New Orleans ? Residents whose homes were flooded during Hurricane Katrina can sue the Army Corps of Engineers over claims the agency ignored warnings about defects in a nearby navigation channel, a federal judge ruled Friday.

The ruling, one of the first significant decisions in a set of cases over what caused the flooding, may force the Corps to hand over documents about the management of the channel.

“Now we will have an opportunity to see what goes on behind closed doors,” said Joe Bruno, a trial lawyer for the plaintiffs.

Eugene Pawlik, a Corps spokesman in Washington, said the agency’s attorneys are reviewing the ruling but did not have any immediate comment.

The Corps and federal government had argued they were immune to legal challenges because decisions about the waterway were based in policy.

But U.S. District Judge Stanwood Duval said there is no way to know that at this point, and said plaintiffs should get a hearing for their allegations.