Class 2 labels: gases (red, green or white diamond)
The package contains gas: compressed, liquefied, dissolved or refrigerated — aerosols, gas cartridges, lighters, fire extinguishers, oxygen, CO₂ bottles.
Who puts it on the box
The sender (consignor).
How to read it
Read the colour: red burns, green is under pressure but neither flammable nor toxic, white with a skull is poisonous to breathe. Consumer aerosols usually travel as limited quantities under the black-and-white diamond instead of these labels.
What it does not promise
It does not promise the cylinder or can is sound or safe to open, and a green label does not promise the gas is harmless: an inert gas can still suffocate in a closed space and every cylinder can burst when heated.
A mark on a parcel is the sender’s statement about what is inside and how it should be handled. It is not a certificate that the parcel is packed safely, that anyone handled it as marked, or that your carrier accepts it: for what you may send, read the carrier’s own terms.
- What it looks like
- Three labels with the figure 2 in the bottom corner: 2.1 flammable gas, a flame on red; 2.2 non-flammable, non-toxic gas, a gas cylinder on green; 2.3 toxic gas, a skull and crossbones on white.
- Regulation
- ADR 2025, 5.2.2.2.2, label models No. 2.1, 2.2 and 2.3; UN Model Regulations 5.2.2.2.2
- Kind of mark
- A dangerous-goods mark or label from the UN Model Regulations, applied in Europe by ADR (road) and its sister agreements for rail and waterways, and on the same pattern by the US 49 CFR. It says the package holds dangerous goods.
- Also called
- Gas label; Flammable gas label; Non-flammable gas label; Toxic gas label
Related
Other marks with the same shape
Sources
Each document was fetched and read on the date shown. Written in our own words; quotations are the documents’ wording.
- Regulator guidance — Health and Safety Executive (UK regulator for the carriage of dangerous goods): Carriage of dangerous goods manual — Consignment procedures: marking and labelling of packages (ADR 5.2) — Package labels are the “hazard diamonds” of ADR 5.2.2 with the class number; specimen labels are in ADR 5.2.2.2.2 and sizes in 5.2.2.2.1.1; the consignor is responsible for marking and labelling. Checked 2026-09-27.
- Law adopting the same mark — US Government Publishing Office (govinfo), 49 CFR, edition of 1 October 2024: 49 CFR Part 172 Subpart E — Labeling (§§ 172.400–172.450, the hazard class labels) — §§ 172.415–172.417: the NON-FLAMMABLE GAS (cylinder, green), POISON GAS (skull, white) and FLAMMABLE GAS (flame, red) labels. Labels are at least 100 mm on each side with an inner border about 5 mm inside the edge (§ 172.407). Checked 2026-09-27.