The spill, which has eclipsed the 1989 Exxon Valdez disaster as the biggest in U.S. history, entered its 43rd day as BP Plc prepared a new and untested plan to use a dome to funnel oil gushing from a well a mile beneath the sea to a tanker on the surface.
The British oil giant's shares sank another 14 percent Tuesday following the failure of its "top kill" attempt to plug the leak Saturday. The company said the cost, so far, of dealing with the spill was some $990 million.
BP's shares have lost more than a third of their value since the oil spill started six weeks ago, a wipeout of about $62.7 billion.
After previous attempts to plug or contain the well failed, BP is to attempt a new kind of containment cap.
Risks and uncertainties
In a statement issued Tuesday, BP said "preliminary operations" were being carried out to cut away the existing, damaged riser at the head of the pipe outlet on the sea floor and deploy a cap called a lower marine riser package (LMRP).
"All of these operations, including the cutting of the riser, are complex, involve risks and uncertainties, and have to be carried out by ROVs at 5,000 feet under water," it added.
"Systems such as the LMRP containment cap have never before been deployed at these depths and conditions, and their efficiency and ability to contain the oil and gas cannot be assured," the statement said. "It is currently anticipated that attachment of the LMRP cap will be attempted later this week; however, operational delays could impact anticipated timeframes."
BP said it continues to drill two relief wells as part of a longer term plan to control the leak. Its statement said the first relief well had reached a depth of 12,090 feet, while the second relief well was at 8,576 feet. The wells are expected to be completed in August.
Obama, criticized by Louisiana officials for being slow to react to the spill, will hold his first meeting with co-chairs of an oil spill commission he established to make policy recommendations about U.S. offshore oil drilling.
The commission will be similar to those that looked into the explosion of the space shuttle Challenger in 1986 and the Three Mile Island nuclear accident in 1979.
Criminal probe expected
U.S. Attorney General Eric Holder will meet with federal prosecutors and state attorneys general in New Orleans. It will be Holder's first trip to survey the damage before what legal experts believe will be a criminal investigation into the disaster.
Although Louisiana's wetlands and fishing grounds have been the worst hit so far by the spill, the National Oceanic and Atmospheric Administration said moderate southerly and southwesterly winds this week may start moving oil closer to the Mississippi and Alabama coasts.
"Model results indicate that oil may move north to threaten the barrier islands off Mississippi and Alabama later in the forecast period," NOAA said in its 48-hour prediction on the expected trajectory of the huge oil slick.
The slick has spread over 100 miles of Louisiana's fragile coast but Mississippi and Alabama have escaped lightly so far, with only scattered tar balls and oil debris reaching its coasts.
But the NOAA forecast was a sober reminder that oil from the unchecked spill, broken up and carried by winds and ocean currents, could threaten a vast area of the U.S. Gulf Coast, including tourism mecca Florida, as well as Cuba and Mexico.
The public anger and frustration over the spill poses a major domestic challenge for Obama, who has been forced to admit publicly that the U.S. government and military do not have the technology to plug the leaking well and must leave this to BP and its private industry partners.
Obama, who made his second visit to the Gulf disaster zone Friday, is sending three of his top energy and environmental officials back there this week. He is trying to fend off criticism that his administration acted too slowly in its response to the spill.
Spill hits business
In Venice, known as "Tuna Town" for its booming fishing business, the spill dampened business over the U.S. Memorial Day holiday when charters are normally in high demand.
"Just since about last Wednesday, we probably lost 150,000 (dollars) that we didn't take in, you know, fuel, ice, bait," said Bill Butler, co-owner of Venice Marina.
BP said in its statement Tuesday that it had received "approximately 30,000 claims" so far and more than 15,000 payments had been made, totaling some $40 million.
Scientists estimate the well is leaking 12,000 to 19,000 barrels of oil per day.
Raising the stakes even higher, Tuesday is the official start of the 2010 Atlantic hurricane season, which forecasters say may be the most intense since 2005, when Hurricane Katrina ravaged the region and disrupted offshore oil and gas output.
A hurricane churning through the Gulf could drive more oil ashore and force BP and the U.S. government to suspend cleanup efforts.