COSHH Symbols and GHS Hazard Labels Explained

The Labelling System You Need to Understand

Every hazardous chemical product sold in the UK carries a label with standardised hazard information. This labelling follows the Globally Harmonised System (GHS), implemented in the UK through the CLP Regulation (Classification, Labelling and Packaging of Substances and Mixtures). The system uses red-bordered diamond pictograms, signal words, and coded hazard statements to communicate risk.

If you are writing COSHH assessments, you need to understand what these symbols mean — they feed directly into the hazard identification section of every assessment. Our step-by-step COSHH assessment guide covers how to use this information in practice.

The 9 GHS Pictograms

There are nine standardised pictograms in the GHS system. Each is a black symbol on a white background inside a red diamond border. Here is what each one means and what it signals for your COSHH assessment.

1. Exploding Bomb

Means: Explosive. The substance can explode under certain conditions (heat, shock, friction).

Found on: Certain peroxides, explosive compounds, self-reactive chemicals.

COSHH implication: Requires strict storage controls (temperature, separation from ignition sources), specific handling procedures, and potentially blast-resistant storage. Uncommon in most SME settings, but some organic peroxides used in manufacturing and construction carry this classification.

2. Flame

Means: Flammable. The substance catches fire easily — as a liquid, gas, aerosol, or solid.

Found on: Solvents (acetone, white spirit, IPA), aerosol sprays, certain adhesives, petrol, many paints.

COSHH implication: Store away from heat and ignition sources. No smoking or naked flames in use and storage areas. Consider whether LEV is needed to prevent vapour build-up. Fire extinguisher provision and type must match the flammable substance.

3. Flame Over Circle

Means: Oxidising. The substance can cause or intensify fire by releasing oxygen.

Found on: Hydrogen peroxide (at higher concentrations), sodium hypochlorite (concentrated), potassium permanganate, some pool chemicals.

COSHH implication: Must be stored separately from flammable and combustible materials. Can react violently with organic materials. Storage and handling procedures must account for the fire intensification risk.

4. Gas Cylinder

Means: Gas under pressure. The container holds gas at pressure and could explode if heated.

Found on: Compressed gas cylinders (argon, nitrogen, CO2, acetylene), some aerosol products.

COSHH implication: Secure storage (cylinders chained upright), protection from heat, handling training, and awareness of asphyxiation risk in enclosed spaces (even "harmless" gases like nitrogen can displace oxygen).

5. Corrosion

Means: Corrosive. Causes severe skin burns, serious eye damage, or corrodes metals.

Found on: Strong acids (hydrochloric acid, sulphuric acid), strong alkalis (caustic soda, oven cleaner), bleach (concentrated), some drain cleaners and degreasers.

COSHH implication: Chemical-resistant gloves (material specified in SDS Section 8), eye protection (splash-proof goggles, not just safety glasses), face shields for decanting or splash risk, emergency eyewash available. One of the most common pictograms across all industries — nearly every cleaning operation encounters corrosive products.

6. Skull and Crossbones

Means: Acute toxicity (severe). The substance is toxic or fatal if swallowed, inhaled, or absorbed through the skin in small amounts.

Found on: Methanol, certain pesticides, some industrial solvents, ethylene glycol (antifreeze).

COSHH implication: Strict access controls, locked storage, specific PPE requirements, detailed emergency procedures, and potentially exposure monitoring. If this pictogram appears on a product you use regularly, your COSHH assessment and controls need to be thorough.

7. Exclamation Mark

Means: Harmful or irritant. Causes less severe health effects than the skull and crossbones: skin irritation, eye irritation, respiratory tract irritation, narcotic effects, or harmful if swallowed.

Found on: Many everyday chemicals — dilute cleaning products, some paints, adhesives, washing-up liquids, and hand sanitisers. This is the most common pictogram in most workplaces.

COSHH implication: PPE requirements (gloves, eye protection where splash is possible), ventilation for vapour-generating products, and awareness that "irritant" does not mean "harmless." Chronic exposure to irritants can cause lasting damage — repeated skin irritation can progress to occupational dermatitis.

8. Health Hazard (Silhouette with Star)

Means: Serious chronic health hazard. The substance causes or is suspected of causing cancer, genetic damage, reproductive harm, respiratory sensitisation (occupational asthma), or organ damage through prolonged or repeated exposure.

Found on: Certain hardwood dusts (carcinogen), isocyanates (respiratory sensitiser), some epoxy resins, benzene, formaldehyde, certain hair colour ingredients.

COSHH implication: This is the pictogram that triggers the most stringent requirements. Respiratory sensitisers require health surveillance under COSHH. Carcinogens require enhanced controls, exposure minimisation, and in some cases 40-year record retention. If you see this pictogram, your assessment needs careful attention to the specific H-phrases to determine exactly which chronic hazard applies.

9. Environment

Means: Hazardous to the aquatic environment. Toxic to aquatic life, potentially with long-lasting effects.

Found on: Many pesticides, some cleaning products, certain solvents, antifreeze.

COSHH implication: Primarily affects disposal and spill response procedures. Must not be washed into drains or watercourses. Spill kits and containment measures should be specified in the assessment.

Signal Words: Danger vs Warning

Every hazardous product carries one of two signal words on its label, or none at all:

Danger — used for the more severe hazard categories. If you see "Danger," the product carries a significant risk and your controls need to reflect that.
Warning — used for less severe (but still real) hazard categories.

