2026-04-12 • GHS Pictograms Editorial Team
Every dangerous good transported by road in Europe must be classified under one of the 9 ADR hazard classes. Each class has its own placard colour, symbol, and documentation requirements under the ADR 2025 agreement.
This guide covers all 9 classes with their divisions, placard descriptions, real-world substance examples, and the closest GHS pictogram equivalents.
👉 Use our GHS vs ADR Inspector to instantly check both the GHS label and ADR placard for any substance by UN number or CAS number.
ADR Class 1 — Explosives
Placard colour: Orange
Symbol: Exploding bomb
UN divisions: 1.1 through 1.6
Class 1 covers substances and articles that can explode, deflagrate, or cause a pyrotechnic effect. It is divided into 6 divisions based on the type of hazard:
| Division | Description | Example |
|---|---|---|
| 1.1 | Mass explosion hazard | TNT, dynamite |
| 1.2 | Projection hazard, no mass explosion | Ammunition |
| 1.3 | Fire hazard, minor blast | Propellants |
| 1.4 | Minor hazard, no mass explosion | Fireworks (consumer) |
| 1.5 | Very insensitive, mass explosion hazard | Blasting agents |
| 1.6 | Extremely insensitive articles | Military ordnance |
Closest GHS equivalent: GHS01 — Exploding Bomb
⚠️ Class 1 goods require a licensed explosives carrier and specific vehicle approval under ADR. Standard hauliers cannot carry Class 1 without special authorisation.
ADR Class 2 — Gases
Placard colour: Varies by sub-class
Symbol: Gas cylinder
Sub-classes: 2.1 (Flammable), 2.2 (Non-flammable), 2.3 (Toxic)
| Sub-class | Description | Placard colour | Example |
|---|---|---|---|
| 2.1 | Flammable gases | Red | LPG, hydrogen, acetylene |
| 2.2 | Non-flammable, non-toxic gases | Green | Nitrogen, compressed air, CO₂ |
| 2.3 | Toxic gases | White | Chlorine, ammonia, phosgene |
Closest GHS equivalents:
- 2.1 → GHS02 — Flame
- 2.2 → GHS04 — Gas Cylinder
- 2.3 → GHS06 — Skull and Crossbones
Gases under ADR must be transported in UN-approved pressure vessels. The cylinder itself must carry the GHS label; the vehicle carries the ADR placard.
ADR Class 3 — Flammable Liquids
Placard colour: Red
Symbol: Flame
UN number range: UN 1170 – UN 3494 (selected)
Class 3 is one of the most common ADR classes in road transport. It covers liquids with a flash point below 60°C, including fuels, solvents, and many industrial chemicals.
| Flash Point | Packing Group | Example |
|---|---|---|
| Below -18°C | I (High danger) | Diethyl ether (UN 1155) |
| -18°C to 23°C | II (Medium danger) | Acetone (UN 1090), Ethanol (UN 1170) |
| 23°C to 60°C | III (Low danger) | Diesel (UN 1202), White spirit |
Closest GHS equivalent: GHS02 — Flame
Class 3 liquids are typically also classified under GHS as Flammable Liquids Category 1–4 depending on flash point and boiling point.
ADR Class 4 — Flammable Solids
Class 4 is divided into three distinct sub-classes:
Class 4.1 — Flammable Solids
Placard colour: White with red stripes
Solids that are easily ignited and burn vigorously. Includes self-reactive substances and desensitised explosives.
Examples: Sulphur (UN 1350), Naphthalene (UN 1334), Matches (UN 1944)
Class 4.2 — Spontaneously Combustible
Placard colour: White (top) / Red (bottom)
Substances liable to spontaneous heating or ignition on contact with air.
Examples: White phosphorus (UN 1381), Activated carbon (UN 1362)
Class 4.3 — Dangerous When Wet
Placard colour: Blue
Substances that emit flammable gases on contact with water.
Examples: Sodium (UN 1428), Calcium carbide (UN 1402), Lithium (UN 1415)
| Sub-class | Key Trigger | Placard Colour |
|---|---|---|
| 4.1 | Flame / friction | White + red stripes |
| 4.2 | Air contact | White / red split |
| 4.3 | Water contact | Blue |
Closest GHS equivalent for all: GHS02 — Flame
ADR Class 5 — Oxidising Substances and Organic Peroxides
Class 5.1 — Oxidising Substances
Placard colour: Yellow
Symbol: Flame over circle
Substances that may cause or intensify fire by releasing oxygen.
Examples: Hydrogen peroxide >60% (UN 2015), Ammonium nitrate (UN 1942), Potassium permanganate (UN 1490)
Closest GHS equivalent: GHS03 — Flame Over Circle
Class 5.2 — Organic Peroxides
Placard colour: Red (top) / Yellow (bottom)
Thermally unstable substances that can decompose exothermically. Many also require temperature control during transport.
