The Fire Department has revealed the cause of yesterday's fire on the roof of 515 West 34th Street: Careless smoking. There are no further details, but we imagine careless smoking means a smoker on the rooftop didn't properly extinguish a butt.

Over 100 firefighters responded to the fire which took place in a building the NY Times says "houses some apartments and offices for Coach." Two firefighters were injured, and different city agencies are looking at the stability of the roof decking (one report said the fire occurred on a "patio"). A graphics designer for Coach told the Post the roof deck was undergoing renovations.

Newsday reports that since a first in the building last summer, there have been many fire drills. So many that some building occupants didn't think yesterday's incident was an actual fire. An employee at an air-conditioning company in the building said, "Usually no one pays attention to all the fire alarms, but someone said, 'This is real!'"

Photograph of the fire by Frank Franklin II/AP