BP could face fines as high at $18 billion after a federal judge said the oil giant acted with gross negligence ahead of the 2010 oil spill in the Gulf of Mexico.

During drilling at the Macondo Prospect in the Gulf of Mexico on April 20, 2010, an explosion on the rig caused by a blowout killed 11 crewmen and ignited a fireball visible from 40 miles away. The fire could not be extinguished, and two days later, the Deepwater Horizon sank, leaving the well gushing at the seabed and causing the largest offshore oil spill in U.S. history.

The explosion and subsequent leak spewed oil into the Gulf of Mexico for three months before it was contained, leading to the ontamination of 16,000 miles of coastline, the destruction of fishing industries, people's livelihoods, and the deaths of thousands of animals.

Government experts estimated 4.2 million barrels, or 176 million gallons, of oil spilled into the Gulf.

In a 153 page ruling, U.S. District Judge Carl Barbier found and concluded that the discharge of oil was the result of BP's "gross negligence and willful misconduct under the Clean Water Act."

Under the provisions of the Clean Water Act, if the defendant acted with ordinary negligence, the maximum amount of a civil penalty is $1,100 per barrel of oil discharged. When the discharge is from gross misconduct "the maximum amount per barrel is nearly quadrupled."

The London-oil oil giant BP may face fines as high as $18 billion -- the maximum penalty under CWA.

James Roy and Stephen Herman, who represented oil spill victims in the trial said, "We hope that today's judgment will bring some measure of closure to the families of the 11 men who tragically lost their lives, and to the thousands of people and businesses still trying to recover from the spill," as reported by The Associated Press.

Judge Barbier held a non-jury trial last year to identify the blowout's causes and apportion blame for the disaster. He wrote in his ruling that BP was 67 percent liable, Transocean at 30 percent and Halliburton at 3 percent. He found profit-driven decisions led to misinterpretation of safety tests and found evidence of "extreme deviation from the standard of care and conscious disregard of known risks."

Under General Maritime Law, Barbier found fault with BP, Transocean and Halliburton for the blowout, explosions and oil spill and concluded that "each Defendant engaged in conduct that was negligent or worse and a legal cause of the blowout, explosion, and oil spill." The Court further found that "BP's conduct was reckless. Transocean's conduct was negligent. Halliburton's conduct was also negligent."

The court also found "that the conduct of BP's employees was egregious enough that exemplary or punitive damages would be appropriate."

BP is expected to appeal the decision.

U.S. Attorney General Eric Holder said Barbier's ruling, "will ensure that the company is held fully accountable for its recklessness and will service as a strong detent to anyone tempted to sacrifice safety and the environment in the pursuit of profit."

The Judge will decided in January how much BP must pay.