A Senate committee asked the Justice Department this week to provide information about legal challenges to New Orleans levee projects by environmental groups, prompting accusations that Republicans are seeking to blame environmentalists for the damage wrought by Hurricane Katrina.

A Justice Department e-mail sent to U.S. attorney's offices in the Gulf Coast region asks for information on cases involving "environmental groups seeking to block or otherwise impede the Corps' work on the levees protecting New Orleans."

Bill Holbrook, spokesman for the committee chairman, Sen. James M. Inhofe (R-Okla.), said the e-mail is the result of a request by a GOP staffer on the Senate Environment and Public Works Committee, which oversees the Corps. He said the committee was investigating whether environmental complaints had contributed to the Katrina disaster by impeding levee improvements in southeast Louisiana.

"This is part of our ongoing work with the Army Corps," Holbrook said. "It's been reported that some of these cases may have prevented things like the modernization of levees. This is part of our normal work, to determine what has happened."

The request, first reported by the Clarion-Ledger newspaper of Jackson, Miss., set off immediate objections from Democrats and environmental groups yesterday and underscored an increasing focus on environmental issues in the political debate over Katrina. Inhofe is pursuing legislation that would temporarily waive clean air and water laws in the region.

For decades, environmentalists, government agencies, fishermen and other groups have engaged in numerous court battles over the extensive system of levees and other structures put in place in an attempt to control flooding and ease shipping in southeastern Louisiana. Many environmental groups and Democrats have suggested that global warming and wetlands depletion may have played a role in worsening storm damage, while many conservatives allege that efforts to protect New Orleans were hampered by environmental objections.

Sen. Charles E. Schumer (D-N.Y.) said in a statement that the Bush administration "should be ashamed of themselves" if they are seeking to blame environmental groups for the flooding and its bungled aftermath.

"The slow recovery had little to do with the levees and everything to do with bad decisions in the immediate aftermath of the storm," Schumer said.

The Sierra Club, which has been involved in lawsuits related to levee projects in Louisiana, said the Bush administration was attempting to "reassign blame" for the government's response to the storm. A spokesman also said the request was part of GOP-led efforts to dismantle environmental limitations on development in the area.

"There have been ongoing efforts to open up these areas to offshore drilling and all kinds of other projects," spokesman David Willett said. "After Katrina, they're looking for baseless fodder to justify that."

A Justice spokesman said the department was only responding to a request from a Senate committee. The request from Inhofe's committee was made on Monday, Holbrook said.