Multiple 911 calls came just before 9:00PM on Monday Evening for reports of fireballs and explosions.

Sioux City Fire Rescue responded to 2300 Boulevard of Champions for multiple reports of a very big explosion and fireball. As they arrived on scene they found a building engulfed in flames that had started to collapse.

It took about an hour for firefighters to extinguish the blaze fueled by gas cylinders stored in the building. They will remain on scene throughout the night to watch for flare-ups.

The building owned by Lessard Contracting appeared to be a total loss, officials will begin their investigation on Tuesday. There were no reported injuries.