British oil major BP has asked a US court to reconsider its ruling that the company was "grossly negligent" over the Deepwater Horizon oil spill disaster.
Lawyers for the company said in a filing with the US district court in New Orleans they spotted a legal mistake in the ruling last month. They claimed Judge Carl Barbier had relied on evidence that had been excluded from the trial to base his findings.
The company is now asking Barbier either to revise his ruling to exclude that evidence, or hold a new trial to allow BP to bring in its viewpoints.
Barbier earlier ruled that "gross negligence" and "wilful misconduct" on the part of BP led to the disastrous oil spill in the Gulf of Mexico in 2010. Due to the ruling, the company faces additional fines up to $18bn (€13.8bn, £11bn).
BP has so far spent more than $28bn on damage claims and cleanup costs. It has set aside only $3.5bn for fines under the Clean Water Act, as it expected the court would find simple negligence in the case.
The company earlier said it would appeal the ruling, which was "not supported by the evidence at trial". BP's call to reconsider the ruling extends its timetable to file an appeal.
In 2010, the Deepwater Horizon oil rig exploded in the BP-owned Macondo Prospect, which spilled oil into the surrounding Gulf of Mexico waters over a three-month period.
Eleven workers on the rig died in the explosion and environmental devastation slicked its way through the waters, poisoning marine life as well as a number of clean-up workers and Gulf of Mexico residents.
BP has been hit by a number of pieces of civil and criminal litigation from people and businesses affected by the spill. Two phases of the trial over BP's negligence and the amount of oil spill have been completed. The third phase scheduled for January will determine the exact amount of fines to be paid by the company.