GHS/CLP Pictograms: Complete Guide to the 9 Hazard Symbols

What are GHS/CLP pictograms?

GHS/CLP pictograms are globally standardized graphic symbols introduced by the United Nations with the GHS and implemented in the European Union through the CLP Regulation. Each pictogram is diamond-shaped with a red border, white background, and black symbol. The system includes 9 pictograms, each identified by a code from GHS01 to GHS09, covering all classes of physical, health, and environmental hazards.

The aim of the harmonized system is to ensure that workers, transporters, consumers, and emergency services can immediately identify the hazards associated with a chemical substance or mixture, regardless of the country of origin or destination. The pictograms must be present on the CLP label of every chemical product classified as hazardous, together with warnings (signal words), hazard statements (H phrases), and precautionary statements (P phrases).

The 9 GHS/CLP Pictograms in Detail

GHS01 — Exploding Bomb

The GHS01 pictogram depicts an exploding bomb and identifies substances and mixtures that present physical hazards of an explosive nature. It applies to the following CLP hazard classes and categories:

• Unstable explosives and Divisions 1.1, 1.2, 1.3, 1.4 — Explosive substances and mixtures, articles containing explosive substances
• Self-reactive substances and mixtures, Types A and B — Materials that may undergo exothermic decomposition even without the presence of oxygen
• Organic peroxides, Types A and B — Organic compounds containing the bivalent -O-O- structure that may decompose explosively

Substances with this pictogram require extremely strict storage and transport conditions, with separation from sources of heat, sparks, and other incompatible materials.

GHS02 — Flame

The GHS02 pictogram shows a flame and covers a wide range of hazards related to flammability. Associated hazard classes include:

• Flammable gases — Category 1 (gases that at 20 °C and standard pressure can ignite when mixed with air)
• Flammable aerosols — Categories 1 and 2
• Flammable liquids — Categories 1, 2, and 3 (flash point ≤ 60 °C)
• Flammable solids — Categories 1 and 2
• Self-reactive substances and mixtures — Types B, C, D, E, F
• Pyrophoric liquids and solids — Category 1 (spontaneously ignite on contact with air)
• Self-heating substances — Categories 1 and 2
• Substances which, in contact with water, emit flammable gases — Categories 1, 2, and 3
• Organic peroxides — Types B, C, D, E, F

This is the most widely used pictogram in the chemical industry, appearing on a wide range of products, from industrial solvents to household aerosol products.

GHS03 — Flame above a circle

The GHS03 pictogram represents a flame above a circle and identifies oxidizing substances:

• Oxidizing gases — Category 1
• Oxidizing liquids — Categories 1, 2, and 3
• Oxidizing solids — Categories 1, 2, and 3

Oxidizing substances, while not necessarily combustible themselves, can cause or aggravate a fire by supplying oxygen. They must be stored away from combustible and reducing materials. Common examples include hydrogen peroxide, potassium permanganate, and concentrated nitric acid.

GHS04 — Gas Cylinder

The GHS04 pictogram depicts a gas cylinder and applies to gases under pressure:

• Compressed gases — Gases that are entirely gaseous at -50 °C
• Liquefied gases — Gases that are partially liquid at temperatures above -50 °C
• Refrigerated liquefied gases — Gases that are partially liquid due to low temperature
• Dissolved gases — Gases dissolved in a liquid solvent (e.g., acetylene in acetone)

The main hazard is the potential energy contained in the pressurized container: a damaged cylinder can become a projectile. Refrigerated liquefied gases also present a risk of cryogenic burns.

GHS05 — Corrosion

The GHS05 pictogram shows the corrosive action on a surface and on a hand, and identifies:

• Skin corrosion — Categories 1, 1A, 1B, 1C (irreversible destruction of skin tissue)
• Serious eye damage — Category 1 (damage to eye tissue not completely reversible within 21 days)
• Corrosive to metals — Category 1 (corrosion rate on steel or aluminum > 6.25 mm/year at 55 °C)

Strong acids (sulfuric acid, hydrochloric acid), strong bases (sodium hydroxide, potassium hydroxide), and numerous other chemical compounds require this pictogram. Handling requires specific PPE: resistant gloves, goggles or visor, protective clothing.

GHS06 — Skull and Crossbones

The GHS06 pictogram with the skull and crossbones and the symbol for acute toxicity:

• Acute oral toxicity — Categories 1, 2, and 3 (LD50 ≤ 300 mg/kg)
• Acute dermal toxicity — Categories 1, 2, and 3 (LD50 ≤ 1000 mg/kg)
• Acute inhalation toxicity — Categories 1, 2, and 3 (LC50 ≤ 10 mg/l for vapors)

This pictogram indicates that even a small amount of the substance can be lethal or cause serious health damage in a single exposure. Cyanides, methanol, organophosphorus compounds, and numerous pesticides require this pictogram. The associated signal word is always "Danger."

GHS07 — Exclamation mark

The GHS07 pictogram with the exclamation mark identifies less serious health hazards:

• Acute toxicity — Category 4 (oral, dermal, inhalation)
• Skin irritation — Category 2
• Eye irritation — Category 2
• Skin sensitization — Categories 1, 1A, 1B
• Specific target organ toxicity (STOT) — Single exposure, Category 3 (respiratory tract irritation, narcosis)

GHS07 and the "residual" pictogram for human health: applies when the hazards are not severe enough to require GHS05, GHS06, or GHS08. Important precedence rule: if a product must bear the GHS06 pictogram (skull), GHS07 must not be used for acute toxicity.

