The Reporter's Handbook on Nuclear Materials, Energy & Waste Management

Dirty Bombs (Radiological Dispersal Devices)

172 | Dirty Bombs (Radiological Dispersal Devices) Written by Michael R. Greenberg, based in part on an interview with Detlof Von Winterfeldt, with comments by Richard L. Garwin Background A dirty bomb, more formally labeled radiological dispersal device (RDD), is a mixture of conventional explosives and radioactive materials derived from medical equipment, food and blood irradiators, other industrial uses, or nuclear civilian and military waste. When a dirty bomb is detonated, injuries and perhaps deaths will result from the blast and shrapnel. Some of the radioactive material will fall near the detonation site, and the remainder will disperse in the air as a cloud and settle far away from the detonation site. The impact of the nuclear material on the surrounding population and neighborhood will be very site and weather specific. No nuclear fission or fusion takes place. Identifying the Issues Dirty bombs have become an issue because they are likely weapons for terrorists . A dirty bomb does not require the technical expertise or funds required to obtain, build, transport, and use atomic or hydrogen bombs. Dirty bombs are a variation of weapons that terrorists already know how to make and use. Dirty bombs can cause health effects for those who are near the blast or who rush to the site and are not protected from exposure to radioactive materials. They are likely to have psychological effects and contaminate large enough areas to cause economic dislocation and stigma. What Reporters Need to Know For a pre-event background story, a reporter should probe with two risk-related questions. Dirty Bombs | 173 1. What sources of radioactive materials are located in the area? How dangerous are the radioactive substances? Are the radionuclides short- or long-lived? The U.S. General Accounting Office reported in 2003 that there were about 2 million licensed sealed sources of radioactive materials in the United States, and the European Union reported another 500,000 in Europe. Calibration equipment contains low levels (<100 curies, or Ci) of cobalt-60, cesium-137, and americium-241. Medical and industrial facilities use radioactive materials for diagnosis, sterilization, and research (1,000 to 5,000 Ci). Larger amounts of radioactive cobalt-60 (2,500 to 25,000 Ci) and lesser amounts of cesium-137 (50 to 15,500 Ci) are found at blood irradiation facilities. Medical facilities use single and multi-beam radiotherapy. The radioisotopes can be very active (500 to 27,000 Ci of cobalt 60 and cesium 137). Industrial irradiators used to sterilize food for preservation have radioactivity levels of a million or more Ci. Facilities that store or reprocess radioactive materials from nuclear power plants or from nuclear bomb production processes also have nuclear weapon waste with millions of Ci, as well as multiple types of radioisotopes. It is important that these differences in radioactivity be ascertained, as well as differences in half-life and type of radiation. (See “Radionuclides.”) 2. How effectively are radioactive materials contained? In a solid form? Enclosed in a tank or encapsulated in a solid form that would limit its mobility? In a liquid form, in tanks below or above ground? In a gaseous form? What is the security protocol for these radiological materials? In the United States and many other countries, the purchase, use, and disposal of radioactive materials are regulated. Yet there always is some chance of theft and misuse. For example, we are concerned about some medical or industrial irradiation equipment, which although containing lower quantities of radionuclides, are housed in portable devices that could be stolen. If there is an event or the reporter is trying to estimate the impact of an event, the following questions are important. 3. How many people are nearby who can be potentially exposed? 4. How much exposure is likely and what is the risk to exposed people? 5. What will be the response of local, state, and federal officials? Is it better to stay indoors or to evacuate? Can people, animals, and materials be relocated so that they are not exposed during a radiation release? Where will exposed and injured people and animals be taken? How will contaminated 174 | The Reporter’s Handbook: Briefs structures, property, and soil be managed? Who will be responsible? What can an individual do? 6. How will the area be secured until it is safe? How long will the public be kept out of the area? Will access be limited in perpetuity? 7. How will government and responsible parties follow up so that the chances of subsequent exposures are reduced? What Are the Risks? The explosion is the first risk. It could kill or severely injure nearby workers (e.g., dockworkers, truckers, security personnel), and people who unfortunately are proximate. If it is a dirty bomb, emergency personnel, such as fire, police, and ambulance workers could be exposed, depending on the rem level. A rem (roentgen equivalent man) is a unit used to measure the radiation dose received by people in a given interval. On average, people receive 300 mrem (millirem) per year, or about 1/3 of a rem per year. A single wholebody CT scan exposes people to more than 1 rem at a time. The exposure of radiation workers is limited to 5 rem per year. Some environmental standards require limiting public exposure to less than 15 mrem per year. Exposures in the millirem range are not likely to produce any health effects at all. Exposures in the higher rem range may produce health effects over the period of many years. Acute effects like