Pedestrians and vehicles have been ordered out of the area surrounding Post and Mason Streets in downtown San Francisco after a construction crew hit a gas main line around 2:15 today. Gas was seen and heard escaping into the air from the street by onlookers.

Robert Lau, an employee at the JW Marriot in downtown San Francisco, explained that he was stopped by a police barricade while he was walking to work. He contacted his manager, who told him the hotel is being ordered to shelter in place.

Media relations spokesperson for SFFD Mindy Talmadge explained that emergency response expects to have the incident contained shortly, and noted that emergency response efforts are being executed normally.

“Everything is going par for the course,” said Talmadge.”This is not an unusual event.”

Occupants of the evacuated building are expected to be able to return shortly, according to Talmadge, who explained that the building was evacuated because it is “old” and some windows were unable to be closed.

Police are clearing traffic in the area and pedestrians within a one-block radius have been asked to leave.

San Francisco Fire and Police Departments and PG&E are all on-scene and working to resolve the issue.

UPDATE 3:55 p.m.: San Francisco Muni temporarily halted Powell cable car service due to the gas leak, but service has been restored. Cable cars are bypassing the affected area.

UPDATE 4:12 p.m.: The flow of gas has been stopped, but repairs are continuing. There is still no word on when those evacuated would be able to return to the building.

UPDATE 4:40 p.m.: Shelter-in-place has been lifted. All SF Fire Department units have left the scene, according to SF Fire Department spokeswoman. PG&E remains on the scene to continue repairs.

UPDATE: Repairs were completed at 5:15 p.m. Pilot lights were relit for affected customers at 6:30 p.m. All streets open.