Hazmat teams are responding to an emergency in Montgomery County after a 1000-gallon propane tank began to leak when its valve was sheared off. The incident was reported around 10 a.m. at Suburban Propane on Derwood Circle in Rockville. Rail traffic along a portion of Metro's Red Line between the Shady Grove and Twinbrook stations has been suspended. Passengers in these stations have been evacuated. Some CSX tracks in the area have also been closed to train traffic. No fire or explosions have been reported. Spokesperson for Montgomery County Fire and Rescue Service, Pete Piringer, said Metro and rail traffic could be shut down for several hours.