Officials say the fire at an old abandoned brass factory was reported at 8:45 p.m.
As crews battled the blaze, authorities kept the public a few hundred feet back to give crews space to work and to keep everyone safe.
“We tried to walk and get closer, but they stopped us right there and told us we couldn’t go farther because there was a wire down,” said Elijah Coates of Waterbury.
“They’re making sure no one goes where they’re not supposed to, they’re keeping everyone safe from the fire zone and downed wires,” said Karen Smith of Waterbury.
Crews are still on scene working to put out hot spots.
For a period of time Bank Street was closed between West Liberty Street and Riverside Street. However, police say the road has reopened.
There has been no word on what caused the fire.
No injuries have been reported at this time.
News 8 will update this story with more information as it becomes available.