RENO -- A geologist who spent a decade researching, compiling and editing a book of scientific analyses of the Yucca Mountain project said the Energy Department's assessment lacks sufficient geological input and is fraught with uncertainty.

"Yucca Mountain is a complex site geologically," Allison Macfarlane told the Nevada Commission on Nuclear Projects at a meeting Friday.

"This is a very uncertain endeavor, and we shouldn't be rushing into it."

Macfarlane and Rodney Ewing, a professor at the University of Michigan, co-edited the book, "Uncertainty Underground; Yucca Mountain and the Nation's High-Level Nuclear Waste."

"It really is all based on geology," Macfarlane said. "It was surprising and alarming to us that there wasn't more geologic input. It's really important, it's essential, that enough people in the policy arena grasp these issues to make decisions."

Some of the 23 scientific papers in the anthology focus on regional climate change over a period longer than recorded human history and raise questions about whether water seeping through the site will, over tens of thousands of years, dissolve canisters encasing spent nuclear reactor fuel and leach radioactivity into groundwater.

Others focus on whether computerized DOE performance models are accurate and adequate, and whether the site could resume volcanic activity.

"The scientific community will review the book. We will not review the book," said Allen Benson, spokesman for the Energy Department and the Yucca Mountain project in Las Vegas.

"There's a lot of good work in that book," Benson said. "But we have spent several billion dollars and more than 20 years of intensive scientific research, which resulted in ... Congress designating Yucca Mountain for development as the repository."

He said the DOE intends to demonstrate in its license application to the Nuclear Regulatory Commission "that we can protect the public health and safety."

"It's not a question of taking our word for it," Benson added.

Macfarlane, 42, a Massachusetts Institute of Technology researcher, said she's not opposed to geologic repositories to dispose of spent nuclear fuel piling up at reactors and government facilities in 39 states.

"But it's not clear Yucca Mountain is the right location," she said, "especially when you extend it out 1 million years. You have to be willing to live with a lot of uncertainty."

The U.S. Environmental Protection Agency revamped its radiation safety standard to cover 1 million years after a federal court in Washington, D.C., rejected an earlier 10,000-year standard.

Aside from concerns over earthquakes and groundwater levels and movement, Macfarlane said the DOE's assessment doesn't take into account global warming.

The DOE, she said, looked at the last 400,000 years to predict future climate changes.

"But what they didn't do is include the potential effect of climate change by accumulation of greenhouse gases, especially carbon dioxide, over the next couple hundred of years."

Macfarlane said current carbon dioxide levels in the Yucca Mountain region are around 380 parts per million. Preindustrial levels were in the 200s.

By 2100, she predicted, "we could easily see numbers in the 1,000s," something that hasn't occurred in 50 million years.

"And that is highly alarming," Macfarlane said, adding that long ago, "we were a lot wetter and a lot hotter everywhere."

Associated Press writer Ken Ritter in Las Vegas contributed to this report.