The Obama administration has once again increased its estimate of the flow of oil from BP's blown-out well.
Three different groups of scientists making educated guesses have come up with upper and lower ranges that go as low as 12,600 barrels a day and as high as 50,000 barrels a day. Marcia McNutt, the federal official charged with determining the flow rate, cited the range of about 20,000 to 40,000 barrels a day as the official estimate.
That would be 840,000 to 1.7 million gallons a day.
All those numbers come with the caveat that they estimate the flow from the well before a kinked riser pipe was lopped off on June 3, a move that inevitably increased the flow, although to what extent remains unclear.
Interior Secretary Ken Salazar told lawmakers on Wednesday that the riser cut increased flow four to five percent -- though given the extraordinary range of guesses involved, it's hard to fathom how he could be so sure.
The new numbers could still be low. One member of the flow group told reporters earlier this week that the flow could well be 100,000 barrels a day. But the actual flow rates are certainly much higher than the 5,000 barrel a day figure that the government stuck to long after the first video from the well head made it clear the real number was magnitudes higher.
"This is obviously a challenging scientific issue, since the leak is located a mile beneath the ocean," McNutt, the head of the U.S. Geologic Service, told reporters in a conference call.
One of the teams of scientists -- led by Richard Camilli of the Woods Hole Oceanographic Institution -- is new to the government's estimating group. McNutt said that team is using acoustic technology to measure the flow rate.
Yet another team, this one led by Energy Secretary and Nobel Laureate Steven Chu, is analyzing differential pressure readings they demanded BP provide from both inside and outside the new containment cap, but McNutt said their measurements are not yet complete.
These estimates still carry with them a great deal of uncertainty. One group estimated a range from 12,600 to 21,500 barrels a day; another estimated a range from 25,000 to 50,000 barrels a day. In other words, both of them can't be right.
At 40,000 barrels (1.7 million gallons) a day, over 52 days, that would mean the blown-out well has belched over 2 million barrels (88 million gallons) of oil into the Gulf of Mexico -- and somewhere around that much gas as well. The 1989 Exxon Valdez spill was estimated at about 250,000 barrels, which would make this spill at least 8 times as big, and counting.
Dan Froomkin is senior Washington correspondent for the Huffington Post. You can send him an e-mail, bookmark his page; subscribe to RSS feed, follow him on Twitter, friend him on Facebook, and/or become a fan and get e-mail alerts when he writes.