US begins destroying its largest cache of chemical weapons

The U.S. Army has begun destroying the nation’s largest remaining stockpile of chemical weapons.

Crews at Pueblo Chemical Depot in Colorado used explosives to tear open a container of mustard agent Wednesday and then flooded it with another chemical to neutralize it.

Depot spokesman Thomas Schultz says the detonation was inside a sealed chamber. Crews are waiting for the neutralization process to finish before draining and cleaning the chamber.

It’s the first of 2,600 tons of mustard agent that will be destroyed over the next four years.

Another 523 tons of mustard and deadly nerve agents are stored at Blue Grass Army Depot in Kentucky. Blue Grass isn’t expected to start destroying its weapons until 2016 or 2017, finishing in 2023

The U.S. signed a 1997 treaty banning chemical weapons.