Pueblo is still home to nearly 200,000 mustard gas weapons from WWII. Workers have started dismantling the last of them.

· Feb. 25, 2022, 4:25 pm
Igor, a robot used to train workers at the Pueblo Chemical Agent-Destruction Pilot Plant, lifts a 155-millimeter shell to demonstrate how liquid mustard agent is removed.Igor, a robot used to train workers at the Pueblo Chemical Agent-Destruction Pilot Plant, lifts a 155-millimeter shell to demonstrate how liquid mustard agent is removed. Courtesy Pueblo Chemical Agent-Destruction Pilot Plant
Igor, a robot used to train workers at the Pueblo Chemical Agent-Destruction Pilot Plant, lifts a 155-millimeter shell to demonstrate how liquid mustard agent is removed.

A U.S. Department of Defense facility near Pueblo charged with destroying many of the military’s last remaining chemical weapons is heading into the final stages of its yearslong effort.

The Pueblo Chemical Agent-Destruction Pilot Plant began disposing of its final stockpile of about 97,000 mustard gas-containing mortar rounds last Saturday. It also has about 92,000 artillery shells left to dismantle.

Since starting destruction operations in 2016, the facility 15 miles east of Pueblo has destroyed more than 600,000 artillery shells — or about 80 percent of its supply — of World War II-era munitions assembled as a potential response to expected chemical weapons use by Nazi Germany. The war with Germany ended without the use of such weapons. 

In the 1950s, an enormous supply of shells and mortar rounds was transported by train from the Army’s Rocky Mountain Arsenal site in Commerce City to the depot near Pueblo that now houses the plant. 

Walton Levi, the government’s site project manager, said the remaining mortar shells require a different method of disposal from what’s been used at the facility so far. Whereas the plant’s fire extinguisher-sized artillery shells are carefully disassembled with the help of two large, yellow robotic arms, the mortar shells are placed inside a so-called Static Detonation Chamber, where they are intentionally exploded.

“The detonation chamber itself is really a big pressure cooker,” Levi said. Following the explosion, the poisonous gas released is exposed to temperatures of approximately 1,700 degrees Fahrenheit, destroying the organic components of the mustard agent. The gas is then run through a series of scrubbers and filters to remove remaining particulate matter. 

Levi said this process can destroy about six of the mortars per hour. 

The Pueblo site is one of two remaining locations in the country still working through disposing of its chemical weapons supply. The plant aims to finish its work by the end of September 2023. That’s the date by which the U.S. agreed to finish eradicating the nation’s full chemical weapons stockpile when it agreed to an international treaty signed in 1997. 

Irene Kornelly, chair of the Colorado Chemical Demilitarization Citizens' Advisory Commission, said she has been involved in the effort to dismantle the weapons for decades.

“I'm actually feeling delighted that we are finally getting rid of these weapons that have been stored in Pueblo forever,” Kornelly said. “And, in my opinion, it’s about time we finish this up.”

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