To settle a lawsuit filed in 2016, the federal government will pay $600 million to South Carolina in recognition of the Department of Energy’s inability to remove several metric tons of plutonium from the state by a legal deadline of 2022, the parties said Monday.

The money is expected by the end of September from the Treasury Department’s Judgment Fund, rather than the DOE budget. The settlement also calls for the Energy Department to move some 9.5 metric tons of weapon-usable plutonium, now stored at the Savannah River Site, out of South Carolina by 2037 — or else pay the state even more money.

That is years sooner than the agency expects to eliminate all the plutonium expected to pass through Savannah River under the dilute-and-dispose program, which is scheduled to reach full capacity around 2028 and operate into the 2040s, assuming the Energy Department’s current funding estimate for the planned facility at the site’s K-Area is adequate, and that Congress delivers the money.

To meet the new deadline for the 9.5 metric tons, DOE is considering at least three disposal options: trucking some of the plutonium out of state; diverting some to fuel the versatile test reactor program run by the agency’s Office of Nuclear Energy; and shipping some to the Waste Isolation Pilot Plant in New Mexico as part of dilute and dispose, formally called Surplus Plutonium Disposition.

“There are several disposal paths forward,” Secretary of Energy Dan Brouillette told reporters after a press conference in Columbia with Alan Wilson, the state attorney general who led the lawsuit. “Dilute and dispose is but one. There are certain types of plutonium that are at the SRS site that we can store today in other locations that DOE owns around the country. So that’s one option for us. We’re going to lay those out over the course of the next few weeks and months.”

To comply with a 2017 court order in a separate lawsuit that South Carolina won, DOE redirected some of the surplus plutonium stored at Savannah River back into the nuclear weapons program, which will use the material to make fissile cores, or pits, for future intercontinental ballistic missile warheads. After re-designating the plutonium for defense use, DOE split 1 metric ton between facilities in Nevada and, it is believed but not confirmed, Texas.

The local Aiken Standard published audio of the question-and-answer session with officials.

In exchange for the up-front payment, and DOE’s promise to move the plutonium out of state faster, South Carolina has agreed not to sue over the 9.5-ton tranche of plutonium until the 2037 deadline, giving the agency 15 years to begin the Surplus Plutonium Disposition Program without fear of imminent legal challenge.

If DOE cannot move any more of the 9.5-ton tranche out of South Carolina by 2037, it would under the settlement be on the hook for $1.5 billion in additional payments, Wilson said Monday. Moving any plutonium out would reduce the fine that comes due that year, he noted. If DOE can remove half of the 9.5 tons out of state by 2037, it will get another five years to ship out the rest.

On Monday, Brouillette said the department plans to relocate the entire 9.5 ton tranche well before 2037.

The 9.5 tons of plutonium DOE plans to speed from Savannah River is part of a 34 metric-ton inventory that was once to be turned into commercial reactor fuel by the site’s now-canceled Mixed Oxide Fuel Fabrication Facility (MFFF). The plutonium covered by the settlement is not the only plutonium stored at Savannah River Site, but DOE has not said how much of the fissile material is parked there today.

Sen. Lindsey Graham (R-S.C.) and other federal and state lawmakers attended the press conference. Notably absent was Gov. Henry McMaster (R), who did not like the terms of the settlement.

“I am not confident that this long-term arrangement provides sufficient assurances that DOE will remove the plutonium from our state in a timely manner,” McMaster wrote in a letter to Wilson dated Aug. 30. The Aiken Standard posted the letter on Twitter. Wilson quickly wrote back, telling McMaster that the governor’s office had no better plan than the terms the federal government offered in its settlement, according to two–page letter the Standard also posted.

The Energy Department started shipping the plutonium to Savannah River in 2002, initially to be processed into commercial reactor fuel. Those shipments only started once the state secured in federal law the penalties and stipulations that led to this week’s blockbuster settlement.

Congress gave DOE until Jan. 1, 2016, to begin processing plutonium in the MFFF, or else begin removing the material from the state. For every day after that that the DOE failed to do either thing, South Carolina was allowed to assess the DOE $1 million a day, up to $100 million a year. The state began suing after the deadline passed and the Energy Department did not pay up. This week’s settlement adds up to six years of missed shipments.

Rep. Joe Wilson (R-S.C.), whose congressional district includes the Savannah River Site and surrounding communities, and who attended Monday’s press conference, said Monday that it is important that “a significant portion of these funds remain in the counties where the Savannah River Site is located,” Barnwell, and Allendale counties.

Ultimately, the South Carolina legislature and the state’s governor will decide how to spread the award around. Some $75 million of it, however, is already earmarked for attorneys who helped Attorney General Wilson build his case. 

Congress created the Judgment Fund in the 1950s so that Congress did not have to pass a law appropriating money to pay every successful court claim against the federal government. Last decade, the fund paid out some $3 billion or $4 billion annually, according to the Government Accountability Office.

In a controversial move in 2016, then-President Barack Obama tapped into the Judgment Fund for a $1.3-billion interest payment on money the U.S. returned to the government of Iran.

The Energy Communities Alliance, a Washington, D.C.-based nonprofit that advocates for the interests of localities that host DOE sites, boggled at the settlement in an email blast on Monday.

“We would not be surprised to see every state attorney general to be prepared for additional suits against [DOE and its National Nuclear Security Administration] based on the size of the settlement (including for breaking cleanup agreements),” The Energy Communities Alliance stated.