Government Slipped Up on Oil Spill Estimates, Says Panel

Dick writes about Earth and planetary science for Science magazine.

One of five staff member reports released today by the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling criticizes the federal government's efforts to scientifically assess the amount of oil that was being spilled in the Gulf of Mexico as well as its initial attempt to gauge the fate of the oil. Another Commission report considered the use of oil dispersants on the spill.

The report chronicles official estimates of the flow starting in late April from the wrecked Macondo well. The estimates began at 1000 barrels per day and were famously stuck at 5000 barrels per day for a month while outside experts estimated flows 10 to 20 times higher. Federal estimates only rose to reasonably accurate levels—not far off the earlier outside estimates—after sensors were implanted in the wellhead and the flow was capped in mid-July.

The report calls the government's approach to the calculation of the 5000-barrel-per-day estimate and its public release "overly casual." According to Commission staff members, the 26 April estimate came in an unsolicited, one-page document prepared by a National Oceanic and Atmospheric Administration (NOAA) scientist with no particular expertise in the video technique involved. Although the scientist made clear that his was a "very rough estimate," it stood for the next month. But as far as Commission staff members have ascertained, the persistent low estimate did not deter front-line responders to the spill, who were working under a worst-case assumption that turned out to be in the ballpark of the actual flow.

White House officials take issue with the report's characterization of their efforts. A joint statement from the acting director of the Office of Management and Budget, Jeffrey Zients, and NOAA Administrator Jane Lubchenco says that "senior government officials were clear with the public what the worst-case flow rate could be: in early May, Secretary [of the Department of the Interior Ken] Salazar and Admiral Thad Allen told the American people that the worst case scenario could be more than 100,000 barrels a day. In addition, BP reported in 2009 that a blowout of the Deepwater Horizon (MC 252) could yield 162,000 barrels of oil a day."

Another interagency effort, estimating what happened to the oil once it was spilled, fared better, according to the report, but the government bungled the rollout of the resulting "oil budget" report. Government officials did not make clear that the calculation was not a rigorous, peer-reviewed procedure but an operational tool designed to aid responders. But the report was doomed to misinterpretation, the report notes, after Carol Browner, the director of the White House Office of Energy and Climate Change Policy, appeared on five TV morning news shows. The official oil budget in no way supported her on-air remark that "the vast majority of the oil is gone," but the media would stick with the characterization for months to come.

In this and other aspects of spill science, the staff members suggests that the Commission might "consider recommending that government scientific study groups disclose more of their underlying methodologies, assumptions, and data, allowing for greater review and input from the rest of the scientific community."

Gulf Oil Spill, oil fate