Crude oil from the massive spill in the Gulf of Mexico has reportedly washed up ashore on the Louisiana coast, threatening environmental catastrophe.
The US coastguard is investigating reports that faint traces of oil have reached the Mississippi delta.
The government has declared a national disaster after 800,000 litres of oil – five times more than first estimated – escaped from a rig.
Hundreds of species of birds, fish and other wildlife are threatened in an area rich in seafood resources.
“I am frightened,” said David Kennedy of the National Ocean Service. “This is a very, very big thing and the efforts that are going to be required to do anything about it, especially if it continues on, are just mind-boggling.”
The Louisiana coastline is the most threatened but there are also fears for wildlife and fisheries in Mississippi, Alabama and Florida.
Thousands of barrels of oil have been spilling into the water after last week’s explosion on a rig operated by BP. The rig has since sunk.
“At the time the accident happened, the safety devices, we believe would have stopped the flow of oil. They didn’t do that, we don’t know why they didn’t do that and ultimately we will find out,” said Doug Suttles, Chief Operating Officer for BP Exploration and Production.
It is feared that the damage could eclipse that from the Exxon Valdez disaster in Alaska in 1989 – until now the worst spill in US history.
President Obama has promised to spare no resources, including potentially the army, in tackling the spill.