ON THE GULF OF MEXICO -- Icy slush foiled plans to use a giant box to contain the uncontrolled oil gusher in the Gulf, leaving BP pondering an alternate solution at sea, while on land, helicopters were expected to drop sandbags in Louisiana to guard against thick blobs of crude that began washing up on beaches.
On Sunday, in a waterfront yard in Port Fourchon, La., a tractor-trailer dumped a load of sand, which workers planned to pack into 5-cubic-yard bags. Once the bags are ready, the Army National Guard will airlift them on Monday to five spots along a four-mile stretch of coastline between Port Fourchon and the Jefferson Parish line, said Lafourche Parish compliance officer Robert Passman.
"We want to block it off to where the oil doesn't get into the marsh areas," said Passman. "What they're trying to do is just prevent. I know it's still east of here but they're just trying to do a little prevention."
As for the solution at sea, BP PLC officials said they were considering several options to stop the daily rush of at least 200,000 gallons of crude from a blown-out well a mile underwater. BP PLC spokesman Mark Proegler said no one has settled on what step the company will take next, but a decision could come by Monday.
With crippled equipment littering the ocean floor, engineers from the oil company -- which is responsible for the cleanup -- scrambled to devise a fresh method to cap the ruptured well. Their previous best hope for containing the leak quickly, a four-story containment box, became encrusted with deep-sea crystals Saturday and had to be cast aside.
Among the plans under consideration:
-- Deploying a new, smaller containment box in the hope that it would be less likely to get clogged. Officials said the new box could be in place by midweek.
"We're going to pursue the first option that's available to us and we think it'll be the top hat," the smaller box, BP Chief Operating Officer Doug Suttles said.
-- Cutting the riser pipe, which extends from the mile-deep well, undersea and using larger piping to bring the gushing oil to a drill ship on the surface, a tactic considered difficult and less desirable because it will increase the flow of oil.
-- Shooting mud and concrete directly into the well's blowout preventer, a device that was supposed to shut off the flow of oil after a deadly April 20 oil rig explosion but failed. The technique, known as a "top kill," is supposed to plug up the well and would take two to three weeks.
The engineers appear to be "trying anything people can think of" to stop the leak, said Ed Overton, a LSU professor of environmental studies.
An estimated 3.5 million gallons of oil have spilled since an explosion on April 20 on the drilling rig, the Deepwater Horizon, 50 miles off the Louisiana coast. At that pace, the spill would surpass the 11 million gallons spilled in the Exxon Valdez disaster by next month. BP is drilling a relief well that is considered a permanent fix, but that could take months to complete.
Above the oil leak, waves of dark brown and black sludge crashed into the support ship Joe Griffin. The fumes there were so intense that a crew member and an AP photographer on board had to wear respirators while on deck.
Philip Johnson, a petroleum engineering professor at the University of Alabama, said cutting the riser pipe and slipping a larger pipe over the cut end could conceivably divert the flow of oil to the surface.
"That's a very tempting option," he said. "The risk is when you cut the pipe, the flow is going to increase. ... That's a scary option, but there's still a reasonable chance they could pull this off."
Johnson was less optimistic that a smaller containment box would be less susceptible to being clogged by icelike crystals.
"My suspicion is that it's likely to freeze up anyway," he said. "But I think they should be trying everything they can."
There was a renewed sense of urgency as dime- to golfball-sized balls of tar washed up Saturday on Dauphin Island, three miles off the Alabama mainland at the mouth of Mobile Bay and much farther east than the thin, rainbow sheens that have arrived sporadically in the Louisiana marshes. Until Saturday none of the thick sludge -- those indelible images from the Valdez and other spills -- had reached shore.
The containment box plan, never before tried at such depths, had been designed to siphon up to 85 percent of the leaking oil to a tanker at the surface. It had taken about two weeks to build it and three days to cart it 50 miles out and slowly lower it to the well.
Icelike hydrates, a slushy mixture of gas and water, clogged the opening in the top of the peaked box like sand in a funnel, only upside-down.
The blowout aboard the rig, which was being leased by BP, was triggered by a bubble of methane gas that escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding, according to interviews with rig workers conducted during BP's internal investigation. Deep sea oil drillers often encounter pockets of methane crystals as they dig into the earth.
Lane Zirlott, 32, a commercial fisherman from Irvington, Ala., said he's not frustrated about BP failing so far to cap the leak because he understands how difficult the job is.
"When they said they were going to put this little cap over this thing, I laughed and said there's no way," he said. "I said there's no way they're going to do that. And then sure enough, it didn't happen."