WASHINGTON/VENICE, La (Reuters) – Energy giant BP Plc seeks to double the amount of oil it captures from its ruptured Gulf of Mexico well, while the US Gulf Coast will be struggling with the environmental mess from the huge spill for years, the Coast Guard said yesterday. Coast Guard Admiral Thad Allen, who leads the government’s relief effort, said London-based BP hoped to collect 20,000 barrels (840,000 gallons/3.18 million litres) per day in its latest effort to contain the worst spill in U.S. history, which has now affected 120 miles (193 km) of coastline.

BP said it had collected 7,541 barrels of oil in the first 12 hours of yesterday. If it collected the same amount the rest of the day, the total would have been more than 15,000 barrels for yesterday, about 35 percent higher than the amount collected on Sunday.

Some scientists are concerned that the May 27 government estimate of up to 19,000 barrels coming daily from the well a mile (1.6 km) under the sea may be too low. BP had estimated the flow at just 5,000 barrels a day.

Neither Allen nor BP gave an estimate of how much oil is still flowing into the Gulf. The 49-day-old spill is causing an ecological and economic disaster along the US Gulf Coast, and testing Barack Obama’s presidency.

BP’s latest effort is the first positive sign after a series of failed attempts fueled public anger at the company.

The earlier efforts generated initial optimism that an end to the crisis was in sight, but those hopes were dashed when the crude kept spewing out. Allen said BP’s latest attempt — placing a containment cap on top of the gushing pipe on the ocean floor — appeared to be going “fairly well.”

Allen said cleaning up the oil spill will take at least four to six weeks after the well is eventually sealed — expected to be in August. But dealing with the long-term environmental effects will take years, he said. “We’re no longer dealing with a large, monolithic spill. We’re dealing with an aggregation of hundreds of thousands of patches of oil that are going a lot of different directions,” Allen said, stressing the broad dispersal of the oil.

“Dealing with the oil spill on the surface is going to go on for a couple of months” once the well is plugged, Allen said. “Long-term issues of restoring the environment and the habitats … will be years.” Obama said after meeting with Cabinet officials at the White House that the economic impact of the spill, which threatens the Gulf Coast’s multibillion-dollar fishing industry, will be substantial.

He said the US government would “ride herd” on BP to make sure that it paid damage claims from Gulf Coast residents, who have complained that the company is not paying them promptly.

He was also pushing BP to be prepared for a possible hurricane in the Gulf. The Atlantic hurricane season, which is forecast to be unusually active this year, began on June 1, typically peaks in August and ends in November.