VENICE, La. -- The surface area of a catastrophic Gulf of Mexico oil spill quickly tripled in size amid growing fears among experts that the slick could become vastly more devastating than it seemed just two days ago.
The newly named federal point man for the oil spill said it was impossible to pinpoint how much oil is leaking from a ruptured underwater well. Commandant Adm. Thad Allen, head of the U.S. Coast Guard, told a conference call Saturday that ''any exact estimation of what's flowing out of those pipes down there is impossible'' because the site is about a mile underwater.
Frustrated fishermen eager to help contain the spill had to keep their boats idle as another day of rough seas kept crews away from the slick, and President Barack Obama planned a trip to the Gulf Coast today.
Documents also emerged showing BP PLC downplayed the possibility of a catastrophic accident at the offshore rig that exploded. BP operated the rig, which was owned by Transocean Ltd.
How far the spill will reach is unknown, but the sheen already has reached into precious shoreline habitat and remains unstopped, raising fears that the ruptured well could be pouring more oil into the gulf than estimated.
The Coast Guard has estimated that about 200,000 gallons of oil are spewing out each day -- which would mean 1.6 million gallons of oil have spilled since the April 20 explosion that killed 11 workers. The environmental mess could eclipse the Exxon Valdez disaster, when an oil tanker spilled 11 million gallons off Alaska's shores in 1989.
The slick nearly tripled in just a day or so, growing from a spill the size of Rhode Island to something closer to the size of Puerto Rico, according to images collected from mostly European satellites and analyzed by the University of Miami.
On Thursday, the size of the slick was about 1,150 square miles, but by Friday's end it was in the range of 3,850 square miles, said Hans Graber, executive director of the university's Center for Southeastern Tropical Advanced Remote Sensing. That suggests the oil has started spilling from the well more quickly, Graber said.
''The spill and the spreading is getting so much faster and expanding much quicker than they estimated,'' Graber told The Associated Press on Saturday.
Louisiana State University professor Ed Overton, who heads a federal chemical hazard assessment team for oil spills, cautioned that the satellite imagery could be deceiving.
He said satellites can't measure the thickness of the sheen and makes it difficult to judge how much oil is on the water.
Another issue is that the oil slicks are not one giant uniform spill the size of an island. Instead, they are ''little globs of oil in an area of big water,'' Overton said.