Empty Oil Tanker in Fender Bender With San Francisco-Oakland Bay Bridge

An empty oil tanker heading out to sea struck a tower in the middle of California’s San Francisco-Oakland Bay Bridge on Monday, causing little damage and no injuries.

The collision by the Overseas Reymar was a “glancing blow” rather than a direct hit, said Captain Peter McIsaac, port agent for the San Francisco pilots who navigate vessels moving into and out of the bay.

All lanes on the bridge remained open to traffic. The "fendering system," made of timbers with steel backing to cushion impacts, was damaged but there was no structural or foundation damage to the bridge, according to a state Transportation Department inspection team.

The tanker was passing beneath the bridge at the time and didn't release any oil, according to officials.

The collision occurred at 11:20 a.m. Pacific time, the U.S. Coast Guard told Bloomberg News in an e-mailed statement. The tanker, which was headed for Esmeraldas in Ecuador was damaged above the waterline, with no breach of the hull.

The San Francisco Chronicle reported that responses from local and state emergency teams were swift, especially compared to the last spill in 2007 that leaked 53,000 gallons of oil into the bay. The Cosco-Busan spill contaminated 26 miles of shoreline, killed 2,500 birds and delayed crab-fishing season.

“We stood people up in the command post, we had vessels on the water, booms were right there and ready as needed," Alexia Retallack, the spokeswoman for the California Department of Fish and Wildlife Office of Spill Prevention and Response, told The Chronicle. "There was no hesitation."

The pilot, whose name was not released, will report to the state Board of Pilot Commissioners, which will conduct its own investigation of the accident, according to CBS News.

The pilot has been working since 2005, according to Charlie Goodyear, a spokesman for the pilots association. California state law requires every large vessel to be guided by a pilot.

Officials said visibility at the time was about a quarter-mile, but they did not say that was the cause.

"There's always the human factor," Coast Guard Lt. Cmdr. Shawn Lansing told CBS News. "That is again what we'll look into and see whether, in fact, it was a human error or something else and take that into consideration in the development of future regulation."