Blog Post - Nuclear Security Matters

Reducing the Risk of “Dirty Bombs”

Mar. 10, 2014

By Tom Bielefeld
In the spectrum of threats to nuclear security, highly radioactive materials such as cesium-137 and cobalt-60 represent a set of concerns and challenges which is much different from that of fissile materials like highly enriched uranium. Unlike the latter, they cannot be used to build a nuclear weapon. However, terrorists could use such sources to construct a so-called “dirty bomb”, an improvised explosive device which spreads the radioactive substances in a populated area. Although, according to most planning scenarios, such a “dirty bomb” would likely cause few radiation-related casualties, its economic effects could still be in the billions of dollars – especially if parts of a city needed to be shut down for weeks or months while they are being decontaminated.

IAEA Code of Conduct on the Safety and Security of Radioactive Sources.

High-activity sources are used and stored in thousands of medical and industrial buildings as well as temporary work sites around the world. Preventing them from falling into the hands of terrorists requires tougher security regulations and greater risk awareness on part of the industry. Law-makers, regulators, and facility managers need to put as much emphasis on theft protection as they have traditionally put on safety measures for accident prevention.   

In 2004, the International Atomic Energy Agency (IAEA) published a revised “Code of Conduct on the Safety and Security of Radioactive Sources” which established a basic guidance for governments about the legal provisions necessary for the protection of high-activity sources in their jurisdiction. The Code has since been endorsed by 120 countries, but many of them have not yet implemented its recommendations in their national laws.

Even among countries with comprehensive security regulations, such as the United States, sources security remains a problem. A 2012 study by the Government Accountability Office, the non-partisan investigative agency working for the US Congress, found that in some of the country’s hospitals, blood irradiators containing powerful cesium-sources are very poorly protected. Experts from the National Nuclear Security Administration have identified more than 2,500 buildings with radioactive materials in the US that may need security upgrades beyond the level required by law.

A number of high-activity sources are also transported on a regular basis, and out on the road is where they are most vulnerable to theft. Last December, when a truck carrying a decommissioned radiotherapy device was hijacked in Mexico, much of the related news coverage focused on that country’s gaps in transport regulations and oversight as well as on its notoriously high crime rate. What many reports missed, however, was that dangerous radiation sources have been stolen in recent years from trucks in the US, too – as well as in Canada and Western Europe. There is little reason to believe that an incident similar to that in Mexico could not have happened in any other country where such devices are used and transported.

A firefighter stands next to the radiation head of a radiation therapy machine in the village of Hueypoxtla, Mexico. (AP/Marco Ugarte)

In a recent article for “The Bulletin of the Atomic Scientists,” I discussed some of the lessons that the US (and other countries) can draw from the Mexican incident. If the US is serious about reducing the risk of “dirty bombs,” improving transport security for high-activity sources needs to be a top priority. However, this can only work with the active participation of all stakeholders, i.e. the federal and state governments, the nuclear regulator, and the private industry. In my article, there are some concrete recommendations for each of the parties involved.

Speeding up the government-funded program to outfit hospitals and industrial buildings with better security systems (currently scheduled to be completed sometime in the late 2020s!) is of similar importance.

Sources security is one of the issues to be discussed in the upcoming Nuclear Security Summit in The Hague. If the US and its like-minded partners could convince all the participating countries to implement national regulations in line with the IAEA’s Code of Conduct, at least for their highest-activity sources and in a timely fashion, this would be an important step forward.

But at the same time, the US and other advanced industrial nations must not forget that they, too, still have important homework to do. Future radiological terrorists may or may not have the international connections necessary to steal radioactive materials in one country and smuggle it into another. But they certainly read the papers and might well be able to spot the existing vulnerabilities in their own neighborhood. 

For more information on this publication: Belfer Communications Office
For Academic Citation: Reducing the Risk of “Dirty Bombs”.” Nuclear Security Matters, March 10, 2014,