UNnummers

UN-nummers are internationally standardized four-digit identifiers used in the transport of dangerous goods to identify substances and articles that pose hazards during transport. They are part of the United Nations Model Regulations on the Transport of Dangerous Goods and support hazard communication, safe handling, and emergency response.

The numbers are assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods. Each UN-number refers to a specific substance or article and is used across all modes of transport, including road, rail, sea, and air. UN-numbers are typically four digits long and are not indicative of relative hazard; hazard is indicated by separate class and packing information.

In practice, the UN-number appears on shipping names, transport documents, and, where applicable, on packaging, labels, and placards. It is used with the correct hazard class, packaging group, and any special provisions to determine required packaging, labeling, and handling requirements. It also aids emergency responders by providing a concise reference to the substance involved.

UN-numbers underpin international regulations such as ADR (road), RID (rail), ADN (inland waterways), IMDG Code (sea), and IATA DGR (air). National rules implement these frameworks and may add regional provisions, but the UN-number system provides the common core for communication and safety across borders.