Nevada Test Site - Environmental Impact

Environmental Impact

Each of the below ground explosions—some as deep as 5,000 feet—vaporized a large chamber, leaving a cavity filled with radioactive rubble. About a third of the tests were conducted directly in aquifers, and others were hundreds or thousands of feet below the water table.

When testing ended in 1992, the Department of Energy estimated that more than 300 million curies of radiation remained in the environment at that time, making the site one of the most radioactively contaminated locations in the United States. In the worst-affected zones, the concentration of radioactivity in affected groundwater reaches millions of picocuries per liter. (The federal standard for drinking water is 20 picocuries per liter.) Although radiation levels in the water continue to decline over time, the longer-lived isotopes could pose risks to workers or future settlers on the NNSS for tens of thousands of years.

The Energy Department has 48 monitoring wells at the site and recently began drilling nine deep wells. Because the contaminated water poses no immediate health threat, the Department has ranked Nevada as a low priority for cleaning up major nuclear weapons sites, and it operates far fewer wells than at most other contaminated sites.