Human rights groups and Ukraine’s ambassador to the United States have accused Russia of using a thermobaric weapon — or vacuum bomb — in the fighting in Ukraine.
The explosion that destroyed an oil refinery in Okhtirka in Ukraine’s Sumi region on Monday is alleged to have been caused by a thermobaric weapon, although this has yet to be independently verified.
It has also been alleged that largely banned cluster bombs were used in the conflict, with Amnesty International accusing Russia of attacking a school in northeastern Ukraine.
The use of thermobaric weapons, which suck oxygen from the surrounding air to generate a high-temperature explosion, is widely condemned by human rights organizations.
But what are these weapons – described by BBC Security correspondent Frank Gardner as “the most powerful non-nuclear weapon in your arsenal? [russo]”—and why are they so feared?
How do vacuum pumps work?
Vacuum pumps, also known as thermobaric explosives, work in two stages.
The first part is the explosive charge which disperses the fuel in a cloud which can then enter surrounding buildings or objects. The second stage ignites the cloud which causes a massive fireball and sucks oxygen from the surrounding areas, causing a shock wave.
Justin Bronk, a researcher at the Royal United Services Institute, says: “Where a normal explosive is about 30% fuel and 70% oxidizer by weight, a thermobaric explosive is all fuel and uses oxygen from the air — so they’re much more powerful for a given warhead size”.
What effects does the bomb cause?
The effects of heat and pressure are aggressive—anyone hit in the initial blast would be instantly vaporized. Anyone caught in the surrounding area would receive serious internal injuries from the shock wave.
“They kill primarily by creating an extremely powerful shock wave that ruptures organs and bursts the lungs,” says Bronk.
“This shock wave propagates in confined spaces, so it is particularly deadly against people in excavated locations such as basements or caves. It also creates extremely high temperatures of several thousand degrees, which can cause horrific burns.”
What is the evidence that they were used in Ukraine?
Oksana Markarova, Ukraine’s ambassador to the United States, told reporters after meeting with members of the US Congress that Russia “used the vacuum pump”.
“The devastation that Russia is trying to inflict on Ukraine is great,” added Markarova.
Footage captured by a CNN reporter near the Ukrainian border appears to show TOS-1 multiple rocket launchers being transported near the Russian city of Belgorod.
There are several other unverified videos circulating on social media that appear to show the TOS-1 being moved in other parts of the country near the border, and several Twitter videos that claim to show the explosion itself. However, the BBC was unable to independently verify these claims.
Where else were they used?
These weapons have been used by Russian and Western forces since the 1960s. The US used them primarily to attack cave complexes in Afghanistan, where al Qaeda was thought to be hiding.
Russia was condemned by Human Rights Watch in 2000 when it was reported that they were used in Chechnya. More recently, Amnesty International reported that both Russia and the Syrian governments used thermobaric munitions against insurgents in Syria.
If these weapons are used in the urban environments of major Ukrainian cities — as they allegedly were in Chechnya, civilian casualties could be extremely serious.
