The Department of Energy is pushing ahead with its plan not to glassify 75 percent of Hanford's radioactive tank wastes despite uncertainties, said the agency's top cleanup official.

"It's a serious proposal, no doubt about it," said Jesse Roberson, DOE's cleanup czar, in a telephone interview.

Details about possible alternatives to melting the wastes into a glassified form remain years away, she said.

That means approval by regulators also is years away, if ever.

The state Department of Ecology made it clear it wants to see a proposal on paper before discussing the idea.

"If this becomes an excuse for stalling (on cleanup), we won't go along with it," said Sheryl Hutchison, a spokeswoman for the Ecology Department.

The proposal may just be the first controversy in a sweeping, nationwide overhaul of plans for cleaning up the radioactive and toxic mess left by Cold War nuclear weapons production.

Officials at DOE headquarters in Washington, D.C., are racing toward a Dec. 31 deadline for a draft of a top-to-bottom review of the existing $300 billion, 70-year nationwide cleanup plan.

Energy Secretary Spencer Abraham wants to trim that by $100 billion and 30 years.

Tackling Hanford's tank wastes is DOE's single most expensive cleanup problem, Roberson said.

Not seeking better and quicker alternatives would be neglecting her duties, she said.

The proposal to eliminate some glassification work became public last month when an internal DOE memo was leaked to the Hanford Advisory Board, catching the Northwest off guard.

Just days earlier, Tom Fitzsimmons, the state Ecology Department's director, and Mike Wilson, the department's nuclear program manager, met two hours with Roberson without hearing anything about the proposal, Hutchison said.

For now DOE is going ahead with plans to treat the most radioactive 10 percent of Hanford's 53 million gallons of tank wastes as soon Hanford's glassification plant is built, Roberson said.

The schedule calls for the initial glassification complex to begin operating in 2007 and run at full speed from 2011 to 2018.

Roberson's proposal means DOE would hunt for at least two faster and cheaper alternatives to treat much of the remaining 90 percent of Hanford's tank wastes.

The concept extends to all of DOE's tank wastes, but Hanford has about 60 percent of the total.

An open question is which DOE sites will have to find alternatives to glassification. Roberson said the entire 75 percent of the total would not be at Hanford.

Also, the final nationwide figure for wastes destined for treatments other than glassification could end up a little higher or lower than 75 percent.

DOE has no estimate of savings from the proposal, nor has it set a timetable to find alternatives to glassification, she said.

Another question is whether the proposal would violate DOE's legal obligations at Hanford and elsewhere.

"The reality is that I'm not sure what the legal ramifications are," Roberson said.

The Tri-Party Agreement, the legal pact governing Hanford's cleanup, calls for all of the site's tank wastes to be glassified.

Roberson said DOE's review team has met with Hanford's regulators, and she believes the agency has aggressively sought feedback from regulators at all of its sites.

Doug Sherwood, the U.S. Environmental Protection Agency's Hanford site manager, agreed. "We had a fair shot at them," he said.

However, Hutchison said the state's talks with DOE's review team "may be adequate by their standards, but not by our standards."