GHS Pictograms Explained: 9 Symbols and What They Mean

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS), maintained by the United Nations, standardizes chemical hazard communication across borders. At its core are 9 pictograms: red-bordered diamonds rotated 45°, containing a black symbol on a white background. Any compliant label — whether it follows EU CLP, US OSHA HazCom 2012, China GB 30000, or Japan JIS Z 7253 — draws from the same 9 symbols.

This article walks through each pictogram, its code, meaning, associated hazard classes, and the signal word ("Danger" or "Warning") typically paired with it.

The 9 GHS Pictograms at a Glance

GHS01-GHS04: Physical Hazards

GHS01 — Exploding Bomb

Applies to unstable explosives, Divisions 1.1-1.4, self-reactive substances (Types A and B), and organic peroxides (Types A and B). If you see this symbol, the material can detonate, deflagrate, or mass-explode. Example H-statements: H200 (unstable explosive), H201 (mass explosion hazard), H240 (heating may cause explosion).

GHS02 — Flame

The workhorse of chemical labeling. Covers flammable gases (Cat. 1A, 1B, 2), flammable aerosols (Cat. 1, 2), flammable liquids (Cat. 1-3), flammable solids, pyrophoric liquids/solids, self-heating substances, and substances that emit flammable gas in contact with water. Ethanol, acetone, gasoline all carry GHS02.

GHS03 — Flame Over Circle

Oxidizers — substances that release oxygen and support combustion. Includes oxidizing gases (Cat. 1), oxidizing liquids, and oxidizing solids. Common examples: hydrogen peroxide (>50%), sodium chlorate, ammonium nitrate. Do not store near GHS02 materials.

GHS04 — Gas Cylinder

For gases under pressure: compressed gases, liquefied gases, refrigerated liquefied gases, and dissolved gases. Note this pictogram is independent of flammability — a compressed nitrogen cylinder gets only GHS04, whereas propane gets both GHS04 and GHS02.

GHS05-GHS06: Immediate Danger

GHS05 — Corrosion

Two hazard groups share this symbol: skin corrosion / serious eye damage (Category 1) and corrosive to metals (Category 1). Common: strong acids (HCl >25%, H2SO4 >15%), strong bases (NaOH >2%), sodium hypochlorite bleach concentrates. The signal word is "Danger" for skin corrosion Cat. 1A/1B/1C, "Warning" for metal corrosion only.

GHS06 — Skull and Crossbones

Reserved for acute toxicity Categories 1, 2, or 3 via oral, dermal, or inhalation routes. Cat. 4 acute toxicity uses GHS07 instead. Always paired with "Danger". Examples: methanol (H301), hydrogen cyanide, sodium azide.

GHS07-GHS09: Health and Environmental Hazards

GHS07 — Exclamation Mark

The most commonly seen pictogram. Covers acute toxicity Cat. 4, skin/eye irritation Cat. 2, skin sensitization Cat. 1, specific target organ toxicity single exposure Cat. 3 (respiratory irritation, narcotic effects), and hazardous to the ozone layer. Not used together with GHS05, GHS06, or GHS08 for the same hazard endpoint.

GHS08 — Health Hazard

Chronic and serious health effects: respiratory sensitization, germ-cell mutagenicity, carcinogenicity, reproductive toxicity, STOT single or repeated exposure Cat. 1-2, and aspiration hazard. Includes many petroleum distillates (aspiration), formaldehyde (carcinogen), toluene (reproductive).

GHS09 — Environment

Hazardous to the aquatic environment — either Acute Cat. 1 or Chronic Cat. 1-2. Chronic Cat. 3 and 4 require an H-statement but no pictogram. Note: GHS09 is optional in some jurisdictions for workplace-only labels (e.g., US HazCom does not require it for workplace labels but is common on shipped containers).

Pictogram Precedence Rules

When a substance falls into multiple hazard classes, GHS specifies which pictograms may be omitted to avoid clutter:

• If GHS06 (skull) applies, GHS07 (exclamation) is not shown for acute toxicity.
• If GHS05 (corrosion) applies for skin/eye, GHS07 is not shown for skin/eye irritation.
• If GHS08 respiratory sensitization applies, GHS07 skin sensitization is optional (competent authority discretion).

Also, only one signal word is used per label — "Danger" always overrides "Warning" when both apply.

Physical Requirements on the Label

• Shape: square set at a 45° angle (diamond).
• Border: red, sufficiently wide to be clearly visible. Black borders are only allowed for supplier-only supply (some transitional allowances).
• Symbol color: black.
• Background: white.
• Size: minimum 1 cm² per pictogram for the smallest package sizes; typically each pictogram occupies at least 1/15 of the total label area (EU CLP Article 17).

Common Mistakes to Avoid

1. Using a black border instead of red. This is only allowed in narrow transport-only cases; supply labels must have a red border.
2. Displaying the symbol upright (square). The pictogram must be a rotated diamond.
3. Missing GHS09 on shipped containers for chronic aquatic toxicity Cat. 2.
4. Using GHS07 alongside GHS06 for the same acute-toxicity endpoint.
5. Signal word "Warning" when "Danger" is required (e.g., GHS02 flammable liquid Cat. 1 is always Danger).

Related Tools

Generate compliant chemical labels and cross-check phrases with our free tools:

• GHS Label Generator — bilingual GHS label with all 9 pictograms, signal words, H/P phrases.
• GHS Pictogram Pack (SVG download) — free vector files of all 9 symbols.
• CLP H/P Phrase Lookup — search all H and P statements with EU-CLP wording.
• SDS 16-Section Template — starter template for Safety Data Sheets.

Sources: UN GHS Rev. 10 (2023), EU Regulation (EC) No 1272/2008 (CLP), US OSHA 29 CFR 1910.1200. This article is for reference only and does not replace regulatory advice from a qualified safety professional.