RENO — Nevada’s attempt to force the federal government to remove half a metric ton of weapons-grade plutonium can move forward, a federal judge in Reno ruled Monday.

The nine-page decision from U.S. District Judge Miranda Du means Nevada will be allowed to file an amended lawsuit asking the court to require the U.S. Energy Department to remove the plutonium that was secretly shipped into the state last year.

The Ninth U.S. Circuit Court of Appeals shot down Nevada’s initial appeal because the complaint only asked to block the shipment of plutonium to Nevada and did not request that it be removed. When the state filed the first lawsuit against the Energy Department in 2018, it was not yet known that the nuclear material had already been shipped to the Nevada National Security Site, a federal facility located roughly 65 miles northwest of Las Vegas. The federal government did not disclose that information until this year.

A federal judge in South Carolina last year ordered the Energy Department to remove one metric ton of weapons-grade plutonium from the Savannah River Site in South Carolina. A half-ton was shipped to Nevada last fall, and the Energy Department announced in August that another half-ton had been shipped to either Texas or New Mexico.

In April, Sen. Catherine Cortez Masto, D-Nev., said she had struck a deal with Energy Secretary Rick Perry to remove the plutonium from Nevada starting in 2021, and that no additional plutonium would be sent to the Silver State.