An e-cigarette battery exploded in a man's pocket in front of horrified shoppers.
Dramatic footage of the incident captured on CCTV shows the man running from a pram, as others ducked for their own safety.
The man was left with "slight injuries" following the incident, which happened in a Boots store in the Trinity Shopping Centre in Leeds on September 19.
West Yorkshire Fire Service said the incorrect storage of the batteries was to blame.
The fire service said the man had spare lithium-ion batteries for his e-cigarette loose in his pocket and a short circuit was caused when one of them came into contact with a metal item also in his pocket, possibly keys or coins.
It added that it was also possible that the two batteries shorted-circuited on one another.
Fire Investigator Jamie Lister said: "This footage clearly shows the dangers of storing batteries alongside any metal objects, be it keys, coins, or even your phone if it has a metal case.
"This is not the first time we have seen injuries caused by a lithium-ion battery exploding whilst being carried in someone’s pocket.
“There does not need to be a fault with the battery, the problem is the incorrect storage of the batteries.”
“There has been a marked increase in the number of fires we have seen, attributable to the incorrect storage of batteries.
“The use of rechargeable lithium-ion batteries is now commonplace in modern society and that’s why we want people to be vigilant because a simple mistake could have a devastating consequence.”
Fire service advice for staying safe with e-cigarette batteries
Use a plastic battery storage case which prevents the terminal ends making contact with anything metal or each other.
Never use damaged batteries.
There does not need to be a fault in the lithium-ion battery.
Fires happen when the ends of the battery (terminals) are exposed and come into contact with another metal object, causing a short circuit.