Firefighters immediately began pulling residents from the house on 90th Street when fire broke out just after 9 a.m.
The body of Christopher Miller was found on the first floor, where the fire is believed to have started in a fireplace. He was pronounced dead at the scene. Authorities say he was overcome by smoke and was found at the bottom of the stairs.
FDNY Marshals determined the fire was caused by embers from the fire place that ignited blankets and pillows on fire. There was no screen in front of the fire place, which prevents that from happening. There were also no working smoke alarms.
The young adults tried to put out the blaze, said fire department Chief Mike Ferran, but by the time they called the fire department it was out of control, he said.
The FDNY says the 12-year old suffered severe burns, mostly to his arms and hands. He is in stable condition.
The young adults and a grandfather were in the basement and escaped.
At least three firefighters suffered minor injuries.