SALMON, Idaho (Reuters) - A former Idaho governor sued the U.S. Department of Energy on Tuesday seeking information he said the agency was concealing about a proposal to ship nuclear waste into the state in violation of a 20-year-old federal agreement.

The case puts Cecil Andrus, a Democrat who served four terms as governor, at odds with Idaho’s current Republican leaders, including Governor C.L. “Butch” Otter, over a plan to transport spent fuel from out-of-state commercial nuclear reactors to the Idaho National Laboratory.

Andrus said he suspected the agency’s intent was ultimately to turn the sprawling nuclear research facility along the Snake River near Idaho falls into a de facto nuclear dump in the absence of a permanent repository for high-level radioactive waste elsewhere in the United States.

In his complaint, filed in U.S. District Court in Boise, Andrus accused the Energy Department of thwarting the public interest by withholding vital details about its proposal.

According to the lawsuit, the agency responded to his Freedom of Information Act query with reams of mostly redacted documents and newspaper clips about its request for a state waiver allowing delivery of spent reactor fuel to the Idaho lab.

The lawsuit seeks a court order compelling the Energy Department to furnish records that are not redacted.

Agency officials were not immediately available for comment on the litigation.

A 1995 legal agreement between the state and the department bans such shipments and ordered the agency to remove nuclear waste already stored at the lab to reduce potential impacts on an aquifer that forms the chief source of drinking water for tens of thousands of Idaho residents.

That accord stemmed from previous lawsuits brought by Andrus and his Republican successor, Phil Batt, alleging the U.S. government was seeking to turn the lab complex in eastern Idaho into a permanent repository for contaminated materials.

In January, Otter and other state leaders expressed conditional support for the shipment of spent nuclear fuel to the lab for a research program that proponents said would boost the facility’s profile and the local economy. But their support was contingent on the department meeting cleanup obligations that have yet to be fulfilled.

Andrus said his latest lawsuit was needed to ensure protection of the public’s health and the environment.

“I suspect they know what they are planning will be very controversial and, for that reason, want to keep it secret,” he said in a statement.