Two reports released Monday call for better monitoring of radioactive contamination in groundwater beneath the Nevada Test Site.
One report by the Alliance for Nuclear Accountability examined water supplies under all Energy Department nuclear weapons sites.
"At many of the major DOE sites, radioactive and toxic materials ... are flowing toward the site boundaries and, sometimes, beyond," said Marvin Resnikoff, whose company conducted the technical assessment for the alliance.
Citizen Alert, an anti-nuclear activist group in Nevada, also released a more than 100-page report completed in 2002 saying some monitoring wells are not placed properly to detect how radioactive pollution would move through underground water reserves.
Peggy Maze Johnson, Citizen Alert executive director in Las Vegas, said the government needs to spend about $2 million each for an unspecified number of additional wells to pinpoint the problem at the nation's vast nuclear weapons testing site.
Nevada Test Site spokesman Kevin Rohrer said he had not yet seen either report, but said radioactive contamination has not been detected the borders of the test site or in drinking water wells.
The Nevada Test Site released an annual environmental report in February. It showed no airborne or groundwater radioactivity offsite based on monitoring by Bechtel Nevada.
Rohrer said the department plans to drill more wells to thoroughly study migration of radioactive material through ground water. He said the site is testing and monitoring as much as its budget will allow.
Citizen Alert plans to ask Nevada Gov. Kenny Guinn to push for declaring the Test Site, 65 miles northwest of Las Vegas, a federal "Superfund" cleanup site, Johnson said. The designation could tap federal funds for clean up.
"We know there is contamination from the fact there was bomb testing, but they don't know how fast its going and in what direction," Johnson said.
The Energy Department paid for the $50,000 Citizen Alert study out of a fund created by a court decision in 1998 letting nonprofit groups study the department's nuclear weapons complex.
The $75,000 Alliance for Nuclear Accountability study, funded through the same judgment account, calls for more public participation and better cleanup of department sites.
The alliance said underground nuclear weapons tests at the Nevada Test Site contaminated ground water, but said the spread of contamination and exact accounting of how much radioactive material remains underground vary.
About 1,000 atomic weapons tests took place from the 1950s to 1992 at the site, a federal reservation larger in size than Rhode Island. The last atmospheric nuclear detonation was in 1962. Underground nuclear testing continued until 1992.
There have been 20 subcritical tests since then, involving tiny amounts of nuclear materials exposed to high explosives, resulting in a blast that project officials say stop short of producing a nuclear chain reaction.