Cooperative Security, Arms Control and Disarmament By Ramesh Thakur  |  11 September, 2023

US Decides to Supply Depleted Uranium Shells to Ukraine

Image: Denis Junker/

At the G20 summit in Bali last year, most of the world’s most influential leaders had strongly deplored ‘the aggression by the Russian Federation against Ukraine’. By contrast, the joint declaration from the just concluded summit in New Delhi does not mention Russia by name. Instead, it talks about ‘the human suffering and negative added impacts of the war in Ukraine with regard to global food and energy security’. It calls on states to ‘refrain from the threat or use of force to seek territorial acquisition’ and notes ‘different views and assessments of the situation’. Not surprisingly, Russia hailed the unexpectedly soft outcome but Ukraine dismissed it as ‘nothing to be proud of’. This consolidates Russia’s diplomatic gains in China, the Middle East and Africa as noted by Walter Russel Mead in The Wall Street Journal.

Another tell: Ukraine was invited to last year’s summit but not this year. India did induct the African Union as a new permanent member of the G20. ‘The Global South is no longer willing to be lectured’, said Russia’s Foreign Minister Sergei Lavrov, attending instead of President Vladimir Putin.

Meanwhile in Washington, General Mark Milley, Chairman of the Joint Chiefs of Staff, told the BBC that Ukraine has less than a month before winter closes in to hinder its counter-offensive. Public support for continued US aid to Ukraine is falling as Ukraine’s offensive falters and the issue has entered the presidential campaign. President Joe Biden is under attack for a lack of clear strategy and war goals. In London, retired Colonel Richard Kemp wrote in The Telegraph that the US has provided ‘just about enough military assistance to keep Ukraine fighting, but intentionally not enough to enable a victory’.

That might be the key to understanding the latest US decision, announced on 6 September, to provide armour-piercing depleted uranium shells to Ukraine.

Uranium is a metal found in nature and Australia holds the largest known reserve of ores, around one-third of the world’s total. It is enriched for use in nuclear power generation from 0.7 per cent in its natural state. Highly enriched (94 per cent) uranium, spun and cascaded through centrifuges, is used to make nuclear weapons.

Depleted uranium (DU) is a by-product left over from the process of enrichment. However, its radioactivity is weak, around 40 percent less than naturally occurring uranium, and its radiation does not penetrate human skin. Militaries are interested instead in its high density. At 19 grammes per cubic centimetre, it is 70 per cent more dense than lead. A small 10cm cube weighs 20kg. This makes it an effective material to use both as tank armour, as in the US M1 Abrams tanks that have been supplied to Ukraine and in Russia’s upgraded T-80BV tanks; and as ammunition to penetrate enemy tanks.

The impact of the penetration is amplified by two additional properties. Because it generates high heat when fired at high speed, DU is exceptionally incendiary and self-ignites at high temperatures. And as it penetrates armour plating, the shearing effect increases its sharpness even as the soaring temperatures cause secondary explosions of the fuel and ammunition of the tank.

Its use has always been controversial, from the 1991 Persian Gulf War (40 tons) and the NATO bombing campaign in Kosovo in 1999 (11 tons), to the invasion of Iraq in 2003. Unlike cluster munitions, the use of DU is not prohibited under any international treaty. Nevertheless, critics who want to expand the scope of international humanitarian law covering armed conflicts have long argued that it can cause ecological damage and long-lasting health effects.

While not a radiation threat, it is toxic chemically and can cause liver damage and some forms of cancer if inhaled or ingested by humans. Dust from the DU used in wars can enter the body and can also contaminate the surrounding sediment and soil. The International Atomic Energy Agency’s helpful factsheet on the human and ecological radiation and toxicity risks of DU can be found here.

In 2015, the US used DU rounds in air raids on Islamic State targets in Syria. After the 1991 Persian Gulf War, Iraq alleged that DU shells had caused a rise in congenital birth defects and other health problems. Similar allegations were raised after the NATO bombing of Kosovo in 1999 and Italy investigated links with illnesses among its soldiers who had served in the Balkans.

The UK was the first NATO country to announce in March that it would give DU rounds to Ukraine for use by Challenger 2 battle tanks. This was met with Russian threats to retaliate in kind. Washington effectively shrugged off the threats, saying if Russia didn’t like it, it could withdraw from Ukraine.

Six months later comes the US decision to do the same. Russia has predictably condemned the decision and repeated its warnings on the risks of escalation. Its US embassy criticised the DU’s ‘indiscriminate effects’ as ‘an indicator of inhumanity’ and blamed the decision on a deluded US refusal ‘to accept the failure of the Ukrainian military’s so-called counteroffensive’.

The DU decision contains a threefold risk of escalation. First, it maintains the trajectory of a slow and steady vertical escalation of the types of armaments and weaponry being used in the Ukraine war. Earlier in the year, the US began supplying Ukraine with cluster munitions, in violation of the international treaty prohibiting such weapons, which the US has not signed, to the public dismay of several of its NATO allies in Europe as well as Canada. This was discussed on this site by Herbert Wulf. Now the US has upped the ante by supplying Ukraine with DU shells.

Second, the decision contributes to the continual softening of existing humanitarian norms against weapons with particularly inhumane characteristics. The history of the 20th century is one of tightening restrictions both on the legal justifications and procedural requirements for waging war that was once an acknowledged attribute of state sovereignty, and on the types of weaponry that may be used in armed conflicts. The supply of DU rounds to Ukraine marks a further weakening of those restrictions.

The final escalation risk is the gravest of them all. As is widely known, Russia has issued repeated reminders of the size and deadliness of its nuclear arsenal with the implied threat of willingness to use them in the Ukraine theatre if pushed too far. Some of Russia’s nuclear weapons were relocated to the territory of Belarus just a few months ago. The use of NATO-supplied DU shells by Ukraine can only reduce the distance—conceptually, psychologically, normatively and operationally—from conventional to nuclear weapons.

Related articles:

Skyfall: Cluster munitions for Ukraine (3-minute read)

America: The biggest danger to the security of the world? (3-minute read)

In search of an exit strategy (3-minute read)



Ramesh Thakur, a former UN assistant secretary-general, is emeritus professor at the Australian National University, Senior Research Fellow at the Toda Peace Institute, and Fellow of the Australian Institute of International Affairs. He is the editor of The nuclear ban treaty: a transformational reframing of the global nuclear order.