GHS08 — Health Hazard

The GHS08 pictogram shows a human silhouette with a stain on the chest and identifies serious long-term health hazards:

• Carcinogenicity (C) — Categories 1A, 1B, and 2
• Germ cell mutagenicity (M) — Categories 1A, 1B, and 2
• Reproductive toxicity (R) — Categories 1A, 1B, and 2 (note: the additional category for effects on or via lactation does not require this pictogram)
• Specific target organ toxicity (STOT) — Single exposure Categories 1 and 2, Repeated exposure Categories 1 and 2
• Respiratory sensitization — Categories 1, 1A, 1B
• Aspiration hazard — Category 1 (hydrocarbons with viscosity ≤ 20.5 mm²/s at 40 °C)

This pictogram is particularly critical because it identifies substances with potentially irreversible effects. CMR substances (Carcinogenic, Mutagenic, Reprotoxic) are subject to particularly strict regulations in REACH and CLP.

GHS09 — Environment

The GHS09 pictogram depicts a dead tree and a dead fish and identifies hazards to the aquatic environment:

• Acute toxicity to the aquatic environment — Category 1 (LC50/EC50/ErC50 ≤ 1 mg/l)
• Chronic toxicity to the aquatic environment — Categories 1 and 2

Substances with this pictogram must not be released into the environment. The classification is based on ecotoxicological data (tests on fish, daphnia, and algae) combined with data on degradability and bioaccumulation. Chronic toxicity Categories 3 and 4 do not require the GHS09 pictogram, but only the relevant H statement.

Rules for Assigning and Prioritizing Pictograms

Article 26 of the CLP Regulation establishes the rules of precedence for pictograms to avoid redundancy in labeling. The main rules are:

• GHS06 takes precedence over GHS07 — If a product bears the skull pictogram (acute toxicity categories 1-3), the exclamation mark must not appear for acute toxicity category 4
• GHS05 takes precedence over GHS07 — If a product is corrosive to the skin (GHS05), the exclamation mark must not appear for skin or eye irritation
• GHS08 takes precedence over GHS07 — If a product bears GHS08 for respiratory sensitization, the exclamation mark must not appear for skin sensitization. If it bears GHS08 for any hazard, GHS07 must not appear for STOT SE Category 3
• GHS02 or GHS06 take precedence over GHS04 — For flammable or toxic gases, the gas cylinder pictogram may be omitted if GHS02 or GHS06 are present

These precedence rules ensure that the label communicates the most serious hazards without visually overwhelming the user. kemXpro automatically applies all precedence rules during classification, eliminating the risk of manual errors.

Signal words: "Danger" and "Warning"

Each CLP hazard class and category is associated with a signal word (warning) that indicates the relative level of severity:

• "Danger" — Used for the most serious hazard categories
• "Warning" — Used for less serious hazard categories

Precedence rule: if a product is classified with hazards that require both "Danger" and "Warning," only "Danger" appears on the label. A CLP label can never contain both signal words at the same time.

Size and labeling requirements

The CLP Regulation, Annex I, Section 1.2.1 establishes the minimum dimensions of pictograms according to the capacity of the packaging:

• ≤ 3 liters: each pictogram must be no smaller than 10 x 10 mm, with a minimum label size of 52 x 74 mm (if possible)
• > 3 liters and ≤ 50 liters: pictograms no smaller than 23 x 23 mm, minimum label 74 x 105 mm
• > 50 liters and ≤ 500 liters: pictograms no smaller than 32 x 32 mm, minimum label size 105 x 148 mm
• > 500 liters: pictograms no smaller than 46 x 46 mm, minimum label size 148 x 210 mm

Each pictogram must cover at least one fifteenth (1/15) of the label surface. The background must be white, the border red and sufficiently wide to be clearly visible, and the symbol black. Pictograms must be printed in color; black and white versions are not permitted in CLP labeling.

Integration with H/P phrases in the CLP label

Pictograms are only one of the mandatory elements of the CLP label. The complete label must contain:

• Product identification — Chemical name, EC/CAS number for substances; trade identifiers for mixtures
• Hazard pictograms — With the rules of precedence described above
• Warning — "Danger" or "Caution"
• Hazard statements (H phrases) — Describe the nature and degree of the hazard
• Precautionary statements (P phrases) — Describe prevention, response, storage, and disposal measures
• Supplementary information — EUH phrases, UFI code (for hazardous mixtures), net quantity
• Supplier details — Name, address, and telephone number

kemXpro ensures consistency between classification, pictograms, warnings, H phrases, and P phrases, automatically generating complete labels that comply with the CLP Regulation.

Automatic assignment with kemXpro

kemXpro radically simplifies the process of assigning pictograms and generating CLP labels:

• Automatic classification — The CLP calculation engine classifies substances and mixtures according to the criteria in Annex I of the CLP Regulation, automatically determining all applicable pictograms
• Application of precedence rules — The rules of Art. 26 CLP are applied automatically, eliminating redundant pictograms
• Multilingual label generation — kemXpro generates labels with pictograms, warnings, H phrases, and P phrases in the language of each target market
• Dimensional compliance — The system automatically adapts the size of the pictograms to the label format and packaging volume
• Real-time updates — When the classification changes (e.g., due to an update to Annex VI ATP), kemXpro automatically recalculates the pictograms and flags the labels that need to be updated
• Direct printing — Integration with printing systems for the production of compliant physical labels with high-resolution color pictograms