A deadly blaze killed a 58-year-old woman in her Williamsburg apartment last night, authorities and her neighbors said.

The fire began at about 9:15 p.m. in the third-floor apartment of a woman identified by her neighbors as Ellen Luckey.

More than 100 firefighters fought the roaring inferno, which engulfed the third and fourth floors of the four-story apartment building on Conselyea Street near Graham Avenue.

Though fire officials released no specific cause for the blaze, neighbors said Luckey likely started the fire with a cigarette.

“She’s always smoking. Everyone knows she’s bad with fire,” said neighbor Lisa Cappiello.