City inspectors previously repeatedly cited The Bronx high-rise where 17 people died in a fire for failing to maintain its self-closing apartment doors — a key defense against rapidly spreading blazes.

Fire Commissioner Dan Nigro singled out malfunctioning self-closing doors during a Monday press conference as a key reason smoke from the flames quickly engulfed much of the 19-story tower in the Twin Parks Northwest complex Sunday, killing at least eight kids and nine adults.

The fire initially erupted in a duplex apartment that spans the second and third floor — and the damage from the flames was confined to that part of the building, according to Nigro.

But Nigro said the failure of the unit’s self-closing door to properly shut allowed the toxic smoke to billow out into the hall. That failure was further compounded as at least one other broken door on higher floors allowed the toxic air to spread.... Read More: NY Post