A massive oil spill expected to hit the southern coast on Friday could affect petroleum shipments and delay plans to open up coastal waters to more drilling, government officials said on Thursday.
The spill -- from a BP Plc rig that exploded in the Gulf of Mexico last week -- is spewing five times more oil than previously estimated and raising fears of severe damage to fisheries, wildlife refuges and beaches in Louisiana, Mississippi, Alabama and Florida.
"This is a spill of national significance," Janet Napolitano, the secretary of Homeland Security, told a news conference at the White House. "We will continue to push BP to engage in the strongest response possible."
The governor of Louisiana, which is still recovering from the ravages of Hurricane Katrina in 2005, declared a state of emergency and the U.S. military said it was reviewing how it might help the efforts to contain the growing slick.
Cameron International Corp, which supplied the blowout preventer for the rig, said on Thursday it was insured for $500 million of liability, if needed. Halliburton Co said it did a variety of work on the rig and was assisting with the investigation.
SHIPPING AND DRILLING
The slick will hit the coast in the Mississippi Delta "sometime later tomorrow," Sally Brice O'Hare, rear admiral of the Coast Guard, said at the news conference with Napolitano.
President Barack Obama said BP was ultimately responsible for the cost of the cleanup and that his government would use every resource to address the spill.
The White House said Obama has been briefed on how the slick may interfere with shipping channels, which could affect tankers delivering petroleum to the U.S. market.
It may also have ramifications for proposals in Congress and by Obama to issue new offshore drilling permits.
Initial indications were that the spill would be worse than one in the Pacific Ocean off Santa Barbara in 1969 which prompted a moratorium on oil and gas drilling off the Pacific and Atlantic coasts, a ban Obama has said he wants to modify.
The Obama administration did not rule out imposing a pause in new deepwater drilling until oil companies can show they can control any spills that may happen.
"Everything is on the table," Deputy Interior Secretary David Hayes told reporters, adding it could take 90 days to install a relief valve to stop the leak.
Eleven workers are missing and presumed dead after the rig disaster, the worst in the United States in almost a decade.
Transocean's Deepwater Horizon rig sank on April 22, two days after it exploded and caught fire while the company was finishing a well for BP about 40 miles southeast of the mouth of the Mississippi River.
The daily leak from the well blowout is now estimated at 5,000 barrels or about 210,000 gallons (795,000 liters).
The Navy said it was supplying the Coast Guard with inflatable booms and seven skimming systems.
BP and the Coast Guard have mounted what the company calls the largest oil spill containment operation in history, involving dozens of ships and aircraft. But they are struggling to control the slick from the leaking well 5,000 feet under the sea off Louisiana's coast.
After underwater robots failed to activate a cutoff valve to stop the leak, BP and the Coast Guard set a "controlled burn" on Wednesday to try to prevent the slick from growing.
"We will not rest until we have done everything to bring this under control," said Andrew Gowers, head of group media for BP, likening the spill's consistency to "iced tea" with the thickness of a human hair.
(Additional reporting by Tabassum Zakaria in Washington; Editing by John O'Callaghan)