Guidance · Reviewed August 2026
What COSHH stands for, what the Regulations require, the nine hazard symbols and what they mean, and the substances COSHH does not cover.
The short answer
COSHH stands for the Control of Substances Hazardous to Health Regulations 2002. They require employers to prevent or adequately control exposure to substances that can harm health at work — chemicals, dusts, fumes, vapours, mists, gases and biological agents. Asbestos, lead and radioactive substances are not covered; they have their own regulations.
What Does COSHH Stand For?
The Control of Substances Hazardous to Health Regulations 2002. The acronym is used interchangeably for the Regulations themselves, the assessments they require, and the general subject of hazardous substances at work — which is why “COSHH assessment”, “COSHH training” and “COSHH symbols” all describe different things.
COSHH is not new. The first version arrived in 1988; the current Regulations date from 2002 and are enforced by the Health and Safety Executive and local authorities. They apply to virtually every workplace, not only industrial ones.
What COSHH Covers — and What It Doesn’t
The scope is wider than most employers assume, and the exclusions catch people out.
Covered by COSHH
Chemicals and products containing them. Cleaning products. Fumes, including welding fume. Dusts — wood, flour, silica. Vapours, mists and gases. Biological agents. And substances produced by a process rather than bought in: the dust from cutting a paving slab is a COSHH substance even though nobody purchased it.
Not covered by COSHH
Asbestos — Control of Asbestos Regulations 2012.
Lead — Control of Lead at Work Regulations 2002.
Radioactive substances — Ionising Radiations Regulations 2017.
Also excluded are substances hazardous only because they are explosive, flammable, at high pressure or at extreme temperature — those are physical hazards, governed elsewhere.
A category error worth avoiding
Listing asbestos on a COSHH assessment is a common and consequential mistake. It gives false confidence that the asbestos risk is managed when it sits under an entirely separate regime with its own duties, licensing and training requirements. See asbestos guidance.
COSHH Symbols: The Nine Hazard Pictograms
Everyone calls them COSHH symbols. Strictly they aren’t — the red-bordered diamonds are hazard pictograms defined under the GB CLP Regulation, the UK’s version of the international Classification, Labelling and Packaging rules. COSHH is what tells you to do something about the hazards those symbols announce.
The shorthand is universal, so we’ll use it. There are nine, coded GHS01 to GHS09, and they are identical worldwide because they derive from the UN’s globally harmonised system.
| Code | Pictogram | What it warns of |
|---|---|---|
| GHS01 | Exploding bomb | Explosive — may detonate on heat, shock, friction or sparks. |
| GHS02 | Flame | Flammable — ignites easily, or gives off flammable gas in contact with water. |
| GHS03 | Flame over circle | Oxidising — may cause or intensify fire in other materials. |
| GHS04 | Gas cylinder | Gas under pressure — may explode if heated, or cause cold burns if liquefied. |
| GHS05 | Corrosion | Corrosive — severe skin burns and eye damage, or corrosive to metals. |
| GHS06 | Skull and crossbones | Acute toxicity — can cause serious harm or death in small amounts. |
| GHS07 | Exclamation mark | Harmful or irritant — skin and eye irritation, drowsiness, dizziness. Common on cleaning products. Less severe than the skull, not harmless. |
| GHS08 | Health hazard | Serious longer-term health effects — carcinogenic, mutagenic, toxic to reproduction, respiratory sensitiser, organ damage. |
| GHS09 | Dead fish and tree | Hazardous to the aquatic environment. |
Two practical points. The orange square symbols are obsolete — the red diamonds replaced them fully in June 2015, and workers who only recognise the old ones need updating. And GHS08 is the one to take most seriously in a COSHH context: it flags the slow, permanent harm that COSHH exists to prevent, and it looks far less alarming than the skull.
The pictogram is only part of the label. Each is accompanied by a signal word — Danger or Warning — plus hazard statements describing the risk and precautionary statements explaining safe handling. All of it also appears in the safety data sheet.
The Eight Principles of Good Control Practice
Schedule 2A of the Regulations sets out eight principles. HSE is explicit that they must all be applied to achieve effective and reliable control, and that they are not ranked — the first is no more important than the last.
- Design and operate processes to minimise emission, release and spread of hazardous substances.
- Take into account all relevant routes of exposure — inhalation, skin and ingestion — when developing control measures.
- Control exposure by measures proportionate to the health risk.
