The rooftop party turned into a rescue mission when the FDNY had to respond with 12 units and 60 firefighters after the stairwell collapsed.
Officials say the man that was injured was jumping on the stairs and was injured with fractured ribs and a broken ankle. He was being treated at Bellevue.
The buildings department says the building is safe, but people were not supposed to be on the roof.
Officials say the building has a lot of college aged students in the building that do a lot of 'partying'.
The investigation continues.