The building housed 26 apartments on five floors that were connected by a central staircase, which filled with smoke early during the fire because of the open door.

As the apartment's kitchen went into flash over heat erupted from the open doorway and ignited multiple layers of oil-based paint in the main stairway.

The New York City Fire Commissioner compared the stairway to a "chimney"[7] as it became a conduit for thick, toxic smoke via the stack effect.

Smoke seeped into rooms through door frame and ventilation systems, setting off fire alarms throughout the complex and awaking residents.

Temperatures that morning were in the teens with wind chill in the single digits, requiring some firefighters to huddle together for warmth as they sprayed water on the blaze.

New York City officials determined shortly afterwards that the fire had started as a result of a child playing with stove knobs.