The all-Chinese crew of the cargo ship that sideswiped a bridge, causing San Francisco Bay's worst oil spill in nearly two decades, were being held for questioning as part of a criminal investigation, a US Coast Guard official said.
The Cosco Busan, which leaked 220,000 liters of heavy fuel oil into the bay on Wednesday, fouling the coastline and killing dozens of birds, was being detained at the Port of Oakland by the Coast Guard. Crew members will be free to go once federal investigators have questioned them, said Captain William Uberti, the Coast Guard commander for the bay region.
Darrell Wilson, a representative for Regal Stone, the Hong Kong-based company that owns the Cosco Busan, declined to comment on Sunday on the investigation.
Uberti said he notified the US attorney's office on Saturday about problems involving management and communication among mem-bers of the crew on the ship's bridge. This includes the helmsman, watch officer and ship's master -- part of the Cosco Busan's Asia-based crew -- as well as the pilot, Captain John Cota, among the most experienced of the seamen who guide ships through the bay's treacherous waters.
Uberti declined to specify what problems he reported to federal prosecutors.
"It was just the way that everybody interacted" on the bridge, he said.
A call to the US attorney's office for Northern California was not returned on Sunday.
A preliminary Coast Guard investigation found that human error, not mechanical failure, caused the ship to crash into a support on the San Francisco-Oakland Bay Bridge.
The wreck left a gash nearly 30m long on the side of the 282m vessel and ruptured two of the vessel's fuel tanks, causing heavy bunker fuel to leak into the bay. The spill has killed dozens of sea birds and spurred the closure of nearly two dozen beaches and piers.
Investigators were focusing on possible communication problems between the ship's crew, the pilot guiding the vessel and the Vessel Traffic Service, the Coast Guard station that monitors the bay's shipping traffic.
A language barrier between Cota and the ship's Chinese crew was not likely a factor in the crash, since the ship's captain and officers are required to speak English, officials said.
The National Transportation Safety Board (NTSB) arrived on Sunday to launch its own investigation. The agency will look at everything from how fatigued the ship's crew and captain were to any mechanical or weather issues that may have been involved in the accident, said Debbie Hersman, a spokeswoman for the safety agency.
The NTSB's investigation, expected to take up to a year, will also examine the initial response by the Coast Guard and the company who owns the vessel, she said.
Hersman would not say whether the NTSB's inspectors would aid federal prosecutors but did say her agency would cooperate with all parallel inquiries.
Meanwhile, the head of the Coast Guard defended his agency's response to the spill while pledging a full and transparent investigation.
"On the surface it would appear that we did everything by the book in this case as far as responding," Commandant Admiral Thad Allen said.
The Coast Guard has come under criticism because of a lag of several hours between when agency officials learned that the spill was thousands of liters -- not 530 liters as initially reported -- and when that information was given to local officials and the public.