A phoned-in bomb threat has forced evacuations near the Crown Center in Kansas City.

The building that was threatened is home to Blue Cross Blue Shield, a number of law firms, the Department of Commerce, the Census Bureau and the Federal Occupational Safety Health Administration. The message was left on a voicemail in the OSHA offices early this morning.

An estimated 1,500 people have been evacuated and sent home for the day. No one was allowed to take their vehicles out of the building’s underground parking.

Police are not commenting on the origin of the threat, but workers believe it was from a disgruntled former federal employee. Federal agents and Kansas City Police are searching the building with drug sniffing dogs.

The investigation continues.

AUDIO: Ray Read reports [:30 MP3]