Examples: Dibenzoyl peroxide (UN 3106), Cumene hydroperoxide (UN 3107)
Closest GHS equivalents: GHS02 + GHS03
ADR Class 6 — Toxic and Infectious Substances
Class 6.1 — Toxic Substances
Placard colour: White
Symbol: Skull and crossbones
Substances that can cause death or serious injury on inhalation, skin absorption, or ingestion.
| Packing Group | Oral LD50 (rat) | Example |
|---|---|---|
| I | ≤ 5 mg/kg | Hydrogen cyanide (UN 1051) |
| II | 5–50 mg/kg | Methanol (UN 1230), Phenol (UN 1671) |
| III | 50–300 mg/kg | Chloroform (UN 1888) |
Closest GHS equivalent: GHS06 — Skull and Crossbones
Class 6.2 — Infectious Substances
Placard colour: White
Symbol: Biohazard (ADR-specific, not a GHS pictogram)
Substances known or reasonably expected to contain pathogens.
Examples: Clinical waste (UN 3291), Biological cultures (UN 2814)
ADR Class 6.2 has no direct GHS equivalent — the biohazard symbol is used in ADR but is not part of the GHS pictogram set.
ADR Class 7 — Radioactive Material
Placard colour: White / Yellow
Symbol: Trefoil (radioactivity symbol)
Categories: I-White, II-Yellow, III-Yellow (based on radiation level)
Class 7 is regulated jointly by ADR and the IAEA Transport Regulations (SSR-6). It covers all radioactive materials including medical isotopes, industrial gauges, and nuclear fuel.
GHS equivalent: None. Radioactive hazards are outside the scope of GHS.
Transport of radioactive material requires special training, vehicle approval, and route planning beyond standard ADR requirements.
ADR Class 8 — Corrosive Substances
Placard colour: Black (top) / White (bottom)
Symbol: Corrosion (liquid attacking metal and hand)
Packing groups: I, II, III based on severity
Corrosive substances cause full-thickness destruction of skin tissue on contact, or corrode steel or aluminium at a rate exceeding 6.25 mm/year.
| Packing Group | Skin destruction time | Example |
|---|---|---|
| I | ≤ 3 minutes | Sulphuric acid >51% (UN 1830) |
| II | 3 min – 1 hour | Acetic acid >80% (UN 2789) |
| III | 1–4 hours or metal corrosion | Battery acid (UN 2796) |
Closest GHS equivalent: GHS05 — Corrosion
ADR Class 9 — Miscellaneous Dangerous Substances
Placard colour: White with black stripes (top)
Class 9 is a catch-all for substances that present a hazard during transport but do not fit into Classes 1–8.
| Type | Example | UN Number |
|---|---|---|
| Environmentally hazardous liquids | Polychlorinated biphenyls | UN 2315 |
| Lithium batteries | EV batteries, laptop batteries | UN 3480 / UN 3481 |
| Dry ice | CO₂ solid | UN 1845 |
| Magnetised material | Industrial magnets | UN 2807 |
| Elevated temperature liquids | Molten sulphur | UN 2448 |
Closest GHS equivalent: GHS07 or GHS09 — Environmental Hazard depending on substance
Lithium batteries (Class 9) are among the fastest-growing ADR compliance challenges due to the explosion of EV and electronics transport. Always check the latest ADR 2025 provisions for UN 3480 and UN 3481.
Quick Reference: All 9 ADR Classes
| Class | Name | Placard Colour | GHS Pictogram |
|---|---|---|---|
| 1 | Explosives | Orange | GHS01 |
| 2.1 | Flammable gases | Red | GHS02 |
| 2.2 | Non-flammable gases | Green | GHS04 |
| 2.3 | Toxic gases | White | GHS06 |
| 3 | Flammable liquids | Red | GHS02 |
| 4.1 | Flammable solids | White/red stripes | GHS02 |
| 4.2 | Spontaneously combustible | White/red | GHS02 |
| 4.3 | Dangerous when wet | Blue | GHS02 |
| 5.1 | Oxidising substances | Yellow | GHS03 |
| 5.2 | Organic peroxides | Red/yellow | GHS02 + GHS03 |
| 6.1 | Toxic substances | White | GHS06 |
| 6.2 | Infectious substances | White | None |
| 7 | Radioactive | White/yellow | None |
| 8 | Corrosives | Black/white | GHS05 |
| 9 | Miscellaneous | White/black stripes | GHS07 / GHS09 |
Official Sources
Tools for ADR and GHS Compliance
- 🔍 GHS vs ADR Inspector — Compare GHS and ADR labels for any substance
- 🏷️ GHS Pictogram Library — Download SVG pictograms GHS01–GHS09
- 🧪 Substance Database — Search 4,000+ substances with full GHS classification
This guide is based on ADR 2025 and GHS Revision 10. Always verify classification with the official ADR agreement and your national competent authority.