The pilot behind the massive oil spill in the San Francisco Bay in a November 2007 incident pleaded guilty on Friday to two criminal charges, according to the US Department of Justice.

John Cota was at the helm of the 900-foot Cosco Busan when it slammed into the San Francisco-Oakland Bay Bridge in heavy fog on Nov. 7, 2007. Following the incident, more than 50,000 gallons of oil were spilled into the water, killing and injuring thousands of birds.

On Friday, Cota pleaded guilty to negligently causing the fuel spill in violation of the Oil Pollution, Act of 1990, a law enacted in the wake of the Exxon Valdez disaster, and to violation of the Migratory Bird Treaty Act for the Deaths of protected migratory birds, federal prosecutors said.

Cota was taking Wellbutrin, a drug usually prescribed to combat depression, as well as medication for migraines and glaucoma. He was also suffering of pancreatitis, a disease often linked to alcoholism. Despite all these evidences, Jeff Bornstein, Cota’s attorney claims there is no link between his client’s prescription drugs and the crash.

John Cruden, acting assistant attorney general, released a statement saying: “Today's guilty plea is a reminder that the Cosco Busan crash was not just an accident, but a criminal act. This is not a case involving a mere mistake. The lesson here is that environmental stewards who abandon ship, act negligently and cause major environmental damage will be vigorously prosecuted.

If U.S. District Court Judge Susan Illston accepts the plea terms, Cota risks a sentence between two months and ten months in prison and a fine between $3,000 and $30,000. Cota is scheduled to be sentenced June 19.