HOUSTON, March 18 (Xinhua) -- A second radiation release was detected nearly a month after a leak was confirmed at a nuclear waste repository in the U.S. state of New Mexico, U.S. media reported Tuesday.
New air sampling data from a monitoring station near the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico indicated another small radiation release at the site, local TV KOB quoted unnamed officials with the U.S. Department of Energy as saying.
Officials said the monitoring station picked up elevated radiation readings around the WIPP on March 11. The facility was shut down on Feb. 14 when air sensors detected unusually high levels of radioactive particles on its underground levels.
Engineers said they believe the new contamination was from previous deposits on the inner surface of exhaust ductwork. Officials assured the public occasional low-level releases are anticipated, but they should be well within safe limits.
Earlier 17 employees working at the site were tested positive for radiation. A statement from the U.S. Department of Energy on March 9 said the affected workers are not "expected to experience any health effects from the exposures" and stressed their levels of exposure are "extremely low."
The repository remained shuttered as crew are reportedly being trained to handle the crisis. The WIPP operators said they will send qualified personnel down the underground facility once it's safe to do so, but they have not given a recovery timetable.
The cause of the leak remains unknown. 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 leak.
The plant stores "transuranic waste" leftover from nuclear weapons research and testing from the nation's past defense activities, according to the Energy Department website.
The waste includes clothing, tools, rags and other debris contaminated with radioactive elements, largely plutonium. They emit alpha and beta radiation, which is in particulate form, so the risk is of inhalation not penetration.