Funding for a $4 billion plutonium processing facility at Los Alamos National Laboratory is well into the home stretch with a $325 million installment now pending in Congress and a long-term commitment almost in hand.

After two decades and four presidents since the idea was first proposed, $289 million has already been invested in building the Chemistry and Metallurgy Replacement Research-Nuclear Facility, Los Alamos National Laboratory's biggest project since World War II.

With that end in view, laboratory officials now face another challenge — The Los Alamos Study Group on Monday filed for an injunction to halt the project until its environmental paperwork more clearly resembles its expanded dimensions.

The environmental impact statement for an earlier version of the facility was written in 2003, according to the study group. "At that time, the facility was to cost one-tenth as much, use one-fiftieth as much concrete, take one-fourth the time to build and entail far fewer environmental impacts," it announced as the lawsuit was filed in U.S. District Court in Albuquerque.

The CMRR has been endorsed by the Obama administration and key members of Congress. The CMRR also was recommended under the Nuclear Posture Review, the nation's central statement of its nuclear weapon policy.

NNSA spokeswoman Jennifer Wagner said in a response that the agency does not comment on pending legislation, but that it has undertaken a supplemental analysis to determine if the EIS should be amended or a new one should be prepared.

Among the questions left unanswered by the NNSA is what effect the legal uncertainty might have in current operations and schedules.

The embattled CMRR facility began as a modern replacement for the lab's antiquated Chemistry and Metallurgy Research facility, but the building began to take on new dimensions over time.

At one point during the Bush administration, a Modern Pit Facility was proposed for Los Alamos, where plutonium handling in the nuclear weapons complex would be consolidated and where new plutonium triggers, known as pits, would be manufactured for modernizing the nuclear weapons stockpile.

Many features of the new facility, including its enlarged capability for plutonium processing, can be traced back to the Modern Pit Facility, including the decision to locate it next to the Plutonium Facility, where an advanced security perimeter is already in place and where a modest program of pit production has begun. The lab maintains that pit processing would continue to take place in the Plutonium Facility, although the two buildings would be linked by tunnel.

Under the Nuclear Policy Review, 50-80 pits per year could be made at Los Alamos, but another concern for the study group is that the evolving design plans have embraced a "hotel concept" which would enable plans to change to encompass unknown future capabilities.

"In a nutshell, NNSA changed the project to which it had committed without telling anyone, and without environmental analysis of alternatives, either to the project, to its design, or to its construction methods," said Greg Mello, executive director of the study group.

Meanwhile the record of LANL presentations on the CMRR makes clear that firm costs have yet to be established, but estimates have mushroomed from a few hundred million to $4.2 billion.

The price tag opens the question of more effective alternatives that may be possible, but that were not considered under the much smaller costs anticipated years ago.

Many factors have influenced the rising costs in recent years. A Bush administration emphasis on securing nuclear facilities called for a project that would be largely underground, but that aggravated seismic issues that arose, which in turn pushed the excavation from 50 feet to 125 feet and will require 225,000 cubic yards of concrete and grout for a foundation.

Far from being on the verge of becoming a reality, Mello said today, "The project never recovered after finding out that the ground on which it sits literally can't support its own weight." As a nuclear facility in an earthquake zone, that makes the whole project almost impossible, he added.

Contact Roger Snodgrass at reoger.sno@gmail.com.