A massive accident shut down the on Golden Gate Bridge this evening. Both north and southbound lanes were closed at around 8:20 p.m. "Four vehicles were involved in the crash that happened in the middle of the bridge at around 8:10 p.m.," reports BCN (via SF Appeal). "It was possibly a head-on collision, but that hasn't been confirmed." Drivers should use the Richmond-San Rafael Bridge as an alternate route.

We'll update as soon as we know more.

Update 9:20: Injuries appear to be minor. Also, no word yet on when the bridge will reopen. The Examiner reports: "There is no estimated time the bridge will be reopened. Traffic heading out of San Francisco is being stopped before the incline, but the effects are backing up city streets. San Francisco police are on scene to help hold traffic while the crash clears."