SPOKANE, Wash. (AP) – The state of Washington believes the federal government is unlikely to meet legal deadlines for emptying underground tanks holding radioactive waste at Hanford.

The state Department of Ecology says it is prepared to take the U.S. Department of Energy back to federal court to get the cleanup back on track.

Maia Bellon, the director of Ecology, wrote to a top Energy Department manager in late May.

She says the state wants to open a frank discussion about challenges the Energy Department is having in meeting cleanup deadlines under the Tri-Party Agreement that was signed in 1989 and has been often amended.

The Energy Department has confirmed that it received the letter and said it would respond through proper channels.

Hanford produced about two-thirds of the nation’s plutonium for nuclear weapons.