More than 100 volunteers from Great Lakes naval base pretended to be injured passengers. The Federal Aviation Administration requires the airport to conduct such drills every three years.
"My heart always knows that we can do better. We try to do better, but today with what we were faced with, I think we did an excellent job," said District Chief John McNicholas of the Chicago Fire Department.
An outside group will evaluate how the emergency responders performed in Saturday's drill.