I've gone back over this article multiple times and I just get more curious about what the hell happened. According to the information given "the battery sparked an explosion outside the apartment" What exploded? Was it the battery or something else? Then they say the burned up scooter was in the stairwell, but the photo shows that obviously the scooter didn't burn up in the stairwell. Then they say the fire was contained to the one apartment, but how is that possible if the scooter exploded in the hallway?
"He had two electric scooters and one gas scooter. All three of them were in his apartment," I don't know of anyplace where it's okay to have a gas powered vehicle of any sort inside your apartment in NYC.
At this point I am of the opinion that something (maybe one of the battery packs, maybe not) somehow triggered a gasoline fire from the gas powered scooter. While no less a tragedy, it paints an entirely different picture.