Sept 4 (Reuters) - BP Plc was found "grossly negligent" on Thursday by a federal judge in connection with its role in the 2010 Gulf of Mexico oil spill. The decision by U.S. District Judge Carl Barbier in New Orleans, who oversees litigation related to the disaster, is likely to boost the British oil company's costs emerging from the biggest offshore spill in U.S. history. :
* April 20, 2010 RIG EXPLODES: An explosion on the Deepwater Horizon oil rig at the Macondo exploration well kills 11 workers and releases millions of barrels of crude oil into the Gulf of Mexico. The well is capped in mid-July. BP ultimately sets aside $42 billion to pay for cleanup costs, damages and penalties.
* November 2012 CRIMINAL CASE SETTLED: BP agrees to pay $4.5 billion in fines and other penalties and pleads guilty to 14 criminal charges. The U.S. government bans BP from new federal contracts, imperiling the company's role as a top U.S. offshore oil producer and No. 1 military fuel supplier. Separately, the U.S. Department of Justice files criminal charges against three BP employees in connection with the accident.
* December 2012 CLASS ACTION SETTLED: Barbier gives final approval to BP's settlement with individuals and businesses claiming to have lost money and property because of the spill. BP initially estimates it will pay $7.8 billion to settle more than 100,000 claims, but the dollar amount is not capped. The company later says the payout may grow substantially, in part because of payouts to many claimants who suffered no harm, and files numerous legal challenges to the agreement.
* February 2013 CIVIL TRIAL BEGINS: Officials from the federal government and several U.S. states begin facing BP in court at a three-phase civil trial over how blame should be apportioned between BP, Transocean Ltd, which owned the drilling rig, and Halliburton Co, which did cement work. Government lawyers urge Barbier to find BP grossly negligent, which could roughly quadruple the amount of fines under the U.S. Clean Water Act.
* Sept. 30, 2013 SECOND PHASE OF TRIAL BEGINS: The second phase begins to determine how much oil was spilled.
* Sept. 4, 2014 JUDGE FINDS BP BEARS MOST OF THE BLAME: Barbier finds BP "grossly negligent" for its role in the oil spill. He assigns 67 percent of the fault to BP, 30 percent to Transocean and 3 percent to Halliburton. BP pledges to appeal.
* January 2015 NEXT PHASE OF TRIAL SCHEDULED TO BEGIN: Barbier is scheduled to determine how much oil was spilled. The amount would be used to calculate damages. (Compiled by David Gregorio; Editing by Howard Goller)