U.S. nuclear waste facility monitored for radiation

An underground nuclear waste repository in the U.S. state of New Mexico is monitored as radiation was detected earlier on the underground levels of the facility, U.S. media reported Sunday.

An air monitor at the Waste Isolation Pilot Plant (WIPP), located near Carlsbad in the southeastern part of New Mexico, detected unusually high levels of radioactive particles on its underground levels late Friday night, local TV KRWG reported, quoting a source with the U.S. Department of Energy.

U.S. Department of Energy spokesman Roger Nelson said in a news release that no workers were underground at the time and no injuries or damages have been reported. The 139 workers above the ground at the site were told Saturday to stay where they were as a precaution. None of them tested positive for contamination, and all non-essential personnel were released.

The WIPP stores waste that emits alpha and beta radiation, which is in particulate form, so the risk is of inhalation not penetration, Nelson said.

The Department said samples were taken at several surface sites around the WIPP and that tests show no contamination has been detected in those surface samples.

It's not immediately known what caused the suspected leak. A truck fire was reported at the underground site on Feb. 5 and prompted evacuations, but officials said the fire was in a different part of the site and did not seem related to the radiation.

The WIPP stores "transuranic waste" leftover from nuclear weapons research and testing from the country's past defense activities, according to the Department of Energy website. That waste includes clothing, tools, rags and other debris contaminated with radioactive elements, largely plutonium.