Two buildings heavily damaged in Wednesday night’s five-alarm warehouse fire in Red Hook are structurally unstable and could collapse, FDNY officials said Thursday.

Battalion Chief Timothy Gimpel said the fire tore through Building 9 of the complex at 481 Van Brunt St. and extended into Building 10. Both are now unsafe.

“The stability of nine and ten, not good right now,” Gimpel said. “They’re going to erect a fence around this area just to anchor and establish a collapse zone so that nobody can go in there and just in case the building comes down.”

Gimpel said structural engineers will shore up the buildings before investigators can enter to determine the cause of the fire. He warned the process will take time.

The warehouse also housed artist studios, and many are concerned about losing their work. Gimpel said officials are working with the property manager and the city’s Office of Emergency Management to eventually allow access, and retrieve the artwork but it could take several days.

The fire began around 11:30 p.m. Wednesday and grew to five alarms by 2:30 a.m., drawing more than 250 firefighters and EMS members. The 150-year-old timber structure fueled the flames, leading to a roof collapse and partial collapse of the fourth floor. Two firefighters were treated for minor injuries.

Crews remain on scene monitoring hot spots.