Watch CNN's American Morning on Friday as Kiran Chetry reports on the Gulf Coast oil spill from Grand Isle, Louisiana. (Photos: Getty Images and Michael Humphrey/CNN)
(CNN) – The Gulf of Mexico undersea gusher has already spilled more oil than the Exxon Valdez disaster - possibly more than twice as much, making it the largest oil spill in U.S. history - government scientists said Thursday.
Scientists observed 130,000 to 270,000 barrels of oil on the water's surface on May 17, and think a similar amount had already been burned, skimmed, dispersed or evaporated.
That would mean 260,000 to 520,000 barrels had been leaked as of 10 days ago. The Exxon Valdez leaked about 250,000 barrels into Alaska's Prince William Sound in 1989. Read more
Full coverage | Track the spill | Should military take over in Gulf Coast? 