A federal criminal investigation has been opened into an oil spill in San Francisco Bay that began when a cargo ship hit the San Francisco-Oakland Bay Bridge last week, the U.S. Coast Guard said Sunday.

A federal criminal investigation has been opened into an oil spill in San Francisco Bay that began when a cargo ship hit the San Francisco-Oakland Bay Bridge last week, the U.S. Coast Guard said Sunday.

“The U.S. attorney’s office has opened a criminal investigation,” Coast Guard Lt. Anya Hunter told reporters.

The oil spilled from a South Korea-bound container ship in dense fog Wednesday.

On Saturday a National Transportation Safety Board team was on its way to California to investigate the cause of the accident which spilled 58,000 gallons of oil into the water.

The oil — heavy-duty bunker fuel from the 900-foot-long ship — has spread along the San Francisco city waterfront and out of the San Francisco Bay, beneath the Golden Gate Bridge toward Marin County.

Authorities closed several beaches and shorelines to the public because of health concerns. They also banned fishing in key locations on Port of San Francisco property.

“We’re going to learn from this case, we’re going to prevent the next one, if at all possible, and if there are people responsible or accountable … they’ll be held accountable,” the Coast Guard’s Rear Adm. Craig Bone said during a news conference Saturday.

It is not unusual for the NTSB to send a team to investigate, he said.

“Any type of incident that is large in nature and has large catastrophic consequences, we counsel with NTSB to discuss whether or not that type of investigation is warranted,” Bone said.

Meanwhile, a member of Congress expressed her uneasiness to the Coast Guard about its handling of the collision and resulting spill.