GHS Pictograms
Authority: UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS); OSHA Hazard Communication Standard, 29 CFR 1910.1200
The UN Globally Harmonized System defines 9 pictograms -- red-bordered diamonds with a black symbol on white -- used on chemical labels worldwide: exploding bomb, flame, flame over circle, gas cylinder, corrosion, skull and crossbones, exclamation mark, health hazard, and environment, each flagging a distinct hazard category.
| Pictogram | Symbol | Hazard Category |
|---|---|---|
| Exploding Bomb | Black bomb with radiating fragments | Explosives, self-reactive substances, organic peroxides |
| Flame | Black flame | Flammable gases, aerosols, liquids, and solids; pyrophorics; self-heating substances; substances emitting flammable gas |
| Flame Over Circle | Black flame above a black circle | Oxidizing gases, liquids, and solids |
| Gas Cylinder | Black gas cylinder | Gases under pressure -- compressed, liquefied, dissolved, or refrigerated |
| Corrosion | Liquid pouring from a test tube onto a hand and a surface | Skin corrosion/burns, serious eye damage, corrosive to metals |
| Skull and Crossbones | Black skull and crossbones | Acute toxicity -- can be fatal or toxic in short-term exposure |
| Exclamation Mark | Black exclamation point | Irritant (skin/eye), skin sensitizer, acute toxicity (harmful), narcotic effects, respiratory tract irritant |
| Health Hazard | Black silhouette with a starburst pattern over the chest | Carcinogen, respiratory sensitizer, reproductive toxicity, target organ toxicity, mutagenicity, aspiration hazard |
| Environment | Dead tree and dead fish beside a body of water | Hazardous to the aquatic environment (acute or chronic aquatic toxicity) |
One System Replacing Many
Before the Globally Harmonized System, individual countries and even individual industries classified and labeled the same chemical differently: a solvent might be marked with one hazard symbol on a shipment leaving a factory and a completely different one by the time it reached a warehouse or store shelf in another country. That inconsistency created real safety gaps for workers and emergency responders who had to interpret unfamiliar labeling systems, plus added cost for manufacturers who had to produce different labels and safety data sheets for each market.
The United Nations developed GHS as a single, voluntary framework that countries could adopt into their own regulations, standardizing both the criteria for classifying a chemical's hazards and the pictograms, signal words, and hazard statements used to communicate them. In the United States, OSHA's Hazard Communication Standard is aligned with GHS, which is why the same nine pictograms now appear on chemical labels and safety data sheets across most industrialized countries.
Reading the Diamond
Every GHS pictogram follows the same visual format: a black hazard symbol centered on a white background, framed by a red border shaped as a square tilted onto one point. That consistency is deliberate -- like NFPA 704's hazard diamond, the format is meant to be recognizable at a glance, even to someone who cannot read the accompanying text or does not speak the label's language.
A single product can carry more than one pictogram at once. A can of aerosol spray paint, for example, may show both the flame pictogram, because its propellant is flammable, and the health hazard or exclamation mark pictogram, if inhaling its fumes poses a respiratory risk -- each pictogram communicates one hazard category independently of the others.