BP has suffered a further blow after it was revealed that Hurricane Isaac has uncovered oil that wasn't cleaned up after the Gulf of Mexico spill in 2010.
Since Isaac made landfall more than a week ago, the water the storm has receded and tar balls and oil have been reported on shores in Alabama and Louisiana, where officials closed a 13-mile stretch of beach on Tuesday.
BP said some of that oil was from the spill, but said some of the crude may be from other sources, too, AP reported.
"If there's something good about this storm it made it visible where we can clean it up," BP spokesman Ray Melick said.
BP still has hundreds of cleanup workers on the Gulf Coast after the Deepwater Horizon drilling rig exploded, killing 11 workers and leading to the nation's largest offshore spill.
Melick said the company was working with the Coast Guard, state officials and land managers to clean up the oil on the Fourchon beach in Louisiana. He said crews would be there on Thursday.
Isaac made landfall near Fourchon on August 28 as a Category 1 storm, pummeling the coast with waves, wind and rain. Seven people were killed in Louisiana and Mississippi.
Ed Overton, a chemist and oil spill expert at Louisiana State University, said the exposed oil was weathered and less toxic, though it could still harm animals - such as crabs, crawfish and bait fish.
He said the storm helped speed up natural processes that break down oil and it might take several more storms to stir up the rest of the oil buried along the coast.
"We don't like to say it, but hurricanes are Mother Nature's way of taking a bath," he said.
The reappearance of oil frustrated state officials.
Garret Graves, a top coastal aide to Louisiana Governor Bobby Jindal, accused BP of not being aggressive enough with its initial cleanup.
"If they would put just a fraction of the dollars they're putting into their PR campaign into cleanup, we'd certainly be much farther ahead than we are now," he said.
BP has spent millions of dollars on its public relations campaign, but the company has not said exactly how much it has invested. Its cleanup and response costs over the past two years were more than $14bn (£8.8bn) and more than 66m man-hours have gone to protect and treat the Gulf shoreline, the company has said.
BP also gave $1m to the American Red Cross and The Salvation Army to help victims of Isaac.
On Wednesday the US government reiterated that it would seek to prove that the oil major’s “gross negligence” caused the Gulf of Mexico disaster – stoking fears that it will become embroiled in a lengthy trial.
The group, which has always denied the charge, saw its shares fall 2.9pc to 423.85p, wiping £2.7bn off its value amid concerns that the dispute will prevent it reaching a settlement with US authorities.