What Are GHS Symbols? Complete Guide to Hazard Pictograms

GHS symbols — also called GHS hazard pictograms — are standardized graphic icons that appear on chemical labels and Safety Data Sheets (SDS) to communicate hazard information at a glance. Whether you are a warehouse worker, laboratory technician, or EHS manager, understanding these symbols is a fundamental safety requirement.

What Does GHS Stand For?

GHS stands for the Globally Harmonized System of Classification and Labelling of Chemicals. It is an international framework developed by the United Nations to create a single, universal language for chemical hazard communication.

Before GHS, dozens of different national and regional systems existed. A chemical classified as “flammable” in one country might carry a completely different symbol in another. This created serious risks for workers and emergency responders dealing with imported chemicals.

GHS was first published by the UN in 2003 and is now in its 10th revision (GHS Rev.10, 2023). It defines:

Classification criteria — how to determine whether a substance is hazardous
Labelling requirements — what must appear on a chemical label
Safety Data Sheet format — the standardized 16-section SDS structure

The 9 GHS Hazard Pictograms

GHS uses exactly 9 pictograms, each a black symbol inside a red diamond-shaped border on a white background. Here is what each one means:

GHS01 — Exploding Bomb

Hazard classes: Explosives, self-reactive substances (Type A and B), organic peroxides (Type A and B).

The exploding bomb pictogram indicates substances that can undergo rapid exothermic decomposition, producing gas, heat, light, sound, or smoke. This is the highest-risk category in physical hazards. Explosives require specialized storage, handling procedures, and regulatory permits in most jurisdictions.

Common examples: Ammonium nitrate, nitrocellulose, dibenzoyl peroxide (Type A).

GHS02 — Flame

Hazard classes: Flammable gases, flammable aerosols, flammable liquids, flammable solids, self-reactive substances (Types C–F), pyrophoric liquids and solids, self-heating substances, substances that emit flammable gases in contact with water.

The flame is one of the most common GHS symbols. Flammable liquids are classified by flash point: Category 1 (< 23°C and initial boiling point ≤ 35°C), Category 2 (< 23°C), Category 3 (23–60°C), and Category 4 (60–93°C).

Common examples: Ethanol, acetone, n-hexane, methanol, diethyl ether.

GHS03 — Flame Over Circle

Hazard classes: Oxidising gases, oxidising liquids, oxidising solids.

Oxidisers do not burn themselves but they supply oxygen to support and intensify combustion in other materials. This makes them extremely dangerous in the presence of any fuel source. A common misunderstanding is to confuse oxidisers with flammable substances — they are categorically different.

Common examples: Hydrogen peroxide (≥ 60%), nitric acid (concentrated), sodium perchlorate, chlorine gas.

GHS04 — Gas Cylinder

Hazard classes: Compressed gases, liquefied gases, refrigerated liquefied gases, dissolved gases.

This symbol indicates gases stored under pressure in cylinders or other pressure vessels. The hazard is primarily physical — a damaged cylinder can rupture explosively, and refrigerated liquefied gases can cause cryogenic burns.

Common examples: Nitrogen (compressed), propane (liquefied), carbon dioxide (dissolved), liquid nitrogen.

GHS05 — Corrosion

Hazard classes: Skin corrosion Category 1, serious eye damage Category 1, substances corrosive to metals.

The corrosion pictogram (depicting damage to a surface and a hand) indicates substances that can cause irreversible damage on contact. Skin corrosion produces full-thickness skin destruction within 4 hours of contact. Serious eye damage means irreversible eye injury within 21 days.

Common examples: Sulfuric acid, sodium hydroxide, hydrofluoric acid, phosphoric acid, formic acid (≥ 90%).

GHS06 — Skull and Crossbones

Hazard classes: Acute toxicity (oral, dermal, inhalation) Categories 1, 2, and 3.

The skull and crossbones is the universally recognized symbol for poison. In GHS, it applies to substances with very high acute toxicity. The threshold for oral toxicity Category 3 is an ATE ≤ 300 mg/kg body weight. Category 1 substances (ATE ≤ 5 mg/kg) include some of the most lethal chemicals known.

Common examples: Hydrogen cyanide (Cat 1), methyl isocyanate (Cat 1), mercury chloride (Cat 2), chloroform (Cat 3).

GHS07 — Exclamation Mark

Hazard classes: Acute toxicity Category 4, skin irritation Category 2, eye irritation Category 2, skin sensitisation Category 1, respiratory sensitisation Category 1, specific target organ toxicity (single exposure) Category 3, narcotic effects.

