The secretive Nevada plutonium shipment that has spawned angry rhetoric from Nevada politicians has a history that starts with Russia. In 2000, the United States entered into a pact with Russia to set aside excess weapons-grade plutonium for civilian use in nuclear reactors. Congress then passed a law that it would turn the excess 34 metric tons of plutonium into MOX, or mix-oxide fuel, at a newly built facility in South Carolina.

But that statute came with a firm deadline: If the MOX facility was not operational by 2014, the Department of Energy would be required to move one metric ton of plutonium stored at South Carolina’s Savannah River Site, a nuclear facility built in the 1950s, within two years.

After years of cost overruns and technical challenges, the Trump administration scrapped the facility. Meanwhile, the state of South Carolina obtained a court order in 2017 requiring the Department of Energy enforce the deadline and move the metric ton of plutonium by 2020.

Less than one year later, the agency said it moved a half-ton of that plutonium to the Nevada National Security Site. The action came after months of questioning from state officials, and its furtive nature has spurred a lawsuit, driving a deep chasm between the state and the agency.

Four months after South Carolina obtained the court order, Nevada officials heard that the federal government might be sending some of the plutonium to the state, according to court records. From August to November, state officials began asking questions about the potential shipment. But Nevada officials received few assurances from Department of Energy officials.

“Beyond a general ‘expectation’ that any plutonium would be removed by approximately 2026-27, [a November 20] letter did not contain any of the requested assurances,” Pam Robinson, the policy director for then-Gov. Brian Sandoval, wrote in a December affidavit.

What Nevada officials didn’t know: the United States had already moved the plutonium.

Who knew what when

That surprising disclosure came months later — on January 30 — when a general counsel for the National Nuclear Security Administration (NNSA) disclosed that the agency had made a half-ton plutonium shipment from South Carolina to the Nevada Test Site prior to November.

Gov. Steve Sisolak responded to the revelation with a heated statement, pledging to continue existing litigation and keep the Department of Energy accountable.

“I am beyond outraged by this completely unacceptable deception from the U.S. Department of Energy,” he said to the media. “The department led the state of Nevada to believe that they were engaging in good-faith negotiations with us regarding a potential shipment of weapons-grade plutonium, only to reveal that those negotiations were a sham all along.”

Members of the state’s congressional delegation also released fiery responses.

State officials worry that the plutonium shipment to the testing facility, which is about 65 miles outside of Las Vegas and occupies an area the size of Rhode Island, could set a precedent for the federal government to send more nuclear materials to the state. In court filings, lawyers for Attorney General Aaron Ford also argued the federal government failed to fully inventory the environmental impacts of the size and type of plutonium being sent to the highly guarded site.

They also view the action as a backdoor move to open Yucca Mountain, the controversial nuclear waste repository that sits in the remote desert about 100 miles outside of Las Vegas.

The NNSA disputes all of these claims. The agency, charged with overseeing and moving nuclear materials, noted that plutonium is often shipped to the test site. In court documents, the agency argued that a 2013 environmental review contemplated the presence of more plutonium storage at the site, and it found only marginal environmental impacts. Finally, the agency argues there is no connection to Yucca Mountain, as the material will be used to modernize weapons.

“It is inaccurate to state that the members of the Nevada delegation were not informed of this movement,” the NNSA said in a statement. “The Department of Energy was as transparent as operational security would permit. Efforts were made to ensure that members of Congress and state officials representing the states involved were notified of the planned movement ahead of time, as early as August 2018 when NNSA publicly released [an environmental analysis].”

State officials concede that it is true the environmental analysis, which contemplated moving the material to Nevada, was released publicly in August. But they argue that the department was less than transparent about whether or not the plutonium had been moved. Between August and the January disclosure, the state argues that NNSA continued to act as though no shipment had occurred. NNSA argued it could not declassify the shipment until Jan. 30 due to security.

At the center of Nevada’s legal strategy against the NNSA is the environmental analysis.

Since Sandoval’s administration filed a lawsuit in November, the state has claimed that the federal government’s environmental analysis for the shipment shortcutted requirements under the National Environmental Policy Act (NEPA) for relying on outdated information. Congress, with its deadline, had required that any shipments out of South Carolina adhere to NEPA. Nevada’s court filings also question the speed of the shipment given the fact that a Department of Energy official had said, in the separate South Carolina litigation, that their preferred method for delivery could take years.

But Nevada has yet to persuade a federal judge of their argument. On Jan. 30, the same day as the disclosure, Reno Judge Miranda Du dismissed the NEPA claims, arguing that the “claim of irreparable harm to Nevada’s lands, environment, and by extension Nevada’s citizens, is merely a theoretical possibility at this junction as Nevada provides no evidence from which this court may infer a likelihood of any concrete or impending harm.” Nevada quickly appealed the ruling.

