What is the role of the UN number in hazmat shipments?

• A. They identify the color of packaging
• B. They identify the material and appear on shipping papers and labels.
• C. They indicate date of manufacture
• D. They are optional for all hazmat shipments

Answer: (B)

The UN number identifies the dangerous goods material with a specific four-digit code, allowing everyone in the shipment chain to know exactly what substance is being transported. This consistent identifier is used across regulations so shippers, carriers, and emergency responders can recognize the material quickly and accurately. In practice, the UN number appears on shipping papers and on labels and placards, alongside the proper shipping name, hazard class, packing group, and quantity. This combination helps determine the appropriate handling, segregation, packing, and emergency response actions if there’s an incident. It doesn’t indicate packaging color or manufacture date, and it’s not optional for hazmat shipments—having the UN number is a required part of safe transport.