The deadly fire that killed 17 people in New York City on Sunday started with a malfunctioning electric space heater, but the smoke that took most of the lives spread because the burning apartment's door was not closed as residents fled.
It is a common thread in some of the city's worst fires of recent years, with tragic consequences.
"The door to that apartment, unfortunately, when the residents left was left open, it did not close by itself. The smoke spread throughout the building, thus the tremendous loss of life," FDNY Commissioner Daniel Nigro said at a Sunday news conference.
In fact, Nigro said, the fire never got beyond the hallway in front of the origin apartment.
In Photos: Bronx Blaze, Worst NYC Fire in 30+ Years, Leaves Dozens Gravely Injured
Another deadly Bronx fire, in 2017, had much the same story -- a blaze started in one apartment, but an open door meant smoke spread and took many more lives.
In the three months after that fire, city officials issued more than 3,800 violations for faulty fire doors that should have closed on their own but did not. They also moved to make fire door inspections mandatory, such that inspectors would have to check doors even if called out to a unit for another complaint.
The fire commissioner said Monday that doors in the apartment building were self-closing, but the door to the duplex unit and one on the 15th floor were not functioning properly. Mayor Eric Adams said the building had few violations, none related to the fire, and Nigro said the federally funded building may have been built outside city fire codes.
The FDNY has an ongoing campaign called "Close the Door" where it encourages people to close doors behind them as they flee fires.