Firefighters have battled two major fires suspected to be caused by faulty lithium-ion batteries across Sydney over the past two days.
A passing firefighter came to the rescue after an e-bike being ridden by a 15-year-old boy along Botany Road in Alexandria burst into flames about 8am on Wednesday.
The boy, who was heading to school, said he felt heat emanating from the battery, which was burning his legs when he was riding it.
Fire and Rescue NSW said the fire occurred when the lithium-ion battery went into thermal runaway.
Thermal runaway is the process when a lithium-ion battery overheats to such a point that materials within the battery cell gasify, building pressure until it explodes.
FRNSW HAZMAT team leader David Jordan responded to the fire, noticing a large black plume of smoke while driving along Botany Road.
"At first, I thought it was a building fire, the smoke was so thick, so I turned the corner and pulled over to assess the situation," Mr Jordan said.
A FRNSW crew later arrived on the scene and extinguished the fire with Mr Jordan.
Firefighters extinguished the blaze. (Supplied: FRNSW)
The teen was unharmed in the incident.
He told firefighters he borrowed the bike from a family friend the night before, and that it had been purchased from a retail store two months prior.
FRNSW said a faulty battery array was behind the fire.
Acting Assistant Commissioner — Community Safety Brendan Cox said this it was fortunate that the teenager wasn't harmed, but that this was a reminder of the risks with lithium-ion batteries.
"Keep an eye on the condition of your devices and ensure they are not damaged or compromised," he said.
House fire believed to be caused by faulty battery
It comes a day after a suspected faulty lithium-ion battery caused a fire to start inside a home at Merrylands.
Emergency services were called to an address on Murray Street after the blaze broke just before 2pm on Tuesday.
A major fire broke out at a property in Merrylands on Tuesday morning. (Supplied: Fire and Rescue NSW)
Six fire trucks and more than 24 firefighters arrived at the scene and battled the intense fire for about 90 minutes.
The fire caused extensive damage to the property.
No one was injured.
FRNSW investigators assessed the scene after the blaze was extinguished and found a large stockpile of lithium-ion batteries and e-bikes inside.
It's believed an e-bike spare parts business was operating at the property.
Investigators believe an e-bike spare parts business was operating at the property. (Supplied: Fire and Rescue NSW)
Year-on-year rise in battery fires
The number of battery-related fires in the state has grown year-on-year.
In NSW, there have been 185 lithium-ion battery-related fires in the first seven months of 2024, according to FRNSW data.
By comparison, there were 163 fires within that same time frame in 2023, and 109 fires in 2022.
FRNSW Commissioner Jeremy Fewtrell told ABC News last week that battery fires have become a top issue for firefighters.
"I would say across firefighters in general, and the firefighting industry, it's the top issue at the moment getting attention, as it should be," he said.
Commissioner Fewtrell said FRNSW was working with other government agencies to determine the best way to address the rising number of fires in the state.