Heavy, sticky oil was starting to clog Louisiana marshes on the Gulf of Mexico as another edge of the partly submerged crude reached a powerful current that could take it to Florida and beyond.
BP is successfully siphoning off at least a portion of the oil spewing into the Gulf after hooking up a mile-long tube that connects the blown-out well to a tanker. Officials also are preparing an attempt to "kill" the well shooting a mixture known as drilling mud into it. Those efforts are expected to take place this weekend.
But one of the persistent storylines is the huge discrepancy between BP's estimate of the amount of oil flowing into the Gulf and those of independent scientists. Since the April 20 explosion, BP officials placed the flow rate at 5,000 barrels a day, or 210,000 gallons - a figure accepted by the government and widely reported as accurate. Those estimates put the total amount of oil spilt into the Gulf at around 6 million gallons.
However, after BP succumbed to pressure to release video footage of the blown-out well, those numbers have fallen under intense scrutiny. Steve Wereley, a mechanical engineer at Purdue University in Indiana, told The Associated Press that he is sticking with his estimate that 3.9 million gallons a day is spewing from two leaks.
"I don't see any scenario where (BP's) numbers would be accurate," he said at a congressional hearing Wednesday.
His estimate of the amount leaked to date, which he calls conservative and says has a margin of error of plus or minus 20 percent, is 126 million gallons - or more than 11 times the total leaked from the Exxon Valdez disaster in 1989.
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Another researcher, Timothy Crone of Columbia University's Lamont-Doherty Earth Observatory, said the latest video suggested a leak of at least 840,000 to 4.2 million gallons a day, though poor video quality made it difficult to come up with an accurate figure.
Interior Secretary Ken Salazar said the government would make "its own independent verification of what the total numbers are," during an appearance on CBS' "The Early Show" Thursday.
As questions linger as to the scope of the damage, here are some other key figures regarding the spill:
• Eleven people were presumed killed in the April 20 explosion on the Deepwater Horizon rig; 115 were evacuated, including 17 who were injured, 3 critically. 1 injured person remains in the hospital.
• BP said May 20 that it was collecting about 210,000 gallons a day from the mile-long tube drawing oil well to a ship on the surface. That figure is equal to the original estimate of leakage. While BP acknowledged they aren't capturing all the oil, a spokesman wouldn't comment on how much oil is still leaking out.
• Oil-eating bacteria, bombs and a device that resembles a giant shower curtain are among the 10,000 fixes people have proposed to counter the growing environmental threat. BP is taking a closer look at 700 of the ideas, but the oil company has yet to use any of them. About 70 BP workers are taking more suggestions at a tip line center in Houston.
• Amount BP says it has spent on the spill thus far: $500 million.
• The government increased the area of the Gulf where fishing is shut down to 46,000 square miles, or about 19 percent of federal waters. That's up from about 7 percent before.
• More than 400 species of wildlife, including whales and dolphins, face a dire threat from the spill, along with Louisiana's barrier islands and marshlands. Officials say 189 dead sea turtles, birds and other animals have been found along Gulf of Mexico coastlines
In the national refuges most at risk, about 34,000 birds have been counted, including gulls, pelicans, roseate spoonbills, egrets, shore birds, terns and blue herons.
• Total response vessels: 627
• Boom deployed: More than 1.65 million feet (regular boom plus sorbent and fire boom)
• Oily water recovered: More than 6.3 million gallons
• Dispersant used: More than 560,000 gallons. But on Wednesday, May 19, the Environmental Protection Agency informed BP that it had to start using a less toxic form of dispersant, according to a Washington Post report.
• Overall personnel responding: More than 17,500
• Fourteen staging areas are in place and ready to protect sensitive shorelines in Biloxi, Miss.; Pascagoula, Miss.; Pass Christian, Miss.; Amelia, La.; Cocodrie, La.; Grand Isle, La.; Shell Beach, La.; Slidell, La.; Venice, La.; Dauphin Island, Ala.; Orange Beach, Ala.; Theodore, Ala.; Panama City, Fla.; and Pensacola, Fla.
• The U.S. Navy is providing assistance in the areas of skimming and salvage operations, including 16 Modular Skimming Systems deployed to Gulfport, Miss. 1,400 total associated Department of Defense personnel have been deployed in support of spill cleanup and mitigation.
• The U.S. Coast Guard is leading volunteer efforts involving oil cleanup on shore if necessary. Shoreline cleanup volunteers must have training, including hazardous materials training required by OSHA and EPA.
• The Environmental Protection Agency has begun tracking air quality from the spill, including particulate matter (PM), ozone, and Volatile Organic Compounds (VOCs), at Venice and Chalmette, La.; Dauphin Island, Ala.; Gulfport, Miss.; and Pensacola, Fla., and posting results here here.
• To address potential wildlife impacts, BP has contracted with Tri-State Bird and Rescue. If oiled or injured wildlife is spotted, people are urged not to attempt to help the animals but to report them to (800) 557-1401.
• BP is now accepting claims for the Gulf Coast oil spill. Please call BP's helpline at (800) 440-0858. A BP fact sheet with additional information is available here (Word doc).
• To report oil on land, call (866) 448-5816.