NEW ORLEANS - The gooey oil washing into the maze of marshes along the Gulf Coast could prove impossible to remove, leaving a toxic stew lethal to fish and wildlife, government officials and independent scientists say.
Officials are considering some drastic and risky solutions: They could set the wetlands on fire or flood areas in hopes of floating out the oil.
But they warn that an aggressive cleanup could ruin the marshes and do more harm than good. The only viable option for many areas is to do nothing and let nature break down the spill.
More than 50 miles of Louisiana's delicate shoreline already have been soiled by the massive slick unleashed after BP's Deepwater Horizon burned and sank last month. Officials fear oil eventually could invade wetlands and beaches from Texas to Florida. Louisiana is expected to be hit hardest.
Plaquemines Parish officials on Louisiana's coast discovered a major pelican rookery awash in oil on Saturday. Hundreds of birds nest on the island, and a photographer saw that at least some birds and their eggs were stained with the ooze. Nests were perched in mangroves directly above patches of crude.
"Oil in the marshes is the worst-case scenario," said Coast Guard Adm. Thad Allen, the head of the federal effort to contain and clean up the spill.
Also on Saturday, BP told federal regulators it plans to stick with the main chemical dispersant it's been spraying in the open gulf to break up oil before it reaches the surface. The Environmental Protection Agency had directed the company to look for less toxic alternatives. But BP said in a letter to the EPA that Corexit 9500, one of the chief agents used, "remains the best option for subsea application."
Oil that has rolled into shoreline wetlands coats the stalks and leaves of plants such as roseau cane - the fabric that holds together an ecosystem that is essential to the region's fishing industry and a much-needed buffer against gulf hurricanes. Soon, oil will smother those plants and choke off their supply of air and nutrients.
In some eddies and protected inlets, the ochre-colored crude has pooled beneath the water's surface, forming clumps several inches deep.
With the seafloor leak still gushing hundreds of thousands of gallons a day, the damage is only getting worse. Millions of gallons already have leaked so far.
Coast Guard officials said Saturday the spill's impact now stretches across a 150-mile swath, from Dauphin Island, Ala., to Grand Isle, La.
Over time, experts say weather and natural microbes will break down most of the oil. However, the crude will surely poison plants and wildlife in the months - even years - it will take for the syrupy muck to dissipate.
Back in 1989, crews fighting the Exxon Valdez tanker spill - which unleashed almost 11 million gallons of oil into Alaska's Prince William Sound - used pressure hoses and rakes to clean the shores. The Gulf Coast is just too fragile for that: those tactics could blast apart the peatlike soils that hold the marshes together.
Hundreds of miles of bayous and man-made canals crisscross the coast's exterior, offering numerous entry points for the crude. Access is difficult, even in the best of circumstances.
"Just the compaction of humanity bringing equipment in, walking on them, will kill them," said David White, a wetlands ecologist from Loyola University in New Orleans.