Did Russia really use chemical weapons in Ukraine? Experts are sceptical

Ukraine forces holed up in the besieged city of Mariupol announced late on Monday the Russians had used “a poisonous substance of unknown origin” – but in the following 24 hours, evidence to corroborate this was a chemical weapons attack has proved harder to find.

A scant initial report, circulating on social media, described victims as having “respiratory failure” and a rather specific diagnosis of “vestibulo-atactic syndrome”, nominally inner-ear problems leading to dizziness and perhaps vomiting, eye twitching and loss of balance.

Liz Truss, the British foreign secretary, said the UK was urgently investigating while a Pentagon spokesperson said the reports “if true, are deeply concerning”. But some observers have expressed scepticism that the available evidence points towards a chemical weapons attack.

Ukraine’s president, Volodymyr Zelenskiy, said overnight the claim was being taken “as seriously as possible” – however, he did not return to it on Tuesday in a speech to the Lithuanian parliament, despite referring to other Russian war crimes.

What information has emerged?

A video from the Azov battalion, a Ukrainian nationalist group linked to the far right and the group behind the initial social media report, was released on Tuesday on Telegram. It filmed three victims, who did not appear seriously harmed, in an incident that appeared to be limited in scope.

The first, a middle-aged man, described seeing “a white smoke” coming from the factory, most likely the vast Azovstal steel plant in the east of the city and one of two locations where Ukrainian forces are holding out. The smoke or fog, he said later, had “a sweet taste”.

The man said he “at once got sick” and that he had suffered tinnitus, tachycardia (a fast heartbeat) and had fallen over. “Mother lost consciousness and three times she was reanimated,” the man added.

An older woman, filmed afterwards in a makeshift bed, complained she was still unable to walk.

A third victim, lying prone with clearly inflamed eyes, also described a “fog more like a smoke” after an explosion. “It was very difficult to breathe,” he said, and reported feeling dizzy and that his legs were “a kind of cotton”.

A military commander concluded that “toxic substances” or “potent toxic substances of suffocating action were used” – but acknowledged it was not possible to engage in a toxicological analysis.

So was it a chemical weapons attack?

It is too soon to say definitively what happened. One chemical weapons expert, Dan Kaszeta, the author of a history of nerve agents, cautioned that remote diagnosis was always difficult and questioned why, in the initial report, such a specific medical phrase as vestibulo-atactic syndrome had been used.

It remained unclear whether chemicals, let alone chemical weapons, had been used on the evidence available, Kaszeta said, adding that on the site under attack there was “lots of scope … for conventional or incendiary weapons to cause chemical problems because of fires and explosions”.

Eliot Higgins, the founder of the Bellingcat investigative journalism agency, said the symptoms described in the video were “inconsistent with any nerve agent I’m familiar with, with no reports of pupil constriction or dilation, convulsions”.

Nevertheless, it was critical for Ukrainian forces to try to recover any munitions used, which may be possible because chemical weapons shells are designed to release their contents rather than explode.

What are politicians saying? What next?

Investigations in the UK and the US are continuing. The Pentagon spokesperson, John Kirby, said overnight that the US had concerns about Russia’s ability to use “riot control agents, including teargas mixed with chemical agents”. Teargas is a banned chemical weapon in war, although it is legal for police forces to use it around the world.

Joe Biden did warn after the Nato summit last month that the west would respond to any Russian use of chemical weapons in Ukraine, with “the nature of the response depending on the nature of the use”.

But the effect of the incident – with three victims filmed – appears limited, and it is hard to see it provoking a significant military response at this stage. With Mariupol surrounded by Russian forces and inaccessible to outsiders there is no prospect of an independent investigation.

Further information could alter the picture, but for the moment the incident on Monday may not be as consequential as had initially been feared.