Dirty Bomb

Summary: The term "dirty bomb" refers to a device that uses conventional explosives to distribute radioactive material. The Al Qaeda attacks of September 11, 2001, raised fears that terrorists could obtain radioactive materials, possibly from a sympathetic country developing nuclear weapons, and attack an urban area with a dirty bomb, also known as a radioactive dispersal device (RDD). The impact of such an attack would have been devastating on residents, even without causing substantial damage to the infrastructure. Used in a major urban area, casualties from radioactivity could number in the tens of thousands. As the twenty-first century progressed, officials continued to be concerned radical terrorist groups could obtain radioactive material to make a dirty bomb.

The term "dirty bomb" refers to a device that distributes radioactive material by means of a conventional explosion; such weapons are known generically as "radioactive dispersal devices," or RDDs, and include other methods besides explosions to distribute radioactive materials (for example, simply releasing radioactive dust into the air and letting a modest wind spread the dust in a high-profile city). Following the September 11, 2001, terrorist attacks against the United States, significant publicity about "dirty bombs" raised fears, both in the public and among government anti-terrorist agencies, that a terrorist group could acquire radioactive material, smuggle it into the United States, and disperse it in an urban area with potentially dire consequences. Responding to US concerns, many other countries around the world also began paying attention to the remote but real possibility of a dirty bomb attack.

Fears of terrorist groups developing and using a dirty bomb persisted during the first decades of the twenty-first century. In 2014, as it took over large portions of Iraq and Syria, the Islamic State of Iraq and Syria (ISIS), an Islamic fundamentalist terror organization responsible for a number of terror attacks and human rights abuses around the world, captured a quantity of uranium in the city of Mosul, Iraq. While the development of a dirty bomb with these materials was little more than a remote possibility, ISIS's actions renewed fears of a terrorist organization using such a device.

While much of the fear over use of a dirty bomb centered on the possibility of their use by a terrorist group, some individuals also expressed fears that dirty bombs could be developed and used by governments. For example, in late 2022, as the Russian invasion of Ukraine faltered and encountered heavy resistance, Russian President Vladimir Putin accused Ukraine of developing a dirty bomb. While most Western intelligence experts doubted the accuracy of this claim, Putin's claim raised fears that Russia would use the false pretense of a Ukrainian dirty bomb to justify the use of nuclear weapons against Ukraine.

Although frightening scenarios are easily conjured up by the idea of a dirty bomb, there is widespread disagreement about the likelihood of such weapons being used and the potential damage they could cause.

Elements of a Dirty Bomb

A "dirty bomb" is understood to be a weapon that uses a conventional chemical explosion to distribute radioactive materials. Unlike a nuclear weapon, which uses an atomic reaction to create an explosion of enormous force (and in which the force of the explosion is the main destructive element), a dirty bomb need only distribute radioactive elements into the atmosphere and disperse dangerous radioactivity in a given area, similar to the nuclear fallout dispersed after the detonation of a nuclear weapon. It is the relative simplicity of a dirty bomb that has long concerned anti-terrorism authorities. Such an explosive device is well within the technical capability of many terrorist groups; the trickier part is obtaining appropriate radioactive elements.

The nature of radioactivity is such that not all elements are suitable for use in an RDD. The half-life of radioactive elements (the time it takes for half the atoms in a given mass of radioactive isotopes to decay into a stable element) ranges up to 700 million years in the case of uranium-235, which is not regarded as highly radioactive. Other isotopes have half-lives of a few hours, making them exceedingly dangerous for a short period - too short for terrorists to construct a bomb and explode it. The danger of radioactivity from such an isotope could be over within a short period. The half-life of cobalt-60, on the other hand, is 5.3 years, making it an ideal element for use in an RDD.

While acquiring the sufficient quantity of a suitable element is not simple, there are many sources available to terrorists. Radioactive isotopes are widely used, albeit in small quantities (home smoke detectors, for example, use minute quantities of radioactive materials.

