Washington

Documents relating to the safety of the proposed nuclear-waste repository at Yucca Mountain in Nevada may have been falsified, the US Department of Energy (DOE) revealed last week.

According to agency officials, a hydrologist at the US Geological Survey (USGS), who was studying how water flowed through the mountain, faked documentation on the times and dates at which certain geological samples were taken from the site.

The independent inspectors-general at both the USGS and the DOE have launched investigations, and the Nevada congressional delegation has called for a federal investigation into the issue.

The Yucca plan would see canisters of nuclear waste stored under the mountain for thousands of years. The water data are crucial because the repository's safety depends heavily on how wet it is likely to get inside, and on how long it takes for water to escape from the mountain rock into surrounding river systems.

A 1996 study by Los Alamos National Laboratory in New Mexico indicated that water takes just a few decades to flow through the mountain, raising fears that storage containers might erode and leak nuclear waste into the water table. But the DOE argues that subsequent studies and models by USGS scientists show that water moves more slowly through the mountain and that there is little threat to the local water supply.

Evidence for the falsification surfaced while the DOE was drawing up an application for a licence to store nuclear waste at the site. E-mails between the hydrologist and several colleagues dating from 1998–2000 were found that indicated he had faked documentation on the data and some computer models used to predict water flow through the mountain, says a USGS spokeswoman.

“What it means scientifically we don't yet know,” says John Garrick, chairman of the Nuclear Waste Technical Review Board, which oversees the Yucca project. “But there is no doubt that it's affected public confidence in the project.”

Senator Harry Reid (Democrat, Nevada), the minority leader in the Senate who opposes the construction of the repository, is calling for a full federal investigation into the alleged misdeeds. “It is abundantly clear that there is no such thing as ‘sound science’ at Yucca Mountain,” he says.