# hazard class

*Last updated: 2026-06-26*

> Shippers, freight forwarders, and dangerous goods safety advisers classify every hazardous substance or article into a hazard class – an internationally standardised category that identifies the nature of the risk, such as flammability, toxicity, corrosivity, or radioactivity.

Shippers, freight forwarders, and dangerous goods safety advisers classify every hazardous substance or article into a hazard class – an internationally standardised category that identifies the nature of the risk, such as flammability, toxicity, corrosivity, or radioactivity. The class is the starting point for all downstream transport requirements, including packaging group, labelling, stowage rules, and quantity limits. Classes 1 through 9 are defined consistently across the major modal regulations: ADR (road), RID (rail), IMDG Code (sea), and the IATA Dangerous Goods Regulations (air). Several classes carry subdivisions; precise identification requires the UN number and, where applicable, a packing group. The hazard class alone does not constitute the full dangerous goods declaration – it must be read alongside subsidiary risks, special provisions, and any applicable tunnel or quantity restrictions.

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

## Quick Facts

| Property | Value |
|---|---|
| Term | hazard class |
| Language | EN |
| Word count | 128 |
| Last updated | 2026-06-26 |
| Source | https://unece.org/transport/dangerous-goods |

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*Logistics Glossary — Freight Academy: [https://www.freight-academy.com/en/glossary/hazard-class-2](https://www.freight-academy.com/en/glossary/hazard-class-2)*

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