radiation sickness and burns occur well above exposure of 300 rem. The next level of risk results from a plume that could spread over as much as 50 square miles in case of a very large release. Even in this instance, the outer edge of the plume will have exposures of only about 100 mrem for a 4-day dose, and about the same amount for a 1-year dose from the residual radioactivity left on the ground after the plume has passed (the “ground shine”). The impact of the plume or of the ground shine on public health may not be detectable, even after many decades, because 100 mrem is a small increase over the normal exposure of an average U.S. resident of about 300 millirem per year. The most likely risk is economic stigma resulting from ground shine. There will be evacuations and business relocation, and there will be residual hotspots. Simulation studies done of Los Angeles show that if we try to remove contaminated hotspots to below 15 millirem per year, which is the Environmental Protection Agency standard, the cost could be hundreds of billions and possibly 1 or 2 trillions of dollars. Cleaning up to 100 millirem would still cost billions of dollars, but this simulation illustrates that cleanup Dirty Bombs | 175 standards have enormous consequences. Ultimately, the challenge is costs versus benefit of cleanup. If multiple dirty bomb attacks occur, there will be serious economic repercussions. The likely targets are valuable economic areas such as ports, tourist attractions, financial centers, and transport nodes. But as we learned during the World War II bombing of Dresden and Tokyo, attacks can be directed at workers and housing to demoralize the public. Overall, there will be some public health repercussions, but the larger risk is to those who own property and operate businesses in the affected areas. We have learned that terrorists like to do what they know how to do best. Hence, a dirty bomb loaded in a truck is a likely method of attack. A bomb likely would be built by one group, transported to the site, and detonated remotely by another. However, we cannot discount the use of trains, ships, planes, or helicopters in such an attack. Nor, in the case of small amounts of medical radionuclides, can we discount suicide bombers with backpacks or suitcases. In June 2002, the United States arrested José Padilla for his involvement with Al Qaeda planning a dirty bomb attack in the United States. In January 2003, British officials found documents in Afghanistan indicating that Al Qaeda had constructed a dirty bomb and had plans about how to use it. Dirty bombs scare people and are likely to reduce property values in areas with residual radioactivity. So it might be the choice of terrorists, especially because it is much easier to acquire radioactive materials from medical and industrial uses than to build a nuclear device. The risks of a dirty bomb attack, we believe are increasing. The materials are relatively easy to obtain and the bombs are not notably difficult to build for those who already have experience in building bombs. The International Atomic Energy Agency (IAEA) points out that almost every nation has radioactive materials in equipment and devices. Some has been stolen, lost, or abandoned. Controlling sources of radioactive materials is critical. This means monitoring and protecting a wide range of materials from less active radionuclides used in hospitals to nuclear waste materials found at storage and reprocessing facilities. The United States has become increasingly engaged in source control. Nuclear processing plants in Russia, Ukraine, India, Pakistan, and now North Korea and soon perhaps Iran have become major concerns. In this regard, the United States faces a major diplomatic challenge in working with other countries to prevent radioactive materials from being transported on ships and other international carriers. It needs to convince other nations that it is to their benefit to restrict the flow of nuclear materials. 176 | The Reporter’s Handbook: Briefs This doubtless means technological and financial assistance as well as diplomacy . (See “International Agencies and Policy.”) The U.S. government has expanded its efforts to intercept radiological materials at ports of entry. Coast Guard officers board merchant vessels and use detectors to look for radiological materials. These efforts have expanded in commercial ports, and new detection equipment is better able to detect efforts to hide radioactive materials. Of increasing concern are pleasure boat docks in the United States and in Mexico, Colombia, and other nearby locations. Inspecting pleasure boat marinas is a major challenge requiring substantial resources. Using legal measures enhanced since the terrorist attacks of 9/11, the United States has been clamping down on entrance of foreigners. After the Iraq war ends, a trained cadre of bomb-making experts will unfortunately be available to focus on other targets, including the United States. With regard to stopping or mitigating the impacts of a dirty bomb attack, an attack is likely to occur in phases and, hence, can potentially be discovered and stopped. Someone will need to obtain a job or gain access at the selected source of radioactive materials. Then the radioactive material would be stolen or purchased illegally. The material must then be transported to a warehouse or other place large enough to build the bomb. Simultaneously, someone must study the selected target or targets. Then the weapon must be transported to the target. From the time the radioactive material is obtained to the time of detonation, the radioactive material can be detected. A dirty bomb plot can also