Kentucky's U.S. senators and their Colorado counterparts asked the Pentagon yesterday to remove spending limits that have "hamstrung" efforts to design chemical neutralization plants in the two states.

In an effort to control costs, officials are redesigning plants to destroy chemical weapons stockpiles at Blue Grass Army Depot in Madison County and in Pueblo, Colo.

But some of the cost-cutting measures under study, such as a proposal to ship waste products elsewhere to be processed, might not be as safe for workers, nearby residents and people who live along transportation routes.

The Department of Defense "has painted itself into a corner by unnecessarily placing a cap on the cleanup costs at Blue Grass," U.S. Sen. Mitch McConnell of Kentucky said in a statement yesterday. "I will never allow misguided cost savings to come at the expense of the safety of Kentuckians."

Lt. Cmdr. Joe Carpenter, a Pentagon spokesman, said officials had just received the letter and would study the concerns raised. The design teams have never been asked to compromise on safety, he added.

Because of strong local opposition to incineration, the Pentagon agreed to destroy the depot's 523 tons of mustard and nerve agent using chemical neutralization.

Before the plants were approved, the Pentagon was required to certify that neutralization would be as safe and as cost-effective as incineration.

The Pentagon certified in 2003 that the Blue Grass plant should cost $2 billion and Pueblo $1.5 billion.

But the senators say the law makes no mention of a definitive cost estimate, and critics have complained that the figures were derived before any design work had begun. Although costs have gone up, the targets haven't changed.

"This fraudulent, baseless number they put in this certification is the root of a lot of problems that we're dealing with now," said Craig Williams, director of the Berea-based Chemical Weapons Working Group.

Officials have been trying to cut $200 million from the cost of the Blue Grass plant. In Pueblo, the problem is much more severe: The plant is $1 billion above the cap.

Teams from the military and the contractor are considering cutting the size of the plants and changing some of the weapons destruction processes.

The senators -- McConnell and Jim Bunning of Kentucky and Wayne Allard and Ken Salazar of Colorado -- asked new Undersecretary of Defense Kenneth J. Krieg to correct the situation "by whatever means possible."