An oil ship has hit a tower of the San Francisco Bay Bridge but did not appear to spill any oil into the bay.
The 750-foot-long Overseas Reymar, sailing under a Marshall Islands flag, was empty except for water that was used as ballast, US Coast Guard Lieutenant Heather Lampert said.
The tanker was about eight kilometres from the Golden Gate Bridge, where the San Francisco Bay opens into the Pacific Ocean.
None of the channels or ports in the San Francisco Bay were listed as shut, according to the Coast Guard's website.
California Department of Transportation inspectors were sent to check for damage to the Bay Bridge, which links San Francisco and Oakland.
The tanker struck a fender at the foot of a support tower in the bridge's western span.
"The fender took the hit like it's supposed to," said Randy Rentschler, director of public affairs at the California Metropolitan Transportation Commission.
He said the collision did not appear to have caused any significant damage to the bridge.
In 2007, the tanker Cosco Busan spilled more than 200,000 liters of heavy fuel oil after striking the Bay Bridge in heavy fog.