U.S. destroys last of its declared chemical weapons, closing a deadly chapter dating to World War I

In southern Colorado, workers at the Army Pueblo Chemical Depot started destroying the weapons in 2016, and on June 22 completed their mission of neutralizing an entire cache of about 2,600 tons of mustard blister agent. The projectiles and mortars comprised about 8.5% of the country’s original chemical weapons stockpile of 30,610 tons of agent.

Nearly 800,000 chemical munitions containing mustard agent were stored since the 1950s inside row after row of heavily guarded concrete and earthen bunkers that pock the landscape near a large swath of farmland east of Pueblo.

The weapons’ destruction alleviates a concern that civic leaders in Colorado and Kentucky admit was always in the back of their minds.

“Those (weapons) sitting out there were not a threat,” Pueblo Mayor Nick Gradisar said. But, he added, “you always wondered what might happen with them.”

In the 1980s, the community around Kentucky’s Blue Grass Army Depot rose up in opposition to the Army’s initial plan to incinerate the plant’s 520 tons of chemical weapons, leading to a decadeslong battle over how they would be disposed of. They were able to halt the planned incineration plant, and then, with help from lawmakers, prompted the Army to submit alternative methods to burning the weapons.

Craig Williams, who became the leading voice of the community opposition and later a partner with political leadership and the military, said residents were concerned about potential toxic pollution from burning the deadly chemical agents.

Williams noted that the military eliminated most of its existing stockpile by burning weapons at other, more remote sites such as Johnston Atoll in the Pacific Ocean or at a chemical depot in the middle of the Utah desert. But the Kentucky site was adjacent to Richmond and only a few dozen miles away from Lexington, the state’s second-largest city.

“We had a middle school of over 600 kids a mile away from the (planned) smokestack,” Williams said.

The Kentucky storage facility has housed mustard agent and the VX and sarin nerve agents, much of it inside rockets and other projectiles, since the 1940s. The state’s disposal plant was completed in 2015 and began destroying weapons in 2019. It uses a process called neutralization to dilute the deadly agents so they can be safely disposed of.

The project, however, has been a boon for both communities, and facing the eventual loss of thousands of workers, both are pitching the pool of high-skilled laborers as a plus for companies looking to locate in their regions.

Workers at the Pueblo site used heavy machinery to meticulously — and slowly — load aging weapons onto conveyor systems that fed into secure rooms where remote-controlled robots did the dirty and dangerous work of eliminating the toxic mustard agent, which was designed to blister the skin and cause inflammation of the eyes, nose, throat and lungs.

Robotic equipment removed the weapons’ fuses and bursters before the mustard agent was neutralized with hot water and mixed with a caustic solution to prevent the reaction from reversing. The byproduct was further broken down in large tanks swimming with microbes, and the mortars and projectiles were decontaminated at 1,000 degrees Fahrenheit (538 degrees Celsius) and recycled as scrap metal.