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," said Darryl Malek Wiley of the Sierra Club's office in New Orleans. "There's more questions than answers."

Unwilling to leave

Still, in the high and dry French Quarter, 48-year-old Jack Jones said he would resist if authorities tried to force him out of the home where he has lived since the 1970s.

While the streets were strewn with garbage, rotting food and downed power lines, Jones kept his block pristine, sweeping daily, spraying for mosquitoes and even pouring bleach down drains to kill germs.

Jones said the sick, the elderly and people who lack supplies should be evacuated — but not folks like him. He has 15 cases of drinking water, a generator, canned ravioli, wine, coffee and three cartons of Marlboros.

"I've got everything I need," he said. "I just want to be left alone."