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.