Nevada lawmakers made one last appeal Thursday to President Bush not to approve the use of Yucca Mountain for the disposal of nuclear waste.

The president could make a decision next week on whether to begin construction of the nuclear waste site.

Gov. Kenny Guinn and Sens. Harry Reid and John Ensign told the president they feared that the shipment of up to 77,000 tons of nuclear waste is a health hazard.  They are awaiting a report detailing whether the science is sound to recommend Yucca.

After the meeting, Guinn told reporters it's crucial the decision take into account unanswered safety questions. Ensign said he thinks the Energy Department's been downplaying those questions as it briefs Bush. 

But the lawmakers were heartened by the president's attention to the matter, even while he remained elusive.

"Mr.  Bush is a man of honor," said Reid, a Democrat. "He believes sound science should dictate Yucca mountain. I can't stress enough what a cordial meeting it was."

Energy Secretary Spencer Abraham endorsed the site last month, stressing the need for a centralized facility to store radioactive nuclear waste in light of recent terrorist threats on U.S. nuclear facilities.

By law, he must wait 30 days to give a formal recommendation to the president. That 30-day period ends this Saturday.

A final decision could rest with Congress, which can overrule a state decision to block the president's decision. The state has 60 days to reject the president's order, and Congress has 90 days after that to uphold or reject the state's decision.

Nevada lawmakers are sure to lobby their colleagues hard if Bush approves the decision, though sources say support right now is with the president.

Ensign and Rep. James Gibbons, both Republicans, are stepping up efforts to try to sway some GOP lawmakers to oppose the site.

"They need time," said one congressional source, who said that perhaps as many as 20 Republicans might have to be convinced to oppose their president if Nevada's objections are to be sustained.

Once the site gets licensed by the Nuclear Regulatory Commission, it will be years before the site would be ready to take any of the waste now kept in spent fuel pools and concrete bunkers at nuclear power plants around the country.  Abraham said he would like the site opened by 2010.

Abraham, who notified Nevada officials on Jan. 10 that he will recommend the site to the president, called it a "scientifically sound and suitable" place to bury the nation's used reactor fuel now kept at the power plants.

The Associated Press contributed to this report.