A Loudoun County Transit commuter bus struck the back of a construction vehicle on the Dulles airport access highway about 9:10 a.m., injuring several riders and tying up traffic in the area.
Dan Schmidt, spokesman for Fairfax County Fire and Rescue, said 13 patients are being transported to area hospitals, a few with serious injuries, but none appear to be life-threatening.
A fuel leak is coming from the bus.
The accident occurred at the Dulles Toll Road and Trap Road. The access road is shut down and traffic is being diverted.