THIS STORY HAS BEEN FORMATTED FOR EASY PRINTING

Some scientists doubt data on dissipation of oil from gulf

3/4 of spill said accounted for; Ecologic effect still unknown

By David A. Fahrenthold
Washington Post / August 5, 2010

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WASHINGTON — The “greatest environmental disaster’’ in US history — which has appeared at times to leave a high-control White House powerless — seemed to have lost its power to scare.

A few hours after BP’s well was declared virtually dead, the Obama administration announced yesterday that only about 26 percent of the oil spilled in the Gulf of Mexico was unaccounted for.

“A significant amount of this,’’ said Jane Lubchenco, head of the National Oceanic and Atmospheric Administration, “is a direct result of the very robust federal response efforts.’’

But, in interviews, scientists who worked on the report said the figures were based in large part on assumptions and estimates, educated guesses with a significant margin of error.

Some outside scientists went further: In a situation in which many facts remain murky, they said, the government seemed to have used interpretations that made the gulf — and the federal efforts to save it — look as good as possible.

“There’s a lot of . . . smoke and mirrors in this report, I’m afraid,’’ said Ian MacDonald, a professor of biological oceanography at Florida State University. “It seems very reassuring, but the data aren’t there to actually bear out the assurances.’’

The government’s accounting of the spilled oil, called an “oil budget,’’ was announced yesterday at the White House. It appeared to answer the most troubling question: Of the 4.9 million barrels that poured out of the well, only 827,000 barrels were siphoned to vessels on the surface. Where did the rest of it go?

Where there had been mystery, now there was a pie chart.

It showed that 5 percent of the total oil had been burned and that 3 percent had been skimmed off the surface. An additional 25 percent had evaporated or dissolved. About another quarter had been “dispersed’’ — broken into tiny droplets by chemicals or by the force of being blasted out of the well.

The dispersed oil, Lubchenco said, “is in the process of being very rapidly degraded naturally, and so Mother Nature is assisting here considerably.’’ She said, however, that “diluted and out of sight doesn’t necessarily mean benign.’’

The remaining 26 percent of the oil was still unaccounted for, although Lubchenco said that did not necessarily mean this oil is causing ecological harm.

Officials made it clear who they thought was responsible for the success of the cleanup. White House press secretary Robert Gibbs said the cleanup “would have been different’’ if federal officials had not pushed BP to work faster.

But scientists who worked on the report said many of the numbers on the White House’s pie chart had significant margins of error. The estimate of how much oil evaporated was calculated using a formula designed for spills near the surface, not 5,000 feet underwater. The calculation of how much oil would be “dispersed’’ as it flowed from the well was a new one, extrapolated from data about the way oil is broken by waves.

And, as for Lubchenco’s assertion that the oil that has been dispersed is “rapidly degrading,’’ Bill Lehr, a NOAA scientist and an author of the report, said the analysis did not include an actual calculation or measurement of what is happening in the gulf. “We haven’t attempted yet to calculate that rate,’’ he said, and instead relied on assumptions based on past spills in the gulf.

Some outside researchers said that, given the uncertainty about what is happening in the gulf, the administration’s assertion that 74 percent of the oil had been accounted for seemed too optimistic. They saw it another way: About half of the oil is probably gone for certain.

They said the other half, including the 24 percent that has been “dispersed’’ but is hidden underwater, is the real total of what is missing.

The situation is “being portrayed as `the oil is out of the environment; it’s gone,’ ’’ said Michael Blum, a professor of earth and ecological science at Tulane University in New Orleans. But, he said, all that is certain is that “the form of the oil has shifted. Dispersed oil is still oil. It’s just in a different form.’’

Even if the government is right and only 26 percent of the oil is left, that would still be 1.3 million barrels, five times the oil spilled from the Exxon Valdez in 1989.

“In terms of the environmental impacts, the story is really not written yet,’’ despite the numbers released, said Steve Murawski, a NOAA senior scientist.

He said yesterday’s analysis indicates “where the oil is. But you know, what did the oil do when it was there?’’

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