CARLSBAD, New Mexico (AP) — The U.S. Department of Energy says new air testing in the nation's only underground nuclear repository shows no detectable radioactive contamination from a leak last month.
Officials at the Waste Isolation Pilot Plant in New Mexico said Sunday that instruments used to measure air quality and radioactivity were sent underground Friday and Saturday in the first step to resuming operations at the plant.
They say initial results indicate no contamination in the air or on the measuring equipment.
Federal officials say four more employees have tested positive for low levels of contamination, adding to the 13 tested immediately after the leak.
Authorities say none should suffer health effects and that there appears to be no danger aboveground.
The plant has been shut down since early February, when a truck caught fire in a separate incident.
Sensors alerted officials to a release of radiation on Feb. 14. Monitors nearby later detected elevated levels of plutonium and americium in the air.
WIPP officials say they may send personnel into the mine next week.
Donavan Mager, a spokesman for Nuclear Waste Partnership LLC, which runs WIPP, said employees have been able to work without having to wear protective equipment in the weeks since the leak.
WIPP is the the only facility in the country that can store plutonium-contaminated clothing and tools from Los Alamos National Laboratory and other federal nuclear sites.