Lithium-ion batteries & closing the fire safety gap
Lithium-ion (Li-ion) batteries are now present across a wide range of maritime operations. They move as containerised cargo, sit inside vehicles carried on RoRo decks, and are increasingly installed as part of ships’ own propulsion and energy systems.
As global demand accelerates, surpassing 1 TWh in 2024 and projected to reach around 4.7 TWh by 2030, their footprint at sea will only expand. With that comes a distinct class of fire risk that cannot be managed through conventional approaches alone. Li-ion battery fires behave differently, escalate differently, and require a coordinated industry effort to ensure crews and ships are equipped for what is now routine operational exposure.
The underlying challenge is thermal runaway, a chain reaction driven by heat generated during overcharging, physical damage, manufacturing defects, or inadequate heat dissipation. Once initiated, thermal runaway can lead to rapid fire spread, flammable gas venting, and repeated reignition. Conventional suppression agents such as CO2, foam, or water mist may not perform as expected, and immersion-based tactics often used ashore are impractical at sea due to space and stability constraints. These characteristics place seafarers in an environment that urgently requires updated understanding, rigorous training, and equipment better matched to Li-ion behaviour.
Vessel-specific risk patterns
Risk profiles vary across vessel types, but several themes recur. On RoRo vessels, enclosed vehicle decks and limited ventilation magnify the consequences of electrical faults. EMSA’s FIRESAFE studies found that electrical fires account for approximately 60% of RoRo deck fires, while a separate study in Sustainability journal identified electrical faults originating in vehicles as the most common cause of fires in enclosed RoPax spaces. Although major incidents such as the Felicity Ace, Fremantle Highway, and Morning Midas have not conclusively identified Li-ion batteries as the initiating source, ageing wiring, fluid leaks, and poor maintenance significantly increase ignition likelihood, and once involved, Li-ion batteries complicate suppression due to thermal runaway.
Containerships face a different challenge. Cells, batteries, and consumer electronics containing Li-ion units are classified as dangerous goods under the IMDG Code, yet mis- or undeclared cargo remains a persistent fire safety concern. Industry initiatives such as the Cargo Incident Notification System (CINS) guidelines, developed with support from the International Group and major carriers including Evergreen and CMA CGM, provide practical guidance, but stronger detection and enforcement mechanisms are still required.
Bulk carriers transporting Battery Energy Storage Systems (BESS) or scrap cargoes containing electronic waste encounter further complications. These vessels typically lack the dedicated ventilation, segregation capability, and advanced suppression systems needed for high-risk battery cargoes. The risk is amplified when scrap contains damaged or unstable batteries, which may remain concealed until ignition occurs. Early identification, encapsulation, and secure stowage are therefore critical controls, but awareness and standardisation across the bulk sector are still developing.
Li-ion batteries integrated into propulsion systems are also growing in number, particularly on short-sea fixed-route ferries. The Maritime Battery Forum’s register surpassed 1,000 battery-powered vessels in 2023 and continues to grow, with increasing battery capacity per vessel too. While these systems support decarbonisation goals, they also concentrate significant amounts of energy onboard, meaning that battery management systems, state-of-charge controls, and emergency procedures must be rigorously maintained.
The three persistent gaps: training, equipment, regulation
Across all vessel types, training remains the most immediate gap. There is currently no mandatory, standardised training specific to Li-ion fires for seafarers or port-side personnel, leaving many unprepared for the detection, cooling, containment, and reignition risks inherent to thermal runaway. The Norwegian Maritime Authority is the only flag state to have issued detailed battery-system training guidance covering both operational procedures and response to thermal runaway, offering a strong blueprint with clear potential for wider adoption.
Equipment is the second barrier. Many vessels still rely on systems designed for combustion engine fires. Water provides important cooling but may not prevent reignition, while CO2 and high-expansion foam have shown inconsistent performance against thermal runaway. The 2019 Ytteroyningen ferry fire demonstrated the limitations of established practices: actions believed appropriate at the time were later found to be ineffective.
Regulatory frameworks are the third gap. While classification societies such as DNV, ABS, and ClassNK have developed comprehensive rules and guidance for energy storage systems and EV carriage, international conventions – notably SOLAS – have not yet been updated to reflect the modern fire risks associated with Li-ion batteries. This regulatory lag leaves owners and crews navigating uncertainty that could be mitigated through clearer, uniform standards.
Moving toward coordinated action
There is progress to build on. Research by RISE into state-of-charge effects and battery behaviour, along with continued work by the Maritime Battery Forum and CINS, is helping improve understanding across the sector. At West, our Loss Prevention team collaborates with these organisations to support Members with up-to-date, evidence-based guidance and facilitate webinars that share emerging findings and lessons learned. But overall alignment remains limited, and the scale of the challenge requires more consistent, coordinated action across the sector.
Li-ion battery fires represent a fundamentally different class of risk and require a corresponding level of readiness. Mandatory, standardised training; updated regulatory frameworks; vessel-specific suppression systems designed for thermal runaway; and strengthened cargo declaration enforcement are all essential steps. As shipping prepares for the next generation of fuels and onboard energy systems, the approach taken to Li-ion safety today will shape the industry’s ability to manage future fire risks effectively.
Our goal is clear: to protect people, ships, and global trade by ensuring safety standards evolve at the same pace as the technologies transforming them.
Further guidance
For further guidance on emerging risks and onboard safety, you can find West’s latest resources here.
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