NEW ORLEANS -- Hurricane Rita rattled even more debris out of New Orleans yesterday, as federal officials began bracing for another possible wave of oil, chemical, and hazardous waste spills.
Federal emergency officials launched helicopters yesterday afternoon, as soon it was safe to inspect fragile containments and clean-up machinery at dozens of sites where hundreds of thousands of gallons of oil spilled during Katrina.
Concerns were high that other tanks, pipelines, or drums that had been weakened during Katrina may have sprung leaks.
Meanwhile, the putrid soup of chemicals and bacteria that had settled into a thick sludge was sloshing again yesterday in the Ninth Ward.
''There is always that worry" that the pollution could spread, said Lieutenant Commander Glynn Smith of the Coast Guard. ''But we have no way of knowing until we look."
New Orleans and its outlying areas suffered severe environmental damage during Katrina, harm that officials have not finished calculating. ''We're starting to look now," Smith said.
As the weather slowly improved yesterday, search-and-rescue operations in dry neighborhoods began again, and bulldozers and excavators roared to life.
Interstate 10, which runs through the city -- and which has been closed to all but emergency officials since Katrina -- was closed even to them yesterday because of extensive flooding.
Most workers found detours, snaking in convoys along backroads. Emergency workers and resident holdouts gathered on a bridge to watch the Ninth Ward, flooded during Katrina, flood again because of a breach that hit the Industrial Canal.
Chinook helicopters dropped 7,000-pound bags on the several-hundred-foot breach, but by 4 p.m. the effort to shore up the levees had succeeded only in filling in a tiny percent of the gap.
Katrina punched a hole in the levee last month, and a 7-foot-high temporary levee failed to hold.
''It is sad," said Lashann Rodgers, a New Orleans resident who stayed during Rita and Katrina. But, she added, with the Ninth Ward a twisted, unlivable mess of steel, wood, and pollution, ''it was the best place for it to happen."
Yesterday, streets bulldozed relatively clear after Katrina were filled again with screens, thick branches, pieces of corrugated roof, and the detritus of an abandoned city. Wind howled against boarded up windows and kept the city's many abandoned animals cowering under porches. It was unclear when residents would be allowed to return, and Mayor C. Ray Nagin said he would have to assess the damage before committing to a specific day. He said he wanted it to be as soon as possible.
The delay to get back into the city was hard for some evacuees. Even those who lost everything want to come back to see for themselves and possibly salvage mementos.
''I have 12 feet of water in my house again," said Dave Ellis of St. Bernard Parish, who has been living in motel about 50 miles from New Orleans for the past month. He watched the reflooding on television yesterday. His daughter's house in southwestern Louisiana was flooded during Rita, and she was driving east last night to stay with him.
''I laugh about it," Ellis said. ''What else can I do? I have nothing -- nothing left."
Federal officials said it would take two to three weeks to pump out the flood waters, which began pouring in Friday through levees patched after the previous hurricane. Yesterday water rose to the tops of cars in one neighborhood and seeped into homes in other sections that had been pumped dry days ago.
''The surge got higher than we expected in the canal," said Dan Hitchings of the US Army Corps of Engineers.
Material from the Associated Press was included in this report.