BP oil leak 'much bigger than official estimates'

Much more oil is spewing into the Gulf of Mexico from a sunken British Petroleum oil rig than official estimates show, experts warned Friday as BP executives stuck to their guns and even tried to play down the size of the slick.

Steven Wereley, an associate professor of mechanical engineering at Purdue University, said 14 times more oil was spewing into the sea than the officially estimated 5,000 barrels a day, National Public Radio (NPR) reported.

Wereley analyzed the sea-floor oil geyser at NPR's request using a technique called particle image velocimetry, which tracks particles and calculates how fast they are moving.

Another scientist, Timothy Crone of Columbia University's Lamont-Doherty Earth Observatory, analyzed the undersea oil gusher for NPR using a different method, and came up with a similar figure.

And Eugene Chiang, a professor of astrophysics at the University of California, Berkeley, also got a similar answer, using just pencil and paper, NPR said.

Florida State University oceanographer Ian R. MacDonald analyzed the slick using satellite imagery, and told the New York Times that his calculations suggested that the leak could "easily" be spewing four to five times as much oil into the Gulf as previously estimated.

The findings suggest the gulf spill is already the worst environmental disaster in US history, eclipsing the 1989 Exxon Valdez spill off Alaska.

But BP disputed the experts' analyses, saying there is no reliable method to calculate how much oil is flowing from the broken pipe on the sea floor.

BP's chief operating officer, Doug Suttles, said Friday on the CBS Early Show that he thought the official estimate of 5,000 barrels of oil pouring into the sea was "reasonable but highly uncertain."

And a BP spokesman noted to AFP that the 5,000-barrels-a-day figure was provided by NOAA, a US federal agency, and the oil company had confidence in it.

There are 42 gallons of oil per barrel. The official estimate would mean that 210,000 gallons of oil are spewing into the Gulf each day. If the experts' estimates are closer to the mark, that would be raised that to nearly three million gallons a day.

BP has estimated that there are at least 50 million barrels of oil in the undersea reservoir that is gushing into the Gulf, according to The New York Times.

BP chief executive Tony Hayward, meanwhile, played down the size of the spill, saying it was "tiny" when compared to the expanse of water it was pouring into.

"The Gulf of Mexico is a very big ocean. The amount of volume of oil and dispersant we are putting into it is tiny in relation to the total water volume," BP chief executive Tony Hayward told British daily The Guardian.