Sens. Wayne Allard and Ken Salazar said earlier this month they had received assurances from the Pentagon that the mustard gas at Pueblo Chemical Depot would not be shipped out-of-state. The Defense Department announced the $150,000 feasibility study the day after their meeting with the senators Jan. 18.

"It is extremely disturbing to me that the Pentagon would study the possibility of relocating the Pueblo's chemical weapon stockpile after the Pentagon assured (us) last week that such an option was unrealistic, not to mention illegal," Allard said.

"While we wait for the promised clarification on these matters, Senator Allard and I believe it is necessary to emphasize our resolve," Salazar said in a statement. "This legislation helps provide that emphasis."

Utah politicians on Thursday expressed strong opposition to moving mustard gas into the state.

"We will utilize all means to prevent any quantity of mustard gas from moving into the state of Utah," said Gov. Jon Huntsman.

"The most dangerous option would be to ship the mustard gas interstate on a publicly accessible rail route through populated areas," he said.

U.S. Rep. Jim Matheson, D-Utah, expressed his concern in a letter to Defense Secretary Donald Rumsfeld.

"Given the hazardous nature of these munitions and the risk associated with transporting them to Utah, I am opposed to any proposal that would lead to relocation," he wrote.

The Army depot at Pueblo is one of two chemical-weapons sites that don't have destruction systems in place yet. The additional costs of the war in Iraq has delayed funding of multimillion dollar destruction systems at Pueblo and the Blue Grass Army Depot near Richmond, Ky.

In addition to Utah, sites with disposal facilities constructed or in operation are in Alabama, Arkansas, Indiana, Maryland and Oregon.