US set to destroy big chemical weapon stockpile at Pueblo Chemical Depot

The Army says it plans to start operating a $4.5 billion plant next week that will destroy the nation’s largest remaining stockpile of mustard agent, complying with an international treaty banning chemical weapons.

Officials said Wednesday that the plant at the military’s Pueblo Chemical Depot in Colorado will begin destroying about 780,000 chemical-filled artillery shells soon after this weekend. They declined to be specific, citing security concerns and possible last-minute delays.

The plant is highly automated and uses water and bacteria to neutralize the mustard agent. At full capacity, it can destroy an average of 500 shells daily. It’s expected to finish in mid-2020.

The depot has already destroyed 560 shells and bottles of mustard agent using a different, slower process. Those containers had problems that made them unsuitable for the plant.