A sauna fire on Fire Island early Saturday morning sent flames 60 feet in the air, a witness said, and destroyed a million-dollar home before firefighters working through the night were able to extinguish the blaze.

The Fire Island Pines Fire Department responded just after midnight to a call regarding a smoky condition inside 234 Bay Walk, Chief Kyle Merker told Newsday.

Assistant Chief Jordan Cohen, who was first on the scene, determined that the smoke was coming from a locked sauna room, the chief said.

“The fire developed very, very quickly,” Merker said. “When I got there, the bottom floor was pretty much engaged, and it was rapidly taking over the rest of the building.”

The wind blowing off the bay fueled the fire, which blew out the windows and spread to the propane barbecue grill on an outside patio, causing the tank to explode, the chief said.

The structure collapsed from the damage and firefighters were forced to cut a hole in the downed roof to pour water onto the remaining embers, he said.

One firefighter put his leg through a floorboard, but was not seriously injured, Merker said.

A photo of the aftermath, posted on the Fire Island Pines Fire Department's social media page, shows the charred black remains of the wooden structure.

A rental ad for the property describes it as a two-story, four-bedroom home with “a formal dining room and state-of-the-art kitchen.” The home also had three and a half bathrooms, a heated pool and a hot tub.

Merker said that it took 120 firefighters from 17 departments, including fireboats from Sayville, East Islip and the Suffolk County Police Marine Bureau, to bring the blaze under control.

“The police marine bureau used their deck gun and really helped to knock down the east side of the fire,” Merker said.

The chief said that part of the firefighting effort was spent preventing it from spreading to neighboring buildings and responding to other calls.

Bob Tortora, the vice president of the Fire Island Chamber of Commerce, said that the fire could be seen from the mainland and flames shot at least 60 feet in the air.