A man was killed in a Brooklyn blaze early today, authorities said.

The 39-year-old accidentally started the fire while smoking in bed at a second-floor Midwood residence on Ocean Avenue near Avenue I, police sources said.

Sixty firefighters rushed to the scene, extinguishing the flames shortly before 1:15 a.m., according to an FDNY spokesman.

The man, whose name was not yet released, died at Kings County Hospital, after EMS rushed him there in critical condition.

Fire marshals don’t believe the fire is suspicious after a preliminary investigation, authorities added.