A 19-year-old man was seriously injured when he fell off a seventh floor fire escape in Hell’s Kitchen, where he was smoking a cigarette, police sources said.

The man had just finished puffing the butt, and was attempting to climb back into the West 44th Street apartment through a window, when he slipped at around 6:30 p.m.

He survived the plunge, but suffered head trauma and multiple fractures, officials said.

He was rushed to Bellevue Hospital in critical condition.