Slick Numbers: How the Oil Spill Estimates Keep Climbing

Late last week, a panel of scientists assembled by the U.S. government doubled its estimate of the amount of oil gushing into the Gulf of Mexico from the ocean floor (and some scientists still think that amount could be too low). This is far from the first time that the government and BP have turned out to be wrong about this disaster -- it's been clear for almost two months now that they're doing a poor job measuring the extent of the spill.

The amount of oil leaking from the wreckage of the Deepwater Horizon oil platform matters because it affects everything from the size of the fine that BP could face to planning for how much oil could wash up on Gulf Coast beaches. But just how poor have the estimates been since the April 20 explosion? Let's look at the numbers:

None (April 22)

BP and the U.S. Coast Guard originally said there was no evidence of oil leaking from the Deepwater Horizon well after the rig exploded and sank

1,000 barrels a day (April 24)

Initial leak estimate reported by BP and the Coast Guard

5,000 barrels a day (April 28)

Revised Coast Guard estimate (originally disputed by BP, which claimed the number was lower)

12,000 to 19,000 barrels a day (May 27)

First estimate from a government-appointed team of scientists called the Flow Rate Technical Group

25,000 barrels a day (May 27)

Alternative estimate suggested by a subgroup of the Flow Rate Technical Group

25,000 to 30,000 barrels a day (June 10)

Latest estimate from the Flow Rate Technical Group, based on new data from the leak

60,000 barrels a day (May 5)

What BP told Congress would be a worst-case scenario for the amount of oil spewing from the seafloor

70,000 barrels a day (May 14)

Estimate from Purdue University engineering professor Steve Wereley based on independent analysis of video of the undersea leak

100,000 barrels a day (May 21)

Upper limit of flow estimate from four independent scientists, including Wereley, in a New York Times op-ed

250,000 barrels total (1989)

Amount spilled by the Exxon Valdez when it ran aground off Alaska, the previous worst oil spill in U.S. history

This post originally appeared at OnEarth magazine.