NEW ORLEANS — A controversial project to build a hurricane barrier for New Orleans 40 years ago and an environmental lawsuit that stopped construction have moved to the center of a political battle to change federal environmental laws.

A House panel has begun examining whether New Orleans' defenses against Hurricane Katrina were compromised by the suit, which resulted in an injunction in 1977. The Army Corps of Engineers dropped the project by 1986 in favor of raising levees in the city.

The hearings are part of an effort by conservatives to change the National Environmental Policy Act (NEPA). Under the law, environmentalists have challenged hundreds of public and private projects.

Separately, Sen. James Inhofe, R-Okla., who is among the staunchest critics of environmentalists, asked the Justice Department last week to collect information on every NEPA suit that blocked Corps of Engineers projects. The request, first reported by the Clarion-Ledger newspaper of Jackson, Miss., set off immediate objections from Democrats and environmental groups.

Amid growing efforts by conservatives to change NEPA, the 1960s-era hurricane barrier and the environmental suit that blocked it have become a cause célèbre in the aftermath of Katrina.

Congress in the mid-1960s approved a massive hurricane barrier to protect New Orleans from storm surges that could inundate the city from the Gulf of Mexico. The system included a lengthy levee along the city's eastern flank and giant floodgates that could shut off Lake Pontchartrain if a hurricane was approaching.

Conservatives have seized on the injunction that scuttled the project as an example of public safety taking a back seat to the environment. But on Friday, Sen. Barbara Boxer, D-Calif., charged that the Justice Department was trying to "smear environmentalists" by blaming them for the federal government's failure to shore up the Louisiana coastline.

Inhofe's staff requested that the Justice Department compile a list of corps projects that were blocked by NEPA suits. Earlier this year, he directed two national organizations that opposed a major Bush administration clean-air initiative to turn over their financial and tax records to the Senate, in part to determine whether they were being influenced by environmental groups.

In the House, Rep. Cathy McMorris, R-Wash., who is chairing a bipartisan panel on improving the NEPA, said the panel is concerned about the growth of litigation under the act and whether it has been used to block projects critical to public safety. McMorris said there are 1,500 active suits under NEPA.

"We are seeing more and more lawsuits tied to NEPA and the NEPA process," she said. McMorris said the panel is not aiming to weaken environmental protections or standards.

Douglas Kysar, a Cornell University professor of environmental law, said the corps project to build the New Orleans hurricane barrier and the suit against it have lit up the conservative cause. "This thing is hot," he said.

But Kysar said the project failed for a number of reasons. He noted that the objections to the project included damage to wetlands, which provide natural protection against hurricane damage.

Kysar also cited a General Accounting Office report in 1976, issued the year before the NEPA suit, that found the project was experiencing massive delays and cost overruns, caused largely by the corps' inability to obtain access to rights of way and the necessary land to build levees and control structures.

Another part of the problem, Kysar said, is that the corps had to justify the cost of the barrier based on projected benefits to saving property. Under the law, it could not put a dollar figure on the value of saving human life.

For decades, environmentalists, government agencies, fishermen and other groups have engaged in 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 Schumer, D-N.Y., said in a statement that Bush administration officials "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.

A Justice spokesman said the department was only responding to a request from a Senate committee.