There are nine hazard pictograms: exploding bomb (explosive), flame (flammable), flame over circle (oxidising), corrosion (corrosive), skull and crossbones (acute toxicity), exclamation mark (health hazard), health hazard (serious health hazard), gas cylinder (gas under pressure) and environment. A product can carry more than one. Read the signal word, hazard statements and precautionary statements as well, because the symbol alone does not tell you how to stay safe.
Hazard symbols are the first thing COSHH training teaches you to look for on a product. At Lift College they are module 2 of our COSHH Training, where you learn the nine hazard pictograms, signal words and hazard statements before moving on to safety data sheets and controls. This guide shows what each symbol means, where you are likely to see it, and how to read the rest of the label.
The 9 COSHH hazard symbols and their meanings
The HSE lists nine GB CLP hazard pictograms. They are the same pictograms used in the United Nations Globally Harmonised System (GHS), so you will see them on chemicals across the world. The meanings and examples below are from the European Chemicals Agency's CLP pictogram guide.
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| Pictogram (symbol) | What it warns of | Where you might see it |
|---|---|---|
| Explosive (exploding bomb) | Unstable explosives, mass explosion, blast or projection hazards; may mass explode in a fire | Fireworks, ammunition |
| Flammable (flame) | Flammable gases, aerosols, liquids, vapours and solids that can catch fire easily | Petrol, lamp oil, nail polish remover |
| Oxidising (flame over circle) | May cause or intensify a fire, or cause a fire or explosion, because it is an oxidiser | Bleach, medical oxygen |
| Corrosive (corrosion) | Causes severe skin burns and serious eye damage; may be corrosive to metals | Drain cleaners, acetic acid, hydrochloric acid |
| Acute toxicity (skull and crossbones) | Toxic or fatal if swallowed, in contact with skin or if inhaled | Pesticides, biocides, methanol |
| Health hazard / hazardous to the ozone layer (exclamation mark) | Skin and eye irritation, skin allergy, drowsiness or dizziness, harmful if swallowed, inhaled or on skin; harms the ozone layer | Washing detergents, toilet cleaner, coolant fluid |
| Serious health hazard (health hazard) | Longer term harm: may cause cancer, genetic defects, organ damage or damage to fertility, asthma if inhaled, or be fatal if swallowed and it enters the airways | Turpentine, petrol, lamp oil |
| Gas under pressure (gas cylinder) | Gas under pressure that may explode if heated, or refrigerated gas that can cause cryogenic burns | Gas cylinders and containers |
| Hazardous to the environment (environment) | Toxic or very toxic to aquatic life with long lasting effects | Pesticides, biocides, petrol, turpentine |
What the oxidising symbol means
The oxidising symbol is a flame over a circle. It is easy to confuse with the flammable symbol, which is a flame on its own. An oxidiser may not burn itself, but it can cause a fire or make a fire burn more fiercely, so keep oxidisers away from heat, sparks, open flames and flammable materials.
Typical precautions on an oxidiser label include keeping it away from heat and ignition sources, wearing protective gloves, clothing and eye protection, and rinsing contaminated clothing and skin with plenty of water before removing clothes.
Corrosive or exclamation mark: why cleaning products differ
The HSE explains that the corrosive pictogram is used for skin corrosion and serious eye damage, while the exclamation mark is used for skin and eye irritants. A product that causes serious eye damage (H318) carries the corrosive symbol; one that causes serious eye irritation (H319) carries the exclamation mark. That is why two cleaning products that look alike can carry different symbols.
Since 1 June 2015 every mixture has had to be classified and labelled under CLP, and the GB CLP Regulation keeps that rule. The HSE notes the newer methods led to more cleaning products being labelled as hazardous, which does not mean the product itself became more dangerous.
How to read a hazard label
A symbol tells you what kind of harm to expect. The words around it tell you how bad it is and what to do. Read the whole label in this order.
- Pictograms. One or more red bordered diamonds showing the type of hazard.
- Signal word. Danger for the more severe hazards, Warning for the less severe ones.
- Hazard statements. Phrases describing the hazard, such as causes serious eye damage or toxic if swallowed.
- Precautionary statements. Usually no more than six, telling you how to prevent harm, such as wear eye protection or do not eat, drink or smoke when using this product.
- Supplier details. Who to contact if you are unsure. For full detail, ask for the safety data sheet, which sets out the hazards, safe handling, PPE and first aid in 16 sections.
Hazard symbols and COSHH
The symbols come from chemical labelling law (GB CLP), not from COSHH itself, which is why people call them COSHH symbols. The link is simple: the HSE says that if the packaging has any of the hazard symbols, the product is classed as a hazardous substance under COSHH. Your employer must then assess the risk and put controls in place.
COSHH also covers hazards that never carry a label, such as dusts, fumes, vapours, mists and biological agents like the germs that cause leptospirosis or legionnaires' disease. It does not cover lead, asbestos or radioactive substances, which have their own regulations. So a missing symbol does not always mean something is safe.
Under regulation 12 of the COSHH Regulations 2002, employers must give anyone who may be exposed suitable and sufficient information, instruction and training, including the risks and the precautions to take. Knowing the hazard symbols is part of that.
Learn the hazard symbols online
COSHH Training from Lift College is 1.5 hours of learning in 5 short modules: what COSHH is, hazards and how they harm (the nine pictograms and routes of exposure), labels and safety data sheets, COSHH assessments and controls, and PPE, storage and spills. There is a knowledge check after each module and a final test, and your CPD certificate issued by Lift College is ready the same day you pass, with a free refresher every 12 months.
New to COSHH? Start with what COSHH is and who needs training, compare providers in our guide to COSHH training online, or see every course on the health and safety courses page.
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Frequently asked questions
What are the 9 COSHH hazard symbols?
What does the oxidising symbol mean?
What does the corrosive symbol mean?
What is the difference between Danger and Warning on a label?
Are COSHH symbols the same as GHS symbols?
Where can I learn the COSHH symbols online?
Sources checked
- HSE, Hazard pictograms (symbols) (checked 27 October 2026)
- HSE, Hazard statements, precautionary statements and signal words (checked 27 October 2026)
- HSE, Cleaning products and GB CLP (checked 27 October 2026)
- HSE, What is a substance hazardous to health? (checked 27 October 2026)
- European Chemicals Agency, CLP pictograms (checked 27 October 2026)