2026-04-12 • GHS Pictograms Editorial Team
Chemical hazard communication relies on two major systems: GHS (Globally Harmonized System) and ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road). While both systems aim to communicate chemical hazards, they serve different purposes, use different symbols, and are governed by different regulations.
Understanding the distinction is critical for chemical manufacturers, logistics managers, and EHS professionals who need to ensure compliance across the supply chain.
What Is GHS?
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) was developed by the United Nations to standardize chemical hazard communication worldwide. In the European Union, GHS is implemented through the CLP Regulation (EC) No 1272/2008.
GHS applies to:
- Chemical products in the workplace
- Consumer products on retail shelves
- Chemical storage and handling
GHS labels are required on containers of hazardous chemicals wherever they are stored or used. They are designed to protect workers and end users.
👉 Use our GHS Inspector Tool to compare GHS and ADR labels side by side for any substance.
What Is ADR?
ADR (from the French Accord européen relatif au transport international de marchandises Dangereuses par Route) is an international treaty governing the road transport of dangerous goods. It is updated every two years and is administered by the United Nations Economic Commission for Europe (UNECE).
ADR applies to:
- Road transport of dangerous goods across Europe
- Loading, unloading, and temporary storage during transport
- Vehicle marking and documentation requirements
ADR labels (called placards) are designed to protect emergency responders, transport workers, and the general public in the event of a road accident.
GHS vs ADR: Side-by-Side Comparison
| Feature | GHS (CLP) | ADR |
|---|---|---|
| Purpose | Workplace & consumer safety | Road transport safety |
| Governing body | UN / EU CLP Regulation | UNECE / ADR Agreement |
| Label location | On product container | On vehicle / outer packaging |
| Symbol shape | Diamond on white background | Solid colour diamond (placard) |
| Classification system | Hazard classes + categories | 9 hazard classes (Divisions) |
| Signal words | Danger / Warning | Not used |
| H/P statements | Required | Not required |
| UN number | Not displayed | Displayed prominently |
| Emergency contact | Supplier details | Transport emergency card (Tremcard) |
| Updated | GHS Rev. 10 (2023) | ADR 2025 |
The 9 ADR Hazard Classes vs GHS Pictograms
ADR organises dangerous goods into 9 hazard classes, which do not map 1:1 to GHS categories. The table below shows the closest GHS equivalents:
| ADR Class | Description | Closest GHS Pictogram |
|---|---|---|
| Class 1 | Explosives | GHS01 (Exploding bomb) |
| Class 2 | Gases | GHS04 (Gas cylinder) |
| Class 3 | Flammable liquids | GHS02 (Flame) |
| Class 4.1 | Flammable solids | GHS02 (Flame) |
| Class 4.2 | Spontaneously combustible | GHS02 (Flame) |
| Class 4.3 | Dangerous when wet | GHS02 (Flame) |
| Class 5.1 | Oxidising substances | GHS03 (Flame over circle) |
| Class 5.2 | Organic peroxides | GHS03 + GHS02 |
| Class 6.1 | Toxic substances | GHS06 (Skull and crossbones) |
| Class 6.2 | Infectious substances | GHS06 (Biohazard in ADR) |
| Class 7 | Radioactive material | No GHS equivalent |
| Class 8 | Corrosive substances | GHS05 (Corrosion) |
| Class 9 | Miscellaneous | GHS07 or none |
Important: The mapping above is approximate. A substance may require different classifications under GHS and ADR. Always consult the official ADR 2025 agreement and the ECHA C&L Inventory for your specific substance.
Key Visual Differences
GHS Pictograms
GHS pictograms feature a black symbol on a white background, enclosed in a red diamond border. There are 9 standardised pictograms (GHS01–GHS09).
Explore all GHS pictograms:
- GHS01 — Exploding Bomb
- GHS02 — Flame
- GHS03 — Flame Over Circle
- GHS04 — Gas Cylinder
- GHS05 — Corrosion
- GHS06 — Skull and Crossbones
- GHS07 — Exclamation Mark
- GHS08 — Health Hazard
- GHS09 — Environmental Hazard
ADR Placards
ADR placards use solid colour backgrounds that vary by hazard class. They must be at least 250mm × 250mm when applied to vehicles, and display the UN number and hazard class number.
When Do You Need Both?
Many chemical shipments require both GHS labels and ADR placards simultaneously:
| Scenario | GHS Label Required | ADR Placard Required |
|---|---|---|
| Chemical stored in warehouse | ✅ Yes | ❌ No |
| Chemical shipped by road | ✅ Yes (on inner packaging) | ✅ Yes (on vehicle/outer packaging) |
| Chemical at point of use | ✅ Yes | ❌ No |
| Empty uncleaned container in transport | ❌ May be exempt | ✅ Yes |
This dual requirement is one of the most common sources of compliance errors. A product correctly labelled for the workplace may still be missing required ADR transport markings.
Common Compliance Mistakes
- Using GHS labels on transport vehicles — GHS pictograms on a vehicle door are not a substitute for ADR placards.
- Ignoring limited quantities exemptions — ADR allows exemptions for small quantities (LQ), but GHS labelling still applies.
- Outdated ADR classification — ADR is updated every two years. Classification valid in 2023 may differ in ADR 2025.
- Missing UN number on transport packaging — Required by ADR, not by GHS.
- Wrong signal word — ADR does not use “Danger” or “Warning”; these are GHS-only terms.
Tools to Help You Stay Compliant
- 🔍 GHS vs ADR Inspector — Enter any UN number or CAS number and see both GHS and ADR labels side by side
- 🏷️ GHS Label Constructor — Build a compliant GHS label with correct pictograms and H/P statements
- 📚 GHS Pictogram Library — Download all 9 GHS pictograms in SVG format
Summary
GHS and ADR are complementary systems, not alternatives. GHS protects people who handle and use chemicals; ADR protects people who transport them. Most companies dealing with hazardous chemicals need to comply with both — and the requirements do not always overlap neatly.
When in doubt, always refer to the official sources:
Have questions about GHS or ADR compliance? Use our Inspector Tool to check any substance instantly.