A lack of communication between crew members played a critical role in the crash of a container ship that led to a massive oil spill in waters off California nearly 15 months ago, federal safety officials said Wednesday.
The 901-foot-long Cosco Busan sideswiped the San Francisco-Oakland Bay Bridge in November 2007. Two fuel tanks ruptured and more than 53,000 gallons of fuel oil spilled into the San Francisco Bay.
Investigators told the National Transportation Safety Board Wednesday that the ship's captain and pilot had little discussion about how the pilot planned to guide the ship through dangerous local waters. For example, the safety officials said there was no discussion of the ship's proper speed or extra precautions that should be taken because of dense fog.
Investigators said the captain's lack of experience with the bay made him more dependent upon the pilot to guide the ship. Language differences also contributed to their lack of communication, and perhaps cultural differences did as well, with the captain less willing to question the authority of somebody with superior knowledge of local waters, investigators said.
Meanwhile, the pilot, John Cota, also committed several errors, including failure to interpret radar images and effectively question officials monitoring vessel traffic when questions arose about his course. Yet, the captain, Mao Cai Sun, didn't step in and take control despite troubling signals. Staff and board members seemed torn over which of the two bore the greatest responsibility for the crash.
Mark Rosenker, the acting chairman of the NTSB, said a competent captain would have demanded more information from the pilot before allowing the ship to leave its pier.
"A commander has the ability to delegate authority but never has the ability to delegate responsibility," Rosenker said.
Yet, investigators said that the captain may have made the problem worse if he had interceded at the last moment because the pilot took steps that avoided a head-on collision.
Investigators also said the pilot's medical records showed he had taken numerous prescription medications in the months leading up to the accident and that some of the medications are shown to have an adverse effect on cognitive performance.
Some NTSB members said they saw an even more fundamental problem that contributed to the accident.
"This accident started when they left the dock," said board member Debbie Hersman. "They should have never left the dock in those conditions."
No one was injured, but the spill contaminated 26 miles of shoreline. It also killed more than 2,500 birds of about 50 species and delayed the start of the crab-fishing season.
The cleanup cost more than $70 million.
Marine investigator Rob Jones told the board that he believed a competent crew could pass under the bridge despite the poor visibility.
"Ships do depart in fog," Jones said. "Ships did depart in fog before the Cosco Busan."
But Hersman replied that a more appropriate question was whether the ship should have attempted to clear the bridge -- not whether it could have done so.
During Wednesday's hearing, investigators were expected to formally cite the probable cause of the accident and to make recommendations on improving safety. The board can accept or reject the staff's findings.