The US has destroyed the last of its declared chemical weapons stockpile, President Joe Biden says, bringing to an end a decades-long effort to eliminate the deadly weapons first used on a large scale in the First World War.

As part of the Chemical Weapons Convention, ratified by the US Senate in 1997, the US and other signatories are required to destroy their chemical weapons stockpiles by September 30, 2023.

“Today, I am proud to announce that the United States has safely destroyed the final munition in that stockpile – bringing us one step closer to a world free from the horrors of chemical weapons,” Biden said in a written statement released by the White House.

The US has been destroying its remaining stockpiles at US Army Pueblo Chemical Depot in Pueblo, Colorado, and Blue Grass Army Depot (BGAD) in Richmond, Kentucky.

In 2022, the last M55 rocket with the VX nerve agent was destroyed at the plant in Kentucky.

‘A stain on history’

The US stockpile of chemical warfare agents reached almost 40,000 tons by 1968, according to the Centers for Disease Control and Prevention.

“Chemical weapons are responsible for some of the most horrific episodes of human loss,” US Senate Republican leader Mitch McConnell said in a statement.

“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.”

Chemical weapons came to the fore during World War I, which became known as the “chemist’s war”.

According to the UN, chemical weapons killed almost 100,000 people during the First World War and have caused more than a million casualties around the world since then.

-AAP