SIOUX FALLS, S.D. (KELO) — Employees working inside a Casey’s convenience store in Hull, Iowa, escaped without injury after a fire broke out this morning, the Sioux County Sheriff’s Office said.

The fire was reporter earlier this morning.

Emergency crews from Hull, Rock Valley and Sioux Center responded. Emergency personnel were advising traffic to drive with caution in the area because of thick smoke and fire personnel.

The cause of the fire is unknown as of now.