James Smith, PhD
Associate Director for Radiation
Division of Environmental Hazards and Health Effects (EHHE)
National Center for Environmental Health (NCEH)
Centers for Disease Control and Prevention (CDC)
There are several unique challenges in responding to radiological or nuclear terrorism. First the medical response infrastructure in the U.S. is untested for a major radiation event involving mass casualties. Furthermore, clinicians are for the most part, inexperienced with treating radiation injuries and there is a general fear of radiation exposure often expressed not only by members of the public, but also by health care givers!
Finally, there could be an exceptionally large number of casualties, plus many more who are worried or concerned but otherwise not hurt. Combined these could readily overwhelm the local hospitals.
There are several differences between radiation and biological or chemical exposures. The effects of radiation exposure have been extensively studied since World War II. We know a lot more about the health effects of radiation than we do about most other agents. Also, unlike many biological or chemical agents, radiation is readily detectable with proper instrumentation. Fortunately, radiation detectors are widely available, they are in use, and are reliable when properly maintained. Let’s discuss some potential terrorist scenarios. Of course, there could be a targeted attack on a nuclear installation. Or, terrorists could choose to use a radiological exposure device, for example, a hidden, or covert radioactive source. Or terrorists could choose a radiological dispersal device or RDD, commonly referred to as a dirty bomb.
And finally, there could be a detonation of an improvised nuclear devise or a stolen nuclear weapon. It’s instructive to discuss the last three of these. The radiological exposure device could employ radioactive sources that are stolen from industrial facilities or from hospitals. These devices have the potential to expose people to lethal doses of radiation by hiding the source in a large public place, such as transit system. Tens to hundreds of people could present with symptoms of acute radiation syndrome. Thousands more could require medical or exposure monitoring. Let’s examine a case study to illustrate how this type of scenario might play out. This incident occurred in Goiânia, Brazil, in 1987. A radioactive source, it was actually a powered Cesium 137 source, was obtained from an abandoned medical facility. Contamination was spread throughout the community by person-to-person contact. About 250 people received significant exposures. Over 50 were hospitalized and there were 4 deaths, among them a small child who had ingested some of the highly radioactive powder. Over 100,000 people were monitored for contamination. That was greater than 10 percent of the total population. Now, can terrorists obtain radioactive sources? Consider that there are about 157,000 licensed users in the U.S. and approximately two million devices containing radioactive sources. The nuclear regulatory commission tells us that about 400 sources are lost or stolen in the U.S. every year.
The radiological dispersal device usually refers to a conventional explosive laced with radioactive material, that is, a dirty bomb. In this case, tens to hundreds could present with conventional traumatic injury, possibly significant radiation exposure, if they are near the detonation, and external or internal contamination. On the other hand, hundreds to thousands could present for radiological screening or counseling. Now, the worst case scenario would be illustrated by an improvised nuclear device or stolen nuclear weapon. This could potentially kill or injure tens of thousands of people. Thousands could present with combined blast, burn, and radiation injury. Hundreds of thousands could be displaced and require exposure and medical monitoring, decontamination, and counseling. Keep in mind, major metropolitan hospitals could be destroyed or rendered inoperable. Some examples of the immediate effects of a one kiloton improvised nuclear device include blast, thermal and radiation injuries. A one kiloton yield represents about ten percent of the yield that occurred with the Hiroshima bombing. The direct blast could result in deaths up to 200 yards away from the source of the blast. Third degree burns and radiation doses lethal to 50% of those exposed could occur out to a distance of one-half mile from the explosion.
In summary, radiation terrorist events are unique, but radiation is readily detected with proper instrumentation. A variety of scenarios exist for radiological and nuclear terrorism. These scenarios are possible and radioactive sources that might be employed are plentiful. Radiation exposures and the numbers of people requiring treatment vary widely with the different scenarios. In all cases, there is the potential for the hospitals to be overwhelmed with a combination of casualties and those who self-refer but are otherwise unhurt.