A satellite imaging expert says oil has reached the Mississippi Delta and the Chandeleur Islands off the Louisiana coast, and the crude is very close to coming ashore.
Hans Graber, director of the University of Miami's satellite sensing facility, said Wednesday that two satellite images also show oil drifting to the south, toward the Loop Current. Scientists say this current could carry oil toward Florida and the Keys.
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Graber says the northern edge of the current may already have picked up some oil.
The Associated Press reported last week that a rainbow sheen of oil had come ashore at the mouth of the Mississippi. BP PLC received a report Tuesday that oil had washed ashore at the Chandeleur Islands, but more than 20 boats were sent there and could not find the oil on shore.
(Scroll down to watch "CBS Evening News" Anchor Katie Couric interview author and expert Mike Tidwell about the massive oil spill in the Gulf and its potential consequences to coastal communities.)
A 12-man crew was making final preparations Wednesday to on a journey to the oil leak site in an unprecedented attempt to help funnel out oil spewing from the bottom of the sea.
The giant-concrete-and-steel box is the latest idea engineers from oil giant BP PLC are trying after an oil rig the company was operating exploded April 20, killing 11 workers. It sank two days later.
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BP is in charge of the cleanup and President Obama and many others have said the company also is responsible for the costs.
BP capped one of three leaks at the well Tuesday night, a step that will not cut the flow of oil but that BP has said will make it easier to help with the gusher.
Meanwhile, the effort to protect delicate coastal wetlands picked up.
Two satellite images taken Wednesday morning indicate oil has reached the Mississippi Delta and the Chandeleur Islands off the coast of Louisiana.
U.S. Coast Guard Lt. James McKnight said crews remained at the Chandeleurs on Wednesday after officials got a report of oil coming ashore, but they have not located it.
"They're sitting there, basically, waiting for the first signs of any kind of a sheen to touch the islands," he said.
Florida officials fearing tourists will cancel their vacations are trying to quash rumors that oil is already washing up on beaches there.
"We are not two or three days away from it hitting the shore," said David Halstead, Florida's emergency management chief. "The beaches are still open."
In Plaquemines Parish, near the southern tip of Louisiana, officials loaded absorbent boom shortly after dawn to take out to the mouth of the Mississippi River. The barge will be used as a distribution point for local fishermen to lay the boom around sensitive marshes.
At a nearby marina, local shrimpers planned to use their boats to put down boom as part of a program BP is running.
The Coast Guard said officials planned to send out about 80 vessels from Biloxi and Pascagoula, Miss., and Orange Beach, Ala., primarily to handle booming. Bryant said two Coast Guard cutters would also conduct offshore skimming operations. Crews in Mississippi are picking up debris from beaches to make cleanup easier if oil comes ashore.
In all, about 7,900 people are working to protect the shoreline and wildlife, and some 170 boats are also helping with the cleanup.
A rainbow sheen of oil has reached land in parts of Louisiana, but forecasts showed the oil wasn't expected to come ashore for at least a couple more days.
"It's a gift of a little bit of time. I'm not resting," Coast Guard Rear Adm. Mary Landry said.
In their worst-case scenario, BP executives told members of a congressional committee that up to 2.5 million gallons a day could spill if the leaks worsened, though it would be more like 1.7 million gallons. In an exploration plan filed with the government in February 2009, BP said it could handle a "worst-case scenario" it described as a leak of 6.8 million gallons per day from an uncontrolled blowout.
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Containment boxes have never been tried at this depth - about 5,000 feet - because of the extreme water pressure. If all goes well, the contraption could be fired up early next week to start funneling the oil into a tanker.
"We don't know for sure" whether the equipment will work, BP spokesman Bill Salvin said. "What we do know is that we have done extensive engineering and modeling and we believe this gives us the best chance to contain the oil, and that's very important to us."
The seas calmed Tuesday, allowing more conventional methods to contain the spill to get back on track as businesses and residents kept an eye on the ocean currents, wondering when the sheen washing ashore in places might turn into a heavier coating of oil. Crews put out more containment equipment and repaired some booms damaged in rough weather over the weekend. They also hoped to again try to burn some of the oil on the water's surface, possibly Wednesday.
Chemical dispersants piped 5,000 feet to the main leak have significantly reduced the amount of oil coming to the surface, BP said.
From the air Tuesday, the site of the Deepwater Horizon explosion looked similar to a week ago except for the appearance of a massive rig brought in to drill a relief well to shut off the spewing oil. That will take months.
People along the Gulf Coast have spent weeks living with uncertainty, wondering where and when the huge slick might come ashore, ruining their beaches - and their livelihoods.
The anxiety is so acute that some are seeing and smelling oil where there is none. And even though the dead turtles and jellyfish washing ashore along the Gulf of Mexico are clean, and scientists have yet to determine what killed them, many are just sure the flow of crude unleashed by the explosion at BP's Deepwater Horizon is the culprit.
The rig was owned by Transocean Ltd. Some of the 115 surviving workers who were aboard when it exploded are suing that company and BP PLC. In lawsuits filed Tuesday, three workers say they were kept floating at sea for more than 10 hours while the rig burned uncontrollably. They are seeking damages.
Guy Cantwell, a spokesman for rig owner Transocean Ltd., defended the company's response, saying 115 workers did get off alive. Two wrongful death suits also have been filed.
While officials worked on cleanup, the long wait took its toll on nerves and incomes.
In Gulf Shores, Ala., the real estate firm Brett/Robinson Vacations sent a note to those renting vacation properties that they would not be penalized for any spill-related cancellations, but urged them not to jump the gun.
"There are many questions and many `what ifs' regarding this event," the message read. "Because changes come about hourly and 30 days is a long way away, we are asking you to wait before canceling your vacation, especially those of you who are scheduled to arrive more than 30 days from today."
There are legitimate concerns, experts say. A second bird found in the slick, a brown pelican, is recovering at a bird rescue center in Louisiana. National Wildlife Federation president and CEO Larry Schweiger says there's no way to know how many birds have been oiled because the slick is so big and so far offshore.
Perdido Key, a barrier island between Pensacola and the Alabama state line with sugar-white sand studded with condominiums, likely would be the first place in Florida affect by the oil spill. Perdido - Spanish for "Lost" - got a sniff Tuesday morning of what may be in store.
"You could smell the smell of it, real heavy petroleum base," said Steve Owensby, 54, a maintenance man at the Flora-Bama Lounge abutting the state line on the Florida side.
The air cleared later, but Owensby's 28-year-old daughter, Stephanie, who tends bar at the lounge, said some visitors have complained of feeling ill from the fumes.
"It's very sad because I grew up out here," she said. "I remember growing up seeing the white beaches my whole life. Every day I've been going to the beach ... a lot of people are out watching and crying."