Gulf of Mexico oil spillPanel sharply raises estimate of oil spilling into the Gulf to 60,000 barrels a day

For a months or so following the 20 April explosion of Deepwater Horizon, BP insisted that the amount of oil being spilled into the Gulf was no more than 5,000 barrels a day. To make sure this figure could not be independently verified, BP refused to release videos showing the oil gushing out of the well. Government scientists and independent experts always suspected that figure was self-servingly low. A U.S. government panel last week raised its estimate of the flow rate from BP’s damaged well to 30,000 a day. Yesterday, the panel raised its estimates yet again, declaring that as much as 60,000 barrels a day could be gushing into the Gulf of Mexico.

The New York Times’s Liz Robbins and Justin Gillis write that the spill was already categorized as the largest in U.S. history, and the new figures sharply increase previous estimates, suggesting a flow equal to an Exxon Valdez — every four days.

Scientists on Tuesday released a flow rate that ranged from 35,000 to 60,000 barrels — up from the rate they issued only last week, of 25,000 to 30,000 barrels a day. It continues a pattern in which every new estimate of the flow rate has been dramatically higher than the one before.

The current range is far above the figure of 5,000 barrels a day that BP and the government clung to for weeks after the spill started.

Robbins and Gillis note that the estimate of 25,000 to 30,000 barrels released last week were based on readings taken from before 3 June, when BP cut an underwater pipe called a riser to install a new device to contain the oil.

The number is far greater now, as scientists and BP officials had predicted, because when BP cut the pipe, the oil began flowing out of a single, concentrated source instead of several openings.

Over the past week, scientists placed pressure meters to the containment cap better to read the rate of flow. Energy Secretary Steven Chu himself was involved in using those pressure readings to help make the latest estimate, the government said.

“This estimate, which we will continue to refine as the scientific teams get new data and conduct new analyses, is the most comprehensive estimate so far of how much oil is flowing one mile below the ocean’s surface,” Ken Salazar, the Interior Secretary, said in a statement released by the Coast Guard. The new estimates seemed in line with the images of voluminous clouds of oil shown from underwater video over the last several weeks.

The numbers came on a day when BP’s ill-fated relief efforts to stop the damaged well hit yet another snag, underscoring once again the fragility of the containment effort: lightning struck the vessel that had been collecting the oil from the well, suspending operations for nearly five hours from 9:30 a.m. Central time until 2:15 p.m.

BP had only been able to collect about 15,000 barrels a day at its peak with the containment cap, and this new calculation, if it holds up, suggests that BP’s latest plans for capturing oil will be adequate, if only barely.

BP has outlined plans to deploy new equipment so that it can capture a minimum of 40,000 barrels a day by the end of June, and a minimum of 60,000 barrels a day by mid-July.