HOUSTON The amount of oil spilled by BP Plc's blown-out Gulf of Mexico well has eclipsed the 1989 Exxon Valdez disaster, and could be flowing at a rate nearly four times BP's recent estimates, according to findings of a U.S. government expert panel released on Thursday.
On May 17, there were at least 130,000 barrels of oil on the surface of the Gulf of Mexico, and a similar amount had been skimmed off the surface or evaporated, according to a panel of government scientists known as the Flow Rate Technical Group.
The findings, made public by U.S. Geological Survey Director Marcia McNutt, confirm that more oil has been spilled from BP's leaking well than the estimated 257,000 barrels that fouled Alaska's Prince William Sound by the grounding of the Exxon Valdez tanker.
If the panel's calculations are accurate, a total of at least 260,000 barrels of oil had spilled into the ocean by May 17.
The high-end estimate of oil on the water that day was 270,000 barrels, with a similar amount contained or evaporated, the panel found.
McNutt declined to confirm that the BP spill has eclipsed the Exxon Valdez, but she did not dispute it.
"This is obviously a very, very significant environmental disaster and I think with the numbers I've given you, you can do the math," McNutt said.
The team's best estimate for the amount of oil pouring from the well is 12,000-19,000 barrels per day, though one of three measurement methods the team used returned a high-end rate of 25,000 barrels per day, McNutt said.
Assuming the well has flowed 12,000 barrels (504,000 gallons/1.9 million liters) a day since April 20 -- the day the Deepwater Horizon rig exploded -- the total amount of oil released by the well is 444,000 barrels (18.65 million gallons/70.59 million liters), nearly twice the amount from Exxon Valdez.
A BP spokesman declined to comment on the government's estimate.
The government's lowest estimate is over twice the estimate repeatedly cited by BP officials of about 5,000 barrels (210,000 gallons/795,000 liters), though company officials have said the estimate is unreliable.
(Reporting by Chris Baltimore; Editing by Eric Beech)