The debate on whether hot water once rose within Yucca Mountain and might someday flood a nuclear waste repository received an airing before a high-ranking science advisory panel. Jean Cline, a University of Las Vegas associate professor who led a two-year mineral study, presented evidence that hot water once existed at Yucca Mountain, but it probably was caused by gradual temperature changes over millions of years.

Geologist Yuri Dublyansky presented an opposing case that the mountain ridge was invaded from below by thermal waters created by a volcanic surge, raising questions about whether a repeat occurrence might flood a repository, corrode nuclear waste canisters and carry off radioactive contaminants into the environment.