The Blue Grass depot and a second depot near Pueblo, Colo., are the two left with chemical arsenals.
The cost of the entire disposal process, once completed, is estimated to be $35 billion, $10.6 billion of which will be spent in Kentucky and Colorado, according to Defense Department spokeswoman Jennifer Elzea and the Assembled Chemical Weapons Alternatives website, the agency responsible for destroying the weapons at the remaining depots.
The Colorado site has 2,600 tons of mustard gas inside more than 800,000 weapons. The 523 tons of mustard gas and nerve agents in Kentucky are inside 101,000 weapons, according to Craig Williams, 65, who is co-chairman of the Chemical Destruction Citizens Advisory Board for the Blue Grass project.
The Kentucky site has been storing mustard gas for years. The first shipment of nerve-agent rockets arrived in 1961, said Lloyd Anglin, of Berea, who worked on the depot's engineering staff at the time.
The rockets came in a locked boxcar, which sat on a railroad spur for four days under armed guard as the engineering team rushed to build a facility "to unload whatever it was," said Anglin, now 90. "The armed guards were there 24-7. Nobody knew what it was except the brass."
The shipments arrived regularly after that and the team learned that they contained agents that would kill on contact. Anglin helped seal some of the rockets in concrete-filled caskets, which were then put on a ship in Wilmington, North Carolina and dropped into the Atlantic Ocean. Most stayed in the earth under grass-topped, domed concrete bunkers called igloos, which are laid out in a widely spaced grid. Deer grazed there and some died, Anglin said, if they ate too close to a monitor vent at a bunker with "leakers." Security fencing around the area has since been improved.