Pueblo Chemical Depot Milestone: Quarter Of Old Mustard Gas Weapons Destroyed

<p>(AP Photo/File)</p>
<p> In this Jan. 29, 2015 file photo, inert shells sit in the entry point of the explosive destruction system inside the Pueblo Chemical Depot in southern Colorado.</p>
Photo:Chemical Weapons Destruction Pueblo 2
In this Jan. 29, 2015 file photo, inert shells sit in the entry point of the explosive destruction system inside the Pueblo Chemical Depot in southern Colorado.

Officials said about one-quarter of the mustard agent contained in decades-old shells stored at the Army’s Pueblo Chemical Depot have been destroyed. A statement from acting site project manager, Walton Levi, said that amounts to 2,600 tons of mustard agent.

The Pueblo depot stores more than 780,000 mustard agent-filled munitions in the form of 155mm and 105mm projectiles as well as 4.2-inch mortars. It’s the largest portion of what remains of the United States’ chemical weapon stockpile.

The plant began operation in September 2016 and has destroyed 112,400 chemical projectiles. Levi said that destruction of a single 155mm round eliminates “11.7 pounds of mustard agent.”

The work to eliminate the mustard-agent weapons at the depot is done under an international treaty banning chemical weapons. An automated biotreatment plant uses water and bacteria to eliminate most of the munitions, but the Army believes about 97,000 shells have interior rust that can interfere with the machinery.

Officials with the Pentagon's Assembled Chemical Weapons Alternatives plan to bring static detonation chambers to the facility to incinerate problematic rounds.