the Control of Lead at Work Regulations 2002, including medical surveillance in specified circumstances
  • Ionising radiation risks are addressed by the Ionising Radiations Regulations 2017; a separate chemical hazard may still fall under COSHH

There’s also overlap with the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR). DSEAR covers fire and explosion risks; COSHH covers health risks. Many flammable solvents trigger both, with the two regulations addressing different aspects of the same substance.

Who has duties under COSHH

Employers must assess risks and meet the applicable prevention, control and supporting duties. COSHH also applies to self-employed people, but Regulation 3(2) excludes them from the monitoring and health-surveillance duties in Regulations 10 and 11 for themselves. This does not remove duties towards employees.

Employees also have specific duties. They must cooperate with their employer, use control measures and PPE as instructed, report defects in equipment or controls, and attend health surveillance appointments where required. These duties come both from COSHH itself and from Section 7 of the Health and Safety at Work Act.

For the full split between employer and employee duties — including what training must cover under Regulation 12 — see COSHH responsibilities for employers and employees.

What a COSHH risk assessment looks like

Regulation 6 requires a suitable and sufficient assessment before relevant work begins. Employers with five or more employees must record significant findings and the steps taken to comply; the assessment duty applies below that threshold too.

Assess the substances, routes and extent of exposure, people at risk and effective controls. Supplier SDSs are useful inputs, but process-generated dust or fume may have no SDS. Review regularly and promptly when the statutory review triggers arise.

Two pages on the site go deeper into this. How to carry out a COSHH risk assessment walks through the process step by step with worked examples. The COSHH risk assessment template is the document you fill in afterwards, with each field explained.

The eight steps of COSHH compliance

The following eight practical headings organise the main operational duties:

  1. Assess the risks (Reg 6)
  2. Decide what precautions are needed (Reg 7)
  3. Prevent or adequately control exposure (Reg 7)
  4. Ensure controls are used and maintained (Regs 8 and 9)
  5. Monitor exposure where required (Reg 10)
  6. Carry out health surveillance where required (Reg 11)
  7. Plan for accidents, incidents and emergencies (Reg 13)
  8. Inform, instruct and train employees (Reg 12)

This is a practical framework, not a legally prescribed step count or an exhaustive list for every activity. The separate compliance guide explains the principal duties and how they fit together.

The hazard symbols you’ll see

Grid of the nine CLP hazard pictograms used on UK chemical labels.

CLP uses nine pictograms covering specified physical, health and environmental hazards. GB CLP applies in Great Britain and EU CLP in Northern Ireland. Not every hazardous workplace exposure has a supplier label, and a physical or environmental pictogram alone does not establish COSHH scope.

Strictly speaking these are “CLP hazard pictograms”, not “COSHH symbols” — but the colloquial term has stuck and you’ll see them referred to as COSHH symbols everywhere. They replaced the older orange-square CHIP symbols in two stages, with substances changing over from 1 December 2010 and mixtures from 1 June 2015. Existing stock could legally be sold through to 1 June 2017. You’ll still occasionally find older containers carrying the orange symbols in workplaces that haven’t refreshed their inventory.

For each pictogram in detail — what it means, example substances, and how to use them in your assessment — see COSHH symbols and their meanings.

The hierarchy of control

When the COSHH risk assessment identifies an exposure risk, the regulations set out the order in which controls must be considered. Substitution comes first under Regulation 7(2): wherever reasonably practicable, the hazardous substance must be replaced with something less hazardous, or the process changed to remove the need for it. Where substitution isn’t possible, Regulation 7(3) sets out a hierarchy of further controls: engineering controls first, then organisational controls and control at source, then PPE only as a last resort.

This is the COSHH-specific version of the general hierarchy of control. It differs in some details from the generic “elimination, substitution, engineering, administrative, PPE” hierarchy that most general health and safety training uses, although the underlying logic is the same. The COSHH hierarchy of control explains each level with examples.

Why COSHH matters

HSE estimates 1.9 million workers had work-related ill health in Great Britain in 2024/25, across all causes. About 11,000 annual deaths are estimated to result from past occupational lung exposure. The 22,000 new breathing/lung problems figure is an annual average across 2022/23–2024/25; 18,000 people who worked in the previous year had work-related skin problems on average across the same period. These are different measures and must not be added together.

The financial picture is similar in scale. Workplace injuries and new cases of work-related ill health cost Great Britain an estimated £22.9 billion in 2023/24, with ill health accounting for roughly 72% of the total.

Preventing exposure and keeping controls effective can prevent occupational disease. Effective management combines suitable assessment, equipment, maintenance, working methods and instruction across the tasks where exposure can occur.

Penalties

Breaches can lead to prosecution. Unlimited fines are available in England and Wales and on indictment; Scottish summary sentencing rules differ. Company officers can be liable under Section 37 where an offence occurred with their consent or connivance, or was attributable to their neglect. Sentences depend on the circumstances.

Improvement notices require corrective action within a period. Prohibition notices stop activities involving serious personal-injury risk and can take effect immediately or after a specified period. HSE may recover relevant regulatory costs through Fee for Intervention where its conditions apply.

Training and what to do next

Regulation 12 requires suitable information, instruction and training for employees liable to be exposed. Cover substances, assessment findings, controls, emergencies, monitoring results and collective surveillance findings, while protecting personal medical confidentiality. Adapt instruction when risks or circumstances change.

Getting people genuinely competent — not just compliant on paper — is the most reliable way to keep COSHH workable in practice. That’s where structured COSHH Training earns its place.

Frequently asked questions

What does COSHH stand for?

COSHH means Control of Substances Hazardous to Health. The 2002 regulations apply in Great Britain; Northern Ireland has separate 2003 regulations.

When did COSHH come into force?

The current Great Britain regulations came into force on 21 November 2002, following earlier versions in 1988, 1994 and 1999. They have since been amended; check the current legislation and relevant HSE guidance.

What does COSHH cover?

COSHH covers chemicals, products containing chemicals, fumes, dusts, vapours, mists, gases, biological agents and asphyxiating gases — any substance that could harm health under the conditions in which it’s used. It applies whether the substance is brought into the workplace or created by a process (such as welding fume or sanding dust).

What doesn’t COSHH cover?

Specific regimes govern asbestos, lead and ionising radiation risks. COSHH excludes hazards solely due to radioactivity, flammability, explosion, temperature or pressure; another health hazard from the same substance may remain within scope.

Who is responsible for COSHH?

Employers have the main duties and employees must properly use controls and cooperate with required arrangements. Self-employed people have duties with specified exceptions. Section 37 liability for company officers requires consent, connivance or neglect in relation to a company offence.

Do I need COSHH training?

Employees liable to be exposed need suitable and sufficient information, instruction and training for the substances, work, controls and emergencies. Refresh or adapt it when needed; the law does not specify one universal course or renewal period.

What’s the penalty for breaching COSHH?

Breaches can result in prosecution and notices. Unlimited fines are available in England and Wales; Scottish summary sentencing rules differ. Company officers may be prosecuted where the Section 37 conditions apply, and relevant HSE cost recovery may also arise.

Make sure your team is trained to recognise and work safely with substances hazardous to health.

Explore the COSHH Training course →

Sources & references

Mark McShane
Mark McShane
Health & Safety Training Specialist, Online CPD Academy

Mark writes about workplace health & safety, COSHH and accredited online training for COSHH Training, part of Online CPD Academy.