Twenty people were taken to the hospital with injuries this afternoon after a double-decker tour bus crashed near San Francisco’s Union Square, according to fire and police officials.
San Francisco police Officer Albie Esparza said four of those people suffered life-threatening injuries after the bus hit at least four vehicles and a construction site’s scaffolding near Post and Stockton streets.
The crash, which was reported at 2:57 p.m., also sent a bicyclist to the hospital with life-threatening injuries, Esparza said.
San Francisco Fire Chief Joanne Hayes-White said three people suffered moderate injuries but are expected to survive and 12 people have minor injuries.
Esparza said it’s unclear what caused the crash, but police are investigating whether it was a mechanical failure, a medical emergency or the influence of drugs and alcohol.
Esparza said the bus started picking up speed in the 500 block of Post Street, and then ran into the scaffolding and cars shortly thereafter.
It was initially reported that there were at least 30 people on board the bus, which stayed upright during the crash.
Hayes-White said crews had to extricate two people on the bus, including the driver, two pedestrians trapped underneath the bus and two people in vehicles involved in the collision.
“It’s going to be a mess tonight.”
The San Francisco Municipal Transportation Agency said the Powell Street cable car line is currently down and MUNI lines in the area are experiencing delays.