In an airtight room behind a coat of armed guards and three rows of high barbed wire at the Army’s Pueblo Chemical Depot in Colorado, a team of robotic arms was busy dismantling some of the last of America’s vast and terrifying stockpile of chemical weapons.
In went artillery shells filled with a deadly mustard agent that the army had stored for more than 70 years. The bright yellow robots pierced, drained and washed each shell, then baked it at 1,500 degrees Fahrenheit. Out came inert and harmless scrap metal, falling off a conveyor belt into an ordinary brown dump with a resounding click.
“That’s the sound of a chemical weapon dying,” said Kingston Reif, who spent years lobbying for disarmament outside of government and is now the deputy assistant secretary of defense for threat reduction and arms control. He smiled as another shell rang into the bin.
The destruction of the stockpile took decades, and the army says the work is almost finished. The depot near Pueblo destroyed its last weapon in June; the remaining handful at another depot in Kentucky will be destroyed in the next few days. And when they are gone, all of the world’s publicly declared chemical weapons will be removed.
The American stockpile, built up over generations, was shocking in its scale: Cluster bombs and terminals filled with nerve agents. Artillery shells that could cover entire forests with a blistering mustard fog. Tanks full of poison that could be loaded onto jets and sprayed on targets below.
They were a class of weapons considered so inhumane that their use was condemned after World War I, but even so, the United States and other powers continued to develop and stockpile them. Some held more lethal versions of the chlorine and mustard agents made notorious in the trenches of the Western Front. Others held nerve agents developed later, such as VX and Sarin, which are lethal even in minute amounts.
US armed forces have not been known to have used lethal chemical weapons in combat since 1918, although during the Vietnam War they used herbicides such as Agent Orange that were harmful to humans.
The United States once also had a vast germ warfare and biological weapons program; those weapons were destroyed in the 1970s.
The United States and the Soviet Union agreed in principle in 1989 to destroy their chemical weapons stockpiles, and when the Senate ratified the Chemical Weapons Convention in 1997, the United States and other signatories committed to eliminating chemical weapons once and for all.
But destroying them was not easy: They were built to be shot, not dismantled. The combination of explosives and poison makes them exceptionally dangerous to handle.
Defense Department officials once projected that the work could be done in a few years at a cost of about $1.4 billion. It now wraps decades behind schedule, at a cost close to $42 billion — 2,900 percent over budget.
But it’s done.
“It was ordeal, that’s for sure – I wondered if I would ever see the day,” said Craig Williams, who began pushing for the safe destruction of the stockpile in 1984 when he learned that the Army was storing five tons of chemical weapons. miles from his house, at the Blue Grass Army Depot near Richmond, Ky.
“We had to fight, and it took a long time, but I think we should be very proud,” he said. “This is the first time, worldwide, that an entire class of weapons of mass destruction will be destroyed.”
Other powers have also destroyed their declared stockpiles: Britain in 2007, India in 2009, Russia in 2017. But Pentagon officials warn that chemical weapons have not been completely eradicated. Some nations never signed the treaty, and some that did, notably Russia, appear to have retained undeclared stocks.
Nor did the treaty end the use of chemical weapons by rogue states and terrorist groups. Forces loyal to President Bashar al-Assad of Syria used chemical weapons in the country numerous times between 2013 and 2019. According to the IHS Conflict Monitor, a London-based intelligence collection and analysis service, Islamic State fighters have used chemical weapons at least 52 times in Iraq and Syria from 2014 to 2016.
The huge American stockpile and the decade-long effort to eliminate it are both a monument to human folly and a testament to human potential, say people involved. The work took so long in part because citizens and legislators insisted that the work be done without endangering surrounding communities.
In late June at the 15,000-acre Blue Grass depot, workers carefully pulled fiberglass shipping tubes holding Sarin-filled rockets from earth-covered concrete storage bunkers and moved them to a series of buildings for processing.
Workers inside, wearing protective suits and gloves, X-rayed the tubes to see if the warheads inside were leaking, then sent them down a conveyor to meet their doom.
