The International Union of Marine Insurance (IUMI) has updated its guidance on transporting electric vehicles by sea, amid the growing volume of EV shipments that pose distinct safety challenges for shipowners, operators and underwriters.
The paper, Risk Mitigation for the Safe Ocean and Short-Sea Carriage of Electric Vehicles, builds on IUMI's 2023 recommendations and reflects new findings on how EV fires behave compared with internal combustion engine vehicles (ICEVs).
According to the association, around 20 million cars are shipped annually, with EV volumes climbing steadily since 2017. Although no major car carrier fires have been conclusively linked to EVs, IUMI noted their fire dynamics demand new loss-prevention measures.
Higher temperatures, gas build-up and re-ignition risks
Tests showed that EV and ICEV fires release similar amounts of energy overall, but EV fires may burn hotter, sometimes exceeding 1,000°C against about 600°C for ICEVs.
Thermal runaway can also generate flammable gases that, if left to accumulate, create an explosion risk. Unlike conventional vehicles, EV batteries can reignite hours or even days after a blaze has been extinguished.
The design of pure car and truck carriers (PCTCs) also complicates fire response, according to the paper. Their large, undivided decks enable rapid fire spread and limit crew access.
IUMI urged operators to activate fixed firefighting systems early and rely on manual intervention only as a last resort. Foam suppression systems face practical limitations, while high-pressure water mist sprinklers are seen as a promising alternative, though widespread adoption would require design changes.
Guidance for insurers and carriers
Among IUMI’s updated recommendations are maintaining EV batteries at the lowest safe state of charge, doubling CO₂ firefighting capacity on PCTCs, marking vehicles with clear drivetrain identifiers, and providing dedicated crew training. The association also highlighted the importance of rapid fire detection and external specialist firefighting support.
IUMI is working with the International Maritime Organization’s fire safety group to develop global standards. Secretary General Lars Lange said the guidance reflects a rapidly changing risk landscape.
"[T]he characteristics of an EV fire are different to those emanating from a standard internal combustion engine vehicle (ICEV) and it is important that carriers, operators and insurers understand the risks involved and the measures that might reduce that risk," Lange said.
