GRAND RAPIDS, Mich. (AP) — A large fire at a recycling center sent a huge plume of black smoke over the city of Grand Rapids on Monday, and was burning so hot that firefighters had to battle the blaze from aerial ladders.

Grand Rapids Fire Chief Brad Brown said that a large fire was blazing inside the building when crews were called to the PADNOS recycling facility at about 3 a.m., local news outlets reported.

“There’s a lot of metal shavings and oils in this building that we’re dealing with,” Brown said.

The roof collapsed mid-morning Monday.

No injuries have been reported. Authorities don’t believe anyone was in the building, but it was still too hot Monday morning for firefighters to enter. About 40 crews have been battling the blaze. Brown said he expects firefighters to be on the scene most of the day.

PADNOS employees were at the scene to open the building and allow fire crews to reach the fire.