Two isotopes are of particular concern to anti-terrorism officials: cesium-137, used in radiation devices to treat cancer and to monitor oil wells, and cobalt-60, also used in cancer therapy and in industrial radiography. These isotopes are used in devices that are usually operated under little security and are sometimes abandoned (or "orphaned"). These isotopes can be handled relatively easily since they would do the greatest damage only when inhaled. There are several sources of such elements in legitimate commerce, or they could be stolen during shipment. Gathered in sufficient quantity, such isotopes are regarded as "ideal" elements for use in an RDD.

Health Risks

Exposure to radioactive materials causes a variety of health problems, namely cancer and even death, depending on several factors: the amount of radioactive material, the method by which an individual is exposed, and the length of time an individual is exposed.

In some cases, a layer of dead skin is enough to protect against harmful effects from some alpha emitters, but exposure to the same level of emitters inside the body (as a result of inhaling radioactive dust, for example) could almost certainly lead to lung cancer. The greater risk posed by exposure of internal organs to radioactivity is presented as a reason that makers of an RDD would try to distribute the radioactive material in the form of finely ground dust.

Some organs are particularly sensitive to different types of radioactive material. Bones, for example, tend to collect strontium and be especially affected by strontium-90, as are breasts and blood. The thyroid tends to concentrate iodine, and iodine-131 can cause thyroid cancer.

Most treatments for exposure to radioactivity focus on cleansing the body of the radioactive substance as soon as possible. While some drugs are effective in combating the effects of radioactivity, these usually require that they be taken in advance of the exposure.

US authorities are divided over the issue of how much of a risk a dirty bomb might pose to individuals in the vicinity. Unresolved questions include how much danger is posed by the dispersed radioactive elements and for how long. In addressing this issue, there are two basic schools of thought, described as the "linear" school and the "threshold" school.

Advocates of a linear model, notably the Environmental Protection Agency (EPA), believe that if there are dangers of illness (e.g., contracting cancer) from a small amount of low-level radiation, those dangers increase proportionately to the amount of radioactive material spread over a given area.

Other experts believe there is a "threshold" effect so that even if the amount of low-level radiation is substantially increased due to an RDD, health risks are only increased once low-level radiation reaches a "threshold."

According to one estimate, three curies [a measure of the intensity of radioactivity] of an appropriate isotope, a fraction of a gram, dispersed over a square mile, "would make the area uninhabitable, according to the maximum dose currently recommended for the general population." This low level of radiation, according to current standards, might be expected to result in an increase in cancers of four per 100,000 people on top of 20,000 cancers expected from other causes.

Some health experts believe that EPA standards for radiation tend to exaggerate the potential health impact of a dirty bomb. In 2015, it was revealed that Israel had conducted a series of dirty bomb tests; these tests found a fairly low level of radiation outside the immediate blast area, backing up the hypothesis that dirty bombs were most effective on the psychological level.

Other Risks

Many observers agree that the social and economic impact of an RDD might be much greater than the expected health consequences of exposure to increased levels of radiation.

It is thought that the very words "radioactive" and "radiation" are not well understood by most Americans and that an RDD could cause widespread panic throughout an urban area (or beyond) where such a weapon was used. Such public concerns, hyped by statements to the effect that even low levels of radiation would render an area "uninhabitable," would likely lead to demands for the demolition of affected buildings or the abandonment of wide areas.

In that scenario, the real cost of a dirty bomb might prove to be measured in lost economic activity if a key urban center were hit, as well as possible public panic and chaos in the immediate aftermath of the attack itself.

Detection & Prevention

After the al Qaeda attacks of 9/11, authorities concentrated on several techniques to prevent the use of an RDD.

Detection. Easily portable radiation detection devices (e.g., Geiger counters and radiation detectors the size of pagers) are used by Customs and Border Protection agents at airports and other transportation centers to detect radioactivity. Authorities believe that shielding sufficient to prevent the detection of radiation would attract the attention of X-ray inspections.

