Despite the stench - and the pair of pants, bottle of hair spray, and plastic oil cans that float by - Kenneth Economy wades barefoot into New Orleans's fetid brown floodwater.
He has no choice, like so many locals trying to right this wronged city. He is trying to restart the motor of a flat-bottomed boat as he and friends work to rescue people and animals out of their neighborhood. Those floodwaters, which have already destroyed an estimated 140,000 to 160,000 homes, now pose a new challenge.
As engineers began pumping out the Big Easy this week, creating small but visible wakes of water behind street signs and tree trunks, the water they're moving carries a volatile mix of everything imaginable - from household paints, deodorants, and old car batteries to railroad tank cars, sewage treatment plants, and landfills. While state officials stop short of calling it a toxic soup, at least so far, federal environmental officials call it catastrophic.
Breaks in the weather, nature's resilience, and engineering ingenuity could mitigate the size and scope of the problem, as they have with some previous natural disasters. But the environmental cleanup will be one of the nation's largest ever, experts say.
"This is an unprecedented mess for the US in recent history, and it seems to be certainly affecting many more people than prior US natural disasters," says Robert Pitt, professor of civil and environmental engineering at the University of Alabama.
Even discounting the area's unique geology and hydrology, officials and other experts say they're dealing with uncharted waters. "If we had never had a levee breach, we still would have had a tremendous amount of water in these sub-basins," says Don Basham, engineering construction chief for the US Army Corps of Engineers.
Meanwhile, a warehouse explosion along the river in New Orleans and an oil spill several days after the hurricane passed through have added to the challenge. "Everywhere we look there's a spill," said Mike McDaniel, secretary of Louisiana's Department of Environmental Quality, in the state's first major assessment of hurricane Katrina's environmental impact. "There's almost a solid sheen over the area right now."
While officials won't know the full extent of the problem until the floodwaters recede - and probably not until weeks or months after that - they do know that the cleanup of what has become an enormous chemical cesspool will be one of the costliest ever. The US Army Corps of Engineers figures that just cleaning up millions of tons of debris - shattered buildings (some with lead paint or asbestos), washed-out motor vehicles, the sodden detritus of private life and commerce - will cost $1.5 billion.
For now, some environmental regulations are being waived in order to address immediate problems. The Louisiana Department of Environmental Quality issued the naval base in Chalmette a variance so it could burn debris, mostly food that spoiled after losing power. The US Environmental Protection Agency has waived the need for Clean Water Act permits to allow the pumping of polluted water out of New Orleans into Lake Pontchartrain.
US Health and Human Services Secretary Mike Leavitt has declared a public health emergency in five states: Alabama, Florida, Louisiana, Mississippi, and Texas. There's no telling when wastewater treatment and other sanitary facilities will become functional. More than 500 sewage plants were damaged or destroyed in Louisiana, including 25 major ones.
But officials say there have not been any outbreaks of infectious diseases. "We are one week out, and so far, so good," says Mr. Leavitt, who toured the area over the Labor Day weekend. The key here is evacuation of people to safer and cleaner locations.
"In most cases, when the remaining population is removed, most of the main threat [from contaminated water] should decrease," says professor Pitt. But he adds that such toxicants as petroleum products, paints, and acids "are much more persistent and may leave a residue of problems after the water recedes, especially in some areas."
At the moment, the Army Corps and other state and federal agencies are concentrating on pumping water from flooded New Orleans, which sits in a bowl-shaped area below sea level. The effort commenced on Monday. By Tuesday, the city's Pump No. 6, one of the world's largest pump stations, joined two others to get the water out.
Draining the city will take up to 80 days, officials say, at which point the remaining sludge can be analyzed for toxic pollutants. Given the area's hot, humid climate there will be mildew, mold, fungus, and disease-carrying mosquitoes to deal with as well.
The water being pumped into Lake Pontchartrain will eventually flow into the Gulf of Mexico. But the pace at which that happens depends on natural processes - winds, future rainfall, cold fronts - that are difficult to predict and impossible to manipulate.
"The water does circulate out of the basin eventually," says Al Naomi, senior project manager for the New Orleans district of the US Army Corps of Engineers. "But it depends a lot on meteorological conditions, which we really don't have much control or much knowledge of, at least not here."
Beyond the immediate environmental impact of Katrina, the hurricane and its aftermath could have widespread and long-range effects as well. The Gulf Coast from Texas to Florida has a concentration of petroleum and chemical plants. Many of these are in or near low-income, largely African-American communities where the "environmental justice" movement has grown and spread. Off the coast of Louisiana is the 12,000 square-mile "Dead Zone," an area very low in oxygen due largely to excess nutrients tied to agricultural chemicals used in the Mississippi River basin.
It's possible that today's new environmental challenges in the region could exacerbate those situations. But nobody can be sure.
"We're starting into territory where nobody's tread before as far as cleanup and remediation is concerned," says Darryl Malek Wiley of the Sierra Club's office in New Orleans. "There's more questions than answers."
For shell-shocked New Orleanians, however, the looming environmental emergency pales in comparison to the arduous task of piecing their lives back together.
Mickey Gilliard barely escaped the floodwaters, but, on Tuesday, his boss called him back to work. An employee of the Jefferson Parish Drainage Department, he is one of hundreds of locals working with Corps of Engineers to stem breached levees and fix downed pumps.
"The waters are horrible," he says, pointing to a half-submerged oil barrel lying in the 17th Street Canal, clearly leaking a dark fluid. "All we can do is to try to start pumping it into the lake and into the river."
Patrik Jonsson reported from New Orleans. Material from Reuters was used in this story.