But Morgan, Lewis also has represented nuclear utilities in lawsuits against DOE, its new employer, the lawmakers said in a letter to Inspector General Gregory Friedman.

Also in 2001-2002 the firm was a registered lobbyist representing the Nuclear Energy Institute, a leading pro-repository group, they said.

"In our view these conflicts could independently warrant the recusal of Morgan from the September contract," the Nevadans said.

DOE spokeswoman Megan Barnett said the Morgan Lewis firm was hired after DOE evaluated potential conflicts. Other DOE officials have said the department was satisfied with safeguards the firm installed to avoid conflict problems.

"We look forward to a review by the DOE IG," Barnett said.

The call for a contract probe is the latest in a series of Nevada protests as state officials try to kill or at least slow down the bid to bury 70,000 metric tons of highly radioactive waste at the mountain ridge 100 miles northwest of Las Vegas.

The Energy Department has declined to make public a copy of the Morgan Lewis contract. In a Nov. 6 letter, DOE officials also declined to expedite a formal request for the document filed under the federal Freedom of Information Act.

Nevada's bid for a new investigation came on the same day the Department of Energy held the final one of eight public hearings on the repository.

The session, which was held in Washington, D.C., likely was the final opportunity for the public to comment on the project before DOE files a construction license application expected by next summer.

Earlier hearings were held in Nevada and California. A hearing Monday in Las Vegas drew more than 200 people.

Wednesday's session drew 48 attendees and 14 speakers.

Five speakers, including representatives from the Nuclear Energy Institute and the National Association of Regulatory Utility Commissioners, encouraged the nuclear waste effort.

Nine speakers, from groups including Physicians for Social Responsibility, and the Alliance for Nuclear Accountabiity, complained there are still too many uncertainties to justify moving forward.

Four representatives attended from Nye County, which has adopted a more accommodating strategy on the repository than most Nevada elected leaders and state government officials.

As the county where Yucca Mountian is located, Nye officials say they hope to lure economic development and other benefits if Nevada fails to stop the government and if the repository becomes reality.

Gary Hollis, chairman of the Nye County Commission, said at the public hearing scientists hired by the county have produced about $30 million in repository studies.

"What we have observed is that this is not only a technically feasible project but that it can be done safely," Hollis told the Washington audience.

Hollis said Nye County residents face less risk from a Yucca repository than they would from radioactive residues migrating into their water from the Nevada Test Site, where nuclear bombs were detonated underground until the early 1990s.

Hollis said the project should be decided "on its merits."

"Regardless of one's decision, either for or against, we need to see an end to the stalling tactics and politicizing of science and bring this project to a conclusion," he said.

Contact Stephens Media Bureau Chief Steve Tetreault at stetreault@stephensmedia.com or (202) 783-1760.