Freight glossaryCargo HandlingEquipmentContainers
Dunnage
Definition
Dunnage is loose material used to support and protect cargo, such as boards, blocks, void fill and inflatable dunnage bags placed between articles or between cargo and the vehicle wall.
What it means
The federal securement rules define dunnage as "all loose materials used to support and protect cargo" and a dunnage bag as "an inflatable bag intended to fill otherwise empty space between articles of cargo, or between articles of cargo and the wall of the vehicle."[1] Dunnage and dunnage bags are among the named ways to immobilize freight.[2]
Wooden dunnage in international shipments counts as wood packaging material. CBP lists dunnage alongside pallets, crates and skids among the items covered by the wood packaging rules,[3] which means it needs ISPM 15 treatment and marking when it enters the U.S.
Example
Two rows of pallets in a van leave an 18-inch gap at one side wall. An inflatable dunnage bag is placed in the gap and inflated so the stacks cannot slide sideways under braking or cornering.
Related
Related terms
- Blocking and BracingBlocking and bracing is restraining cargo with structures placed against or around it, such as blocks...Glossary
- Cargo SecurementCargo securement is restraining freight on or inside a vehicle, with walls, blocking, bracing, dunnage or...Glossary
- ISPM 15ISPM 15 is the international standard for wood packaging material, such as pallets, crates and dunnage, that...Glossary
- PalletA pallet is a flat, portable platform, usually wood, with a top deck and a bottom structure that lets a stack...Glossary
Related guides
Sources
- Legal Information Institute, Cornell Law School, “49 CFR § 393.5, Definitions (cargo securement),” Federal regulation. Accessed September 30, 2026.
- Legal Information Institute, Cornell Law School, “49 CFR § 393.106, General requirements for securing articles of cargo,” Federal regulation. Accessed September 2026.
- U.S. Customs and Border Protection, “Frequently Asked Questions on Wood Packaging Materials,” Government guidance. Accessed September 2026.
General operational information, not legal, customs or regulatory advice. Rules and rates change; confirm current requirements with the agency, carrier or contract that governs your shipment.