Effects of Radiological Terrorism

adiological Dispersal Devices (RDDs) are often referred to as "weapons of mass disruption" (rather than "weapons of mass destruction"). This term is used to show that dirty bombs could create panic and disrupt the normal functioning of society, but would probably not result in a large number of deaths and widespread physical destruction. The same can generally be said about attacks on nuclear facilities. To date, there have been no successful incidents of radiological terrorism using either dirty bombs or other forms of RDDs. There have been several notable radiological accidents at and attempted attacks on nuclear power plants. But there has not yet been a successful malicious attack resulting in extensive destruction. Therefore, the physical (on humans and on surrounding infrastructure), financial, environmental, psychological, and political effects of a radiological terrorist attack cannot be fully grasped. Experience with past radiological incidents, computer simulations, and some mock terrorist attacks, however, have been used to estimate some of these effects, based on known effects of radiation, conventional bomb blasts, and other factors. Some of the results and predictions are discussed below.

Physical and Environmental Effects
 

Photo Credit: IAEA
Contaminated rubble after the 1987 radiological incident in Goiania, Brazil. The incident helped to demonstrate some of the potential physical and environmental damage that could be caused by a dirty bomb.
The extent and severity of injuries resulting from a dirty bomb attack or an attack on a nuclear facility depend on a number of factors. For a dirty bomb attack, factors would include the type and amount of radioactive material and conventional explosives used, the type of radiation, how much radioactive material was aerosolized, and the area
in which the attack took place. Effects of an attack on a nuclear power plant would depend on whether radiation is successfully released and the amount released. Weather conditions, such as wind speed and humidity, and the level of emergency response can also influence the effects of either a dirty bomb or a nuclear facility attack.
 

See a detailed description of the  radiological accident in Brazil  in the multimedia section.

An attack on a nuclear power plant is unlikely to result in high numbers of immediate radiation-related casualties. If the attack results in a large-scale release of a radioactive cloud or plume, people in the surrounding areas might inhale particles and experience some radiation poisoning. In high enough doses, this exposure can slightly increase the risk of long-term illnesses, such as lung cancer and leukemia.

Immediate deaths resulting from a dirty bomb attack are more likely to be caused by the conventional bomb blast and the ensuing panic than from the radioactive material itself. Even in the case of high-intensity radioactive materials, scattering the material will dilute some of its intensity. This does not mean, however, that the radioactive material will cause little or no damage. Those people injured by the conventional explosives may also be contaminated by the radioactive material. This could lead to slower recovery or permanent internal and external damage. People close to the area of the explosion who are not physically wounded can still inhale microscopic particles (micron-sized), which can stay lodged in the body and emit radioactivity, or can be directly exposed to beta or gamma radiation. As in the case of an attack on a nuclear facility, people exposed to high enough radiation levels may experience a slightly increased risk of long-term illnesses. People in surrounding areas (extending anywhere from blocks to miles) will also likely be affected by the radiation as the radioactive particles travel downwind. Since a dirty bomb blast may appear at first to be simply a conventional bomb attack, people covered in radioactive dust may unwittingly spread this material to hospitals and homes as they try to evacuate the area.

Most predictions have assumed that to maximize the effect, terrorists would conduct a dirty bomb attack in a densely populated city, such as New York City, Washington, D.C., or London. If this occurs, the RDD attack would contaminate the buildings surrounding the blast area. In addition to damage caused by the conventional explosives, some radioisotopes can chemically bind to concrete, metal, and other surfaces. Radioisotopes can also settle in surface cracks in buildings and sidewalks. This can make decontamination efforts very difficult. In some cases, the buildings would have to be completely demolished before the area is considered safe enough for people to return.

Photo Credit: UN
Manhattan skyline
Radioactive particles might also combine with soil in the area or settle on the ground. This could be particularly harmful if the area is close to groundwater sources, in which case the area's water supply could become contaminated. However, very large amounts of radioactive materials would be required to contaminate water supplies. In addition, some radioactive compounds are not water-soluble. Particles that settle on the ground could scatter again when wind blows through the area or when vehicles pass by, continuing the risk of radiation inhalation. Decontamination in these cases could involve removing the entire top layer of soil. This could further delay the return of workers and residents to the contaminated area.

Any physical health effects from a passive radiological weapon—that is, one that exposes a person or people to high doses of radiation without the use of conventional explosives—would be the direct result of the radioactivity. Health effects would vary depending on the radioisotope used, the length of time of exposure, and the distance and presence of any shielding between the radioactive source and the person(s) affected. The manner of use and deployment of a radiological weapon would greatly affect how much harm would be done. For example, a high-intensity gamma radiation source stored in a public trash bin might cause different health symptoms and physical damage than the release of radioactive particles in a subway ventilation system.

Chapter 2, page 1 of 2

This material is produced independently for NTI by the Center for Nonproliferation Studies at the Monterey Institute of International Studies and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, agents.
Copyright © 2004 by MIIS.