The exclamation mark is the most frequently seen GHS pictogram. It covers a broad range of less severe but still significant hazards. Many everyday industrial chemicals — solvents, cleaning agents, adhesives — carry this symbol.

Common examples: Isopropanol, acetone (eye irritation), limonene (skin sensitiser), toluene (STOT SE Cat 3).

GHS08 — Health Hazard

Hazard classes: Respiratory sensitisation Category 1, carcinogenicity Categories 1A, 1B, and 2, germ cell mutagenicity Categories 1A, 1B, and 2, reproductive toxicity Categories 1A, 1B, and 2, specific target organ toxicity (single and repeated exposure) Categories 1 and 2, aspiration hazard Category 1.

The health hazard symbol (a body with a starburst on the chest) covers serious long-term health effects. CMR substances — Carcinogens, Mutagens, and Reprotoxins — always carry GHS08. This is a critical symbol for occupational health risk assessment.

Common examples: Benzene (carcinogen Cat 1A), formaldehyde (carcinogen Cat 1B), lead compounds (reproductive toxin), silica dust (STOT RE Cat 1).

GHS09 — Environmental

Hazard classes: Hazardous to the aquatic environment — acute Category 1, chronic Categories 1 and 2.

The environmental pictogram (a dead fish and tree) indicates substances that are acutely or chronically toxic to aquatic organisms. Substances classified as H400 (very toxic to aquatic life, LC50 ≤ 1 mg/L) carry this symbol. Proper disposal is essential — these chemicals must never be discharged to drains or water bodies.

Common examples: Tributyltin compounds, chlorpyrifos, copper sulfate, many pesticides.

Signal Words: DANGER vs WARNING

Every GHS-labelled product carries exactly one signal word:

DANGER — assigned to more severe hazard categories (e.g., flammable liquid Cat 1–2, acute toxicity Cat 1–3)
WARNING — assigned to less severe categories (e.g., flammable liquid Cat 3–4, acute toxicity Cat 4)

If a substance has multiple classifications, the most severe signal word applies. A substance with both a DANGER and a WARNING classification will only show DANGER on the label.

GHS in the European Union: CLP Regulation

In the EU, GHS is implemented through CLP Regulation (EC) No 1272/2008 (Classification, Labelling and Packaging). CLP has been mandatory for all chemical substances since December 2010 and for mixtures since June 2015.

The EU maintains the ECHA CLP Annex VI — a harmonized classification list of over 4,000 substances with mandatory classifications that manufacturers must follow. These are called “harmonized classifications” (CLH). For substances not in Annex VI, manufacturers perform their own classification (self-classification).

Key EU-specific additions to GHS include EUH phrases — supplemental hazard statements used only in Europe, such as EUH014 (reacts violently with water) and EUH029 (contact with water liberates toxic gas).

GHS in the United States: OSHA HazCom 2012

In the USA, OSHA adopted GHS through the Hazard Communication Standard (HazCom 2012), also known as 29 CFR 1910.1200. It has been in full effect since June 2016.

HazCom 2012 brought US labels and SDSs into alignment with GHS Rev.3. One important difference: the US does not adopt every GHS hazard class — for example, the environmental hazard class (GHS09) is not currently required by OSHA HazCom, though many manufacturers include it voluntarily.

The US EPA has its own requirements for environmental hazard communication under FIFRA (pesticides) and other statutes.

Other Countries

GHS adoption varies globally:

Japan — adopted since 2006, one of the earliest adopters
Canada — WHMIS 2015 aligned GHS with national additions
Australia — Model Work Health and Safety Laws, aligned with GHS Rev.3
China — GB 30000 standard series, closely follows GHS
South Korea — K-GHS, mandatory since 2013

As of 2024, over 70 countries have implemented GHS in some form.

What Must Be on a GHS Label?

A complete GHS label requires six mandatory elements:

Product identifier — chemical name, CAS number, or trade name
Supplier information — name, address, phone number
Signal word — DANGER or WARNING
Hazard pictogram(s) — the relevant GHS symbols
Hazard statements — H-phrases (e.g., H225: Highly flammable liquid and vapour)
Precautionary statements — P-phrases (e.g., P210: Keep away from heat and ignition sources)

Supplemental information — such as EUH phrases or physical/chemical properties — may also be included.

Explore Our Chemical Hazard Database

Our database contains 5,000+ substances from ECHA CLP Annex VI with complete GHS classifications including pictograms, signal words, H-statements, P-statements, and ATE values.

Browse our database of 5,000+ chemicals →

Search by chemical name, CAS number, or EC number to find the complete GHS classification for any substance.

Data source: ECHA CLP Annex VI (ATP22), UN GHS Rev.10. For regulatory decisions, always consult the current official ECHA classification list.