Dan Brouillette (copy)

Deputy Secretary of Energy Dan Brouillette, who President Donald Trump has nominated to be the next secretary of energy.

Dan Brouillette, who President Donald Trump has tapped to become the next U.S. secretary of energy, committed Thursday to removing a cache of defense plutonium from Nevada that was quietly dispatched from South Carolina sometime last year.

Brouillette, currently the deputy secretary of energy, made the promise publicly during an hours-long nomination hearing before the Senate Energy and Natural Resources Committee.

The matter was first raised by U.S. Sen. Catherine Cortez Masto, a Nevada Democrat who has wrangled with the Department of Energy more than a few times.

"When we met this week, you assured me that you were committed to honoring that agreement," she said. "Do you mind reaffirming your commitment today?"

"I do not mind at all, senator," Brouillette responded in part.

The weapons-grade plutonium in question – about a half-metric ton – was sent from the Savannah River Site to the Nevada National Security Site to partially satisfy a 2017 federal court order. The material will eventually be sent to New Mexico, to Los Alamos National Laboratory, for integration and use in nuclear weapons work.

News of the clandestine plutonium shipments, disclosed in court documents only after the fact, roiled Cortez Masto and her fellow Nevada officials. She promised to hold the DOE accountable, as did her counterparts.

In late April, Secretary of Energy Rick Perry wrote Cortez Masto, pledging plutonium relocation efforts would begin in 2021. They would wrap by the end of 2026. The Nevada congressional delegation's "concerns" spurred the move, Perry continued.

That agreement, though, was apparently jeopardized when Perry announced he would be leaving his post atop the Department of Energy by the end of the year. Cortez Masto on Twitter said it was absolutely critical the next secretary "honor the written commitment I secured from Sec. Perry to remove the secret shipment of plutonium from our state beginning in 2021."

National Nuclear Security Administration chief Lisa Gordon-Hagerty has also vowed to follow through on the Perry-Cortez Masto pact.

"But what we're doing is making sure that we are continuing to stay with our agreement, which is we will have the material out of the state of Nevada by the end of 2026, and hopefully sooner," Gordon-Hagerty told the Aiken Standard in June.

Gordon-Hagerty also serves as the Department of Energy's under secretary for nuclear security.

Colin Demarest covers the Savannah River Site, the U.S. Department of Energy, the National Nuclear Security Administration and government in general. Follow him on Twitter: @demarest_colin