US celebrates zero chemical weapons while defending sending cluster munitions to Ukraine

State Department official says Washington will continue to push for 'world free from the horrors of chemical weapons'

Technicians work to destroy the US chemical weapons stockpile at the Army Pueblo Chemical Depot. AP

The recent destruction in the US of its last remaining declared chemical weapons stockpile is a “historic” milestone, a State Department official said on Tuesday, as Washington gears up to supply Ukraine with controversial cluster munitions.

Bonnie Jenkins, undersecretary for arms control and international security, said the move signified the US commitment to ridding the world of chemical weapons, which were banned under the Chemical Weapons Convention of 1997.

“We are a step closer to a world free from the horrors of chemical weapons,” Ms Jenkins told journalists during an online briefing.

“Not only is this moment historic, but it is an amazing accomplishment by the United States government and all the dedicated individuals who, for many decades, worked to demilitarise and destroy the stockpile.”

On Friday, the White House announced that it had eliminated the last its chemical weapons stockpile at a military base in Richmond, Kentucky, closing a decades-long chapter of global warfare.

The US was facing a September 30 deadline to destroy its remaining chemical weapons under the treaty.

The Organisation for the Prohibition of Chemical Weapons, headquartered in The Hague, the Netherlands, confirmed that the stockpile had been “irreversibly destroyed”.

A man walks past an unexploded tail section of a 300mm rocket which appeared to contain cluster bombs after shelling in Ukraine's Lugansk region. AFP

The munitions were the last of the 51,000 M55 rockets containing the GB nerve agent, also known as sarin, a deadly toxin. The weapons had been stored at the depot since the Cold War.

The use of chemical weapons in warfare dates back to the First World War. They are estimated to have killed at least 100,000 people during the war and over the following decades.

But the announcement came as the administration of US President Joe Biden decided to provide cluster munitions to Ukraine, a weapon banned in many countries due to its propensity to cause civilian casualties long after a conflict ends. Unexploded cluster bomb rounds can kill and main civilians, usually children, even after hostilities have ceased.

On Tuesday, Ms Jenkins defended the Biden administration's decision, arguing the two issues are not related and saying that Ukraine would use the weapons responsibly.

“The destruction and elimination of chemical weapons that we're talking about today is separate from the issue of cluster munitions,” Ms Jenkins said.

“We recognise, of course, that these munitions create a risk of severe harm from some unexploded ordinances, but this is the reason why we have differed for so long, making such a decision.”

On Sunday Mr Biden said the “difficult decision” to send the cluster munitions was made after receiving written assurances from Kyiv.

“Ukraine would not be using these munitions in some foreign land – this is their country that they're defending, these are their citizens that they're protecting and they are motivated to use weapons that will help them achieve their goals but also minimise risks to their citizens,” Ms Jenkins said.

More than 120 countries, including Nato members, have banned the weapons under the Convention on Cluster Munitions. The US, Ukraine, Russia and dozens of other countries are not signatories.