BP faces a $3.5bn reduction in the maximum fine it will pay for its role in the worst environmental disaster in history after a US judge ruled that the energy company recovered hundreds of thousands of barrels of oil in the Gulf of Mexico.
US District Judge Carl Barbier ruled that BP managed to recover 810,000 barrels of oil from the spill site, following the Deepwater Horizon oil rig disaster in the Gulf of Mexico in April 2010, and should therefore be excluded from certain penalties it may face.
Ahead of its civil trial under The US Clean Water Act on 25 February, the court added that "the 'Collected Oil' flowed from the subsurface reservoir, through the well, through the blow-out preventer, and never came into contact with any ambient sea water, and was not released to the environment in any way."
The estimates are critical because the total amount of oil that was spilled into the ocean is vital for the verdict and will determine the final penalty.
The US government's final total estimate is 4.9 million barrels, which equates to a rate of 53,000 and 62,000 barrels of oil per day.
Analysts calculated that the BP would have to face as much as $21bn (€15.7bn / £13.6bn) in fine payments under the Clean Water act, as the maximum fine payable under the act is $4,300 per barrel.
In a statement on its website, BP says that "under the Clean Water Act, civil penalties are assessed only on oil that has actually entered the environment and potentially caused harm."
BP also says "although there is inherent uncertainty in [the US government's] quantification, the company believes that the government's public estimate of 4.9 million barrels of oil released is at least 20 percent overstated."
While the energy giant faces a reduction in its US Clean Water Act fines, it still faces, and has paid, billions of dollars in settlements and litigation costs.
At the end of January this year, BP paid a record $4bn fine for the fatal Gulf disaster after US District Judge Sarah S. Vance accepted the group's guilty plea to 11 felony counts.
BP faces five years of probation for its role in the blast and the spill the followed and read out a statement in court which was later reprinted on the company's website.
"We are deeply sorry for the tragic loss of the 11 men who died and the others who were injured that day," said Luke Keller, a Vice President of BP America.
"Our guilty plea makes clear, BP understands and acknowledges its role in that tragedy, and we apologize - BP apologizes - to all those injured and especially to the families of the lost loved ones. BP is also sorry for the harm to the environment that resulted from the spill, and we apologize to the individuals and communities who were injured," he added.
Meanwhile, Transocean Deepwater was ordered by a US federal judge to pay $400m to settle criminal charges and has already agreed to a separate $1.4bn in civil and criminal penalties with the Department of Justice for its role in the Deepwater Horizon oil rig disaster.
BP shares rose slightly in early trading, reaching 447.78p as of 0852 GMT.
The overall civil case under Barbier i: Oil Spill by the Oil Rig "Deepwater Horizon" in the Gulf of Mexico, on April 20, 2010, No. 10-md-02179, in the U.S. District Court, Eastern District of Louisiana.