RENO, Nev. - A federal judge denied Nevada's latest request Thursday to immediately block all future shipments of weapons-grade plutonium to a nuclear security site near Las Vegas.

The state wanted the shipments blocked until potential safety and environmental risks could be reviewed further. U.S. District Court Judge Miranda Du denied the state's request a day after the Energy Department revealed that it had already sent half of the highly radioactive material that it had planned to move from South Carolina to the Nevada National Security Site.

The judge in Reno said in a 16-page ruling that proceedings will continue on a regular schedule in a lawsuit Nevada filed in November seeking to block plans the Energy Department approved in August to transfer a full metric ton of plutonium to Nevada.

The department disclosed for the first time Wednesday that the shipment was sent sometime before November and said it doesn't intend to ship any more to the site 70 miles (113 kilometres) north of Las Vegas.

Nevada Attorney General Aaron Ford asked Du in new court filings to schedule a status hearing Monday on the growing controversy. On Thursday, Du directed lawyers for the state and the federal government to work together to come up with a time to hold such a hearing.

Gov. Steve Sisolak said the state is considering seeking a contempt of court order after he says the government lied about the transfer of the plutonium. The Energy Department is currently under a federal court order issued earlier in South Carolina to remove the material from the Savannah River nuclear site by January 2020.

Nevada's lawyers on Wednesday again requested that the court block the shipments, saying the Justice Department had assured them no shipment would occur before February of this year. Ford's office argued the court should not accept the government's assertion that it would not send more plutonium to Nevada.

Sen. Catherine Cortez Masto said she met with officials for the Energy Department's National Nuclear Security Administration Thursday evening and expressed her "dismay over how they failed to inform" Sisolak and Nevada's members of Congress "about their plans to bring weapons grade plutonium to our state."

"The Department of Energy and NNSA negotiated in bad faith, hiding the timing of their shipment and refused to share crucial information with members of Congress who had the security clearance to know," she said.

Energy Department officials say they had to keep the previous shipment secret until now for national security reasons. They disputed claims that Sisolak and Congress members didn't receive prior notice of the plans.

The department said in a statement Thursday that completion of a supplement analysis of the plan by DOE's National Nuclear Security Administration in August served as notification "ahead of time" that they would move the plutonium out of South Carolina in compliance with the 2020 deadline.

"NNSA routinely ships this type of material between its sites as part of our national security missions and has done so safely and securely for decades," DOE said.

Nevada argues the department has failed to adequately study the potential dangers of moving the material, which still has the potential to be used to help develop nuclear weapons, to an area that is subject to flash floods and earthquakes. Nevada says the state's lands and groundwater may already be contaminated with radioactive materials.

Wednesday, Du rejected the state's November request to block the shipments. On Thursday, she said her Wednesday ruling made the additional request moot.

She said federal law requires her to defer to the Energy Department's conclusion that no additional environmental studies are necessary unless the state could prove it would be irreparably harmed by the shipments.

"Nevada's claim of irreparable harm to Nevada's lands, environment and by extension Nevada's citizens, is merely a theoretical possibility at this juncture as Nevada provides no evidence from which this court may infer a likelihood of any concrete or impending harm," Du wrote.

She noted that the government has transported nuclear materials to the Nevada site before and historically uses plutonium in testing operations there.

"Thus, it is highly hypothetical that shipments of additional plutonium to NNSS and staging there would lead to imminent immediate harm," Du wrote.

Officials in Nye County where the site is located said on Thursday that they would have preferred the Energy Department conducted additional studies of the potential impact of the shipments in compliance with the National Environmental Policy Act but that the safety concerns were being blown out of proportion.

Darrell Lacy, director of Nye County's Nuclear Waste Repository Project Office, said DOE has trained Nye County and state law officers and emergency response crews to handle any emergency.

"We assume that the shipments of these type of materials are a routine matter in Nevada," Lacy said. "We do not think this movement of 1,000 pounds of plutonium placed our residents or the environment in a high-risk situation."

News from © The Associated Press, 2019