Russian forces have used cluster munitions to attack Ukraine at least six times since the start of their invasion on Feb. 24, and Ukraine is believed to have used them at least once, according to a new report from Human Rights Watch — which is urging both countries to stop and join the international treaty to ban their use.
Hundreds of civilians have been killed by the cluster bombs, which have left hospitals, schools and homes completely destroyed. “Russian forces’ repeated use of cluster munitions in populated neighborhoods in Ukraine causes immediate and long-term civilian harm and suffering and needs to stop,” said Mary Wareham, the arms advocacy director for Human Rights Watch who authored the report. “Ukraine should also stop using these brutal weapons before more civilians are harmed.”
Although the exact number of cluster bomb attacks remains unknown, hundreds have been reported to the organization. The Russian army has been accused of using the munitions in major Ukrainian cities such as Kharkiv, Mykolaiv, Chernihiv and Vuhledar. At the end of March, U.N. human rights chief Michelle Bachelet said credible reports indicated that Russia had used cluster munitions in populated areas at least two dozen times since Feb. 24.
Neither Ukraine nor Russia has denied using cluster bombs. In April, Ukraine’s military reportedly used the munitions to retake a city that had been under Russian control. However, Ukrainian officials said in response: “The Armed Forces of Ukraine strictly adhere to the norms of international humanitarian law.”
On Feb. 28, Ukraine’s ambassador to the United States, Oksana Markarova, accused Russia of also using vacuum bombs, or controversial thermobaric weapons, in its invasion. A CNN team reported seeing a Russian thermobaric rocket launcher — which is capable of launching vacuum bombs — south of Belgorod, Russia, near the Ukrainian border, on Feb. 26, but so far there is no evidence that the actual thermobaric weapons have been used by Russia. The Kremlin denied the use of cluster munitions or vacuum bombs.
To understand what cluster munitions and vacuum bombs are, the kind of destruction they cause and why they’re controversial, Yahoo News spoke to David Johnson, a principal researcher at the RAND Corporation, an American global policy think tank. The interview, which took place in March, has been shortened and edited for clarity.
Yahoo News: What are cluster munitions, and how do they work?
David Johnson: So the way to think about a cluster munition, it is a container that has things inside of it. Those things are individual munitions. In the case of an artillery shell, the back pops out and it starts dropping these things out, essentially. And they spread in a certain pattern, and they each are independent explosions. They can be either antipersonnel or anti-vehicle. They also have cluster munitions that are scatterable mines, where a projectile delivers so many mines. But the cluster munition itself describes a category of dispensing, not the weapon itself. The submunition is what’s deadly.
Are cluster munitions banned, and why are they controversial?
The problem with cluster munitions is that they leave unexploded ordnance because they don’t always all go off. The ban on them is, as I understand the convention, they can have only a certain number of warheads in a dispenser, and there has to be less than a certain percentage of dud rate. But that’s a convention, not a law. [In 2008, more than 100 countries agreed to a global treaty banning the use of cluster munitions, but neither Russia nor Ukraine signed on.]
There’s no prohibition against using cluster munitions against enemy formations. And again, it’s not a war crime by the Geneva Conventions, the weapon. Using it against civilians is, like every weapon.
It’s an absolute in military planning that you are seriously careful about avoiding civilian casualties. And that’s when war crimes happen.
What are vacuum bombs, and how do they work?
The conventional system is explosives and steel, and the fragments kill you, and perhaps the blast.
“Vacuum bomb” is not a particularly good description. It’s a thermobaric weapon. And nobody ever hears the word “thermobaric” very much, so it’s confusing. I think the difference between thermobaric systems that are either single-warhead or cluster munitions is that the way a thermobaric warhead works is, there is a two-stage system.
One is an aerosol. When it first hits, it flows the aerosol and essentially completely blankets the range of the system in this vapor. The second stage ignites it. And so it’s like you’re standing in a room and [it] also fills the room full of natural gas or gasoline that’s been vaporized, and throwing a match into it. And it’s horrendous.
So there are multiple delivery systems on these things, but the one that I think the Russians use the most, in fact, is the TOS-1. It’s the one that’s on an armored chassis with all the tubes.
It has  220 mm rockets, and the only purpose of those is to shoot thermobaric rounds. One launcher with these  things can launch in 15 to 30 seconds, all the rockets in it. And it will essentially blanket an area that’s 200 by 400 meters. So you think about something longer than two football fields and wider than four. And it vaporizes what’s in there. So it’s devastating. It’s also very effective. The Russians used them extensively in Grozny [the capital of Chechnya] to take down buildings. The range of them is, initially they were 2.5 kilometers, now they’re about 6.
How dangerous are vacuum bombs?
I’ll read from a 1993 Defense Intelligence Agency report on this [“Fuel-Air and Enhanced-Blast Explosive Technology — Foreign”]: “The blast kill mechanism against living targets is unique and unpleasant. What kills is the pressure wave, and more importantly, the subsequent rarefaction vacuum, which ruptures the lungs. If the fuel deflagrates but does not detonate, it lights up but doesn’t explode, victims will be severely burned and will probably also inhale burning fuel. Since the most common fuels are toxic, breathing those things before they’ve dissipated will also be problematic.”
There’s a [separate] Central Intelligence Agency report that notes, “The effective fuel-air explosive explosion within confined space is a mess. Those near the ignition point are obliterated. Those at the fringe will likely suffer many internal and thus invisible injuries, including burst eardrums, crushed inner-ear organs, severe concussions, ruptured lungs and internal organs, and possibly blindness.”
So it is devastating; it’s horrendous. And I think it’s unconscionable to use these against civilians. Against enemy forces, it’s no more problematic than dropping a dozen 500-pound bombs on them. You’re dead, you’re dead. But against civilians, this is particularly pernicious because it’s useful inside of buildings in particular. And so you don’t know what’s inside the building when you use the thermobaric against it. So there’s nowhere to hide, essentially, because the aerosol just permeates everywhere.
Are vacuum bombs banned?
What is banned is using them against civilian populations. The weapons themselves are not banned against other military formations.