New Orleans is building a mountain, a heap of broken concrete and soiled mattresses and shredded curtains plopped out on the edge of a swampy road that routinely draws comparisons to a hellish scene from Dante's "Inferno."

This place is called the Old Gentilly Landfill, an ancient dump that was shut down after being identified by federal regulators as a possible hazardous waste site nearly a quarter-century ago and that taxpayers have spent millions to clean up. The rebirth after Hurricane Katrina of Old Gentilly -- designated as a disposal site for "clean waste" from construction and demolition operations -- is the starkest example of how Louisiana is relaxing environmental laws to deal with the immensity of the storm's residue. Debris, such as soggy carpeting and plastic furniture that before the storm could never have gone into this kind of landfill, has been cleared by state environmental regulators to be dumped here in the open air. The state is allowing dumping at unlined Old Gentilly, even though more-modern landfills are nearby.

"The rules that were in place before this, they don't apply," said Chuck Carr Brown, the assistant secretary of the Louisiana Department of Environmental Quality responsible for landfill regulation.

Everyone knows that Katrina produced an amazing amount of waste -- 22 million tons, according to state estimates, about 15 times the debris removed after the Sept. 11, 2001, attacks. Picking up trash is a relatively unsophisticated job; disposing of it is a much more complex task because of the potential long-term environmental effects of putting garbage in the ground.

New Orleans has a bad track record with hurricane debris. After Hurricane Betsy in 1965, the city used the same approach that is now being used: reopen an old landfill.

The decision after Betsy to resurrect the Agriculture Street Landfill was disastrous. The landfill has been designated a Superfund site, federal regulators have slapped millions of dollars in fines on the city, cancer-causing substances have been found there, and lawsuits have been filed because houses and a school were built on top of it.

After Katrina, Old Gentilly shuddered back to life without a peep on a road notorious for illegal dumping east of New Orleans -- there was no one around to complain. New Orleans, which owns the landfill and pays two private companies to operate it, had been trying for two years to reopen Old Gentilly. But the process accelerated after Katrina, and many of the state-imposed requirements -- such as the types of waste that could be deposited and a mandate to build perimeter fencing -- vanished with a single stroke of Brown's pen on Sept. 29, a month after the storm.

Brown bristled at the notion that residents, who approved a bond measure to clean up the site, might complain once they return and find it reopened. "What taxpayers?" he said. "They're all displaced. I don't think anybody's worried about garbage. . . . I think they want us to dispose of this." Anyone who questions using Old Gentilly and other now-closed dumps that Brown plans to reopen, he said, "does not have the best interests of the state of Louisiana in mind."

But Brown's decisions have begun to draw attention on Capitol Hill and among environmentalists. The Sierra Club of Louisiana, which calls Old Gentilly "a Superfund site waiting to happen," and the Louisiana Environmental Network plan to file a lawsuit Monday challenging the reopening of Old Gentilly. Sens. James M. Inhofe (R-Okla.), chairman of the Senate Environment and Public Works Committee, and David Vitter (R-La.) have sent a letter to the U.S. Army Corps of Engineers, which awarded garbage contracts, pointing out that there is enough space in modern landfills, "making it unnecessary to open old dumps that do not meet today's standards."

One of the landfill operators -- Jimmie Woods -- was subpoenaed for documents last year in connection with a federal investigation of alleged corruption in the administration of former New Orleans mayor Marc Morial. Woods did not return phone calls.

"It's just good ol' Louisiana politics," said Wade P. Scott, owner of a modern landfill in nearby St. Charles Parish. He said there is more than enough capacity to handle "several Katrinas" between his landfill and another in Jefferson Parish, owned by businessman Fred Heebe. Brown says the landfills in St. Charles and Jefferson parishes could not process the waste fast enough, though Scott says it would be easy to set up multiple entrances to speed the flow.

Robert Wiygul, a lawyer for the environmental groups filing suit Monday, said placing new debris on the old dump at Gentilly could squeeze toxic liquids out of the buried garbage.

"You don't want to get rid of one mess by creating another mess that is going to haunt you for years to come," he said.

Brown rebuts the claim, saying soil borings showed no liquid beneath the surface, setting up what is likely to be a contentious court battle. While they argue, out in the bogs of New Orleans a mountain grows.

The Old Gentilly Landfill outside New Orleans has become a repository for all manner of debris left by Hurricane Katrina. Environmentalists say the grounds are "a Superfund site waiting to happen," and a legal challenge is planned. A state official defends the use of the site and says few options exist.