Un Number
Is a UN Number the same as a hazard class?
No. The UN Number is the specific identifier for a substance or article, while the hazard class describes the type of danger such as flammable liquid, toxic, or corrosive.
Is every chemical assigned a UN Number?
No. The number applies to dangerous goods in transport; non-hazardous chemicals do not receive one, and some substances share a generic UN Number when they have similar transport hazards.
Where should a warehouse verify the correct UN Number?
Start with the SDS, then confirm against the official transport regulations or recognized dangerous-goods databases for the relevant mode of transport.
A UN Number is a four-digit identifier assigned to hazardous materials and dangerous goods for transport. Used worldwide, it standardizes identification across shipping modes and emergency response systems. It is part of the UN dangerous goods framework maintained under the United Nations Recommendations on the Transport of Dangerous Goods and is applied in modal rules such as ADR, IMDG, and IATA.
In a manufacturing facility or warehouse, the UN Number is the critical master-data field for managing hazardous raw materials, intermediates, and finished goods. It is drawn from the SDS and verified against the proper shipping name and transport rules before a pallet is booked into stock, repacked, or released to a carrier. The UN Number determines whether a chemical enters flammable storage, how it is segregated from oxidizers or acids, which packaging group applies, and what labels or placards are printed for outbound freight. Inventory systems use it as a control attribute to block incompatible materials, support dangerous-goods picking logic, and ensure shipping documentation matches container contents. At receiving and dispatch, it also drives emergency response because responders identify the transported good from the UN Number shown on documents, labels, or vehicle markings.
Wrong UN Number from bad SDS data: A plant may receive a container with an outdated or supplier-incorrect SDS, causing the ERP record to carry the wrong code. This leads to incorrect labels, wrong placarding, and noncompliant transport paperwork.
Confusing proper shipping name with trade name: Operators may enter a commercial product name instead of the official dangerous goods description, breaking classification and assigning the wrong UN Number to mixed or generic materials like 'flammable liquids, n.o.s.'
Master-data mismatch at receiving: If the UN Number on the pallet, SDS, and freight document do not match, receiving may delay putaway, quarantine stock, or reject the shipment, bottlenecking inbound flow and causing production shortages.