New Mexico Environment Secretary Ryan Flynn gave Los Alamos National Laboratory until Wednesday to propose steps for locking down the barrels.
New Mexico's government said dozens of nuclear-waste drums may pose an "imminent" and "substantial" danger to residents, the Associated Press reports.
New Mexico Environment Secretary Ryan Flynn gave Los Alamos National Laboratory until Wednesday to propose steps for locking down the 57 barrels, which it packed using materials tied to a burst container in an underground area of the Waste Isolation Pilot Plant near Carlsbad. The Energy Department has linked the breakage to a February radiation release that spread contaminants to 22 workers and forced personnel to vacate much of the repository.
A significant number of the problematic drums may be outside, either at the nuclear-weapons laboratory or a short-term holding location in Andrews, Texas. A pair of the barrels were transferred into underground holding areas of the waste storage site prior to the February radiation leak, Flynn indicated in an order on Monday.
He said data supplied to his agency suggests that "the current handling, storage, treatment and transportation of the hazardous nitrate salt-bearing waste containers at [Los Alamos] may present an imminent and substantial endangerment to health or the environment."
The laboratory said it is committed to mitigating any danger from the containers, which it prepared using a cat-litter and nitrate-salt mixture believed to have generated heat and ruptured the barrel at the waste storage facility.
Los Alamos personnel have placed the waste drums in additional packaging and moved them into housing with countermeasures against possible fires, the Los Alamos facility said in released comments. The laboratory said it is also watching the containers for possible heat increases.
Meanwhile, investigators are seeking to determine if the problematic packaging was linked to recent transition from inorganic cat litter to an organic version of the material, which is incorporated in the packing as an absorbent.