It was the last time humans would ever handle the weapons. From there, robots did the rest.
Chemical munitions all have essentially the same design: a thin-walled warhead filled with a liquid agent and a small explosive charge to detonate it on the battlefield, leaving a spray of small droplets, mist and vapor – the “poison gas” that soldiers have. feared from the Somme to the Tigris.
For generations, the U.S. military promised to use chemical weapons only in response to an enemy chemical attack — and then began stockpiling so many that no enemy would dare. From the 1960s the United States had a very secret network of factories and storage complexes around the globe.
The public knew little about how vast and deadly the stock had grown until a snowy spring morning in 1968, when 5,600 sheep mysteriously died on land adjacent to an Army testing site in Utah.
Under pressure from Congress, military leaders acknowledged that the military had tested VX nearby, that it had stored chemical weapons at facilities in eight states and that it had tested them outdoors in a number of locations, including one site 25 miles from. Baltimore.
Once the public learned the extent of the program, the long road to destruction began.
At first, the Army wanted to do openly what it had done in secret for years with outdated chemical munitions: load them onto obsolete ships and then dump the ships at sea. But the public responded with fury.
Plan B was to burn the supplies in huge incinerators – but that plan also hit a wall of opposition.
Mr. Williams was a 36-year-old veteran and furniture maker of the Vietnam War in 1984 when Army officials announced that a nerve agent would be burned at the Blue Grass depot.
“There were a lot of people asking questions about what was going to come out of the stack, and we didn’t get any answers,” he said.
Outraged, he and others organized opposition to the incinerators, lobbied lawmakers and brought in experts who argued the incinerators spewed toxins.
Incinerators in Alabama, Arkansas, Oregon and Utah, and one on Johnston Atoll in the Pacific, used to destroy a large part of the supply, but activists blocked them in four other states.
Following orders from Congress to find another way, the Defense Department developed new techniques to destroy chemical weapons without burning.
“We had to figure it out as we went along,” said Walton Levi, a chemical engineer at the Pueblo depot, who began working in the field after college in 1987 and now plans to retire after the last round is destroyed.
At Pueblo, each shell is pierced with a robotic arm, and the mustard agent inside is sucked out. The shell is washed and baked to destroy any remaining traces. The mustard is diluted in hot water, then broken down by bacteria in a process not unlike that used in sewage treatment plants.
It yields a residue that is mostly ordinary table salt, Mr. Levi said, but is laced with heavy metals that require handling as hazardous waste.
“Bacteria are amazing,” Mr. Levi said as he watched shells being destroyed during the last day of operations at Pueblo. “Find the right ones, and they’ll eat almost anything.”
The process is similar at the Blue Grass repository. Liquid nerve agents drained from these warheads are mixed with water and caustic soda and then heated and stirred. The resulting liquid, called hydrolyzate, is trucked to a facility outside Port Arthur, Tex., where it is incinerated.
“It’s a good piece of history to have behind us,” said Candace M. Coyle, the Army’s project manager for the Blue Grass depot. “That’s the best part about it, is that it won’t hurt anyone.”
Irene Kornelly, the president of the citizens’ advisory board that has overseen the process at Pueblo for 30 years, kept track of when nearly one million mustard shells were destroyed. Now 77, she stood leaning on a cane and craned her neck to watch the last one be removed.
“Truthfully, I never thought this day would come,” she said. “The military didn’t know if they could trust the people, and the people didn’t know if they could trust the military.”
She looked around at the plant’s beige buildings and the empty concrete storage bunkers on the Colorado prairie beyond. Nearby, a crowd of workers in overcoats with emergency gas masks slung over their hips gathered to celebrate. The plant manager blasted “The Final Countdown” over the PA and handed out red, white and blue Bomb Pops.
Mrs. Kornelly smiled as she took it all in. The process was smooth, safe, and so laborious, she said, that many residents of the region forgot that it was happening.
“Most people today have no idea this all happened – they never had to worry about it,” she said. She paused, then added, “And I think that’s just as well.”