The fire on the cargo ship Fremantle Highway, which has been burning since Tuesday off the coast of Ameland, has once again highlighted the need for better sector safety rules for lithium-ion batteries, experts told the NRC.

An electric car, now reported to be one of 498 on the ship instead of 25, may have been the cause of the fire, experts said, although an investigation has yet to confirm this. Until now firefighters have not been able to board the ship because of the intensity of the blaze.

Battery fires are caused by a phenomenon called “thermal runaway”, where the battery heats up over time because of a technical fault or damage and is then “impossible to control”, Nils Rosmuller, a lecturer in transport safety at the Dutch public safety institute NIPV, told the paper.

In the case of a car, “all six to seven thousand battery cells will burn until they are all burned out. Fires like this can take days,” he said.

Putting out fires caused by a thermal runaway is one of the most challenging aspects of transporting electric cars, the NIVP said in a report following an electric vehicle fire on cargo ship Felicity Ace last year.

The ship, which carried thousands of electric cars, went down near the Azores after burning for two weeks, sparking fears of widespread pollution.

Apart from a ban on the transport of electric cars by a Scandinavian shipping company, very few measures have been taken, Rosmuller said.

The legal framework is not keeping up with the developments, he said. “Usually the safety lessons are only learned after an accident. The same happened with electric car charging stations. We used to just plug in but now there are safer systems,” he said.

Batteries in private ownership – in devices, cars, bikes and used collectively for neighbourhood energy storage – are proliferating, and more attention has to be paid to safety surrounding their use as well, experts say.

Some 117 electric cars went up in flames in the Netherlands last year alone, the NIVP reported.

“Putting out these fires is very difficult, particularly because the batteries are in a case which protects it from rain and dust but also prevents firewater from getting to the battery. A car with an unstable battery has to be towed away and there is always a chance it will ignite again,” a police spokesman said.

E-bike fires are also becoming more common, Rosmuller said. “In the Netherlands these bikes are often stored in a shed so damage is usually limited.” Rosmuller is particularly worried about shared electric moped schemes.

“People don’t usually treat something that doesn’t belong to them very carefully. Rough treatment can cause battery damage and increases the risk of a fire,” he said. The same goes for second-hand batteries for solar energy storage where you have no guarantee of its quality, he added.