The pilot of the container ship that spilled 53,000 gallons of oil into San Francisco Bay was charged Tuesday with two felony counts of lying to Coast Guard officials about his prescription drug use.

Capt. John Cota, 60, previously was charged with two misdemeanor environmental crimes for his role in the Nov. 7 accident that fouled the bay, killed or injured thousands of birds and forced the closure of Bay Area beaches.

The new, more serious charges accuse Cota of lying on annual medical reports in 2006 and 2007 that are required by the U.S. Coast Guard.

The indictment alleges that Cota "knew that the information he provided was neither complete nor true, including the information ... regarding current medications, the dosage, possible side effects and medical conditions for which the medications were taken," according to the U.S. Attorney's office.

The indictment, which includes the two previous charges, didn't provide details about the drugs Cota allegedly lied about or neglected to include on the two annual medical reports.

The shipping fuel leaked into the ecologically sensitive bay after the Cosco Busan freighter sideswiped a support tower of the San Francisco-Oakland Bay Bridge in heavy morning fog.

Federal investigators told the National Transportation Safety Board last week that Cota had a drunken driving conviction and a history of alcohol abuse and took numerous prescription drugs that could have impaired his judgment.

The NTSB was told that Cota was prescribed many pills, including lorazepam, an anti-anxiety drug, imitrex for migraines, provigil to increase wakefulness, and darvon compound 65 for pain.

"These new felony allegations, aside from not being provable, bear no relevance whatsoever to the causes or consequences of the Cosco Busan oil spill," said the pilot's lawyer, Jeff Bornstein.

Bornstein said Cota was not under the influence while at the helm of the Cosco Busan and he passed drug and alcohol tests administered two hours after the crash.

Bornstein complained that federal investigators have focused their criminal probe solely on Cota when the ship's Chinese crew and U.S. Coast Guard shared responsibility.

Six Chinese crew members have been detained in the Bay Area since the spill so they can testify against Cota.

While technically under arrest as "material witnesses," they have been staying at a San Francisco apartment and drawing their salaries and a stipend.

The crew's lawyer have asked a judge to let them testify before trial so they can return home as soon as possible. Cota's trial is expected to start in September at the earliest.

The crew's lawyers propose taping their testimony, which would include cross-examination by Cota's lawyers, and showing it to a jury. Cota's attorney would prefer to have the crew testify live in front of a jury.

"It's much better to have people testify in the courtroom so a jury can not only hear, but see the witnesses," Bornstein said.

A judge is expected to decide the issue soon. Cota is due back in court on May 5.