JUDY WOODRUFF: Now: the latest from the U.S. Gulf Coast and the oil spill.
Interior Secretary Ken Salazar said this evening that the companies involved made -- quote -- "very major mistakes." And he said the government wouldn't issue any new permits for offshore drilling for at least three weeks, while an investigation is completed.
Today, crews launched a major project to slow the spread of the spill, while researchers worked to limit damage to crucial fishing areas.
NewsHour correspondent Tom Bearden reports from the scene. Tonight, he's in Alabama.
TOM BEARDEN: As the sun rose over the Gulf, viscous oil lapped against the boat that carried the 100-ton containment box to the site of the spill. The plan called for the four-story concrete and steel tower to cover the leaking pipe from the sunken oil rig.
TONY HAYWARD, CEO, BP Group: It's never been done at 5,000 feet below the sea, but that's the option that the team are now working on.
TOM BEARDEN: By Monday, the containment box could be temporarily channeling the hemorrhaging crude oil and piping it to the surface.
BP operated the sunken rig and hopes to capture 85 percent of the oil that's gushing from the seabed. If it works, a second box could be placed over the wellhead itself. Still, U.S. officials are assuming a worst-case scenario.
The U.S. secretary of homeland security, Janet Napolitano, spoke today in Biloxi, Mississippi.
JANET NAPOLITANO, U.S. homeland security secretary: I hope it works. It has not been used at that depth before, but we're still proceeding as if it won't. The best-case scenario would be that the oil never reaches landfall, but I don't think we can depend on that. The -- this thing has spread. And -- and the oil takes various forms.
TOM BEARDEN: In the meantime, at BP's darkened operations center in Houston, Texas, engineers continue trying to guide deep-sea robots to shut off the flow of oil at the wellhead. So far, they have managed to close just one small leak.
On the surface, calm seas have allowed for more controlled burns, skimming, and chemical dispersal efforts. Yesterday, 18 flights dropped 150,000 gallons of those chemicals.
BOB FRYAR, senior vice president, BP: With time, this -- this dispersant breaks it up, and it will take care of itself. That's where nature kicks in and takes care of it.
TOM BEARDEN: Frantic efforts also continue to keep oil from reaching the Louisiana coastline, home to nearly 40 percent of the country's wetlands.
But the Associated Press reported today seeing pinkish, oily residue along the shore at New Harbor Island. The uninhabited barrier island is part of the Chandeleur Islands, a national wildlife refuge.
Here in South Alabama, booms are still being deployed in Mobile Bay. Governor Bob Riley has approved a plan to string booms across the entrances to the entire bay. Two swinging doors operated by tugboats would allow ship traffic to pass. That's more than five miles of booms. The offshore fishing grounds remain closed, and some area fisherman have found work stringing and managing booms.
This is part of the long line of containment booms that stretch all up and down the Mississippi and Alabama and Louisiana Gulf Coast. These are designed to keep the oil from coming onshore, but, as we saw just over there, it is difficult to keep them from drifting into shore. There have to be maintenance boats out to pull them away and reestablish the barrier.
But some of the people working on the booms are operating swamp boats that were brought in from Louisiana, and some local people who are not working are pretty angry about that.
MAN: We commercial fishermen, and we don't even own a boat like that!
TOM BEARDEN: Inside the bay being protected by that boom, Auburn University scientists are working on a project that might help the oyster business recover if the oil does severe damage. This is a test project to see if oysters can be cultivated in shoreline farms. There are 170,000 oysters in these submerged enclosures.
Bill Walton is a university biologist.
BILL WALTON, biologist, Auburn University: With the oil spill coming, we decided that we would put out oysters just before the spill hits, in sort of canaries in the coal mine. And, so, we have got 10 sites along the coast stretching from the Mississippi line over to the Florida line where we put oysters out, and we're going to track to see how well they survive, see what their growth rates are, and then obviously be able to look at contaminant levels.
TOM BEARDEN: LaDon Swann is the director of the Auburn Marine Research Center.
Do you think that barricade is adequate to keep oil out of this bay?
LADON SWANN, director, Auburn Marine Extension and Research Center: It can't hurt. And I think, if you look at the data, I think the best that has ever been done in terms of recovering the oil is about 10 percent at any spill. So, if that helps you achieve a 10 percent recovery rate, or maybe even better, that is great. But it -- Mother Nature will do what it does.
TOM BEARDEN: Swann says, if the oyster beds are devastated, the project might be able to help fishermen and restore the natural oyster reefs more quickly.
LADON SWANN: Could we help market -- a product for the market? We could help with some of (INAUDIBLE) the reefs, because these oysters, we can spawn those in a hatchery on Dauphin Island. We can grow those up until they're large enough to set on smaller pieces of shell. And then we can plant on some of these reefs that are trying to be reestablished.
TOM BEARDEN: Walton says the entire regional economy is tottering on a precipice.
BILL WALTON: We have got guys who already are put out of work because of those closures that are in effect. But that has this cascading effect.
I mean, you drive through Bayou La Batre, and you will see all sorts of delivery trucks that are parked in parking lots right now, not delivering seafood. The guys who sell ice are not selling ice right now. I mean, the restaurants right now are selling seafood, but, obviously, there are going to be big impacts on that. So, it's really -- it's going to a very dramatic effect. No matter how long the closure is, it's going to affect a lot of people.
TOM BEARDEN: Today, the Obama administration announced a low-interest loan program for businesses affected by the spill.