Critics of the Yucca Mountain Project have long maintained that the federal government will do anything to keep its heavy equipment humming northwest of Las Vegas.

As research has uncovered flaws in designs of the planned nuclear waste repository, the Department of Energy has spared no expense in attempting to remedy them, insisting each fix would be good enough to meet arbitrary health and radiation standards. Over the years, even as congressional audits exposed shoddy management, wasted resources and questionable science, the federal government has stuck to its assumptions that nuclear waste is best kept inside a mountain, and that Southern Nevada has the only mountain suitable for the repository.

But last year's disclosure that U.S. Geological Survey employees might have fabricated and falsified data to satisfy quality assurance bureaucrats took the project's reputation to a new low. E-mail messages sent by government hydrologists between 1998 and 2000 suggested they made up dates, deleted some information and submitted official documents with data that did not match their own records related to water infiltration at the repository.

The allegation that well-paid federal scientists and contractors were using bogus information to prop up a project that already has cost billions of dollars hinted at a massive fraud against taxpayers. Congressional hearings and an inquiry by the Energy Department's inspector general followed. In December, the inspector general finished its investigation and forwarded its findings to the U.S. attorney's office in Nevada.

On Tuesday, Energy Department Inspector General Gregory Friedman announced that the e-mails "did not meet the level of criminality," and that the U.S. attorney's office "could not show intent" to commit crimes. As a result, no criminal charges would be pursued.

Case closed.

Details of the evidence that supported the U.S. attorney's decision could have gone a long way toward restoring public confidence in the scientists tasked with developing a safe storage site for the nation's most dangerous nuclear waste.

But Tuesday's announcement was hollow. It provided no meaningful supporting information for the U.S. attorney's decision, nor any details about the interviews and research conducted during the inquiry.

As a result, the decision stinks of collusion. How can taxpayers be certain that the probe, like the allegations it was supposed to investigate, wasn't loaded with fabrications? Considering how badly the Bush administration wants to move forward with the Yucca Mountain Project, how can the public be sure the probe was conducted free of partisan influences? Has the work environment that allowed these e-mails to be ignored for years been improved?

Allegations surrounding the e-mails were serious enough to halt work on project design and research on canister corrosion and have the hydrologists redo their work, but not serious enough for complete public disclosure?

News of the decision to not prosecute wasn't even announced by Nevada's U.S. attorney, Daniel Bogden -- it was issued by the Department of Energy.

This isn't about jailing scientists so Yucca Mountain Project opponents can have their pound of flesh. This is about bringing at least some perception of integrity to a project plagued by a culture of dysfunction.

Energy Secretary Samuel Bodman and Mr. Bogden should come clean with the public on these issues. And if they won't, Nevada's congressional delegation should force them to.