By Chris Baltimore and Steve Gorman
HOUSTON/PORT FOURCHON, Louisiana (Reuters) - A small containment dome won't begin trapping oil from BP <:BP.LO:>s leaking oil well until at least next week instead of later on Thursday, a spokesman for BP Plc said, a fresh setback in efforts to contain what could become the worst oil spill in U.S. history.
London-based BP has changed its timing for placing the undersea dome meant to pump oil from the mile-deep (1.6 km) leak to a vessel on the surface, after a company executive on Wednesday told reporters the device could be in place by late Thursday.
"Probably towards the end of next week is when we will start to move it and put it over the leak," BP spokesman Jon Pack said. "So nothing particularly noteworthy is happening with that right now."
This is its latest attempt to control the roughly 5,000 barrels (210,000 gallons/795,000 litres) per day that has been gushing from the broken well for more than three weeks.
A build-up of slushy gas hydrates stymied BP's first attempt last week at covering the leak with a huge metal dome.
London-based BP, Transocean Ltd and Halliburton Co are all under scrutiny for their roles in the April 20 Deepwater Horizon rig explosion that killed 11 workers and triggered what could be the largest U.S. oil spill ever.
Scientists say coastal wetlands threatened by the spill, which provide critical habitat for bird life and serve as rich nurseries for the region's valuable shrimp and oyster stocks, are already dwindling from erosion and development.
Oil pollution would accelerate the process by killing the vegetation that holds the marshes together. It threatens regional economic mainstays including fishing and tourism as well as wildlife throughout the region.
"If we allow that oil to come in and touch our marshlands, that'll shut us down for about five to six years," said Rodney Dufrene, 23, a new shrimp boat owner from the hamlet of Cut Off, north of Port Fourchon, Louisiana.
The National Oceanic and Atmospheric Administration said the oil continued to spread with winds and currents and this week's southeasterly winds could push the oil closer to Breton Sound and the Mississippi Delta.
BP, whose shares have tumbled and wiped out $30 billion (20.4 billion pounds) of market value since the rig fire on April 20, said on Thursday the oil spill had cost it $450 million so far.
BP stock closed up 1.1 percent in London further extending weeks of steep declines.
Global scrutiny of the offshore oil industry could intensify after a second drilling rig sank off Venezuela, although no fatalities were reported and authorities said there was no leak from the natural gas well.
NO CERTAINTY OF SUCCESS
While troops and volunteers helped with a massive spill response and containment effort on the shoreline, BP pushed forward with a multipronged subsea attempt to control the flow of oil that could be in place as soon as the end of the week.
"All of the techniques being attempted or evaluated to contain the flow of oil on the seabed involve significant uncertainties because they have not been tested in these conditions before," BP cautioned in a news release.
The company is trying to stop the flow through the underwater blowout preventer -- which did not work as it was supposed to after the rig explosion -- and also by placing the top hat dome over the main leak.
Officials have said BP is studying whether to try just positioning the top hat over the leak or inserting a tube directly into the existing equipment. Both methods would involve siphoning the crude to a tanker.
Allen said the company was also doing pressure tests to see whether they could just sever the blowout preventer or cut the pipe above it and replace it with a new preventer.
Crews also began drilling a relief well 10 days ago, but that is expected to take about three months to complete.
As the undersea effort goes on, signs of the oil have begun to show up on land.
At Port Fourchon, the tip of southeastern Louisiana's La Fourche Parish and the main supply harbour for the Gulf's deepwater oil and gas industry, gooey, rust-coloured globules were found washed up on a beach.
Cleanup crews have found oil ashore at Whiskey Island in Louisiana's Terrebonne Bay, west of the Mississippi Delta. Crude has also been found at the Chandeleur Islands and Port Eads in the state, as well as on Alabama's Dauphin Island.
So far, 87 sea turtles, 18 birds and six dolphins have been found dead, officials said. Scientists are testing to determine if the oil spill killed them, or if they died of other causes.
Tar balls that washed up on Dauphin Island beaches on Saturday have been tested and appear to be from the oil spill.
A chemical assessment from Louisiana State University's environmental sciences department said the tar balls are a "high probability match" to the oil spill, the Deepwater Horizon information centre said in a news release.
Despite the spill, U.S. ports and shipping lanes remain open though ship speed limits at the entrance to the Mississippi have slowed traffic.
Residents in the Gulf region are growing increasingly frustrated at the failure to contain the leak and voiced their fears over the looming oil spill heading towards them.
"What's my future? My kids' future? We're floating in space here. Nobody knows anything," said Terry Drawdy, owner of Drawdy's Crab Co in Alabama's Bayou La Batre. "All this uncertainty is killing me. It's eating me alive, man."
Nearly 100 lawsuits have already been filed across the Gulf region and the disaster, which lawyers see becoming one of the biggest class actions in U.S. history, involves billions of dollars in potential liabilities.
(Additional reporting by Kelli Dugan in Mobile, Alabama, Tom Brown and Pascal Fletcher in Miami, Victoria Bryan in London and Anna Driver in Houston; Writing by Deborah Charles and Ed Stoddard; Editing by Eric Beech)
