Crews are investigating a fire that broke out in the back warehouse of Banner Supply on Youngstown's south side just before 7 a.m. Tuesday.

The warehouse contained mostly vinyl, shingles and a few vehicles, all of which could have served to fuel the fire, officials said.

No one was injured in the fire, but officials said the entire building was engulfed in flames and smoke was visible from miles away.

Damage is expected to exceed $3 million.

Investigators are still looking for a cause.