Oil clean up crews work along Timbalier Island near Grand Isle, Louisiana April 20, 2011. [Photo/Agencies]

NO EXXON VALDEZ

But the spill's effects are far less serious than the 1989 Exxon Valdez disaster, which soaked Alaska's  environmentally fragile coast in heavy oil, said Edward Overton, an ecologist and professor emeritus at Louisiana State University in Baton Rouge.

"I think it's too early to tell, but I am extremely optimistic," Overton said. "We're way off what Exxon Valdez was, way off."

In Florida, where the oil spill cost the state's tourist-dependent economy more than $1 billion, officials were eager to tout their hotels, restaurants and resorts.

"Bookings are up and our beaches are spotless," Florida Gov. Rick Scott declared after touring Destin's white-sand beaches. "The fishing is good and the seafood tastes great."

But across the Gulf Coast, residents who still feel the spill's impact fear they will be abandoned by BP and an army of contractors who swarmed over the coast in the largest oil-spill response in US history, involving nearly 50,000 workers and 7,000 offshore vessels at its height.

"Oil is still washing up on our beaches and on the islands. Now that the media is gone, the BP effort has all but disappeared and so has our livelihood," said Craig Moore, a charter boat captain in Long Beach, Mississippi.

President Barack Obama, who was criticized as reacting too slowly to the spill, said the government will keep pressure on BP, and that "the job isn't done."

"We continue to hold BP and other responsible parties fully accountable for the damage they've done and the painful losses that they've caused," Obama said in a statement.

BP has paid out about $5 billion in claims for economic losses through a spill fund administered by Washington attorney Kenneth Feinberg. The spill wiped about $70 billion from BP's market value and spurred it to replace its gaffe-prone British chief executive with an American, Bob Dudley.

"At BP we regret that the accident happened and the impact it has had on the environment of the Gulf Coast and the people living there," Dudley wrote in an op-ed in the Wall Street Journal on Wednesday.

Also on Wednesday, BP sued Cameron International Corp, the Houston-based company that made the blowout preventer, the fail-safe device that failed to automatically shut in BP's Macondo well.