Shipping Lithium Batteries by Sea: An IMDG Code Guide

Shipping lithium batteries by sea is governed by the International Maritime Dangerous Goods (IMDG) Code, which classes lithium ion and lithium metal cells and batteries as Class 9 dangerous goods. To ship them compliantly you need to identify the correct UN number, confirm the cells or batteries have passed the required UN tests, pack, mark and label them as the Code requires, and declare them accurately on a dangerous goods declaration.

Why lithium batteries are regulated at sea

Lithium batteries store a large amount of energy in a small space. If a cell is damaged, defective, overcharged or short-circuited it can enter thermal runaway, a self-sustaining reaction that generates heat, flammable and toxic gases, and fire that can spread from cell to cell. Industry guidance from CINS, TT Club, ICHCA International and the International Group of P&I Clubs notes that such fires are hard to extinguish and may reignite.

The IMDG Code is mandatory under SOLAS chapter VII and is updated on a two-year cycle.

UN numbers for lithium batteries

Choosing the right entry depends on the chemistry (lithium ion or lithium metal) and on how the batteries are presented for transport.

Amendment 42-24 introduced UN 3556 and UN 3557, so lithium battery powered vehicles are no longer shipped under UN 3171, which is now limited to vehicles powered by wet batteries, metallic sodium batteries and sodium alloy batteries. The same amendment brought sodium ion batteries into Class 9 for the first time, under UN 3551, UN 3552 and UN 3558 (vehicles).

Classification and testing

All of the lithium battery entries above are Class 9 (miscellaneous dangerous substances and articles). Before a cell or battery type can be shipped, it must have passed the tests in the UN Manual of Tests and Criteria, Part III, sub-section 38.3. Under Amendment 42-24, manufacturers and later distributors must make the test summary available, so the consignor and others in the supply chain can confirm compliance.

Special provisions that commonly apply

Small cells and batteries: special provision 188

Special provision 188 relieves small cells and batteries from most of the Code’s requirements if they meet all of its conditions. The limits are 20 Wh per lithium ion cell and 100 Wh per lithium ion battery, and 1 g of lithium per lithium metal cell and 2 g aggregate lithium content per lithium metal battery. Other conditions cover type testing, packaging that prevents short circuits, a 1.2 m drop test, a 30 kg gross mass limit per package and, in most cases, the lithium battery mark.

Damaged or defective batteries: special provision 376

Batteries that have been identified as damaged or defective, so that they no longer conform to their tested type, fall under special provision 376. This includes batteries recalled for safety reasons, those that have leaked or vented, and those that cannot be diagnosed. Stricter packing instructions apply, packages need additional marking, and batteries likely to react dangerously under normal conditions of transport may need competent authority approval or may be forbidden.

Batteries for disposal or recycling: special provision 377

Batteries shipped for disposal or recycling can use special provision 377, which allows packing instruction P909. Packages must be marked “LITHIUM BATTERIES FOR DISPOSAL” or “LITHIUM BATTERIES FOR RECYCLING”.

State of charge

Thermal runaway is generally more severe at higher states of charge. Under the IATA Dangerous Goods Regulations, lithium ion cells and batteries shipped on their own by air (UN 3480) must be at no more than 30% of rated capacity. The IMDG Code does not apply an equivalent general limit to sea transport, but industry loss prevention guidance, including from TT Club and Allianz, recommends shipping at a reduced state of charge where possible.

Packing, marking and labelling

• Packaging: use the packing instruction listed in the Dangerous Goods List for the UN number. Cells and batteries must be protected against short circuits and against movement that could cause damage.
• Class 9 lithium battery label: packages that are fully regulated carry the Class 9 lithium battery label (model 9A), which has black vertical stripes in the upper half and a battery symbol in the lower half.
• Lithium battery mark: required for packages prepared under special provision 188, showing the relevant UN number(s).
• Placards: cargo transport units carry the standard Class 9 placard. The 9A label design is not used as a placard.

Documentation

A fully regulated lithium battery shipment needs a dangerous goods declaration giving the UN number, proper shipping name and class, followed by the number and kind of packages and the total quantity. A typical description reads “UN 3480, LITHIUM ION BATTERIES, 9”. If you are packing the batteries into a container yourself, you will also sign the container packing certificate. Our guide to completing a dangerous goods declaration explains each element.

Misdeclaration and container fires

A significant share of serious container ship incidents is linked to misdeclared or undeclared dangerous goods. Allianz reports that industry incident reporting systems attribute around a quarter of serious incidents on container ships to misdeclared cargo, and it identifies lithium ion batteries as a growing fire risk. Batteries shipped as “spare parts”, “electronics” or “toys” never reach the stowage, segregation and firefighting planning that a correct declaration would trigger.

How Hazcheck can help

• Hazcheck Detect screens booking data in real time to identify cargo that may be misdeclared or undeclared dangerous goods, including batteries hidden behind generic commodity descriptions.
• Hazcheck Validate checks declared lithium battery bookings against the IMDG Code, including segregation and stowage, and produces DG documentation. Hazcheck Validate Desktop offers the same checks as a desktop application.
• The IMDG Code e-Reader gives you searchable access to the full Code, and our IMDG Code e-learning covers classification, packing and documentation.

To discuss your lithium battery shipments, contact our team.

Frequently asked questions

Are lithium batteries dangerous goods when shipped by sea?

Yes. Lithium ion and lithium metal cells and batteries are Class 9 dangerous goods under the IMDG Code, whether shipped on their own, packed with equipment or contained in equipment. Small cells and batteries meeting special provision 188 are relieved from most requirements.

What is the difference between UN 3480 and UN 3481?

UN 3480 covers lithium ion cells and batteries shipped on their own. UN 3481 covers lithium ion batteries contained in equipment, such as a laptop, or packed with equipment, such as a spare battery in the same box as a power tool.

Can damaged lithium batteries be shipped by sea?

Damaged or defective batteries can sometimes be shipped under special provision 376, which requires stricter packaging and additional marking.

Is there a state of charge limit for lithium batteries at sea?

Air transport limits UN 3480 to 30% state of charge. The IMDG Code sets no equivalent general limit, but a reduced state of charge is recommended good practice.

How are electric vehicles shipped in containers?

From Amendment 42-24, lithium ion battery powered vehicles are shipped as UN 3556 and lithium metal battery powered vehicles as UN 3557, replacing UN 3171 for these vehicles.

Sources

• IMO: Dangerous goods (IMDG Code)
• ICHCA: IMDG Code Amendment 42-24 summary of main changes
• Britannia P&I: IMDG Code Amendment 42-24
• TT Club: Guidelines for safe transport of lithium-ion batteries in containers (CINS, ICHCA, IG P&I, TT Club)
• Allianz Commercial: Cargo and battery fires
• Shashi Kallada: Understanding IMDG Code special provision 188
• Shashi Kallada: Shipping defective lithium batteries
• Shashi Kallada: Lithium battery marking, labelling and placarding
• IATA briefing on lithium batteries (air state of charge, for contrast)