Massive oil spill in Gulf of Mexico heads to shore

VENICE, Louisiana (Reuters) - A massive oil spill in the Gulf of Mexico washed up to wildlife refuges and seafood grounds on the Louisiana coast on Friday, as authorities struggled to avert what could become one of the worst U.S. ecological disasters.

With leading edges of the huge slick lapping up to outlying marshes and waterways on the fringes of the Mississippi Delta, the U.S. Coast Guard prepared protective booms along the coast in Louisiana and other at-risk states in a desperate bid to prevent oil from soiling the shore.

"We continue to bring every asset to bear to fight this spill," Coast Guard Rear Admiral Sally Brice-O'Hara told CNN.

At President Barack Obama's urgent request, Department of Homeland Security Secretary Janet Napolitano, Interior Secretary Ken Salazar and Environmental Protection Agency Administrator Lisa Jackson were due to fly over the affected Gulf area on Friday to assess the situation.

The leak from a blown-out oil well on the ocean floor off Louisiana is pouring out crude oil at a rate of up to 5,000 barrels (210,000 gallons or 955,000 liters) a day.

The accident forced Obama to put a hold on politically sensitive plans to expand offshore U.S. oil drilling. He unveiled plans in March for a limited expansion, in part to try to win Republican support for climate change legislation.

The White House said on Friday that no new drilling would be allowed until a review was conducted of the oil spill, which happened after an offshore rig exploded and sunk last week.

Obama has pledged to "use every single available resource," including the U.S. military, to contain the 120-mile (193-km) wide slick, while making clear that London-based BP, the majority owner of the ruptured well, was responsible for the cost of the clean-up.

The spill has pounded BP's share price and those of other companies involved in the project.

As alarm over possible contamination spread along the U.S. Gulf Coast, the Louisiana Department of Health said residents in coastal cities, including New Orleans, were likely smelling the sulfurous odor from the spill.

The last flight by a Coast Guard plane on Thursday had situated the thin surface "rainbow sheen" of the slick just 10 meters (33 feet) from the Pass-a-Loutre wildlife reserve in Louisiana. It seemed inevitable that some of the oil would reach shore, although the Coast Guard was awaiting fresh information from its aircraft and vessels.

THREAT TO FOUR STATES

The escalating threat has deepened fears of severe damage to fisheries, wildlife refuges and tourism in Louisiana, Mississippi, Alabama and Florida.

So far, efforts to stop the flow of oil have failed. If unchecked, it will take about 50 days for the leak to eclipse the 1989 Exxon Valdez spill in Alaska, the worst U.S. oil spill on record that sent 10.8 million gallons (49 million liters) of crude oil into Prince William Sound.

The Gulf Coast and its marshlands are home to hundreds of species of wildlife, including manatees, sea turtles about to nest, dolphins, porpoises, whales, otters, pelicans and other birds. The wetlands are also a stopover for millions of migrating birds now transiting through the area.

The Gulf is also one of the world's most fertile seafood grounds, teeming with shrimp, oysters, mussels, crabs and fish. It supports a $1.8 billion industry second only to Alaska.

Louisiana Governor Bobby Jindal, whose state is still recovering from the ravages of Hurricane Katrina in 2005, declared a state of emergency and asked the Defense Department for funds to deploy up to 6,000 National Guard troops to help.

Homeland Security Secretary Napolitano declared it "a spill of national significance," meaning that federal resources from other regions could be used to fight it.

Shrimp fishermen in Louisiana have filed a class-action lawsuit against BP, Swiss-based rig company Transocean Ltd, Halliburton and Cameron, accusing them of negligence. None of the companies had an immediate comment on the lawsuit.

The Navy said it was supplying the Coast Guard with inflatable booms and seven skimming systems.

In Mobile, Alabama, U.S. Coast Guard Captain Steve Poulin, said authorities were preparing for "shoreline impact", although it was not possible to predict exactly when.

"We have a booming strategy for coastal Mississippi, Alabama and the Florida Panhandle," Poulin said.

BP and the Coast Guard have mounted what the company called the largest oil spill containment operation in history, involving dozens of ships and aircraft.

BP admitted struggling to control the spill, which is 5,000 feet under the sea off Louisiana's coast, and appealed for help. It has asked the Pentagon for access to military imaging technology and remotely operated vehicles to try to help it plug the ruptured well.

Eleven workers are missing and presumed dead after the rig exploded 11 days ago.

PAUSE IN DRILLING?

There are signs the spill may be worse than one in 1969 off Santa Barbara, California, which prompted a moratorium on oil and gas drilling off the Pacific and Atlantic coasts -- a ban Obama has said he wants to modify.

Bill Nelson, a Democratic senator from Florida, said he was filing a bill to temporarily prohibit the administration from expanding offshore drilling, citing the risk of a potential "environmental and economic disaster" from the latest spill.

Underwater robots failed to activate a cutoff valve on the ocean floor to stop the leak and BP is now hoping to cover the well with a giant inverted funnel that would capture the oil at the sea floor and channel it directly to a tanker ship at the surface. But that will take four weeks to put in place, by which stage over 150,000 barrels could have been spilled.

If the funnel does not work, BP will have to rely on stemming the flow by drilling a relief well, which would take two to three months.

The White House said Obama had been briefed on how the slick may interfere with shipping channels, which it said could affect tankers delivering petroleum to the U.S. market.

While the Mississippi is a major export route for U.S. grains and the region is a significant importer of crude oil, there were no reports of disruptions.

Shares in BP and Transocean continued to fall on Friday as investors feared a significantly higher cleanup cost. BP is down around 12 percent and Transocean down nearly 15 percent since the rig explosion on April 20.

The Louisiana Offshore Oil Port, which handles more than one million barrels a day of crude imports and is connected by pipeline to the biggest U.S. refining region, said it did not expect any effect on its operations, which remained normal.

(Additional reporting by Joshua Schnyer and Rebekah Kebede in New York and Kelli Dugan in Mobile, Alabama; Writing by Christopher Wilson and Pascal Fletcher; Editing by Stacey Joyce)