The actual risks from the use of such horrific weapons by terrorists against the American population are difficult to determine. Most communities face a much greater threat from unintentional anthrogenic or natural disasters. Traditional events—those due to accident, nature, or human error—can be predicted or at least anticipated based on historical records, and the magnitude of the consequences can be estimated. For instance, the existence and location of floodplains are known, as are areas prone to tornadoes or hurricanes, and local emergency planning committees are aware of the locations and quantities of highly toxic materials. Armed with such information, engineering and administrative controls instituted as an outcome of previous disasters have greatly lessened the consequences of these events.
The key elements of effective risk management are threat and vulnerability assessments. These processes, discussed in greater detail in Chapter 3, form the backbone for risk assessment. Risk assessment drives mitigation initiatives to prioritize actions to reduce either the probability that an event will occur or lessen the consequences should it happen. Modeling and simulation are powerful tools to identify community or facility vulnerabilities to a wide range of potential threats but do little to determine the actual threat.
The WME threat is based on terrorist motive, opportunity, and availability of the weapons or agents. Little need be said concerning terrorist motivation to do harm against the United States and its citizens. Although the United States is the most open society in the world, difficulties in gaining entrance to the nation while harboring significant caches of these weapons lessen, but do not eliminate, the opportunity. It is only the lack of the availability of such weapons, or the skills and resources by which to produce them, that keeps the overall threat low. Advances in science may work against these odds in the future, however. It is generally presumed that terrorists will have the greatest difficulty in obtaining or fielding those weapons that produce the greatest threat: nuclear or biological weapons. Chemical-warfare attacks and the use of radiological dispersal devices are considered to pose an intermediate threat, and the use of conventional explosives or the intentional release of toxic industrial materials poses the greatest threat.
It is equally difficult to measure the threat against a specific community or organization. Most terrorist attacks historically were targeted against governments, the military, or industry. Although these organizations and entities remain high on terrorist lists, a trend has developed over the last decade toward attacks against the civilian population. This shift is in keeping with the prime motivation of terrorists to create terror. Although the random sniper attacks near Washington, DC, in fall 2002 did not use WME, the effect was the same: a population significantly affected by fear. Finally, extremist organizations within our borders, such as religious cults or single-issue terrorists, may target organizations traditionally not prone to such attacks. One can only imagine the overall effect on its citizens if hospitals in small towns across the United States were targeted for explosions in a random fashion over several weeks or months.
