Authorities say a 1-year-old boy is dead and two other children are fighting for their lives after a fire erupted inside a building on Bainbridge Avenue on Monday.

Fire officials say 79 firefighters and EMS personnel arrived at 2609 Bainbridge Ave. just before 3:30 p.m. Crews found and rescued the 1-year-old and two 6-year-olds, a boy and a girl, from the second-floor apartment where the fire started.

The children suffered smoke inhalation injuries. EMS rushed them to St. Barnabas Hospital, where the 1-year-old died, according to police. The two 6-year-olds are listed in critical condition.

Two adults and three firefighters suffered minor injuries and were taken to local hospitals, according to fire officials.

Citizen app footage shows black smoke rising from the rooftop while firefighters work their way inside from the fire escape.

Firefighters got the blaze under control just over an hour later.

The Red Cross tells News 12 its Disaster Action Team is on scene and working to connect with impacted residents.

During an FDNY press conference, Malcolm Moore, assistant chief of Special Operations for the FDNY, said it appeared the apartment door was left open, allowing the blaze to rapidly spread up the building's staircase, but crews were able to save another resident from a top-floor apartment.

Moore stressed the importance of closing the door — a topic the FDNY addressed in a press conference just four days ago.

“Please close the door when there’s a fire in your building,” said FDNY First Deputy Commissioner Dan Flynn during Thursday's event. “Close every door possible, every door in a public hallway, every door in your building, every door to your apartment.”

Moore says the building's hallways and the front portion of the apartment where the fire started suffered extensive damage, but the rest of the building is mostly undamaged.