By Jonathan Stempel
Nov 13 (Reuters) - A judge weighing how much BP Plc should be punished over the 2010 Gulf of Mexico oil spill onThursday refused to overturn his own finding that the oilcompany's conduct was "grossly negligent."
The decision by U.S. District Judge Carl Barbier in NewOrleans means BP could still face close to $18 billion ofpenalties for violating the federal Clean Water Act.
It marks the latest setback in BP's effort to curb costsfrom the April 20, 2010 explosion of the Deepwater Horizon rig,which led to 11 deaths and the largest U.S. offshore oil spill.The trial is expected to resume in January.
Barbier had on Sept. 4 ruled that BP committed grossnegligence and was 67 percent at fault for the spill.
The gross negligence finding roughly quadrupled the maximumcivil penalty that BP could face under the Clean Water Act.
BP later argued that this ruling relied on inadmissibletestimony from an expert for Halliburton Co, whichprovided cementing work at the spill site.
But the judge disagreed, saying BP "opened the door to thistestimony" through a cross-examination of the expert.
"BP's assertions that it was 'unfairly surprised' and'prejudiced' by the court's reliance on this testimony lack anybasis in fact or law," Barbier wrote in an 11-page order."Rather, it seems BP was a 'victim' of its own trial strategy."
BP had no immediate comment on the order.
On Monday, Barbier rejected BP's bid to oust Patrick Juneau,an administrator overseeing payouts to businesses andindividuals claiming damages from the spill.
BP has complained that Juneau's awards, made under a 2012settlement agreement it signed, are too generous and are goingto claimants who were not harmed. An appeal by BP related tothat settlement is pending before the U.S. Supreme Court.
The case is In re: Oil Spill by the Oil Rig "DeepwaterHorizon" in the Gulf of Mexico, on April 20, 2010, U.S. DistrictCourt, Eastern District of Louisiana, No. 10-md-02179. (Reporting by Jonathan Stempel in New York; Editing by GrantMcCool)