SPOKANE, Wash. — Frustrated by federal government delays, the state of Washington on Monday issued its own plan for cleaning up the nation’s most contaminated nuclear weapons site.

Democratic Gov. Jay Inslee said his plan seeks to keep the cleanup of the Hanford Nuclear Reservation on schedule.

For decades, Hanford made plutonium for nuclear weapons and is now engaged in cleaning up the radioactive waste left from the work.

The waste is stored in 177 giant underground tanks, some of which are leaking, on the sprawling site near Richland.

Inslee said he has become concerned about the federal government’s failure to meet cleanup deadlines imposed by a 2010 federal court decree. Nearly all the court-imposed deadlines are likely to be missed, he said.

U.S. Secretary of Energy Ernest Moniz, in a press release Monday, said he shared Inslee’s desire to amend the federal consent decree governing Hanford cleanup. The Energy Department released its own revised plan on Monday to clean up Hanford.

“Both of our plans move in the near-term toward processing low activity waste and recognize the need to overcome technical problems in other areas of the project,” Moniz said. “We will review the state’s proposal and look ahead to further discussions.”

The Energy Department said the scientific complexity of the work demanded changes in the agreement.

Of particular concern is the stalled construction of a one-of-a-kind waste treatment plant to convert the most dangerous radioactive wastes into a glasslike substance for eventual burial.

“Since the consent decree was entered, extensive analysis by DOE and independent experts has shown that the WTP as currently designed cannot be assured for 40 years of safe operation,” the Energy Department said. “A new approach is needed.”

The Energy Department proposed changing the decree by focusing first on the liquid portion of the waste and continuing to research solutions for the rest of it.

Meanwhile, Inslee and state Attorney General Bob Ferguson said they were prepared to take legal action against the Energy Department to keep the cleanup on schedule.

“Although I appreciate Secretary Moniz placing a high priority on Hanford, the state needs a plan that includes a detailed and comprehensive path forward,” Inslee said.

The state and federal governments first made a deal in 1989 to clean up Hanford. In 2008, the state filed a lawsuit in federal court when it became clear the Department of Energy would be unable to meet key deadlines.