Chloropicrin is a poisonous, oily fluid with an extremely acrid smell. If humans come into contact with the substance they are likely to experience a blistering of the skin, irritation of the eyes and breathing difficulty. Chloropicrin fumes are especially dangerous, attacking the pulmonary veins in a victim's lungs when inhaled. The result: Pulmonary edema with gurgling breathing sounds and foamy red sputum, which, in extreme cases, can result in death.

The effects of chloropicrin were already well-known at the time of the First World War. Originally developed as a pesticide, Russia was able to weaponize the substance. The German army also began using it in gas grenades on the French front in 1916.

Chemical weapons in Ukraine?

Now, more than a century later, the US State Department says the Russian army is using the substance once again, and Russian troops are rumored to be using other chemical weapons as well. The US Pentagon says the aim of such deployments is to dislodge Ukrainian troops from fortified positions in order to achieve tactical progress on the battlefield.

Should the US claim prove true, it would be a violation of the international Chemical Weapons Convention (CWC). In effect since 1997, the treaty bans the development, manufacture, stockpiling and use of chemical weapons. Moreover, it stipulated that all existing chemical weapons stockpiles be declared and destroyed under international supervision by 2012. Proof that this did not in fact happen was on full display in Syria, where the army of President Bashar Assad allegedly carried out chemical weapons attacks against targets outside the capital Damascus in 2018.

Russia once possessed the world's largest arsenal of chemical weapons, but it is also a CWC signatory. In 2017, the Organization for the Prohibition of Chemical Weapons (OPCW) confirmed that Russia had destroyed its chemical weapons stockpiles, and the Kremlin has vehemently denied that it has used such weapons in Ukraine. Nevertheless, attacks on Kremlin enemies such as Sergei Skripal in 2018 and Alexei Navalny in 2020 make it clear that Russia still possesses — and uses — toxins as weapons.

Russia and Ukraine using cluster bombs

The repeated use of cluster bombs has been well-documented since Russia launched its invasion of Ukraine on February 24, 2022. According to the non-governmental organization Human Rights Watch, Russian troops have used at least six different types of cluster bombs in the conflict since that time. Just this week, Russia is said to have used cluster bombs in attacks on the Black Sea port of Odesa.

But the Ukrainian army has used cluster bombs as well. In July 2023, US President Joe Biden approved the delivery of cluster bombs to Kyiv. These bombs explode in midair, releasing hundreds of smaller bomblets that rain down across large swathes of land. Not all of the bomblets explode upon impact, meaning that they can pose a potentially lethal threat for many years. Although such arms were outlawed by 108 member states when the Convention on Cluster Munitions went into effect in 2010, neither the US, Russia, nor Ukraine were among the signatories.

Widespread use of mines

Ukraine is now the most-mined country on earth. Several million explosive devices are said to be buried there in an area twice the size of Austria. In the past year, the fighting in eastern Ukraine has ground down to a war of attrition, with the front moving little in either direction. In an attempt to protect defensive positions, both armies have blanketed either side of the front with anti-tank and anti-vehicle mines.

In an effort to make it more difficult to clear these away, Kyiv and Moscow have both turned to planting masses of anti-personnel mines — which were outlawed in the 1997 Anti-Personnel Landmines Convention — among the heavier explosive devices. Ukraine is among the treaty's 163 signatories; Russia, however, is not.

The destruction of the Kakhovka Dam east of Kherson in the summer of 2023 was especially devastating, as the wave of water released in the event also washed away an untold number of mines, redistributing them to places still largely unknown today.

Phosphorous bombs over Mariupol and Bakhmut?

Phosphorous bombs are made with white phosphorous and a combination of petroleum and caoutchouc, an elastic material, and are often used as incendiary bombs. These react to air, igniting and reaching temperatures of up to 1,300 degrees Celsius (2,372 degrees Fahrenheit). When they explode, they release hundreds of burning fragments even the smallest of which can lead to severe burns. Vapors from phosphorous bombs are also extremely poisonous.

The Geneva Convention prohibits the use of phosphorous bombs on civilians and in urban areas — though the treaty does not ban their use outright. Ukraine has accused Russia of having used phosphorous bombs in fighting near the Azovstal Iron and Steel Works in Mariupol, as well as in attacks on the city of Bakhmut; Moscow denies this.

Although Ukraine has asked supporters to supply phosphorous bombs to help it defend itself, it never received them.        

Depleted uranium munitions for Kyiv?

What Kyiv has received from the US are armor-piercing uranium munitions. These are missiles that are jacketed with depleted uranium capable of penetrating a tank's armor. The fine uranium powder released when the shell pierces the interior of the vehicle ignites on contact with air, burning out the entire hull of the tank.

There are no conventions outlawing the use of such munitions. Nevertheless, experts have warned of the long-term health risks posed by depleted uranium dust. Hundreds of tons of depleted uranium munitions were fired during the course of the US' 2003 Iraq War. A report conducted by the organization International Physicians for the Prevention of Nuclear War (IPPNW), which analyzed areas that saw the heaviest use of depleted uranium munitions in Iraq, documented increases in incidences of birth defects, cancer and other health issues. Still, neither the World Health Organization (WHO) nor the International Atomic Energy Agency (IAEA) have confirmed that depleted uranium munitions pose an elevated health risk to civilians.

This article was translated from German by Jon Shelton