The US-Israel-Iran war is already in its fourth week, and there are no signs of abating. Iran has absorbed major USIsraeli strikes and launched widespread retaliation across the Middle East, but so far it appears to be on the backfoot tactically in terms of military hardware losses and pressure from coordinated USIsrael attacks. However, there is one more ace up Tehran’s sleeve that it can use to cause significant disruption and damage: the dirty bomb.
Despite sustained drone and missile strikes across the Middle East, Tehran has so far failed to dampen the appetite for war in Washington and Jerusalem. But by using a dirty bomb, feared but rarely used, such a weapon could offer Tehran’s increasingly hardline leadership a way to cause the heavy costs it seeks to inflict, without resorting to full-scale nuclear warfare.
A dirty bomb, or radiological dispersal device, is designed to spread radioactive material using a conventional explosion, contaminating the surrounding area. While far less destructive than a nuclear weapon in terms of immediate blast impact, it can cause severe long-term harm by polluting agricultural land and water sources, and increasing the risk of diseases such as cancer and acute radiation syndrome among those exposed.
So what exactly is a dirty bomb? How does it differ from a nuclear weapon? And does Iran have the capability or intent to deploy one in its war with the US and Israel?
WHAT IS A DIRTY BOMB, AND WHAT ARE ITS EFFECTS?
According to the US Nuclear Regulatory Commission, a dirty bomb is a type of radiological dispersal device that combines a conventional explosive, such as dynamite, with radioactive material in the form of powder, pellets, or other sources. When detonated, the explosion scatters radioactive material over an area, causing contamination.
A dirty bomb differs significantly from a nuclear weapon in that its primary impact is contamination, rather than the catastrophic blast and heat of a nuclear explosion. Speaking to Foreign Policy, Marion Messmer of Chatham House noted, “A dirty bomb isn’t a Weapons of Mass Destruction (WMD). WMD’s are called such because of the severe impact they would have. A nuclear weapon destabilises and unleashes destruction. The radioactivity is much higher than just scattering some radioactive material.”
According to the Centres for Disease Control and Prevention (CDC), the main danger comes from the explosion itself, which can cause serious injuries and property damage. The radioactive materials used are unlikely to cause immediate serious illness except for those very close to the blast.
However, the CDC warns that radioactive dust and smoke can spread beyond the blast site and pose health risks if inhaled. High exposure may lead to acute radiation syndrome (ARS), which damages bone marrow, the gastrointestinal tract, and the cardiovascular system, potentially resulting in infections, internal bleeding, and organ failure.
According to the World Health Organisation, long-term exposure can increase the risk of leukaemia, cancers, cardiovascular disease, and cataracts.
The most significant impact, however, may be economic. A 2012 University of Southern California study estimated that a dirty bomb attack in Los Angeles could cause nearly $16 billion in losses over a decade, driven largely by cleanup costs and prolonged psychological and behavioural disruption that such an explosion would cause among the city’s residents.
CAN IRAN MAKE A DIRTY BOMB?
Can Iran make a dirty bomb? The short answer is yes. According to the US Nuclear Regulatory Commission, dirty bombs can be assembled from commercially available radioactive materials such as Caesium-137 (used in radiotherapy), Americium-241 (used in smoke detectors), and Cobalt-60 (used for sterilising surgical tools), among others.
Tehran, meanwhile, according to the International Atomic Energy Agency, possesses 440 kilograms of highly-enriched uranium (HEU) enriched to 60% uranium-235. While a nuclear warhead typically requires enrichment to 90%, nuclear expert Edwin Lyman, writing for the Bulletin of the Atomic Scientists, states that 60% enriched uranium can be used to create both dirty bombs and traditional nuclear weapons if Iran chooses to.
In fact, Iran’s potential capability to build and deploy a dirty bomb has also been cited as one of the reasons for US strikes. Speaking to CNBC on March 10, US Special Envoy Steve Witkoff argued that the Islamic Republic had 460 kilograms of uranium enriched up to 60%, which could have been used to make a dirty bomb. “They could easily have taken the 60% enriched material and made a dirty bomb out of it. That would have been a really easy step,” he said.
WILL IRAN USE A DIRTY BOMB IN THE WAR WITH THE US AND ISRAEL?
Foreign Policy Magazine reported in 2025, in the aftermath of the 12-day war, that the likelihood of Iran using a dirty bomb was low, as it would invite massive retaliation, trigger a crisis of confidence across the Gulf and the wider Middle East, and risk alienating China and Russia.
Andreas Krieg of King’s College London had the argued that “Iran is highly unlikely to deploy a dirty bomb on Israel or any foreign country. The costs, political, military, and reputational, would be catastrophic.” He added, “Iran has historically prioritised strategic ambiguity and deniability. A dirty bomb attack would eliminate those buffers, triggering massive international retaliation and risking regime collapse.”
However, as recent events suggest, these guardrails have been steadily eroding since February 28, as US and Israeli strikes wiped out large sections of Tehran’s leadership, including Supreme Leader Ali Khamenei (who had issued a fatwa forbidding such weapons and Ali Larijani, (one of the few leaders in Iran with the political capital to extract a negotiated settlement with the US).
Writing on X, journalist Gerald Posner, citing a US national security analyst, noted, “If the Iranian regime believed it faced total defeat, a radiological strike could be framed internally as retaliation against Israel and its American ally.” He added, “The physical destruction would be far smaller than a nuclear weapon, but the psychological and political impact could be enormous.”
If Iran’s leadership, now increasingly dominated by , were to consider such a move, there are a few possible pathways.
According to a report by security and defence policy expert Chris Kremidas-Courtney of the Euro Atlantic Resilience Center, a dirty bomb would likely be used as a tool of last resort to offset conventional military disadvantages. One option would be deployment through proxy groups such as Hezbollah or the Houthis, allowing Tehran to retain plausible deniability, though such an operation would likely require direct technical support.
Operationally, the aim would not be mass casualties but disruption. Iran could target dense urban centres, symbolic locations, ports, or financial hubs to trigger panic, mass evacuations, and long-term pollution, imposing economic and psychological costs far beyond the immediate damage.
Strategically, such a device could also be used in critical global chokepoints like the Strait of Hormuz or other major maritime routes. A radiological attack in these areas could disrupt shipping, spike global oil prices, and signal that escalation cannot be geographically contained.
It is still unclear if Iran actually has a dirty bomb and if it will use it. But in a war already marked by decapitation strikes, regional escalation, and economic shock, a dirty bomb would represent a dangerous escalation. For the regime in Tehran, their backs on the wall, and their moderate leaders being replaced by hardliners, it would be wise to consider a dirty bomb attack as a plausible event.
