The United States has destroyed the last of its declared chemical weapons stockpile, President Joe Biden confirmed, a milestone that closes a chapter of warfare dating back to World War I.
Workers at the Blue Grass Army Depot in Kentucky destroyed rockets filled with GB nerve agent, also known as sarin, on Friday, completing a decades-long campaign to eliminate a stockpile that by the end of the Cold War totalled more than 30,000 tonnes.
In a White House statement, Biden said the move brings “us one step closer to a world free from the horrors of chemical weapons”.
“I am grateful to the thousands of Americans who gave their time and talents to this noble and challenging mission for more than three decades,” he said. “Today—as we mark this significant milestone—we must also renew our commitment to forging a future free from chemical weapons.”
Republican Senate minority leader Mitch McConnell also welcomed the news, saying earlier on Friday that “chemical weapons are responsible for some of the most horrific episodes of human loss”.
“Though the use of these deadly agents will always be a stain on history, today our nation has finally fulfilled our promise to rid our arsenal of this evil,” McConnell said in a statement.
The US faced a September 30 deadline to eliminate its remaining chemical weapons under the international Chemical Weapons Convention, which took effect in 1997 and was joined by 193 countries.
Chemical weapons were first used in modern warfare in World War I, during which they were estimated to have killed at least 100,000 people.
Despite their use being subsequently banned by the Geneva Convention, countries continued to stockpile the weapons until the treaty called for their destruction.
They also have been used in modern warfare – notably by Iraq during its conflict with Iran in the 1980s and more recently in the Syrian war.
US workers at the Army Pueblo Chemical Depot in southern Colorado started destroying the weapons in 2016, and on June 22, they completed their mission of neutralising an entire cache of about 2,600 tonnes of mustard blister agent.
In the 1980s, the community around Kentucky’s Blue Grass Army Depot opposed the Army’s initial plan to incinerate the plant’s 520 tonnes of chemical weapons, leading to a decades-long 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.
Kentucky’s disposal plant was completed in 2015 and began destroying weapons in 2019, using a process called neutralisation to dilute the deadly agents so they could be safely disposed of.
At the Colorado site, to dispose of the mustard blister agent, robotic equipment removed the weapons’ fuses and bursters before the mustard agent itself was neutralised with hot water and mixed with a corrosive 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 538 degrees Celsius (1,000 degrees Fahrenheit) and recycled as scrap metal.
Problematic munitions that were leaky or overpacked were sent to an armoured, stainless steel detonation chamber to be destroyed at high temperatures.
The Colorado and Kentucky sites were the last among several, including Utah and the Johnston Atoll island in the Pacific Ocean, where the nation’s chemical weapons had been stockpiled and destroyed. Other locations included facilities in Alabama, Arkansas and Oregon.
Kingston Reif, an assistant US secretary of defense for threat reduction and arms control, said the destruction of the last US chemical weapon “will close an important chapter in military history, but one that we’re very much looking forward to closing”.
Officials have said the elimination of the US stockpile is a major step forward for the Chemical Weapons Convention. Only three countries — Egypt, North Korea and South Sudan — have not signed the treaty. A fourth, Israel, has signed but not ratified the treaty.