be detected by following evidence regarding conventional bomb-making material, and by preventing the movement of those who build, move, and detonate the weapon. The implications of such efforts, however, are likely to mean substantial resources devoted to monitoring and surveillance of hazardous materials, and people who are likely to abuse them. This, of course, has potential implications for civil liberties. Misunderstandings Some reporters could portray a dirty bomb as a public health disaster, as if it were a major accident at a nuclear power facility or a nuclear weapons detonation. Research in Los Angeles shows that we could expect a radiation cloud of 100 millirem up to several miles from the source for 3 to 4 days and some residual ground contamination. This, in itself, would not be a public health disaster. But it certainly would be an economic problem. Although a dirty bomb is newsworthy, overstating the impact would potentially scare people Dirty Bombs | 177 into evacuating when they might be safer staying. The more time they spend outside, the more the dose and the more likely they are to become involved in an accident while fleeing the area. As much as possible, reporters need to put aside a tendency toward the dramatic in these kinds of situations and focus on details of the situation at hand. For example, remarkably different impacts can result from a bomb with the same hazard potential. On one hand, it can have no radiological-related effects if the bomb was poorly constructed so that there was no release or if it was detonated in an area where there were few people or if the wind blew the blast materials away from people. On the other hand, if it was competently produced, the bomb could release 20% or more of the radiological materials toward a populated area. Misunderstandings can be avoided by obtaining accurate information from trustworthy sources. Pitfalls Coverage of this issue today in the United States has been satisfactory. However , we worry about what would happen in an actual event. A major concern is the presentation and visual display of information without the proper context. The public is unlikely to understand the public health risk associated with a 100- rem exposure, or a 100-millirem exposure per year. If they see a map showing exposures in a given area, they are likely to assume that everyone and everything in the plume is at high risk. Anything inside of the plume, even if the risk is minimal, could suffer a long-term stigma. People and businesses might leave and not return. Property values will decline and could remain depressed. The tendency for journalists will be to want to display any traces of a cloud, even if the risk is minimal. The National Radiological Atmospheric Center in Livermore does real-time simulations. They can quickly provide detailed radiological exposure maps (see llnl.gov for a list of papers or call 925-422-4950 for telephone access). But what should be displayed? Should it be the area of 100 rem, which may result in radiation sickness? Or 100 mrem, which is not likely to lead to significant or even detectable health effects? Or 15 mrem, which is detectable by today’s instrumentation but will certainly not produce health effects? If a bomb is successfully detonated, anywhere from 1% to 80% of the radionuclides could become airborne and respirable. The plume created after an event will depend on the specific meteorological conditions at that time in that location. We use mathematical models to predict what might happen. For 178 | The Reporter’s Handbook: Briefs example, simulations done in Los Angeles for a very large dirty bomb source suggest that a 4-day dose of 1,000 millirem (1 rem) would occur in the area immediately around the detonations and 100 millirem in the larger area under the plume. The ground contamination will increase the exposure if much of it becomes airborne again and is inhaled or becomes absorbed into food or water supplies. Decontamination can reduce exposure from this source. For context , public background radiation averages about 300 millirem a year; a CT scan delivers a dose of 1.3 rem, and the worker radiation standard is 5 rem per year. Journalists can avoid serious economic and political damage to communities by understanding the implications of exposure to low levels of radioactivity from a dirty bomb. This means that journalists need to work closely with local and state health officials to precisely describe the implications of radiological fallout from dirty bombs. Resources Carnegie Mellon University. Center for Risk Perception and Communication home page. sds.hss.cmu.edu/risk. Electric Power Research Institute (EPRI) home page. www.epri.com. International Atomic Energy Agency home page. www.iaea.org. Kelly, H. A. (2002, March 6). Testimony of Dr. Henry Kelly, President, Federation of American Scientists, before the Terrorist Nuclear Threat. Senate Committee on Foreign Relations. www.tinyurl.com/ywu59a. National Academy of Sciences. Nuclear and Radiation Studies Board home page. dels. nas.edu/nrsb. Union of Concerned Scientists home page. www.ucsusa.org. United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) home page. www.unscear.org. University of Southern California. Center for Risk and Economic Analysis of Terrorism Events (CREATE) home page. www.usc.edu/dept/create. U.S. General Accounting Office. (2003). Non-proliferation: U.S. international assistance efforts to control sealed radioactive sources needs strengthening. GAO-093-638. U.S. Nuclear Regulatory Commission home page. www.nrc.gov. (See also state government environmental or public health agencies, radiation control sections.) ...