Key spill-size issue: How much and does it matter?

NEW ORLEANS (AP) - Just how much oil is spewing from the ruptured well in the Gulf of Mexico and how important is it to know that? Experts can't agree on either question.

Some scientists who have studied a new video of the gusher estimate the leak could be 14 times worse than the government says. The feds say stopping the spill, not measuring it, is key.

But does the size matter now anyway?

Many veteran spill experts say trying to figure out how much oil is spewing is like trying to assess the damage of a house fire while firefighters are still trying to put it out. The size will matter later when the damage is tallied.

Others - especially lawyers, environmental advocates and the media - say numbers are needed to get a handle on how big the problem is. But a National Academy of Sciences report seven years ago said the size of a spill doesn't directly correlate to how bad the environmental damage is.

When BP, which owns the well, released a video Wednesday of the spewing oil, the whole magnitude of the problem seemed to change.

Soon after the explosion three weeks ago, the government said oil and gas were flowing from the seabed at a rate of 210,000 gallons - or 5,000 barrels - a day. Now, after viewing the video, some scientists calculate it at 2 million gallons a day or even higher.

But those estimates come with giant-sized asterisks. Because the video doesn't give experts a proper look, they could be off by millions of gallons of oil a day.

"The amount of oil leaking is a big, big deal; it's not to be taken lightly if it really is off by the factors that we're hearing. Ten times as much is 10 times as bad - at a minimum," said Darryl Felder, a University of Louisiana at Lafayette biology professor.

The National Oceanic and Atmospheric Administration declined repeated efforts by The Associated Press to explain in detail its 210,000 gallon-a-day estimate, except to say "in the absence of direct measurements, NOAA made an estimate of flow rate based on aerial observations."

Initially, BP and the government put the leak at 42,000 gallons a day. That changed a couple of weeks ago to 210,000, which BP and government officials say they aren't changing.

"We've used satellite imagery, overflights, visual observation," said BP spokesman John Crabtree. "All the methods of calculating how much oil that's leaking are inexact."

To make their estimates, the scientists essentially tracked particles or billows of oil across the video screen, then used the size of the pipes, particles and speed of the video to come up with a rate.

Some of the oil could be lingering under the water's surface. In previous cases, it's been as much as half of the spill, said University of California Berkeley engineering professor Bob Bea.

The environmental impact will be vastly different depending on the size of the spill, some experts agreed.

If the flow turns out to be closer to the higher end estimates, "that's a major catastrophe," Bea said. If it's closer to the government's estimate, it is something that can be handled.