The Pueblo Chemical Agent-Destruction Pilot Plant has destroyed more than 1,000 U.S. tons of mustard agent in the obsolete chemical weapons stockpile stored in Colorado.

“We’re getting closer and closer to the day when these weapons will be gone forever,” said Walton Levi, site project manager, PCAPP. “This milestone emphasizes the work we are doing to ensure the safety of our workforce, our neighbors in surrounding communities and in our nation.”

Starting in the 1950s, more than 2,600 U.S. tons of the blistering agent was stored at the U.S. Army Pueblo Chemical Depot, encapsulated in 155mm and 105mm projectiles and 4.2-inch mortar rounds. The weapons are now being destroyed by Congressional mandate under the international Chemical Weapons Convention treaty.

Since operations began in 2016, more than one-third of the agent in the Colorado stockpile has been eliminated and more than half of the 155mm projectiles have been destroyed.

When the 155mm shells are gone, the main plant will be reconfigured to process 105mm projectiles. The plant uses neutralization followed by biotreatment to eliminate the chemical agent, and recycles the munitions casings.

“We’re proud of our workforce and their ability to overcome challenges that arise from having a first-of-a-kind facility,” said Ken Harrawood, project manager, Bechtel Pueblo Team. “Our focus is on day-to-day operations and doing it in the safest manner possible.”

The 4.2-inch mortars will be disposed of using explosive destruction technology. Three Static Detonation Chamber units have been acquired to destroy overpacked and problematic munitions that have deteriorated and are unsuitable for the plant’s automated processes, such as the 4.2-inch rounds. Construction for the SDCs is underway as the main plant continues to operate.