A fire tore through an NYPD warehouse in Brooklyn on Tuesday, potentially damaging years’ worth of “biological evidence,” authorities said.

The three-alarm blaze broke out inside a warehouse at the NYPD’s Erie Basin Auto Pound, along the Red Hook waterfront, around 10:30 a.m., FDNY Chief of Department John Hodgens said at a news briefing.

Outside contractors working at the site discovered the fire and alerted police and the FDNY, NYPD Chief of Department Jeffrey Maddrey said at the briefing.

The NYPD uses the warehouse to store “biological evidence,” including DNA from past crimes like burglaries and shootings, Maddrey said. The facility also houses confiscated e-bikes and historic vehicles, he said.  

The department does not store rape kits at the site, he noted.

“The evidence goes back a long time, 20, 30 years,” he said. “Some of the evidence was also from [Hurricane] Sandy, probably from Sandy, as well.”

Firefighters who arrived to the scene of the massive fire Tuesday morning attempted an “interior fire attack,” but became “overwhelmed by the amount of fire,” Hodgens said. They soon switched to an “exterior attack” that used drones and FDNY marine boats, he said.

A total of 150 firefighters and EMS personnel responded to the blaze, which left three firefighters, three EMS personnel and two civilians with minor injuries, according to Hodgens.

Hodgens said the warehouse was “not really a very sturdy type of building,” leaving it with “large collapse potential.”

The FDNY said the fire was under control at 6:04 p.m. on Tuesday. 

The NYPD will not know the "magnitude of what was destroyed in there" until firefighters put out the blaze, Maddrey said.

It wasn’t immediately clear what sparked the blaze. An investigation is ongoing.