Sources. More attention is being paid to drying up sources of dangerous isotopes, especially in the area of "orphaned" devices containing small quantities of materials that by themselves are not regarded as dangerous. The US Nuclear Regulatory Commission and the Department of Energy established a task force to consider stricter licensing and monitoring of legitimate sales and shipments of radioactive isotopes. The Department of Energy launched the Orphan Sources Initiative to track and retrieve orphaned sources, such as devices found in scrap yards; a similar project was started to collect sources used by the government. Overseas, the International Atomic Energy Agency has worked to coordinate efforts to control potential sources of radioactive materials, especially in the former Soviet Union, which has thirty-five sites for storing radiological waste and 1,000 sources of "orphaned" isotopes.

Encouraging alternatives. US officials have also turned to encouraging the use of alternative sources of radiation, such as X-ray machines and particle accelerators, which can create the same effects as radioactive isotopes through electric power. When these machines are turned off, they no longer emit radiation.

Officials warn, however, that these measures are far from foolproof and that radioactive isotopes could be smuggled into the United States or shipped in unexamined containers. Ironically, public discussion of such dangers may serve to exacerbate the related concerns over public panic or possible demands for unwarranted destruction and demolition of affected structures if an RDD were used.

Despite these effective measures, as long as radical terrorist groups continued to express interest in dirty bombs, as they did according to global investigations throughout the late 2010s, the threat was still a viable one.

Bibliography

Bufford, Jessica. "Preventing a Dirty Bomb." NTI, 2021, www.nti.org/about/programs-projects/project/preventing-dirty-bomb/. Accessed 2 Nov. 2022.

"Frequently Asked Questions (FAQs) About Dirty Bombs." Centers for Disease Control and Prevention, 4 Apr. 2018, www.cdc.gov/nceh/radiation/emergencies/dirtybombs.htm. Accessed 2 Nov. 2022.

Ioanes, Ellen. "What to Expect after Russia’s Latest Escalatory Nuclear Rhetoric." Vox, 30 Oct. 2022, www.vox.com/2022/10/30/23426491/russia-ukraine-dirty-bomb-nuclear. Accessed 2 Nov. 2022.

Levinson, Chaim. "Haaretz Exclusive: Israel Tested 'Dirty Bomb Cleanup' in the Desert." Haaretz, 8 June 2015, www.haaretz.com/2015-06-08/ty-article/.premium/israel-tested-dirty-bomb-cleanup-in-the-desert/0000017f-e236-d7b2-a77f-e3371bd60000. Accessed 2 Nov. 2022.

Medalia, Jonathan. "Terrorist 'Dirty Bombs: A Brief Primer," Congressional Research Service: Report; 4/1/2004. http://search.ebscohost.com/login.aspx?direct=true&db=tsh&AN=18287348&site=isc-live

Nuclear Regulatory Commission (NRC): Fact sheet on dirty bombs. (2023). Mass.gov. Retrieved Oct. 7, 2023, from https://www.mass.gov/info-details/nuclear-regulatory-commission-nrc-fact-sheet-on-dirty-bombs

Robinson, Robert A. "Nuclear Security: Federal and State Action Needed to Improve Security of Sealed Radioactive Sources," GAO Reports August 6, 2003. http://search.ebscohost.com/login.aspx?direct=true&db=tsh&AN=18209930&site=isc-live

Shea, Dana A. "Radiological Dispersal Devices: Select Issues in Consequence Management," Congressional Research Service: Report; 12/7/2004. http://search.ebscohost.com/login.aspx?direct=true&db=tsh&AN=18317623&site=isc-live

"The 'Dirty Bomb' Scenario," Atlantic. 293:3 (April 2004) p. 42. http://search.ebscohost.com/login.aspx?direct=true&db=tsh&AN=12445603&site=isc-live

Zink, John. "Revealing the Secrets of the Dirty Bomb," Power Engineering 107:3 (March 2003) p. 24. http://search.ebscohost.com/login.aspx?direct=true&db=tsh&AN=9318523&site=isc-live