Lithium-ion battery explosions like the one that critically injured a person in Wellington on Saturday are unstoppable, Fire and Emergency New Zealand (FENZ) warns.

The chemical reaction that happens when such batteries fail causes fires that cannot be put out, meaning all the public can do is get away from the blaze and call 111 for help.

Firefighters rushed to the Century City apartments on Saturday evening when a charging e-scooter exploded, leaving one person with life-threatening injuries. They remain in a critical condition in Hutt Hospital’s intensive care unit days later.

The dramatic incident has prompted a reminder from FENZ on how to safely use lithium-ion batteries - and what to do if they “fail catastrophically”.

Risk reduction and investigations manager Pete Gallagher said if someone noticed their battery beginning to malfunction, they should not try to intervene.

“If you see signs of batteries swelling or an unusual smell, disconnect immediately and get out of its way,” he said.

“There’s really no homeowner option for fighting a lithium-ion battery fire and that’s because the battery itself, once it enters the start of what we call ‘thermal runaway’, it’s a chemical reaction inside the battery that’s generating the heat, and there’s just no way to stop that.”

Even firefighters could not put out these fires straight away.

Firefighters rushed to the scene on Saturday night. Photo / Alex Cairns

“Essentially we allow the reaction to occur by keeping everyone out of its way. We let it do its thing until we’re able to cool it down. That’s not really an option for a homeowner.”

There had been numerous trials of methods to extinguish these fires, but there remained very little that could be done aside from allowing the chemical reaction to run its course.

FENZ was concerned Kiwis had little understanding of the risks of the batteries and how to use them safely, despite them being “in everything.

“We use them in our daily lives from cellphones to power tools, to laptops and computers, to e-scooters and e-bikes through to electric vehicles.”

The batteries are most at risk when they get too flat or are left on the charger longer than necessary. Gallagher said the batteries liked to be “stable”, so dropping below about 20 per cent charge could present a risk.

“If the batteries are abused, if they suffer some physical damage, if they’re dropped, that can also cause that chemical reaction inside the battery to start. It generates more and more heat. The heat can’t escape and they burst into flames.”

FENZ recommended people store and charge e-scooters and e-bikes somewhere other than inside their home, as they were larger and could potentially cause more damage if they caught fire than a cellphone would. But if people could not store them elsewhere, Gallagher recommended putting them in an area with a smoke alarm, and not in an exit-way.

“Lithium batteries can be used safely but you need to understand the risks involved with them and take adequate precautions.”

Gallagher also recommended installing smoke alarms as a preventative measure.

“Generally [the batteries] emit smoke before they fail catastrophically,” he said, adding a smoke alarm would give people the earliest possible warning system. They should then get themselves and others away from the battery and call 111.

Melissa Nightingale is a Wellington-based reporter who covers crime, justice and news in the capital. She joined the Herald in 2016 and has worked as a journalist for 10 years.