By Matthew Bigg
VENICE, Louisiana (Reuters) - The U.S. government pressured energy giant BP <:BP.LO:>to avert an environmental disaster as a huge, unchecked oil spill reached coastal Louisiana, imperilling fish and shrimp breeding grounds and vulnerable wetlands teeming with wildlife.
With oil gushing unchecked from a ruptured deepwater well in the Gulf of Mexico off Louisiana, President Barack Obama's administration piled pressure London-based BP Plc, the owner of the blown-out well, to do more to shut off the flow and contain the spreading slick.
Obama sent Interior Secretary Ken Salazar and Homeland Security Secretary Janet Napolitano to Louisiana to assess the situation.
Salazar met with BP executives and said he told them to "work harder and faster and smarter to get the job done."
"We cannot rest and we will not rest until BP permanently seals the wellhead and cleans up every drop of oil," he said.
Crude oil is pouring out at a rate of up to 5,000 barrels (210,000 gallons or 795,000 litres) a day, according to government estimates, but experts said the quantity of crude escaping was difficult to measure.
Experts said there was little hope that BP would succeed with a relatively quick fix to cap the well.
BP hopes to cover the well with a giant inverted funnel that would capture the oil and channel it to a tanker ship.
But that would take four weeks, by which time over 150,000 barrels could have been spilt. If the funnel does not work, BP will have to try stemming the flow by drilling a relief well, which would take two to three months.
"At 5,000 barrels a day, in two months' time it's going to be a bigger spill than the Exxon Valdez, said Tyler Priest, director of global studies at the University of Houston's Bauer College of Business. "You're looking at a huge disaster."
Forecasters predict the spill will soon invade the coastlines of Mississippi as well as Alabama and Florida, which both declared states of emergency.
"The problem here is we have a leak that's uncontrolled right now, leading to a source of oil that's not infinite, but it's very very large, and we're not going to know the total impact and the oil release until we actually shut it down," Coast Guard Admiral Thad Allen said on CNN.
"I think 5,000 barrels per day is a good estimate for now, but I think we need to understand, we can have something catastrophic happen down there, we need to be prepared for the worst-case scenario, and that's where we're headed."
DRILLING IN NEW AREAS SUSPENDED
Louisiana Governor Bobby Jindal said he was worried about BP's ability to cope with the disaster.
"I do have concerns that BP's current resources are not adequate" to meet three main challenges from the disaster: stopping the leak of oil from a damaged undersea well, protecting the coast and carrying out a swift cleanup," Jindal, told a news conference in Louisiana, where he was flanked by high-level federal officials.
The accident forced Obama to suspend politically sensitive plans to expand offshore oil drilling, unveiled last month partly to woo Republican support for climate legislation.
Obama said domestic oil drilling remained an important part of U.S. energy policy, but the White House said no new offshore oil drilling areas would be allowed until a review was conducted of the spill and safeguards put in place.
Napolitano called on BP to commit more resources. She said BP was "the responsible party" under U.S. law and is "required to fund the cost of cleanup operations."
Two Air Force C-130 aircraft equipped to spray dispersant chemicals were despatched to join the containment effort.
"There are now five staging areas to protect sensitive shorelines; approximately 1,900 federal response personnel are in the area; and more than 300 response vessels and aircraft on the scene 24/7," Obama told reporters at the White House.
CEO Tony Hayward promised an "aggressive" cleanup campaign, saying the company would clean up the oil spill and compensate those affected. "We are taking full responsibility for the spill. ... We are going to be very, very aggressive in all of that," he told Reuters in London.
BP admitted it was struggling to control the leak, which is very deep at 5,000 feet (1,525 metres) down on the sea bed, and asked the Pentagon to supply underwater imaging technology and robots.
Defense Secretary Robert Gates authorized mobilization of about 6,000 Louisiana National Guard troops to help remove oil contamination and protect critical habitats.
BOOMS 'NOT EFFECTIVE'
The Coast Guard have deployed floating booms to try to protect the coastline but Jindal said the booms were "not effective," although other officials said that was due partly to shifts in the weather.
"Weather is one of our biggest challenges. Wind and waves are up. Seas are at 6 to 8 feet (1.8 to 2.4 metres), which can make it difficult to deploy boom," said Ayana Mcintosh-Lee, a BP spokeswoman.
There are already 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 had said he wanted to modify.
Officials said a "sheen of oil" from the 120-mile (193-km) oil slick had reached barrier islands in a Louisiana wildlife reserve on the fringes of the Mississippi Delta.
"So far, it's minimal oil that has come ashore, but when you look at the wind we have to prepare for the worst. ... If it goes inland, it will be massive and out of control," Plaquemines Parish President Bill Nungesser told Reuters.
The Gulf Coast and its marshlands are home to hundreds of species of wildlife, including manatees, sea turtles now 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.
In addition, the Gulf is one of the world's most fertile seafood grounds, teeming with shrimp, oysters, mussels, crabs and fish. It supports a $1.8 billion (1.2 billion pound) industry second only to Alaska.
"There are a lot of angry people right now," said Christopher Creppel, 25, a fisherman in Venice, Louisiana. "This will not just put us out of business this year. It will put us out of business for years to come."
The cost to Louisiana's fishing industry could be $2.5 billion and the impact on tourism along Florida's Gulf coast could be $3 billion, estimated Neil McMahon, analyst at investment firm Bernstein.
Shares of companies that provided services or operated the sunken Deepwater Horizon drilling rig that set off the leak fell sharply as worry mounted about liability from the spill. Shares of BP, Halliburton Co and Transocean Ltd all dropped.
(Additional reporting by Chris Baltimore and Kristen Hays in Houston, Tom Bergin in London, Phil Stewart in Washington, Joshua Schnyer and Rebekah Kebede in New York; Writing by Christopher Wilson; Editing Sandra Maler)