Dirty Bombs and Nuclear Terrorism: The Next Threat

Should the United States be concerned about a nuclear or radiological terrorist attack?

In short, yes.

I recently attended the Global Security Colloquium in Amman, Jordan, which focused heavily on the threat posed by weapons of mass destruction in the hands of terrorists. The content and tone of the discussion were frightening – experts in the field widely believe that nuclear terrorism is the greatest threat to global security. Despite efforts to secure nuclear and radiological material in ex-Soviet countries and across the world, the threat is greater than ever. ISIS is the most technologically and economically sophisticated terrorist group ever and is dangerously close to obtaining radiological terrorism capabilities, if not nuclear. Simply put, the United States and other Western countries are not doing enough to address the catastrophic possibility of a terrorist group detonating an improvised weapon or dirty bomb in a population center, an event which would cause mass casualties, global chaos, and widespread economic collapse.

There are several scenarios in which a terrorist group could obtain the materials necessary for a nuclear or radiological attack, each with differing levels of impact and probability. For example, a terrorist group such as ISIS could obtain a fully operational nuclear weapon. Though this eventuality is highly unlikely due to heavy security at nuclear weapons storage sites, cooperation from an insider combined with an outside assault could make this a possibility. Nuclear storage locations in Pakistan and the Incirlik air base in Turkey, which stores 50 US warheads only 200 miles from the Syrian border, could be susceptible to such an attack, largely due to the prevalence of extremist groups in the two countries. Increased surveillance, vigilance, and employee screening at nuclear storage facilities are required to mitigate this threat, but high existing security measures make this possibility unlikely for a terrorist group to pursue. Instead, groups like ISIS appear to be heavily focused on dirty bombs and improvised nuclear devices (IND).

A possibility that causes experts much more concern is one in which a terrorist group could steal highly enriched uranium (HEU) or plutonium and manufacture a crude IND similar in yield to the atomic bombs detonated in Hiroshima and Nagasaki. Though most weapons-grade uranium and plutonium are stored in heavily guarded military sites, roughly 17% of the 1,800-metric-ton global stockpile is still contained in poorly guarded civilian locations. A terrorist group would only need around 5-6 kilograms of plutonium (only about the size of a grapefruit) or 25 kg of uranium (about the size of a bag of sugar), and experts agree that an untrained but capable team could utilize unclassified public diagrams to assemble a crude “gun-type” fission weapon with a yield of around 10 kilotons, the equivalent of 10,000 tons of TNT. If this type of 10-kiloton atomic weapon were detonated in a crowded area like Times Square or Grand Central Station during rush hour, more than 250,000 people would likely die, hundreds of thousands would be injured, the economic loss would be in the trillions, and the world would immediately be plunged into a global economic crisis. This weapon could likely be smuggled in a lead container into the United States or Europe by truck or ship. The United States is currently spearheading programs to secure the hundreds of tons of weapons-grade uranium and plutonium in civilian locations, but this effort needs to be accelerated and prioritized in order to effectively mitigate this threat.

Use of a fully functional nuclear weapon by a terrorist group would be disastrous, but is still highly unlikely, despite the advanced economic and technological capabilities of modern terrorist groups. More likely, and perhaps more concerning, are less lethal attacks that would utilize methods involving radiological dispersion.

A dirty bomb is a radiological dispersal device that combines conventional explosives, such as dynamite, with radioactive material. The explosion of the conventional explosive would spread radioactive material throughout an area, creating a radiation threat and causing mass panic. The necessary radioactive material for such a weapon is present and poorly guarded throughout the world at nuclear research facilities, medical research facilities, oil excavation sites, universities, and other locations. In 2015 alone, there were 188 publicly reported incidents of radiological material being lost or stolen, and a lack of international reporting requirements means that the true figure is likely higher. A global organization like ISIS could purchase or steal radiological material relatively easily, and then detonate a dirty bomb in a city with very little technical expertise. The barrier to a dirty bomb attack is low, and many experts have expressed surprise that such an attack has not already occurred.

For example, the type of pressure cooker bomb that injured 31 in Chelsea, New York in September could have been made with Cesium-137 stolen from a medical facility or purchased illegally. The radiological version of this weapon would pose a serious radiation risk to people in the blast radius of the conventional explosive, and possibly nearby populations, but the direct health impacts would likely be minimal compared to the psychological and economic impact of such an attack. As with Chernobyl and other instances of radiation release, the relatively few immediate deaths and the slightly increased risk of cancer would likely be overshadowed by widespread psychosomatic illnesses, precautionary (and unnecessary) abortions, mass psychological trauma and paranoia, and trillions of dollars in economic damage and cleanup efforts. Though more difficult to achieve, a similar effect could also be accomplished by an attack on a nuclear power plant, either through a physical attack or a sophisticated cyber-attack.

This March, it became clear that ISIS militants linked to the suicide attacks in Belgium were conducting surveillance of nuclear scientists and nuclear power plants in Brussels, likely with the goal of obtaining either radiological materials for a dirty bomb or highly enriched uranium for a nuclear weapon. Though ultimately no damage was done, it is clear that this type of attack may be within ISIS’s reach in the near future. The United States needs to work not only to secure highly enriched uranium, but also to work with Russia, China, and other major states to secure civilian-use radiological materials and ultimately diminish the use of these dangerous materials in civilian industries. Otherwise, the threat of a terrorist dirty bomb attack will continue to grow as these groups grow increasingly capable and international. The US should also invest in increased numbers of radiation detectors at both guarded and unguarded borders, as well as near major cities, in order to give authorities an opportunity to stop a planned attack. Military and civilian locations that hold weapons-grade uranium and plutonium must be forced to adopt international standards of physical security, employee screening, and cyber-security.

These policies would take unprecedented international cooperation and financial support to enact, but the international community needs to find common ground on an issue that could destroy global security as we know it.