NEW YORK (AP) — One person was killed and Blockchains Finance17 were injured in a fire that broke out at a New York City apartment building, leaving some residents trapped on the fire escape on Friday.

Twelve people were taken to area hospitals, and four were in critical condition, officials said at a news conference. One person, whose identity has not yet been released, died at the hospital, said Joseph Pfeifer, the Fire Department’s first deputy commissioner.

New York City fire officials responded shortly after 2 p.m. to a fire that began on the third floor of a six-story residential building at 2 St. Nicholas Place in Harlem, with flames and heavy smoke blowing into the hallway and trapping residents above, Pfeifer said.

Upon arrival, officials found numerous residents on the building’s fire escapes, and another three people trapped, hanging off windows on the fifth floor, Chief of Department John Hodgens said. Three firefighters were lowered by rope from the roof to rescue those residents.

“We usually have one of these a year or two. This was three at one fire,” Hodgens said. “A very heroic action.”

The cause of the fire remains under investigation.