Nevada National Security 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 Energy Department estimated that more than 300 million curies of radiation remained, making the site one of the most radioactively contaminated places in the United States. In the worst affected zones, radioactivity in the tainted water reaches millions of picocuries per liter. (The federal standard for drinking water is 20 picocuries per liter.) Although radiation levels in the water have declined over time, the longer-lived isotopes will continue to pose risks 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.