Crews in boats were patrolling coastal marshes early Friday looking for areas where the oil has flowed in, the Coast Guard said.
The leak from a blown-out well a mile (more than a kilometer) underwater is five times bigger than first believed. Faint fingers of oily sheen were reaching the Mississippi River delta late Thursday, lapping the Louisiana shoreline in long, thin lines. Thicker oil was about five miles (eight kilometers) offshore. Officials have said they would do everything to keep the Mississippi River open to traffic.
The oil slick could become the nation's worst environmental disaster in decades, threatening to eclipse even the Exxon Valdez in scope. It imperils hundreds of species of fish, birds and other wildlife along the Gulf Coast, one of the world's richest seafood grounds, teeming with shrimp, oysters and other marine life.
“It is of grave concern,” National Oceanic and Atmospheric Administration official David Kennedy told The Associated Press about the spill. “I am frightened. This is a very, very big thing. And the efforts that are going to be required to do anything about it, especially if it continues on, are just mind-boggling.”
As the oil floated in, the National Weather Service warned of high tides and coastal flooding in the threatened area because of strong winds from the south. Tides could run 2 to 3 feet (up to a meter) higher than usual from Friday through Sunday.
Oil clumps seabirds' feathers, leaving them without insulation - and when they preen, they swallow it.
Prolonged contact with the skin can cause burns, said Nils Warnock, a spill recovery supervisor with the California Oiled Wildlife Care Network at the University of California. Oil swallowed by animals can cause anemia, hemorrhaging and other problems, said Jay Holcomb, executive director of the International Bird Rescue Research Center in California.
The spewing oil - about 210,000 gallons (795,000 liters) a day - comes from a well 40 miles (65 kilometers) drilled by the rig Deepwater Horizon, which exploded in flames April 20 and sank two days later. BP PLC was operating the rig that was owned by Transocean Ltd. The Coast Guard is working with BP to deploy floating booms, skimmers and chemical dispersants, and set controlled fires to burn the oil off the water's surface.
Protective boom has been set out on Breton Island, where colonial species such as pelicans, gulls and skimmers nest, and at the sandy tips of the passes from the Mississippi River's birdfoot delta, state wildlife official Robert Love said.
The leak from the ocean floor proved to be far bigger than initially reported, contributing to a growing sense among some in Louisiana that the government failed them again, just as it did during Hurricane Katrina in 2005. President Barack Obama dispatched Cabinet officials to deal with the crisis.
Cade Thomas, a fishing guide in Venice, worried that his livelihood will be destroyed. He said he did not know whether to blame the Coast Guard, the government or BP.
“They lied to us. They came out and said it was leaking 1,000 barrels when I think they knew it was more. And they weren't proactive,” he said. “As soon as it blew up, they should have started wrapping it with booms.”
BP shares continued falling early Friday. Shares were down 2 percent in early trading on the London Stock Exchange, a day after dropping 7 percent in London. In New York on Thursday, BP shares fell $4.78 to close at $52.56, taking the fall in the company's market value to about $25 billion since the explosion.
The spill could eclipse the worst oil spill in US history - the 11 million gallons (41.64 million liters) that leaked from the grounded tanker Exxon Valdez in Alaska's Prince William Sound in 1989 - in the three months it could take to drill a relief well and plug the gushing well 5,000 feet (1,525 meters) underwater on the sea floor.
Ultimately, the spill could grow much larger than the Valdez because Gulf of Mexico wells tap deposits that hold many times more oil than a single tanker.
The US Fish and Wildlife Service was focusing on national wildlife refuges on a chain of barrier islands.
“We're trying to go for the ones where the pelicans are nesting right now,” said Tom McKenzie, the agency's regional spokesman, adding that about 900 were on North Breton.
About 34,000 birds have been counted in the national refuges most at risk, McKenzie said. Gulls, pelicans, roseate spoonbills, egrets, shore birds, terns and blue herons are in the path of the spill.
Mink and river otter also live in the delta and might eat oiled carcasses, Love said.
Bird rescuer Holcomb worked on the Valdez disaster and was headed to Louisiana. He said some birds may avoid the oil spill, but others won't.
“These are experiences that the birds haven't encountered before,” he said. “They might think it's seaweed. It's never harmed them before.”
BP has requested more resources from the Defense Department, especially underwater equipment that might be better than what is commercially available. A BP executive said the corporation would “take help from anyone.” That includes fishermen who could be hired to help deploy containment boom.
An emergency shrimping season was opened to allow shrimpers to scoop up their catch before it is fouled by oil.
This murky water and the oysters in it have provided a livelihood for three generations of Frank and Mitch Jurisich's family in Empire, Louisiana.
Now, on the open water just beyond the marshes, they can smell the oil that threatens everything they know and love.
“Just smelling it, it puts more of a sense of urgency, a sense of fear,” Frank Jurisich said.
The brothers hope to get all the oysters they can sell before the oil washes ashore. They filled more than 100 burlap sacks Thursday and stopped to eat some oysters.
“This might be our last day,” Mitch Jurisich said.
Without the fishing industry, Frank Jurisich said the family “would be lost. This is who we are and what we do.”
Louisiana Gov. Bobby Jindal declared a state of emergency so officials could begin preparing for the oil's impact. He also asked the federal government if he could call up 6,000 National Guard troops to help.
In Buras, Louisiana, where Hurricane Katrina made landfall in 2005, the owner of the Black Velvet Oyster Bar and amp; Grill couldn't keep his eyes off the television. News and weather shows were making projections that oil would soon inundate the coastal wetlands where his family has worked since the 1860s.
“A hurricane is like closing your bank account for a few days, but this here has the capacity to destroy our bank accounts,” said Byron Marinovitch, 47.
“We're really disgusted,” he added. “We don't believe anything coming out of BP's mouth.” Mike Brewer, 40, who lost his oil spill response company in the devastation of Hurricane Katrina nearly five years ago, said the area was accustomed to the occasional minor spill. But he feared the scale of the escaping oil was beyond the capacity of existing resources.
“You're pumping out a massive amount of oil,” he said.
“There is no way to stop it.”
