(Reuters) - An underground nuclear waste dump in New Mexico that leaked radiation in February was cited by federal mine safety inspectors for dozens of workplace violations, almost all of which have been remedied, officials said Monday.
Operations at the Waste Isolation Pilot Plant in the southeastern New Mexico desert have been indefinitely suspended as a team of investigators seek the cause for a radiation release in a salt mine 2,100 feet below ground where contaminated debris from federal nuclear weapons sites and laboratories is buried.
The release exposed 22 workers to low levels of radiation and ranked as the worst such accident since the U.S. Energy Department facility opened in 1999.
Investigators have said a chemical reaction between nitrate salts and organic kitty litter is believed to have created sufficient heat to rupture a drum containing items tainted by radioisotopes like plutonium which had originated from the Los Alamos National Laboratory near Santa Fe.
A Los Alamos scientist told a New Mexico legislative panel last week that the drum that leaked radiation was likely improperly packaged with chemically reactive contents that included a lead-lined glove, the state lawmaker who chairs the Radioactive and Hazardous Materials Committee told Reuters last week.
The federal Mine Safety and Health Administration in June inspected the surface facilities at the sprawling complex near Carlsbad and issued 52 citations, ranging from exposed electrical wiring to housekeeping matters, plant spokesman Tim Runyon said in a statement.
Violations included the absence of a sign warning against open flames or smoking near flammable materials to walkways blocked by boxes, according to a document released by the facility.
The plant must still address safety guards needed on equipment designed to remotely lift lids from nuclear waste containers, said Runyon.
He could not immediately say when facilities at the plant were last inspected by federal officials or whether it has faced workplace-related citations in past.
Government investigators who probed an accidental fire in the salt mine a week before the radiation leak found that the MSHA had inspected the nuclear waste repository just twice in three years instead of the required four inspections annually.
Agency spokeswoman Amy Louviere declined to respond on Monday when asked how the agency had responded to questions about the lack of inspections raised in a March letter by U.S. Senator Tom Udall of New Mexico.
Editing by Dan Whitcomb and Eric Walsh