What’s a dirty bomb, and why is Russia talking about one now?

Police stand guard as smoke billows from the site of an explosive drone attack in Kyiv on Oct 17, 2022. PHOTO: NYTIMES

LONDON - In Russia’s latest advocacy campaign over its invasion of Ukraine, Moscow has focused on accusations that Kyiv might be planning to use a so-called “dirty bomb” – a conventional explosive device laced with toxic nuclear material.

Kyiv and its Western allies say there is no truth at all to the accusation, and that the idea that Ukraine would poison its own territory is patently absurd. They say Moscow could be making the allegation to justify an escalation of its own.

What is a dirty bomb?

It is a type of weapon that was thought of and tested more than three-quarters of a century ago, in the early years of the atomic age, but never fielded by a military force.

In the wake of the Sep 11 attacks, government officials occasionally warned that terrorists could build one with radioactive materials used in many commercial industries, and dirty bombs became a boogeyman in the public consciousness, an object of fear.

The more formal name of the bombs – radiological dispersal devices, or RDD – offers a fairly straightforward description of what these weapons are and how they work. Essentially, they are improvised bombs that use conventional high explosives to spread radioactive material into the surrounding area. But the fact that no military is known to have fielded one in its arsenal is a good indicator that they are not useful on the battlefield.

The most commonly imagined version is small enough to fit in a backpack and contains perhaps 9kg or less of explosives, with a smaller mass of radioactive material placed on top.

How much damage can it do?

Dirty bombs do not create city-flattening atomic explosion, but are designed to spread toxic waste.

People who inhale or ingest radioactive dust could be injured or killed, and contaminated buildings would have to be bulldozed and sent to a landfill. Excavators would likely dig up radiated soil a yard deep and tear down nearby trees – all of which would be sent to landfills as well.

Experts say the immediate health impact would probably be limited, since most people in an affected area would be able to escape before experiencing lethal doses of radiation. But the economic damage could be massive from having to evacuate urban areas to abandoning whole cities.

In testimony to the United States Senate during the Obama administration, physicist Henry Kelly, then president of the Federation of Scientists, outlined a wide range of hypothetical scenarios, depending on the amount and type of nuclear material used and how far it was spread.

A bomb using radioactive caesium from a misplaced or stolen medical device might require the evacuation of an area of several city blocks, making it unsafe for decades.

A piece of radioactive cobalt from a food irradiation plant could, if blasted apart in a bomb in New York, contaminate a 1,000 sq km area and potentially make the island of Manhattan uninhabitable, Dr Kelly said.

An academic paper published in a US military magazine on the topic in 2004 noted that “economic and psychosocial effects are likely to be the most serious damage mechanisms from any use of an RDD”.

“The fear of ionising radiation is a deep-seated and frequently irrational carry-over from the Cold War,” the report said. And while an attack with this kind of device “is unlikely to cause mass deaths”, it has the potential to “cause great panic and enormous economic losses”.

What does Russia allege?

Moscow sent a letter detailing its allegations about Kyiv to the United Nations late on Monday, and diplomats said Russia planned to raise the issue at a closed meeting with the Security Council on Tuesday.

The head of Russia’s nuclear, biological and chemical protection troops, Lieutenant General Igor Kirillov, told a media briefing that Ukraine’s aim for such an attack would be to blame Russia.

“The aim of the provocation would be to accuse Russia of using a weapon of mass destruction in the Ukrainian military theatre and by that means to launch a powerful anti-Russian campaign in the world, aimed at undermining trust in Moscow.”

What is the response of Ukraine and the West?

Kyiv and its Western allies say Moscow’s allegation that Ukraine would intentionally make some of its own territory uninhabitable is absurd, especially at a time when Ukrainian forces are recapturing territory on the battlefield.

In a joint statement, the US, Britain and France called the Russian allegations “transparently false” and warned Moscow against using them as a “pretext” for escalation.

The Kremlin warned the West on Tuesday it was dangerous to dismiss Moscow’s position.

Ukrainian President Volodymyr Zelensky suggested Moscow might be using the allegations as cover for plans for a similar attack of its own: “If Russia calls and says that Ukraine is allegedly preparing something, it means one thing: Russia has already prepared all this.” REUTERS, NYT

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