BUSHWICK, Brooklyn (WABC) -- Investigators discovered 50 lithium ion batteries after a fire that left a person critically injured in Bushwick.
Heavy flames shot from the second floor of the building on Goodwin Place just after 1:45 a.m. Tuesday.
A 67-year-old woman was rushed to the hospital with injuries described as critical. At least one other person was also injured.
Fire marshals say the culprit was a lithium ion battery.
It is believed a resident of the building was running a makeshift E-bike repair shop.
"When these catch on fire, they burst into flames and there is almost no way out of your room or your apartment," said FDNY Commissioner Laura Kavanagh.
Witnesses said the fire sounded like an explosion.
"We did find several batteries in there, approximately 50 inside, we believe that one of the occupants was repairing the batteries in the home," said Chief fire Marshall Dan Flynn. "There were also many that were charging at the time, nobody was watching them charge. They were charging overnight."
Lithium ion batteries have been the FDNY's top concern in recent years.
Since 2019, there has been an alarming rise in fires, injuries and deaths -- nearly eight times as many fires in that span and more than nine times the number of injured.
It is sparking so much concern the FDNY commissioner recently sent a letter to the Consume Product Safety Commission, thanking it for issuing multiple recalls of E-bikes.
Flynn had a message for anyone who owns one:
"Don't charge them overnight, don't charge them unattended, make sure they are not blocking your primary means of egress. Always have a second way out. Don't repair them. If the battery is not working properly, replace it. Don't try to fix it."
Also make sure to buy a certified battery and don't mix and match batteries with different E-bike brands.
The legislation the FDNY has been lobbying for would ban sales of black market lithium ion batteries.