The Sioux City Fire Department held a large-scale disaster exercise this morning that included a couple dozen departments from the surrounding tri-state area. Sioux City Assistant Fire Chief Jim Clark says the exercise included a simulated explosion, a building collapse, fuel spills, training fires and vehicle accidents.He says the idea is they can use the plan to coordinate large-scale activities for a petro chemical spill. Clark says the exercise planning involved federal, state officials, as well as the local departments. He says in order to test the plan they needed to bring in other people from the area. The exercise began at nine a-m and lasted until one o’clock. Clark says they’ll evaluate the exercise to see how they can improve their plans.