A fuel-air explosive, aka a thermobaric weapon, detonates near a small building (left), which is obliterated about a second later (right). Source: YouTube

• Also called aerosol bombs or air-fuel bombs, vacuum bombs are thermobaric weapons. The name is derived from the Greek for heat and pressure.
• While most conventional weapons use a mixture of fuel and oxidizing agent to cause an explosion, these bombs are nearly 100% fuel and rely on oxygen in the air to explode.
• After the first explosion, the fuel is finely dispersed in the atmosphere like a cloud, then it ignites, causing a massive explosion.

On February 28, the Ukrainian Ambassador to the United States accused Russia of using thermobaric weapons in Ukraine, but his claim has yet to be officially verified.

After meeting with US lawmakers in Washington, Oksana Markarova told reporters, “They used the vacuum bomb today, which is actually prohibited by the Geneva Convention.”

What are vacuum bombs?

Also called aerosol bombs or air-fuel bombs, vacuum bombs are thermobaric weapons. The name is derived from the Greek for heat and pressure.

While most conventional weapons use a mixture of fuel and oxidizing agent to cause an explosion, these bombs are nearly 100% fuel and rely on oxygen in the air to explode. After the first explosion, the fuel is finely dispersed in the atmosphere like a cloud, then it ignites, causing a massive explosion.

After the detonation and the shock wave, there is a vacuum effect, when all the oxygen is extracted from the air because the bomb does not have its own oxidizing agent.

What are the damages suffered?

Vacuum bombs have immense destructive power. In a February 2000 report, Human Rights Watch quotes a CIA study: “Those near the ignition point are annihilated. Those on the fringes are likely to suffer numerous internal, and therefore unseen, injuries, including burst eardrums and crushed inner ear organs, severe concussions, ruptured lungs and internal organs, and possibly Blindness.

Have these weapons been deployed?

On February 26, Frederik Pleitgen, a journalist with the American network CNN, posted a video on Twitter titled “Russian launcher of thermobaric ‘vacuum bombs’ seen by the CNN team in Ukraine”.

Pleitgen wrote: “The Russian military has deployed the TOS-1 heavy flamethrower which fires thermobaric rockets… South of Belgorod.” Belgorod is a Russian city not far from the Ukrainian border.

“We know that the Russians have such weapons systems in the region,” confirmed Frank Sauer of the Bundeswehr University in Munich.

The Russian army has deployed the TOS-1 heavy flamethrower, which fires thermobaric rockets, south of Belgorod. pic.twitter.com/XCxMI3bNB3

— Frederik Pleitgen (@fpleitgenCNN) February 26, 2022

Where would they have been used?

Russia is accused of using the bomb in the Ukrainian town of Okhtyrka in Sumy Oblast. Photos and videos showing the alleged impact have been posted on social media.

Asked about it on Monday, White House spokeswoman Jen Psaki said the United States had not independently verified the information. “I have no confirmation on this. […] We have seen the reports. If true, it would potentially be a war crime.

Two days later, Linda Thomas-Greenfield, the US ambassador to the UN, gave a speech to the UN General Assembly in which she made similar allegations and told Russia to stop his war.

“We have seen videos of Russian forces moving exceptionally lethal weapons into Ukraine, which has no place on the battlefield. This includes cluster munitions and vacuum bombs – which are prohibited by the Geneva Convention,” she said.

What did the experts say?

“Looking at the photos from Ukraine, I think it is entirely possible that spray cans were used there. However, it is not possible to confirm this with certainty from the video footage,” said Sauer from the University of the Bundeswehr.

Military expert Gustav Gressel, who works at the European Council on Foreign Relations, a pan-European think tank, reviewed the footage for DW. He reasoned in the same way: “In my opinion, no other weapon, apart from nuclear weapons, would have this force.”

But he added that it could not be ruled out that something explosive was hit. “However, in this case we would be more likely to hear a series of bangs,” he said. A report in German Frankfurter Allgemeine Zeitung Daily said there were doubts even in Western intelligence circles that the explosion being analyzed was caused by a vacuum bomb.

If Russia were found to have used vacuum bombs in Ukraine, it would be considered a war crime and could be brought to justice by Ukraine. “The possession of such weapons is not prohibited, but their use in populated areas is [outlawed] because they have an expansive effect,” Sauer said.

This article was first published by DW and has been republished here with permission.