It looks more and more likely that Nevada's most glowing new addition won't be a glitzy casino but a nuclear waste site, as a House committee edged a proposal by President Bush closer to reality Thursday.

Critics said allowing the Yucca Mountain Nuclear Waste Storage Facility to operate would open the way for a "potential mobile Chernobyl" in America's backyard.

The congressional resolution, which would overrule Nevada Gov. Kenny Guinn's veto of the waste site, was approved 41-6 by the Energy and Commerce Committee, boding well for a full House vote to approve the measure.

"It will be an overwhelming vote of support" for the waste site in the coming weeks, supporter Rep. Joe Barton, R-Texas, predicted.

Nevada has challenged President Bush's decision to put 77,000 tons of radioactive waste under Yucca Mountain 90 miles northeast of Las Vegas. Congress must approve or reject the Bush decision within 90 days. 

The crucial battle will take place in the Senate, where the Democratic leadership opposes the waste site — for now.

"We know there's going to be opposition (in the Senate)," Energy Secretary Spencer Abraham said. "The action in the House demonstrates the broad bipartisan support we have to move ahead."

He said that the scientific studies conducted so far assure the safety of storing the waste, which will remain dangerous for more than 10,000 years, at the Yucca site. There are still more studies to be completed, however.

He said it was "a preposterous assertion" that the waste would be safer at sites in 39 states — including at 103 commercial reactors and federal waste sites — than buried at a single location under tight security.

But some Democratic critics of Yucca Mountain said before voting Thursday that too many unanswered scientific questions remain and that transporting the waste in thousands of truck or rail shipments would pose its own security and safety risks.

"I think we're voting somewhat blindly today," Rep. Anna Eshoo, D-Calif, said. "Unfortunately the administration has rushed ahead on the decision."

Rep. Ed Markey, D-Mass., said that there were 293 outstanding scientific issues not yet resolved about the Yucca site and that the transportation of the wastes would create "a potential mobile Chernobyl" with trucks full of waste "leaving sites every four hours for 24 years."

"We will have a new national nightmare," argued Markey.

Supporters of the site countered that there have been thousands of shipments of nuclear material and no accidents involving radiation releases. Abraham has pledged that the remaining scientific issues would be resolved before the licensing process for the site by the Nuclear Regulatory Commission, or during it.

"Developing a safe, central repository for this waste is simply critical for the future of nuclear power," Rep. Billy Tauzin, the committee chairman, said.

The Associated Press contributed to this report.