The fire broke out at the Rapid Process Paper Recycling Plant on Humboldt Street in Greenpoint around 7 p.m. and left four firefighters with minor injuries.
The flames could be seen for miles as the fire went to four alarms, fueled by tons of paper and cardboard inside. About 200 firefighters were on the scene.
The walls of the building became so unstable that firefighters had to pump water from a distance to avoid any collapse. Officials said the entire structure will have to come down after the scene is secured.
"The building was a recycling plant, and they had numerous bales of cardboard and rags," FDNY Deputy Chief Brendan McSweeney said. "We have numerous hotspots in there."
All the company's employees were accounted for, and no one was hurt except for the firefighters. Those injuries prompted the fight to be fought from tower ladders for safety reasons.
"We have deployed a tower ladder apparatus on the front of the building and a tower ladder apparatus on each side of the building," McSweeney said. "And they're being supplied by our engine apparatus with water. And from a high point, we are applying water to the interior components of the building."
At one point, firefighters used their ladder as a battering ram to break through a wall. Later, a long cinder block wall simply collapsed.
The fire is now contained, but it is expected to be hours before it is completely extinguished. The water was also flooding Greenpoint Avenue and Humbolt Street, sending paper and other debris floating down the street.
The Department of Sanitation was expected to respond after the fire situation is wrapped up, and the Department of Environmental Protection was working to keep the drains clear.