-LRB- CNN -RRB- -- The pilot of a tanker that crashed into the San Francisco Bay Bridge in 2007 , causing a major oil spill , was under the influence of multiple prescription medications that impaired his judgment , federal officials said in a report Wednesday . The November 2007 crash left a gash in the tanker 's side and led to an oil spill that killed more than 2,000 birds . The National Transportation Safety Board said the pilot of the Hong Kong-registered Cosco Busan , was `` medically unfit '' on November 7 , 2007 . That , and a master pilot 's poor oversight of his performance , were major factors in the crash that dumped 53,000 gallons of oil into the bay , the NTSB said . `` How a man who was taking a half-dozen impairing prescription medications got to stand on the bridge of a 68,000-ton ship and give directions to guide the vessel through a foggy bay and under a busy highway bridge is very troubling , '' said acting NTSB Chairman Mark V. Rosenker . The pilot , John Cota , was charged with criminal negligence in federal court last year . He faces two misdemeanor charges that could result in up to 18 months in prison and $ 115,000 in fines . The 901-foot ship left Oakland , California , en route to South Korea when Cota gave orders that steered the ship directly toward a support tower on the bridge . While the ship avoided a direct hit , it hit a support system at the tower 's base , cutting a 212-foot gash in the ship 's side , the NTSB said . The board ruled that Cota and Chinese master pilot Mao Cai Sun never thoroughly discussed a plan before they took off on a foggy night when visibility was less than a quarter-mile . The oil spill killed about 2,500 birds of 50 different species , according to the report . The crash caused more than $ 70 million in environmental cleanup costs , $ 2 million in damage to the ship and $ 1.5 million in damage to the bridge . The report also blamed the ship 's operator , Fleet Management Ltd. , for not properly training crew members and the U.S. Coast Guard for not providing adequate medical oversight of the pilot . It said the Coast Guard should have revoked the pilot 's license , the pilot should have given a meaningful pre-departure briefing about plans for the voyage and the master pilot should have taken a more active role in ensuring the ship 's safety . `` There was a lack of competence in so many areas that this accident seemed almost inevitable , '' Rosenker said .