Whether a solvent drum, a lithium battery in a shipping carton or a hazardous-substance cabinet in the workshop: warning and dangerous goods labels are not decoration but legally regulated safety marking. Incorrect or incomplete marking risks fines, rejected shipments — and in the worst case lives. This overview shows which rule sets apply and what matters for size, colour and material.
Three regulatory worlds: transport, hazardous substances, workplace
In practice you encounter three different marking systems that are often confused:
| Bereich | Rule set | Typical marking |
|---|---|---|
| Transport of dangerous goods | ADR (road), RID (rail), IMDG Code (sea), IATA-DGR (air) | Hazard labels (diamonds) for classes 1–9, environmentally hazardous mark, LQ mark, orientation arrows |
| Hazardous substances in packages | CLP Regulation (EC) No 1272/2008 based on the GHS | GHS pictograms GHS01–GHS09 with signal word and H-/P-statements |
| Workplace & buildings | DIN EN ISO 7010, ASR A1.3 | Warning, prohibition, mandatory and rescue signs |
ADR hazard labels: size, border, colour
Hazard labels for packages are squares standing on a point (diamonds). ADR requires a minimum size for packages of 100 × 100 mm , with a line 5 mm from and parallel to the edge. If the package is too small, labels may be reduced as long as they remain clearly visible. For containers, tanks and vehicles, placards of at least 250 × 250 mm are used — which is why we stock the common motifs in 100 × 100 mm as well as 250 × 250 mm and 300 × 300 mm.
Each of the nine classes has a clear colour and symbol combination — for example red with a flame for flammable liquids (class 3), orange with an exploding bomb for class 1, or a black-and-white upper half with a corrosive symbol for class 8. Colours must match the requirements and must not drift: a faded red hazard label that looks pink is no longer unambiguous.
Hazard labels must be “weather-resistant” and ensure durable marking throughout carriage. For sea transport the IMDG Code even requires that marks and labels withstand at least three months’ immersion in seawater while remaining legible.
GHS pictograms under CLP
For hazardous substances in containers the CLP Regulation applies. The red-bordered diamonds with a black symbol on a white background (GHS01 to GHS09) show at a glance whether a substance is flammable, corrosive, toxic or environmentally hazardous. Minimum size depends on packaging capacity — from 1 cm² pictogram area on the smallest packages up to at least 46 × 46 mm on containers over 500 litres. Important: a GHS pictogram does not replace an ADR hazard label and vice versa; transport packages often need both.
Additional and handling marks
Besides class labels, the regulations often require further marks:
- Environmentally hazardous substances (dead fish and tree) for substances that endanger aquatic environments.
- Limited Quantities (LQ) — the black-and-white diamond for dangerous goods in limited quantities.
- Lithium battery mark with UN number and telephone number, plus the class 9A hazard label.
- Orientation arrows (“This way up”) for liquids in inner packagings.
- Elevated temperature substances, Cargo Aircraft Only und Magnetized Material in air transport.
Checklist for correct marking
- Determine the dangerous goods class and UN number from the safety data sheet (section 14).
- Clarify the mode of transport — ADR, IMDG or IATA have partly different additional requirements.
- Choose the right size: 100 × 100 mm for packages, from 250 × 250 mm for containers and vehicles.
- Select material to match the substrate and environment (see our application guide).
- Apply labels so they are clearly visible, not folded and not obscured — remove old, invalid labels.
Note: this article is an overview and does not replace advice from your dangerous goods safety adviser. Always follow the currently applicable version of each regulation.