Chemical weapons threat raises stakes for Mariupol’s last stand

The Ukrainian city of Mariupol is on the verge of falling to Russian forces after a brutal siege that has lasted more than 40 days. Recent reports of a chemical weapons attack are raising fears in the city, but is the threat real?

After more than 40 days spent defending the city of Mariupol, the 36 Marines Unit of the Ukrainian Army posted a message to Facebook on Monday. “Today will probably be the last fight, as the ammo is running out,” they wrote. “Some [of us] will die, some will be captured. I beg you to remember the Marines.”

In the past six weeks, Russian forces have worked to surround and suffocate the port city in southeast Ukraine. Humanitarian corridors have been blocked. Civilians have been attacked. Schools and hospitals have been bombed. Satellite images show a once-thriving city largely reduced to rubble.

According to Mayor Vadym Boychenko, 90 percent of the infrastructure in the city has been destroyed, and the death toll could surpass 20,000. On April 11, he said corpses were “carpeted through the streets”.

On the same day, a new threat emerged. Ukraine’s Azov battalion reported that a Russian drone had dropped a "poisonous substance" on troops and civilians in Mariupol, causing respiratory failure and neurological problems.

“The threat of chemical weapons is real,” Russian military strategy expert Katarzyna Zysk told FRANCE 24. “The civilian population and the government have good reasons to be very afraid of that.”

Avoiding ‘unbearable humiliation’

Use of chemical weapons was banned by the international community after World War I, with agreements reinforced in 1972 and 1993 to prohibit their development, stockpile or transfer.

Consequently, Russia's use of chemical weapons in Ukraine would be a war crime, but one it may be willing to commit. “Russia is losing this war and the humiliation is unbearable and unacceptable for the Russian authorities,” said Zysk. “Chemical weapons would help tactically to win battles but also pile psychological pressure on the Ukrainian government to stop the resistance and accept the Russia’s conditions for ending the conflict.”

Chemical weapons could also provide a quick end to conflict in the Mariupol. “It makes military sense at the moment for Russia to clear Mariupol as quickly as possible, because that would free a lot of forces for their planned offensive in the Donetsk area,” chemical weapons expert and former head of the Organization for the Prohibition of Chemical Weapons (OPCW) laboratory, Marc-Michael Blum, told FRANCE 24.

A blatant large-scale chemical attack would risk outraging the international community, already hostile to Russia. But a smaller, targeted attack would be much harder to prove, especially in an area inaccessible to the outside world, such as Mariupol.

“In Mariupol we have a small pocket of Ukrainian resistance, who are cut off,” Blum said. “There's no chance that any people affected by a chemical attack will go to hospital where samples can be taken. It's more likely that they will either be captured or killed by the Russians. So, there are grounds to believe that Russia can conceal the use of chemical weapons, because you can’t prove it happened.”

A lack of proof

However, Blum is skeptical about the chemical attack reported by the Azov battalion in Mariupol. Ukraine's President Volodymyr Zelensky was also cautious in a televised address on April 11, saying only that Russian forces “could” start using chemical weapons in the city.

That is because proving that a chemical attack has taken place is a long and complicated process, similar to proving other war crimes. On-site samples must be collected and analyzed, along with witness accounts, videos, photographs and any other documentation.

“Once you have that proof a chemical weapon was used, only then can you go further and say, well, who used it? But attribution is even more difficult,” Blum said. “The amount of real credible information [from Mariupol] is still very limited.”

Complicating matters further is the fact that officially, Russia has no chemical weapons. It signed in 1993 the Chemical Weapons Convention that came into force in 1997, banning signatories from storing, developing or using chemical weapons.

On September 27, 2017, OPCW verified the total elimination of Russia’s declared chemical weapons stocks.

Since then, small-scale chemical attacks have been attributed to Russia due to evidence of the Russian nerve agent Novichok. These include the 2020 attack on Russian opposition leader Alexei Navalny and the 2018 attack on the former Russian military officer and double agent for the British intelligence agencies, Sergei Skripal, and his daughter, Yulia Skripal.

Russian involvement in larger-scale chemical attacks in Syria and Chechnya are widely suspected, but unproven. “We lack any real credible information that Russia still has large stockpiles, meaning tonnes of chemical warfare agents,” Blum said.

“But is it a possibility? It's a large country and has a history of kind of trying to cheat on such conventions.”

‘Plausible deniability and doubt’

Russia maintains that use of chemical weapons in Syria was staged by Western intelligence or carried out by opposition forces – accusations that are difficult to disprove. If Russia were to use chemical weapons in Ukraine, Zysk expects it would make similar claims.

“A few weeks ago, this narrative from the Russian government came up about biolabs in Ukraine, basically trying to say that if a chemical attack happens it could be the Ukrainians themselves” she said. “That creates plausible deniability, and doubt.”

Even before the war began, a conflicting narrative began to emerge. As early as December 2021, Russian Defense Minister Sergei Shoigu said that US military contractors were smuggling tanks “filled with unidentified chemical components” into Ukraine as a “provocation” towards Russia.

By March 9, 2022, the war was under way and the US was warning that Russia could use chemical weapons in Ukraine but attribute them to Washington as a “false flag” to justify an invasion.

In Mariupol, “of course, you can also look at it from the other side”, Blum said. “Ukraine is understandably desperate, so is there some interest for the Ukrainians to declare a chemical weapons attack that never happened?”

The report of an attack on Monday elicited a swift response from the UK government. If the claims were found to be true, “all options were on the table for what the response could be”, said British Armed Forces Minister James Heappey.

‘This could be the fate of other cities’

For six weeks, news from Mariupol has been dominated by stories of pure destruction.

Ukraine has accused Russia of engineering a humanitarian crisis in the city by blocking corridors that would allow essential supplies and medical aid in or citizens to flee. Those who have managed to escape have described scenes “worse than a horror film”.

Whether or not chemical weapons have or will be used, the threat of an attack has been hanging in the air for months, ramping up fears in an already desperate situation. “There is a strong psychological element,” Zysk said. “The threat of chemical weapons is very scary.”

Creating fear of a chemical attack, even without the attack itself, could be one last way Russian forces are attempting to break morale in Mariupol, and in Ukraine. On the other hand, carrying out an attack would be a way for Russian forces to spread even more fear and quickly clear the city. In the process they would gain an important victory for Putin and a strategic foothold, blocking Ukrainian access to the Sea of Azov.

Either option seems beneficial to Russia. The only certainty looks to be that Mariupol will soon fall, and the excessive destruction in the city sends a clear message. “Mariupol is a warning to the Ukrainian authorities,” said Zysk. “It’s saying, look what we are doing here. This could also be the fate of other cities.”