When we pick up a cleaner, paint, or spray in a store, we usually first notice the pictures or graphic symbols on the packaging, the intended use, or the price. But we rarely stop to look at the small red-and-white pictograms with graphic symbols on the label — and yet they’re there for a very clear reason: to warn us about hazards.
These symbols aren’t just intended for laboratory workers, chemists, or industry professionals. They’re meant for all of us — whether we’re cleaning the bathroom at home, painting a fence, fixing a car, or buying everyday chemicals.
I wrote this article so you can more easily and quickly recognize hazardous chemicals and their properties as represented by the different pictograms. After reading, you’ll better understand the pictograms, they’ll seem less intimidating, and — most importantly — you’ll be able to use them in practice whether you encounter chemicals at work or at home.
The pictograms use the GHS system — which stands for Globally Harmonized System — a global standard for classifying and labeling chemicals. GHS sets unified criteria for how hazardous chemicals are categorized and labeled. In the European Union, GHS is implemented through the CLP Regulation (EC Regulation No. 1272/2008).
Under the GHS and CLP systems, pictograms are standardized symbols with clear shapes, colors and graphics. Simply put — they are small visual elements on the packaging that quickly tell us what type of hazard we are dealing with, regardless of language.
There are nine different pictograms covering physical hazards, health hazards, and environmental hazards. These pictograms warn us about things such as flammability, corrosivity, toxicity, and more, and they are a legally required part of the label on all hazardous chemicals.
The pictograms assigned to each chemical are determined in its safety data sheet — the personal identification card of every hazardous chemical. The mandatory label elements, which include the pictograms, are listed in Section 2.2 of the corresponding safety data sheet.
The size, shape and color of the pictograms are legally defined in the CLP Regulation. They must be large enough to be noticed at first glance and must not be covered by other information. In short, pictograms are visual symbols that represent the hazards associated with chemicals.
Of course, pictograms visually alert you to a type of hazard, but they don’t tell you how to handle the chemicals safely. That’s why each pictogram is accompanied by relevant statements:
- Hazard statements (H-statements) — which describe the specific risk, and
- Precautionary statements (P-statements) — which guide safe handling and precautions.
Now let us take a look at all 9 pictograms which, under the CLP Regulation, cover physical hazards, hazards to human health, and environmental hazards. Each pictogram is associated with a specific H-statement, as listed below.
1. Explosive (GHS01)
What does it mean? The substance may explode when heated, subjected to impact, friction, or contact with another substance.
Where does it occur? Explosives, pyrotechnics, unstable organic peroxides.
Risks: Sudden, violent reactions, projection of fragments, thermal shocks.
H-statements: H200, H201, H202, H203, H204, H205
2. Flammable (GHS02)
What does it mean? The substance may ignite rapidly when in contact with heat, a spark, or a flame.
Where does it occur? Solvents, alcoholic solutions, aerosols, gases, gasoline.
Risks: Fire, rapid spread of flames, possibility of explosion in enclosed spaces.
H-statements: H220, H221, H222, H223, H224, H225, H226, H228, H242
3. Oxidizing (GHS03)
What does it mean? The substance releases oxygen or supports the combustion of other substances.
Where does it occur? Strong oxidizing agents, nitrates, peroxides.
Risks: Acceleration of fire, possibility of vigorous reactions, flammability of nearby materials.
H-statements: H270, H271, H272
4. Gas under Pressure (GHS04)
What does it mean? The gas is stored under high pressure (compressed, liquefied, or dissolved).
Where does it occur? Technical gases, CO₂, oxygen, butane.
Risks: Explosion of the container when heated, cylinder slipping or falling, suffocation due to displacement of oxygen.
H-statements: H280, H281
5. Corrosive (GHS05)
What does it mean? The substance is corrosive – it damages metals, skin, and eyes.
Where does it occur? Strong acids and bases, cleaning agents, lyes.
Risks: Deep tissue damage, loss of eyesight, damage to equipment.
H-statements: H290, H314, H318
6. Toxic (GHS06)
What does it mean? The substance may cause death or serious poisoning even in small quantities.
Where does it occur? Pesticides, laboratory chemicals, certain monomers.
Risks: Rapid systemic effects – failure of the respiratory system, nervous system, or heart.
H-statements: H300, H301, H310, H311, H330, H331
7. Irritant / Harmful (GHS07)
What does it mean? The substance causes irritation of the skin, eyes, or respiratory tract; it may cause an allergic skin reaction or acute toxicity of a lower category.
Where does it occur? Cleaning agents, cosmetic raw materials, polymers, adhesives.
Risks: Burning sensation, rashes, dizziness, drowsiness when inhaling vapours.
H-statements: H302, H312, H315, H317, H319, H332, H336
8. Serious Health Hazard (GHS08)
What does it mean? Long-term or serious health hazards: carcinogenicity, mutagenicity, reproductive toxicity, respiratory sensitization, effects on organs, aspiration hazard.
Where does it occur? Solvents, certain metals, petroleum derivatives.
Risks: Chronic diseases, organ damage, breathing difficulties, long-term effects after exposure.
H-statements: H304, H334, H340, H341, H350, H351, H360, H361, H362, H370, H371, H372, H373
9. Hazardous to the Environment (GHS09)
What does it mean? The substance is toxic to the aquatic or other ecosystem and may accumulate in the long term.
Where does it occur? Pesticides, metals, petroleum distillates, biocides, paints with certain additives.
Risks: Fish mortality, destruction of habitats, bioaccumulation in the food chain.
H-statements: H400, H410, H411, H412, H413
Hazard pictograms provide a quick visual warning, but they do not replace the need to read the full label and safety data sheet. Together with hazard statements (H-statements) and precautionary statements (P-statements), they form the basis for safe handling, storage, and use of chemicals.
Understanding these symbols helps reduce accidents, protects health, and ensures compliance with chemical safety regulations.
If you have any additional questions or need help understanding any of the pictograms, you can always contact me at spela.hudobivnik@gmail.com. I will be happy to help.
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