TULSA, Oklahoma - A bomb threat forced the evacuation of the IC Bus Plant at Tulsa International Airport Monday afternoon.

Workers told News On 6 the evacuation began at about 1 p.m. Security moved bus employees to the outside of the south end of the mile-long building.

IC Bus shares the building with Spirit AeroSystems which was also evacuated.

Employees told News On 6 managers told employees that if they had their car keys they could leave, the rest could only wait for the all-clear, which came at about 3:45 p.m.

The Tulsa County Sheriff's Office said bomb dogs from the Tulsa Police Department searched the building and found no device.

The building that was evacuated was originally built during World War II when it was called Air Force Plant 3. It contains 3.8 million square feet of floor space