NEW MEXICO - Chronic lapses in safety procedures at the Los Alamos National Laboratory in New Mexico may have led to a radiation leak that has forced a prolonged shutdown across the state of the only permanent US nuclear waste repository, federal inspectors said on Wednesday.
The inspectors, in a sharply critical report, sought to explain how a barrel of plutonium-tainted debris from the nuclear weapons lab near Santa Fe ended up improperly packaged before it was shipped off for burial 300 miles away at the Waste Isolation Pilot Plant.
The leak of radiation, a small amount of which escaped to the surface and contaminated 22 workers at the plant, ranks as the facility's worst mishap since it opened in 1999.
Previous findings by government regulators suggest the waste drum contained a volatile mix of nitrate salts and organic matter that ruptured the barrel after it was placed in a vault half a mile underground at the plant.
Such a mix was shown to be "inherently hazardous" in a 2000 study by the US Environmental Protection Agency. But flawed procedures at Los Alamos fostered a culture "that permitted the introduction of potentially incompatible materials" in waste drums there, according to the report by the US Energy Department's Office of Inspector General.
The lab's "waste processing and safety-related control procedures should have prevented the addition of these potentially incompatible materials. However, the process failed in this matter," federal inspectors said in the report.
Energy Department officials and their contractors, charged with ensuring that nuclear waste processed at Los Alamos could be safely disposed of at the Carlsbad facility, failed to heed a 2012 technical paper advising that waste drums containing nitrate salts be treated with an absorbent such as kitty litter composed of inorganic solids and instead used organic kitty litter, according to the report.
In a written response to the report, the Energy Department's nuclear security managers said processing at Los Alamos of so-called transuranic waste was suspended in May for safety reasons.
Managers said they also imposed "additional precautionary protection measures to ensure our workers, the public and the environment are protected."
The report led Don Hancock, head of the watchdog group called the Southwest Research and Information Center, to demand the government hire new contractors to manage the lab and the waste dump and for tougher regulation at both facilities.
"All of those entities made mistakes," he said.