SAN FRANCISCO -- The attorney for the pilot of the freighter that spilled 53,000 gallons of oil into San Francisco Bay is blaming the Coast Guard and others for the mishap and said Friday his client will refuse to testify next week at a government hearing investigating the crash.

Federal prosecutors charged Capt. John Cota last month with environmental crimes stemming from the Nov. 7 incident, when the Cosco Busan sideswiped a support tower of the San Francisco-Oakland Bay Bridge in heavy fog. The crash fouled the fragile bay with sludgelike fuel, killing or injuring thousands of birds and temporarily closing several beaches.

Cota's lawyer Jeff Bornstein said the Coast Guard had the responsibility to track the ship and warn the pilot a crash was imminent.

"They had the last clear chance to avoid the accident," Bornstein said outside court Friday after a May 27 trial date was set for his client. "To put all the blame on Captain Cota is unfair and unjust."

Cota also has said the radar on the Cosco Busan was unreliable and there was confusion about symbols on at least one of the navigational charts.

Bornstein said Cota would refuse to answer questions from the National Transportation Safety Board next week at a two-day hearing in Washington because of the pending charges. He has written a letter to the board saying Cota will invoke his 5th Amendment right against self incrimination.

"This is not to suggest that Captain Cota has 'anything to hide' and his cooperation up to now clearly demonstrates that is not the case," Bornstein wrote.

Cosco Busan's master Capt. Mao Cai Sun and a "handful" of crew members are also refusing to testify, said NTSB spokesman Peter Knudson.

Knudson said the ship's operator, Fleet Management Ltd., will testify.

Cota is the only person charged in the incident. He is accused of killing migratory birds and illegal dumping, and faces up to 18 months in jail and more than $100,000 in fines if convicted. He has pleaded not guilty.

Prosecutors have suggested they may revise or add charges, which would delay Cota's trial. Assistant U.S. attorney Stacey Geis declined to elaborate outside court Friday.

In his letter to the NTSB, Bornstein raised eight issues that investigators should look into including the Coast Guard's failure to issue a fog warning.

Coast Guard officials have adamantly defended their traffic officials, who questioned Cota about his course -- but didn't advise him of danger -- as he steered parallel to the bridge instead of toward the appropriate span opening. The Coast Guard says their Vessel Traffic Service is an advisory system unlike air traffic control and their officers fulfilled their duty.

Coast Guard spokesman Dan Dewell said that it was customary for the ship's master and the pilot to make their own determinations on weather conditions and other issues.

"It's the captain and, in the case where a pilot's required, the pilot who are responsible for knowing where they are, knowing where they're going, and safely navigating the ship," Dewell said. "The VTS is an advisory system. We provide information to ships and did so in this case."

The letter from Cota's attorneys also raised a series of questions about the Cosco Busan's master and officers, including whether they were properly trained and sufficiently skilled in use of instruments on board the ship. A spokesman for Cosco Busan's owner, Hong Kong-based Regal Stone Ltd., did not immediately respond to a request for comment.

Several Chinese crew members have remained in the Bay Area under court order "as material witnesses." Their attorneys have filed court documents seeking their release. A judge will consider that issue May 5.