BP seeks to cut Gulf oil spill exposure by up to $3.4B

British oil giant BP wants a federal judge to rule that the roughly 800,000 barrels of oil that the government says was collected at the head of its runaway undersea Gulf of Mexico well in 2010 should not be counted in determining the company’s civil fine for Clean Water Act violations.

Such a ruling could reduce BP’s fine by as much as $3.4 billion if the court were to rule that BP acted with gross negligence when its Macondo well blew out 50 miles off the coast of Louisiana, leading to the worst offshore oil spill in U.S. history. Eleven rig workers were killed when the Deepwater Horizon drilling rig, which BP had been leasing from Transocean, exploded and sank.

The U.S. government has asserted that the well discharged 4.9 million barrels of oil, or 206 million gallons. BP stated again in its filing Friday that it believes the spill was  significantly smaller, though it hasn’t publicly provided its own estimate.

With a finding of gross negligence, the 4.9-million-barrel figure would carry a maximum Clean Water Act fine of more than $21 billion.

The law allows for a fine based simply on the amount of oil discharged. BP points out in its motion that some courts have interpreted the law in the past to mean that oil has to be discharged into water or the environment to count.

Before it capped the well in July 2010, BP used various systems to capture  some of the gushing oil before it spilled into the water a mile below the Gulf surface. The government concluded in August 2010 that some 800,000 barrels of oil was collected at the wellhead, the assemblage of equipment that is attached to the opening of an oil or gas well. For months after the finding, Interior Department officials refused to say whether the government believed none of that oil first touched the water before being collected. It has never said otherwise, either.

A Justice Department spokesman declined to comment on the BP filing.

A civil trial over the oil spill is set to begin Feb. 25 in New Orleans. The first phase of the trial will deal with apportioning blame among  BP and the other companies involved in the disaster. The second phase will deal with the amount of oil that spilled.

BP donated $22 million from the sale of oil recovered from the spill to the U.S. National Fish and Wildlife Foundation to fund projects that benefit wildlife in the Gulf, according to the company.