# Class 4 Flammable Solids

*Last updated: 2026-06-26*

> Class 4 dangerous goods exist to manage the fire risk posed by solid materials that can ignite easily or undergo spontaneous combustion during normal transport conditions.

Class 4 dangerous goods exist to manage the fire risk posed by solid materials that can ignite easily or undergo spontaneous combustion during normal transport conditions. The class is divided into three divisions: 4.1 (readily flammable solids such as sulphur or certain metal powders), 4.2 (spontaneously combustible substances such as white phosphorus), and 4.3 (substances that emit flammable gases on contact with water, such as calcium carbide). Each division carries distinct packaging requirements, hazard labels, and stowage instructions. For divisions 4.2 and 4.3, temperature monitoring is frequently mandatory. Sea and air transport generally impose tighter controls than road carriage under the respective modal regulations.

**Source:** [https://www.unece.org/trans/danger/publi/adr/adr_e.html](https://www.unece.org/trans/danger/publi/adr/adr_e.html)

## Quick Facts

| Property | Value |
|---|---|
| Term | Class 4 Flammable Solids |
| Language | EN |
| Word count | 104 |
| Last updated | 2026-06-26 |
| Source | https://www.unece.org/trans/danger/publi/adr/adr_e.html |

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