A product will never carry both signal words. If multiple hazards apply and they have different signal words, the label uses "Danger" (the more severe takes precedence).

The signal word gives you a quick triage tool: a "Danger" product generally requires more rigorous controls than a "Warning" product with the same type of hazard.

H-Phrases (Hazard Statements)

H-phrases are coded statements that describe the specific nature of the hazard. They appear on the label and in Section 2 of the SDS. Each H-phrase has a number and a standard wording.

Physical hazards (H200-H299)

H220 — Extremely flammable gas
H225 — Highly flammable liquid and vapour
H226 — Flammable liquid and vapour
H228 — Flammable solid
H271 — May cause fire or explosion; strong oxidiser
H280 — Contains gas under pressure; may explode if heated

Health hazards (H300-H399)

H300 — Fatal if swallowed
H301 — Toxic if swallowed
H302 — Harmful if swallowed
H304 — May be fatal if swallowed and enters airways
H310 — Fatal in contact with skin
H311 — Toxic in contact with skin
H312 — Harmful in contact with skin
H314 — Causes severe skin burns and eye damage
H315 — Causes skin irritation
H317 — May cause an allergic skin reaction
H318 — Causes serious eye damage
H319 — Causes serious eye irritation
H330 — Fatal if inhaled
H331 — Toxic if inhaled
H332 — Harmful if inhaled
H334 — May cause allergy or asthma symptoms or breathing difficulties if inhaled
H335 — May cause respiratory irritation
H340 — May cause genetic defects
H341 — Suspected of causing genetic defects
H350 — May cause cancer
H351 — Suspected of causing cancer
H360 — May damage fertility or the unborn child
H361 — Suspected of damaging fertility or the unborn child
H370 — Causes damage to organs
H372 — Causes damage to organs through prolonged or repeated exposure

Environmental hazards (H400-H499)

H400 — Very toxic to aquatic life
H410 — Very toxic to aquatic life with long-lasting effects
H411 — Toxic to aquatic life with long-lasting effects

For your COSHH assessment, the health hazard H-phrases (H300-H399) are the most directly relevant. Pay particular attention to H317 (skin sensitiser), H334 (respiratory sensitiser), H340/H341 (mutagen), H350/H351 (carcinogen), and H360/H361 (reproductive toxin) — these trigger specific requirements for enhanced controls and health surveillance.

If you need plain-English explanations and PPE recommendations for specific H-phrases, our hazard label decoder translates the codes into practical guidance.

P-Phrases (Precautionary Statements)

P-phrases are coded advice on how to handle, store, and dispose of the substance safely. They appear on labels and in the SDS.

P2xx — Prevention (e.g., P280: "Wear protective gloves/protective clothing/eye protection/face protection")
P3xx — Response (e.g., P305+P351+P338: "IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing")
P4xx — Storage (e.g., P403+P235: "Store in a well-ventilated place. Keep cool")
P5xx — Disposal (e.g., P501: "Dispose of contents/container in accordance with local regulations")

P-phrases are useful for the control measures and emergency procedures sections of your assessment. They give you the manufacturer's specific recommendations rather than generic advice.

Old CHIP Symbols vs New GHS

If you have been managing chemicals in the UK for a while, you may remember the old orange-and-black square hazard symbols from the CHIP Regulations (Chemicals (Hazard Information and Packaging for Supply) Regulations). These were replaced by the GHS/CLP system in 2015 for mixtures (2012 for pure substances).

The key differences:

Feature	Old CHIP	Current GHS/CLP
Symbol shape	Orange square, black border	White diamond, red border
Number of symbols	7	9
Hazard descriptions	Risk phrases (R-phrases)	Hazard statements (H-phrases)
Precautions	Safety phrases (S-phrases)	Precautionary statements (P-phrases)
Signal words	None	"Danger" or "Warning"

If you still have products with the old orange CHIP labels in your workplace, they are likely very old stock. The labelling requirements changed over a decade ago. Replace the products or at minimum obtain a current SDS from the supplier — the formulation may have changed, and your COSHH assessment needs to be based on current information.

Using Label Information in Your COSHH Assessment

When you sit down to write or review a COSHH assessment, the label and SDS give you the hazard identification section almost ready-made:

Record every pictogram that appears on the label
Record the signal word (Danger or Warning)
List every H-phrase and write out what each one means in practical terms for your workers
Check the P-phrases for specific handling, storage, and emergency advice
Cross-reference with the SDS — Section 2 should match the label, and Sections 4, 7, 8, and 11 give you the detailed information to build the rest of your assessment

If you are writing a COSHH assessment for the first time, our COSHH assessment guide walks through how each piece of label information feeds into the assessment structure.

Making Sense of Labels Across Your Workplace

Once you understand the GHS system, reading a chemical label takes seconds rather than minutes. The pictograms give you the type of hazard at a glance. The signal word tells you the severity. The H-phrases give you the specifics. The P-phrases tell you what to do about it.

COSHHmate is being built to make this even faster. The guided assessment builder will help you record the right hazard information from each label and SDS, so you can focus on the controls and risk evaluation rather than decoding symbols.

If you want COSHH assessments that are accurate, complete, and based on proper hazard data, join the waitlist to be first to know when COSHHmate launches.