BP: "Right now we are going to a containment operation...Because this is being done at 5,000 feet with robots, we're going to take our time"

BP engineers on Monday scrambled a new high-risk operation to stem the devastating Gulf oil spill now described as the worst environmental disaster in US history.

The Washington Post reports,

"White House energy and climate adviser Carol Browner declared Sunday that the oil spill was "probably the biggest environmental disaster we've ever faced in this country" and said that "we are prepared for the worst." On the CBS show "Face the Nation," she said that the "American people need to know that it is possible we will have oil leaking from this well until August, when the relief wells will be finished."

BP officials warned Monday they may not be able to plug the Gulf of Mexico oil leak until August, as Louisiana residents urged Washington to go on a wartime footing to fight the spill.

"Drilling relief wells is still seen as the best solution," but they will not be onstream for at least eight weeks, BP spokesman John Currie told AFP, as US officials warned the spill is now the worst environmental disaster to ever befall the United States.

Hours after the British oil giant acknowledged the failure of its "top kill" attempt to plug the underwater well, company officials said it could take a week to carry out a bid to place a cap over the leak.

"Right now we are going to a containment operation," BP Managing Director Bob Dudley told CNN television of the latest attempt to deal with the ruptured well nearly one mile (1,600 meters) under water.

"Because this is being done at 5,000 feet with robots, we're going to take our time, do it extremely carefully. By the end of the week, we should have this in place," Dudley said.

While the "top kill" would have sealed the well using heavy drilling fluid and cement, the new effort aims only to contain most of the leak, and might temporarily increase the amount of oil gushing into the Gulf of Mexico, officials said.

The leak will only be sealed when BP finishes drilling two relief wells, but those are not expected to be ready until August.

Hundreds of thousands of gallons of oil spew uncontrolled into the sea each day and at least 20 million gallons are now estimated to have escaped since the leased Deepwater Horizon oil rig exploded on April 20 and sank, killing 11 workers.

Some 500 people braved rains in New Orleans' French Quarter Sunday to denounce BP and Barack Obama administration's response to the disaster.

"Eco-murderers!" shouted Belinda Sopczak of New Orleans. Her protest sign featured a crude sketch of a black skull with BP's green and yellow logo over both eye sockets, and bearing the words "British Polluters."

Obama's top environmental advisor, Carol Browner, said that it was possible that "we will have oil leaking from this well until August when the relief wells will be finished."

The new bid involves using robots to sever a damaged pipe carrying oil from the wellhead and placing a containment device called a Lower Marine Riser Package (LMRP) over the leak.

Oil would then be siphoned up to a container ship at the surface.

But it is uncertain how much oil would be contained, Browner said on CBS's "Face the Nation progamme.

"When you cut the riser, the kink may be holding some of the oil in and so we could see an increase, experts are saying, of as much as 20 percent," she said, adding the increase could last four to seven days as the cap is prepared.

"Once the cap is on, the question is how snug is that fit? If it's a snug fit then there could be very, very little oil. If they're not able to get a snug fit then there could be more."

Larry Crowder, a professor of marine biology at Duke University, said if the spill continues for a couple more months, then oil almost certainly would get into the Loop Current that flows clockwise around the Gulf.

It then would be a week to 10 days before it got to the Florida Keys, and a couple of weeks more before the Gulf Stream carried it to North Carolina.

"If you have enough oil, it can go a big distance," Crowder warned. "There's almost no place that's off-limits."

Since the spill began, an estimated 12,000 to 19,000 barrels of crude have leaked into the Gulf each day.

The disaster has already closed stretches of coastal fishing waters, endangering the seafood industry and tourism, and threatening a catastrophe for Louisiana marshes, home to many rare species.

And scientists warned that the damage to the shorelines could be only the tip of the iceberg.

The damage to the sea floor could be extensive, they said, and oil could also devastate marine life between the Gulf floor and its surface.

Government data released Thursday suggested between 18.6 million gallons and 29.5 million gallons of oil have poured into the Gulf -- far more than the roughly 11 million gallons of crude spilled in the 1989 Exxon Valdez disaster.

The spill has been a public relations nightmare for BP, which faced new allegations of negligence Sunday after The New York Times said internal company files showed the firm had serious concerns about the Deepwater rig weeks before the accident.

Congressman Ed Markey, who forced BP to make available a live video feed of the oil leak, said Sunday he had "no confidence whatsoever in BP."

"BP has been making it up as they go along the whole way," he said on "Face the Nation."

(with additional Raw Story reporting)

More from AFP report:

No new attempt to plug the leak would be made before Wednesday at the earliest, Currie said, adding it will take that long to put in place what is called the lower marine riser cap (LRMC).

At least 20 million gallons of oil are feared to have already flooded into the Gulf since the Deepwater Horizon rig exploded 41 days ago on April 20 and sank into the sea two days later with the loss of 11 lives.

BP's last attempt to stop the leak, dubbed the "top kill," failed on Saturday leaving an estimated 12,000 to 19,000 barrels of oil belching into the Gulf every day.

The giant slick is threatening Louisiana's fragile wetlands, as well as the Gulf region's fishing and tourism industries, amid fears that hurricane season which starts Tuesday could push more oil up onto the Florida, Texas, Mississippi and Alabama coastlines as well.

"I think what the American people need to know is that it is possible we will have oil leaking from this well until August when the relief wells will be finished," White House energy advisor Carol Browner warned Sunday.

Louisiana Senator David Vitter called for a military-style chain of command to handle the crisis, saying the procedure has been slow and bogged down in red tape.

"We need the federal response to really get with it and go on a wartime footing and we need a military-style chain of command where orders are given and executed immediately," Vitter told local radio.

He also called for supertankers to be deployed to the site of the spill, around 50 miles (80 kilometers) off the coast of Louisiana, to suck up the oil.

Such a technique had been used by the Saudis to clean up large slicks in the Middle East, he said.

Angry Louisiana residents believe BP's efforts to stop the leak have been no more than a well-managed show while it builds the relief wells.

"It's all just smoke and mirrors," New Orleans resident Danielle Brutsche told AFP.

"I never thought 'top kill' would work, and I don't think BP did either. And what they're doing now, trying to cap the leak, I think they're just doing it to distract us so it looks like they're doing something while they build the relief wells," she said.

But BP's Currie told AFP the company was "heavily invested" in trying to stop the spill. "We have spent 900 million dollars on this so far, and that would be a mighty expensive show we were putting on," he said.

"We continue to develop options we think will work and to investigate and implement them. We want this to work as quickly as anyone. We are heavily invested in stopping this."

The LRMC attempt involves cleanly cutting off the riser from the well and then lowering a cap onto the leak to seal it. Oil would then be siphoned up to a container ship on the surface.

But the technique would only contain the leak not stop it and could even temporarily increase the amount of oil gushing into the Gulf as it would make the hole on the riser bigger, officials said.

New Orleans lawyer Shaun Holahan on Sunday tucked into a plate of oysters at the Plaquemines Seafood Festival, saying she had come to the annual event "because I think it's the last one they'll ever have.

"The oil in the water has probably killed off the larvae, meaning there will be no shrimp or fish or oysters next year... and probably not for years to come," Holahan said.

Marcus Bronson, also of New Orleans, said the slow-moving efforts to stop the spill would kill off Louisiana's fishing industry and heritage.

"At least 100,000 fishermen will lose their livelihoods and then another 100,000 people who work in the background and depend on fishing will lose theirs, and we'll have a depression in Louisiana," he said.