- Choose the most effective and reliable control options that minimise the escape and spread of hazardous substances. Regulation 7 sets out the hierarchy: eliminate the substance; modify the substance, process or workplace; apply controls such as enclosure and extraction; adopt ways of working that minimise exposure; and only then equipment worn by the individual.
- Where adequate control cannot be achieved by other means, provide suitable PPE in combination with other measures.
- Check and review all elements of control measures regularly for continuing effectiveness.
- Inform and train employees on the hazards, the risks and the controls.
- Ensure that introducing controls does not increase overall risk to health and safety.
PPE is principle five, not principle one
Masks and gloves protect only the wearer, only while worn correctly, and they fail silently. Substituting a substance or extracting at source protects everyone in the room without anyone having to remember anything. COSHH requires exposure to be prevented where reasonably practicable, and only adequately controlled where prevention is not.
Which Businesses Need to Comply?
Almost all of them. Fumes and dust in the workplace from industrial processes cause lung disease and asthma. Paints, glues, lubricants and beauty industry products — dyes, bleaches — are harmful to employees and the public alike. Dermatitis arises from working with plants, cement, or in wet environments such as kitchens.
Few businesses hold no hazardous substances at all. The workplaces that get caught out are usually the ones that don’t consider themselves industrial: offices with cleaning stores, salons, kitchens, care homes, workshops.
The harm is frequently slow. Occupational lung disease, dermatitis and asthma develop over years of exposure that felt harmless at the time, and by the point symptoms appear the damage is often permanent.
What Employers Must Actually Do
HSE breaks the duty into six practical steps.
| Step | In practice |
|---|---|
| Find the hazards | Identify every substance present or generated. Safety data sheets from suppliers describe the substance; ask suppliers where you have nothing. |
| Assess the risk | Decide how harm could occur — skin and eye contact, swallowing, breathing in — and to whom. This is the COSHH assessment. |
| Provide controls | Prevent exposure where reasonably practicable; control it adequately where not. Secure storage for some substances, particular care with flammables. |
| Make sure they’re used | A control nobody uses is not a control. Supervision matters as much as provision. |
| Keep them working | Extraction loses performance, filters clog, masks stop fitting. Local exhaust ventilation needs thorough examination and testing at least every 14 months. |
| Inform and train | Regulation 12 requires suitable information, instruction and training for anyone exposed. See COSHH training courses. |
Work out what your workplace needs
A health and safety risk review identifies the gaps, or map training requirements by hazard and job role — free, no account needed. The tools sit on envicourse.com, our course marketplace, and open in a new tab.
Frequently Asked Questions
What does COSHH mean?
Control of Substances Hazardous to Health. It refers to the UK Regulations of 2002 that require employers to prevent or adequately control workers’ exposure to substances that can damage health.
How many COSHH symbols are there?
Nine, coded GHS01 to GHS09: explosive, flammable, oxidising, gas under pressure, corrosive, acute toxicity, harmful or irritant, serious health hazard, and hazardous to the environment. They are properly called hazard pictograms and are defined under the GB CLP Regulation rather than COSHH itself.
Which substances does COSHH not cover?
Asbestos, lead and radioactive substances, each of which has its own dedicated regulations. Also excluded are substances hazardous only because of physical properties — explosive, flammable, under pressure or at extreme temperature — rather than their effect on health.
Is a safety data sheet the same as a COSHH assessment?
No. The data sheet comes from the supplier and describes the substance. A COSHH assessment is yours and describes how you use it — quantity, frequency, method, environment, people. Two workplaces using the identical product need different assessments, and a folder of data sheets is not compliance.
Does COSHH apply to the self-employed?
Yes. If you have employees of any kind, COSHH applies in full. If you have none but take hazardous substances onto other people’s premises, most of COSHH still applies — the main exceptions relate to monitoring and health surveillance.
Are the old orange hazard symbols still valid?
No. The orange square symbols were fully replaced by the red-bordered diamond pictograms in June 2015. If workers recognise the orange squares but hesitate over the red diamonds, that is a training gap worth closing — it is a recurring finding in COSHH assessment audits.
Related Guidance and Training
COSHH risk assessment →
PPE guidance →
RPE guidance →
Dust in the workplace →
All guidance topics →
General guidance only, reviewed against HSE guidance and the COSHH Regulations 2002 in August 2026. This page does not replace the Regulations or your own risk assessment. Envico is an independent training intermediary and is not affiliated with the HSE.