Operational Guide · Registers & Logbooks

# Lithium Batteries: Thermal Runaway and Fire Response on Board

Fires linked to lithium-ion batteries are growing sharply in maritime transport: understanding the thermal runaway phenomenon and response techniques is essential, since conventional extinguishers do not stop it.

lithium batteries thermal runaway fire lithium-ion

## Operational Explanation

Thermal runaway is an uncontrolled self-heating phenomenon that can occur in a damaged, overcharged or overheated lithium-ion battery, with internal temperatures that can exceed 300°C, generating flammable gases and spreading rapidly to adjacent cells. Unlike a conventional fire, thermal runaway does not stop simply by cooling the external surface: the internal chemical reaction continues to feed itself.

The spread of containers carrying electric vehicles, Battery Energy Storage Systems (BESS) and battery-powered devices has made this risk one of the leading causes of fires on board container ships in recent years, often in combination with mis-declared or poorly secured cargo.

Amendment 43-26 update: the CCC Sub-Committee, at its 11th session, and the E&T 43 editorial and technical group agreed substantial changes to the carriage of vehicles, including those with conventional fuels, hybrids and lithium batteries: a new Special Provision SP980 and updates to provisions SP961 and SP962, designed to make the classification of battery-powered vehicles clearer and safer compared with the framework already introduced by Amendment 42-24. This level of detail adds to, without overlapping, the new general UN entries for battery-powered vehicles already introduced by the 2024 edition of the Code.

## Regulatory Reference

The IMDG Code (Amendment 42-24) governs the classification of lithium batteries (Class 9) and introduces new entries for sodium-ion batteries and battery-powered vehicles; the updated EmS Guide provides specific emergency procedures for lithium battery fires. Amendment 43-26 (adopted at MSC 111, May 2026, voluntary application from 2027, mandatory from 2028): new SP980 and updates to SP961/SP962 for the carriage of battery-powered vehicles. There is not yet a single, binding IMO standard for extinguishing thermal runaway on board, but P&I and manufacturer guidance recommend specific approaches.

## Scope of Application

All ships carrying containers with lithium batteries, electric vehicles or energy storage systems, with particular attention to firefighting crew training on the specific features of this type of ignition source compared with conventional fires.

## Procedure / How to Complete It

1. Check the correct classification and securing of units containing lithium batteries before loading, in accordance with the CTU Code.
2. If early warning signs are detected (smoke, abnormal heat, acrid odour) from a container with batteries, isolate the area and immediately notify the Master.
3. Apply the massive water-cooling strategy to contain propagation to adjacent cells, without expecting it to extinguish the internal chemical reaction.
4. Avoid opening the affected container directly until it is certain that the thermal runaway reaction has burned itself out, due to the risk of reignition and the release of toxic gases.
5. Document the event and conduct a post-emergency debrief to check the effectiveness of the response and update the SMS procedures accordingly.

## Practical Example

Example: a container with a damaged Battery Energy Storage System (BESS) generates smoke and abnormal heat during transport; the crew applies continuous massive cooling with seawater to the outside of the container for hours, without attempting to open it directly, until the reaction has completely burned itself out.

## Real Cases

The incident involving the container ship Genius Star XI (December 2023, Pacific Ocean) was caused by lithium energy storage units that were not properly secured, which shifted during heavy weather until they suffered internal structural deformation, triggering thermal runaway and two separate fires with damages of USD 3.8 million. According to insurance data, the industry recorded roughly one container-ship fire every 17 days in the most recent two-year period, with mis-declared or poorly secured dangerous goods identified as a recurring cause.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
Treating a lithium battery fire with the same techniques as a conventional fire | Ineffective extinguishing and risk of reignition after an apparent shutdown | Train the crew specifically on the prolonged massive-cooling strategy, not simple extinguishing
Premature opening of the affected container to check its internal condition | Exposure to toxic gases and risk of sudden reignition | Wait until it is certain the reaction has burned out before any opening, in accordance with the updated EmS procedures
Cargo securing not specifically checked for heavy units such as BESS | Cargo shift in heavy weather, with risk of structural ignition | Apply reinforced lashing checks for high-risk units such as batteries and storage systems

## PSC Observations

Although there is not yet a specific, standardised PSC check on lithium batteries, PSCOs may check crew training on responding to this type of emergency as part of the general check of firefighting procedures and dangerous goods management.

## Operational Tips

- Include specific thermal runaway scenarios in periodic fire drills, explicitly distinguishing them from conventional fires.
- Do not rely on conventional portable extinguishers as a definitive measure against a lithium battery ignition inside a closed container.
- Check that crew training is up to date with the latest editions of the EmS Guide, which reflect the growing prevalence of this type of cargo.

## Checklist

- Specific crew training on thermal runaway and differences from conventional fires
- Prolonged massive-cooling procedure defined in the SMS
- Reinforced lashing check for units containing batteries/BESS
- Updated EmS Guide available and used in periodic drills
- Post-emergency debrief procedure for lithium battery events

## FAQ

Why aren't conventional extinguishers enough against thermal runaway?
Because the reaction is generated by an internal chemical process within the cell that self-feeds even in the absence of external oxygen; massive, prolonged cooling serves to contain the propagation, not to stop the internal reaction that has already been triggered.
How much has the risk linked to lithium batteries grown in maritime transport?
According to industry data, the volume of lithium-ion batteries carried in 2025 was roughly six times higher than five years earlier, with demand expected to double again by 2030.
What was distinctive about the Genius Star XI case?
The fire was caused by lithium energy storage units that were not properly secured and shifted and were damaged during heavy weather, showing how poor cargo securing, in addition to classification, is a primary risk factor.
What does the new SP980 in Amendment 43-26 introduce?
A Special Provision dedicated to the carriage of vehicles, including those with conventional fuels, hybrids and lithium batteries, with related updates to provisions SP961 and SP962: it clarifies the classification of battery-powered vehicles in more detail than the framework already introduced by Amendment 42-24, with voluntary application from 2027 and mandatory application from 2028.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

IMDG Code — Carriage of Dangerous Goods in Packaged Form EmS Guide and MFAG: Responding to Emergencies Involving Dangerous Goods

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