The federal government has sued in U.S. District Court, seeking to overturn Initiative 297 on grounds that it violates federal law governing nuclear waste and interstate commerce. The initiative has not been enforced pending resolution of the lawsuit.

The state, which is defending the initiative, had asked U.S. District Judge Alan McDonald in Yakima to allow the state Supreme Court to first decide how the measure should be interpreted.

Specifically, the state wanted its highest court to decide if the entire measure would be nullified if the McDonald finds part of the initiative unconstitutional.

Citing previous case law, the court ruled that the parts of the initiative that are constitutional could be enacted even if other parts are found to be unconstitutional.

The state court did not decide whether I-297, or parts of it, are unconstitutional. The case now returns to Judge McDonald for a decision on that question.

At issue are the federal government's plans for disposing of waste from nuclear weapons production nationwide. The Energy Department chose Hanford to dispose of some mildly radioactive waste and mixed low-level waste, which is laced with chemicals.

The south-central Washington site also would serve as a packaging center for some transuranic waste before it is shipped elsewhere for long-term disposal. Transuranic waste is highly radioactive and can take thousands of years to decay to safe levels.

Waste shipments to the site had already been halted under another lawsuit.