The fire broke out in a cooling tower on the roof. Heavy smoke from the fire filled the sky around the 12-story structure and could be seen miles away.
D.C. Fire and EMS spokesman Pete Piringer says the two-alarm fire was brought under control quickly and there were no injuries.
"Fire investigators are still conducting in to exaclty what may have happened. But, they believe the fire was accidential. Damage is estimated to be about $100,000, but again the good thing is the evacuation went smoothly and there were no injuries," he says.
It's not clear when workers will be able to return to the building.