DEATH TRAP

FDNY fire hero collapsed in Harlem inferno

Hero firefighter Michael Davidson lost his life Thursday night in this Harlem building blaze when his oxygen tank ran out and he collapsed amid pitch-black smoke before his fellow B rave s t could find him.

The firefighter who died in a Harlem blaze ran out of oxygen and collapsed in a wall of blinding smoke as he tried to escape the burning basement, sources told The Post on Friday.

His fellow Bravest from Engine Co. 69 had made it to safety during the Thursday-night inferno — and realized Michael Davidson, 37, was missing only when they got outside.

The father of four from Floral Park, LI, had passed out inside the St. Nicholas Avenue building during the 11 p.m. blaze. A short time later, he was dead. The tragedy struck one floor below the shuttered St. Nick’s Jazz Pub, which was being used that night for the filming of “Motherless Brooklyn,” a movie from the actor Edward Norton. In addition to writing and directing the film, Norton stars in it with Bruce Willis and Alec Baldwin.

The film crew had shot scenes for the movie that day and were wrapping up when Norton noticed smoke spewing from the basement.

The actor flagged down a cop from the NYPD’s Movie-TV Unit, and the officer radioed for help.

With Davidson leading the charge as the company’s nozzleman, firefighters plunged into the darkness of the five-alarm cellar blaze.

They hauled their hose down a short landing onto the floor of the former bar, then down another flight of stairs.

What they found was a hellscape of lapping flames and billowing smoke, with the base of the fire toward the rear.

“They did the best they could,” FDNY Commissioner Daniel Nigro said at a press conference.

But they were ordered by a deputy chief to fall back as their oxygen supplies dwindled and the structural integrity of the nearly 100-year-old building rapidly deteriorated, sources said.

With the fire crew following their hose back out, Davidson made it as far as the bar before his air ran out, sources said.

In the pitch-black of the crumbling five-story brownstone, his colleagues never saw him drop, sources said.

They fled outside, but once they realized he was missing, they went back in for him and found him passed out and badly burned on his legs, sources said.

He was taken to Harlem Hospital Center, where he was pronounced dead.

Both a son and brother of FDNY firefighters, Davidson leaves a wife, three daughters, ages 1, 3 and 7, and a 6-year-old son. His wife is a breast-cancer survivor.

Two other firefighters were hospitalized with serious but non-life-threatening injuries, and three civilians were treated for minor injuries at the scene.

As Davidson’s family and colleagues mourned him Friday, FDNY and NYPD investigators at the scene tried to piece together the cause of the conflagration.

The NYPD’s Crime Scene Unit was outside the building photographing a production truck and several “junction boxes” used for “Motherless Brooklyn” — which has been filming in the brownstone and surrounding neighborhood since March 6.

But there was no indication the shoot played a role in the blaze.

The Stephen Siller Tunnel to Towers Foundation announced Friday that it’s donating $100,000 toward Davidson’s mortgage.

“The producers, crew and staff of the movie have agreed to work with Tunnel to Towers to help it reach its goal of getting the mortgage paid off,” the foundation said.

Investigators also want to look at the building’s boiler, which the landlord had worked on as recently as Wednesday.

Department of Buildings records showed 21 open violations against the building dating to the early 2000s, including at least two for failing to file an annual boiler inspection.

The landlord, Vincent Sollazzo, couldn’t be reached for comment.

The investigation was hampered by hazardous conditions inside the blackened husk of the building, including unstable support beams and about two feet of standing water in the cellar, sources said. Crews must shore up the structure before sending fire marshals in.

Davidson is the 1,150th FDNY member to die in the line of duty.

He is also the the sixth member of the FDNY family to die in 12 days.