An acrimonious relationship

After NNSA’s disclosure in January, Ford added to the state’s legal strategy by attempting to enjoin NNSA from shipping the other half-ton of plutonium from South Carolina to Nevada. The court denied that temporary restraining order on Jan. 31. On Feb. 7, the state filed another injunction to prevent “shipping any plutonium” during the appeal.

On Friday, NNSA told the court that it had complied with the South Carolina order to move one metric-ton of plutonium and that no additional material would come to Nevada under the order. The court filing suggests the other half-ton has been or will be sent to Pantex, a site in Texas.

Still, state officials had worried the environmental analysis could be used to justify a shipment from Pantex to Nevada even after it was removed from South Carolina. NNSA attorney Bruce Diamond said the plutonium in question would not be shipped from Pantex to Nevada.

Moreover, attorneys for the NNSA argued that the state’s latest injunction, if granted, would “cease subcritical experiments performed by the Stockpile Stewardship Program (which helps to ensure the Nation’s nuclear weapons stockpile remains safe), eliminate experiments aimed at simulating the extreme material states in nuclear weapons, idle the majority of NNSS facilities and associated workforce, and cancel procurements and planned capital investments.”

The NNSA filing describes plutonium shipments to the test site as “a regular occurrence.” The test site is part of a program that runs experiments on nuclear weapons and nuclear storage.

The state will likely respond to that filing next week, but attorneys for Nevada remain wary of the assurances. Given the issues earlier in the year, state officials feel they can’t trust the agency. They remain aware that, in the coming years, the Department of Energy is required to remove more plutonium — about five metric tons — out of South Carolina to comply with the law.

In many ways, the conflict has become about trust, a legacy of the state’s tenuous relationship with nuclear materials. Just as Nevada found itself at the center of Cold War testing at the test site, the state now finds itself at the center of the legacy-problem: what to do with the plutonium.

“Plutonium is nasty stuff,” said Allison Macfarlane, a George Washington University science and technology professor who chaired the U.S. Nuclear Regulatory Commission from 2012 to 2014. “But we've made so much of it on the weapons side in this country — and the civilian side in other countries — that we really need to manage it very carefully unless we eliminate it.”

With South Carolina’s MOX facility mothballed, the options are more limited.

Even without the court order, experts said keeping the material in South Carolina was less secure than keeping it at the Nevada test site, which is already part of the weapons complex.

“It's really untenable to keep it at Savannah River,” said Robert Rosner, a University of Chicago physicist who chairs the Science and Security Board for the Bulletin of the Atomic Scientists.

Is it all about Yucca?

For state officials and the Nevada congressional delegation, the shipment adds insult to injury.

The state was already on guard that the Trump administration might seek to restart the licensing process for Yucca Mountain. Although the administration has sent mixed signals on the issue, Energy Secretary Rick Perry had said last year that his agency had a “legal responsibility” to move forward with the controversial underground repository for storing nuclear waste.

In October, during an interview with The Nevada Independent, U.S. Sen. Catherine Cortez Masto said one of her biggest regrets was voting on Perry’s nomination, in part because of Yucca.

On its face, the two issues are distinct.

NNSA has said there is no connection between the shipment and the geologic repository, saying the shipment is about active material and Yucca Mountain’s goal is to store nuclear waste.

But the state is concerned that there could be a nexus. They see the treatment of the state in the plutonium case as indicative of how the federal government would treat it on other issues.

Rosner said there is no direct connection to Yucca Mountain, but he said one indirect issue could be that both materials could be transported through major metropolitan areas, including Las Vegas. However, the theoretical physicist and former director of the Argonne National Laboratory said the state’s “transportation arguments are the weakest arguments of all."

He noted that plutonium — like many nuclear materials — is regularly shipped around the country. In fact, he said that much more lethal materials, such as Cesium, are shipped for medical treatments, including radiotherapy in cancer patients. Although it is still a health risk, plutonium is significantly less radioactive than Cesium, which decays quickly, Rosner explained.

“The strongest arguments are whether it is in a place that is geologically stable,” he said.

Nevada has long argued that leaks at Yucca Mountain pose a risk to the regional groundwater supply. The state is also concerned seismic activity could affect the storage and deposition of nuclear waste. At times, the Department of Energy has adjusted its plans to avoid a major fault line or use “drip shields” meant to prevent stored waste from infiltrating into the geology.

State officials also object to Yucca Mountain on equity grounds. Why should Nevada be required to store nuclear waste when it doesn’t have nuclear reactors or rely on nuclear energy?

In his first State of the State speech, Sisolak vowed to continue fighting Yucca.

“Let me make something perfectly clear: Not one ounce of nuclear waste will ever reach Yucca Mountain while I'm governor,” Sisolak said during the Jan. 17 speech. “Not on my watch."

Update: This story was updated at 11:10 a.m. on Thursday, Feb. 21 to correct the name of Richard Rosner, a theoretical physicist at the University of Chicago.