The FDNY commissioner announced Friday that the deadly East Village fire was caused by lithium batteries from an e-bike.

Investigators say in that apartment there were at least seven e-bikes responsible for the fire on Thursday.

One man died, a woman was critically injured and two teens were injured.

Fire officials warn that when the batteries are damaged or overcharged, they release hydrogen gas and explode violently.

"The intensity of this fire was such that it blew the windows out and actually blew a wall down within the apartment on top of a bed in which these teenagers were sleeping," says Commissioner Daniel Nigro. "So, what we are urging is as we approach Christmas and we know some people will get these bikes for gifts, they should not be charged overnight. They should not be charged in an area where you are sleeping or by an exit door."

Nigro says he would prefer they are charged outdoors in an unoccupied space.

Investigators say this year alone, 75 fires in the city have been caused by batteries in e-bikes, killing a total of four people. Those numbers are up from last year, with 44 fires reported and zero deaths.