According to the International Maritime Dangerous Goods Code (IMDG Code), BESS is classified as Class 9 hazardous goods, with the United Nations number UN3536.
Because batteries are classified as dangerous goods due to fire and explosion risk. That means stricter packaging, labelling, documentation, and carrier approvals. This guide explains everything you need to know to stay compliant and avoid costly delays – from battery classifications to mode-specific rules and best practices for shipping safely.
Except for containerized lithium-ion battery energy storage systems and vehicles powered by lithium batteries (pure electric or hybrid), packages containing lithium batteries or battery packs must be affixed with the 9A dangerous goods label as shown in Figure 4 or the lithium battery mark as shown in Figure 5, as required.
Are battery energy storage systems a threat to maritime safety?
12. March 2025 In recent years, demand for the maritime transportation of containerised Battery Energy Storage Systems (BESS) has grown significantly. However, due to the high safety risks associated with energy storage containers, their transportation poses new challenges to maritime safety.
How do I identify a lithium battery hazardous goods container?
Except for vehicles driven by lithium batteries (pure electric or hybrid), containers containing lithium battery hazardous goods must have Class 9 hazardous goods labels and UN number markings affixed to each side and each end of the container (for lithium-ion battery energy storage systems, on two opposite sides).
Segregation: It is recommended to segregate lithium battery containers from those containing other dangerous goods, particularly flammables, by at least one container bay (6 meters). Securing: All cargo must be secured within its container and on the vessel in accordance with the CTU Code and the vessel's Cargo Securing Manual.
Most lithium batteries are classified as Class 9 dangerous goods but the exact handling requirements depend on: Other battery types – like lead-acid, nickel-metal hydride (NiMH), and dry cell batteries — may fall under different categories, but all require proper classification, documentation, and packaging to move legally and safely.