RENO, Nev. -- A Nevada congressman called for U.S. Energy Secretary Rick Perry's resignation Wednesday after the department acknowledged multiple shipments of low-level radioactive waste to a site north of Las Vegas may have been mislabeled and out of compliance with safety regulations for years.
The department had announced earlier that shipments of the waste from Tennessee to Nevada have been suspended while it investigates whether the materials were "potentially mischaracterized" as the wrong category of low-level waste. Low-level waste can include equipment or worker's clothing contaminated by exposure to radiation, while mixed low-level waste can include toxic metals.
Deputy Energy Secretary Dan Brouillette also has ordered a department-wide assessment of its "procedures and practices for packaging and shipping all radioactive waste types," according to a memo.
Department spokeswoman Shaylyn Hynes said none of the materials shipped to Nevada as early as 2013 from the Y-12 facility in Oak Ridge, Tennessee, posed any health or safety threats to workers or the public.
But she acknowledged the shipments slated for disposal at the Nevada National Security Site were not in compliance with the site's acceptance criteria.
The department's National Nuclear Security Administration has launched an internal investigation "to determine how this went undetected for a six-year period," Hynes said in a statement on Wednesday.
The low-level waste material is unrelated to weapons-grade plutonium that the department secretly shipped to the same Nevada site last year from South Carolina and is currently at the center of a legal battle with the state of Nevada in the 9th U.S. Circuit Court of Appeals.
But Rep. Steven Horsford, D-Nevada, said in calling for Perry to "resign immediately" that the new disclosure is further evidence that Nevada has been covertly "coerced" into illegally receiving nuclear materials "through negligence or outright trickery."
Nevada Gov. Steve Sisolak and other members of Nevada's congressional delegation stopped short of demanding Perry resign but were equally critical of his department's handling of the waste.
"The level of incompetence at the Department of Energy is only matched by its dishonesty," Rep. Dina Titus, D-Nevada, said.
Sisolak said Brouillette telephoned him on July 3 to inform him that the department "has been shipping incorrectly labeled low-level waste" from Tennessee to Nevada.
Sisolak also released a letter he and Democratic Sens. Catherine Cortez Masto and Jacky Rosen sent to Perry on July 5 expressing their concerns and demanding more details.
The Democratic governor said he was more fully briefed on the situation during both classified and unclassified meetings in Las Vegas on Tuesday with senior department officials, including Lisa Gordon-Hagerty, head of DOE's National Nuclear Security Administration.
Sisolak said he originally was told the waste shipped out of compliance with the department's criteria governing low-level waste disposal at the Nevada site included 32 total shipments that began in 2013 and ended last December. But his office clarified there were six shipments that included a total of 32 canisters.
Sisolak said the department hasn't determined yet whether the material labeled as low-level waste may have included mixed low-level waste, which is regulated more stringently under state and federal guidelines and requires treatment prior to disposal.
For example, Sisolak said the Energy Department entered into a settlement agreement with the state in May after DOE was cited for accepting low-level radioactive waste at the Nevada site that was subsequently found to be contaminated with chromium at a toxicity level higher than is allowed by the Resource Conservation and Recovery Act — "thereby rendering it a mixed, low-level radioactive waste."
Hynes said Wednesday the department leadership first was notified on July 3 that certain shipments of waste managed by a contractor at the Y-12 facility failed to comply with the Nevada site's criteria, and may have been "mischaracterized" as low-level waste.
"The components that were shipped have been disposed of in a safe and secure manner at the NNSS, and as a precaution, planned future shipments of components from Y-12 have been temporarily suspended," she said.
Eds: This story corrects an earlier version to show there were six shipments with a total of 32 canisters, not 32 shipments as previously stated by the governor.