Hazmat firefighters in Somerset and Bristol investigating ways of fighting fires caused by a type of battery found in smartphones and e-scooters.

Lithium-ion batteries are rechargeable batteries used in all sorts of electrical devices. Although safe when used properly, if misused or damaged the batteries can go into "thermal runaway" — causing a fire that can pose a particular challenge to firefighters.

These fires can return after apparently being extinguished and local firefighters are part of a national effort to find new ways to fight this challenge. 

At a meeting of the Avon Fire Authority — which runs the fire service across the former county of Avon area — on March 29, councillor for Bathavon South and member of the fire authority Neil Butters said: "Lithium batteries was mentioned. […] I was wondering what degree there is a coordinated response nationally to dealing with them?

"Because there is this problem of [Lithium-ion battery fires] seemingly going out and then coming back again. I think I heard recently of one authority that had a completely submersive arrangement for dealing with them."

Sean Spearing, Avon Fire and Rescue Service's group manager for risk management, said: "We are seeing some services that have taken steps to look at containment.

"Now if we look at containment — and that is a large skip […] that we can put a vehicle in that has a thermal runaway — the issue then becomes that there is no clear evidence that the water contained in there will immediately put it out because thermal runaway is about the energy in each cell that carries on though to each battery cell as it goes and keeps going — even under the water."

Mr Spearing added that if a vehicle was submerged for a long period of time, there was then an issue with what to do with contaminated water.

He said: "I am also a hazmat officer within the fire and rescue service. It's something that we are looking at as a service, but also through tactical hazmat, and other agencies that are looking at how we would actually effectively manage lithium ion batteries going forward."

When a lithium-ion battery fire tore through a warehouse of Voi e-scooters last year in Bristol where there is an e-scooter trial, firefighters had "considerable difficulty" extinguishing the blaze, with the e-scooters having to be submerged because their batteries were sealed.

Brenda Massey, who chairs the fire authority, branded the vehicles a "fire risk."

Responding at the time Voi UK general manager Jack Samler called it a "rare incident" and said: "Voi has strict measures in place to ensure all batteries are handled and stored in a safe manner throughout its operations."

A Voi e-scooter trial was also rolled out in Bath. One was considered in Weston-super-Mare but scrapped amid safety fears for children and the elderly.