US is sending Ukraine ammunition that can not only pierce Russian tank armor but also ignite inside

• The US officially announced on Wednesday it would send Ukraine depleted-uranium tank ammunition.
• These shells give Kyiv the capability to blast holes in Russian armor, and the fragments may ignite inside.

The Biden administration announced plans to send Ukraine tank rounds with depleted-uranium penetrators. This powerful ammunition gives Kyiv the capability to not only punch holes in Russian armor but also do additional damage inside enemy vehicles as the fragments potentially ignite.

The Pentagon listed the 120 mm depleted-uranium tank ammunition as part of a $175 million security-assistance package that was officially revealed on Wednesday. The announcement coincided with a surprise visit to Kyiv by US Secretary of State Antony Blinken. Other capabilities noted in the military aid, which are set to be pulled directly from Pentagon inventories, include artillery, missiles, anti-armor systems, and ammunition for High Mobility Artillery Rocket Systems, or HIMARS.

These depleted-uranium rounds will be fired from American M1 Abrams tanks, which are set to arrive in Ukraine at some point this fall. The US announced earlier this year it would send older — but refurbished — M1A1 variants to Kyiv on an expedited timeline, and Ukrainian soldiers spent the summer training on the Abrams tanks in Germany.

Depleted uranium is a dense — and somewhat radioactive — material that the US military first began using decades ago to produce tank armor, mortar shells, and ammunition.

The material is especially useful when used to make penetrator rods for tank rounds because it sharpens when it strikes enemy armor, allowing it to pierce the vehicle's hard outer shell. Rounds made from other materials tend to mushroom upon impact. The material is also pyrophoric, which means the penetrator heats up as it enters the target vehicle, and the small dust and fragments can ignite and even start fires.

So when the round hits, it does more than just explode on the exterior or break through and release shrapnel. It's an event characterized by high heat and pressure, and the amount of damage it can do inside a tank or armored vehicle is substantial, especially if it ignites the ammunition stockpile.

"With a tank round, it's all about getting inside the tank, penetrating the armor and getting into the crew compartment and destroying the tank," Thomas Spoehr, a retired lieutenant general in the US Army who served in the military for decades with the 1st Armored Division, previously told Insider.

Since the introduction of these rounds, there have been concerns over the environmental and health impacts of depleted uranium, which reportedly led to earlier debates in Washington over whether the US should send the ammunition to Ukraine.

During the nuclear-enrichment process, highly radioactive uranium that's used to make nuclear weapons — called U-235 — is extracted from natural uranium ore. A byproduct of this process is depleted uranium, which contains relatively low levels of radiation and isn't necessarily a major threat to an individual's health unless a large amount of it is ingested or enters the body as shrapnel. But if this does happen, whether through metal fragments or dust particles, there is a potential for significant health complications such as kidney failure.

The US is not the first NATO member to send Ukraine depleted-uranium ammunition.

In March, the UK announced it would send these rounds — which a British official said at the time were "highly effective in defeating modern tanks and armored vehicles" — to Kyiv alongside the advanced Challenger 2 tanks that it pledged earlier in the year. Russian President Vladimir Putin threatened an escalation in response, claiming the West was stoking nuclear tensions, but the UK pushed back and said it had been using depleted uranium in tank rounds for decades.

The US pushed back as well. "This kind of ammunition is a fairly commonplace, been in use for decades," a White House National Security Council spokesperson, John Kirby, told reporters around the time of the UK announcement in March. "I think what's really going on here is Russia just doesn't want Ukraine to continue to take out its tanks and render them inoperative."

Indeed, Russia has lost nearly 2,300 tanks since the beginning of its full-scale invasion in February 2022, open-source intelligence collected by Oryx indicates. Moscow has also lost over 2,700 infantry fighting vehicles and over 960 armored fighting vehicles, adding to its tally of neutralized armor.

Ukraine has also lost many tanks, but it has also gotten new ones, such as the British Challenger and German-made Leopard. The latest US security-assistance announcement, which includes the depleted-uranium tank rounds, comes ahead of what is expected to be an imminent delivery of 31 Abrams tanks.

These capable tanks will arrive at a crucial moment for Ukrainian forces, which are making slow but steady gains in the occupied eastern and southern regions in a counteroffensive that has been building momentum despite some early setbacks when it was launched three months ago.

"We are determined in the United States to continue to walk side by side with you," Blinken said alongside Ukrainian President Volodymyr Zelenskyy in Kyiv on Wednesday.

"And President Biden asked me to come, to reaffirm strongly our support, to ensure that we are maximizing the efforts that we're making and other countries are making for the immediate challenge of the counteroffensive as well as the longer-term efforts to help Ukraine build a force for the future that can deter and defend against any future aggression," Blinken said, "but also to work with you and support you as you engage in the critical work of strengthening your democracy, rebuilding your economy."