By Kathy Finn
NEW ORLEANS (Reuters) - Two years after the worst offshore oil spill in U.S. history, mats of oily tar from BP Plc.'s ill-fated Macondo well have turned up on Louisiana's shore after Hurricane Isaac stirred up submerged oil deposits, BP officials said on Tuesday.
BP said the oil that washed ashore after Hurricane Isaac made landfall in Louisiana on August 28 was not unexpected, after Tropical Storm Bonnie in July 2010 buried oil under tons of sand. Isaac's winds and tidal surge peeled back layers of sand and exposed tar balls and tar mats that were buried under up to five feet of sand, BP said.
"What we have seen to date in the form of buried tar mats and tar balls exposed by Isaac have been identified in the isolated areas that we worked" before the storm, said Mike Utsler, President of BP's Gulf Coast Restoration Organization, speaking at a news conference at a New Orleans hotel. "It's not unexpected to see this material where it's been exposed."
BP's statement shows the London-based oil giant's continued challenge in managing the aftermath of the April 20, 2010, explosion aboard the Deepwater Horizon rig as it was drilling the mile-deep Macondo 252 well off Louisiana's coast. The rig sank two days later.
The well spewed 4.9 million barrels of oil into the Gulf of Mexico for 87 straight days, unleashing a torrent of oil that fouled the shorelines of four Gulf Coast states and eclipsed the 1989 Exxon Valdez spill in Alaska in severity.
Oil has turned up anew in areas where BP has already mounted cleanup operations on beaches in Grand Isle, Port Fourchon, Elmer's Island and Grand Terre, Utsler said.
Louisiana's coast was the hardest-hit by the spill, with about 650 miles of oiled coastline. BP responders sprayed millions of gallons of chemical dispersants on the spill, causing oil to sink to the bottom of the Gulf.
After hiring tens of thousands of workers and boats to scour Louisiana's coast and waters for oil in 2010, BP is also waging a public relations blitz in Gulf Coast states. It has purchased radio and television commercials touting Gulf beaches and restaurants as "open for business." In court filings, it claims that the Gulf's ecosystem is seeing a "robust recovery" from the spill.
"We've made tremendous progress but we're still working hard and we're committed to that progress," Ulster said on Tuesday.
In a full-page ad in the New York Times on Monday, BP restated its commitment to the Gulf. The ad said the company has spent more than $23 billion on the clean-up effort and "Many areas are reporting their best tourism seasons in years."
The U.S. government and Gulf coast states have painted a darker post-spill picture. In a recent legal filing, the Justice Department pointed to dolphins in Louisiana's Barataria Bay that showed signs of severe ill health, as well as dead and dying deep-sea coral due to the spill.
Natural resources in the Gulf "continue to suffer significant harm from the Spill, and it is not possible at this time to conclude that they have recovered," the Justice Department said in an August 31 filing.
Louisiana says BP's claim of a "robust recovery" is "grossly misleading" and points to continued heavy oiling in the state's sensitive marshes and swamps, where 220 miles of coastland are still oiled and oil tar balls are recovered every week. At least four fisheries are still closed to continued oil concentrations, the state said.
"Not only does BP oil remain uncontrolled in the nearshore Louisiana ecosystem, but BP is executing one of the worst oil responses in history," Louisiana Attorney General James "Buddy" Caldwell wrote in a September 7 filing.
(Editing by Chris Baltimore and David Gregorio)