# UN Number

*Last updated: 2026-06-26*

> Unlike a hazard class, which describes a category of danger, a UN Number uniquely identifies a hazardous substance or group of substances with global validity.

Unlike a hazard class, which describes a category of danger, a UN Number uniquely identifies a hazardous substance or group of substances with global validity. The four-digit code – for example UN 1203 for petrol or UN 1090 for acetone – is assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods and applies regardless of transport mode or the countries involved. It must appear on dangerous goods transport documents, orange warning placards, packages, and containers. Shippers, freight forwarders, and drivers rely on it across all modes: road (ADR), rail (RID), sea (IMDG), and air (ICAO/IATA DGR). It forms the basis for emergency response and regulatory inspection. Not to be confused with the CAS number, which identifies individual chemical substances for scientific purposes and has no significance under transport law.

**Source:** [https://unece.org/transport/dangerous-goods](https://unece.org/transport/dangerous-goods)

## Quick Facts

| Property | Value |
|---|---|
| Term | UN Number |
| Language | EN |
| Word count | 134 |
| Last updated | 2026-06-26 |
| Source | https://unece.org/transport/dangerous-goods |

## Related Pages

* [ADR – Dangerous Goods by Road](https://www.freight-academy.com/information/lkw/adr)
* [IATA Dangerous Goods (DGR)](https://www.freight-academy.com/information/luftfracht/iata-gefahrgut)

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