3
Methodological Approach to Determining Vulnerabilities

Vulnerabilities associated with the chemical infrastructure arise from the properties of chemicals, the properties of the chemical supply chain, and the environment within which the infrastructure and supply chain exist. The consequences from a deliberate exploitation of one or more of these vulnerabilities can be further magnified or dampened by public or societal response to the event. The description of the chemical categories, the generalized model of the chemical supply chain, and a consideration of environmental and social factors lead to a series of questions that can be used to identify those vulnerabilities that are of potentially catastrophic consequences.

CHEMICAL PROPERTIES OF CONCERN

Casualties are most readily caused by exploiting the toxic, explosive, or flammable properties of chemicals. By far the largest number of casualties would be anticipated from situations involving toxic inhalation hazards, that is, large-scale release of toxic chemicals in a gaseous form. For example, hazard estimates by staff of the U.S. Environmental Protection Agency’s (EPA’s) Chemical Emergency Preparedness and Prevention Office for a worst-case accident involving a flammable substance give a median population within the vulnerable zone1 of 15, and for toxic inhalation risk give a

1  

The area of the vulnerable zone impacted by an actual event depends upon the quantity and toxicity of the chemical released, as well as meteorological conditions such as wind



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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities 3 Methodological Approach to Determining Vulnerabilities Vulnerabilities associated with the chemical infrastructure arise from the properties of chemicals, the properties of the chemical supply chain, and the environment within which the infrastructure and supply chain exist. The consequences from a deliberate exploitation of one or more of these vulnerabilities can be further magnified or dampened by public or societal response to the event. The description of the chemical categories, the generalized model of the chemical supply chain, and a consideration of environmental and social factors lead to a series of questions that can be used to identify those vulnerabilities that are of potentially catastrophic consequences. CHEMICAL PROPERTIES OF CONCERN Casualties are most readily caused by exploiting the toxic, explosive, or flammable properties of chemicals. By far the largest number of casualties would be anticipated from situations involving toxic inhalation hazards, that is, large-scale release of toxic chemicals in a gaseous form. For example, hazard estimates by staff of the U.S. Environmental Protection Agency’s (EPA’s) Chemical Emergency Preparedness and Prevention Office for a worst-case accident involving a flammable substance give a median population within the vulnerable zone1 of 15, and for toxic inhalation risk give a 1   The area of the vulnerable zone impacted by an actual event depends upon the quantity and toxicity of the chemical released, as well as meteorological conditions such as wind

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities median population within the vulnerable zone of 1,500.2 Damage to infrastructure and subsequent economic loss are more readily caused by the flammable and explosive properties of chemicals. Some chemicals are significantly more hazardous than others. For example, it is possible to rank chemicals with toxic inhalation properties according to toxicity, by using, for example, the Department of Transportation Hazmat Tables, which list toxicities according to LD50.3 A compound such as methyl isocyanate has a much lower LD50 (i.e. is significantly more toxic) than, for example, chlorine. Properties of the specific chemicals involved are important to first responders attempting to mitigate a specific incident to prevent a catastrophic result. However, this report is concerned with identifying research and development that will help prevent any incident from crossing the threshold of catastrophic impact. Depending on actual event circumstances, which include many factors other than toxicity, chlorine can be of equal or of more concern than methyl isocyanate. As a result, above a certain threshold, the relative toxicity (or flammability or explosivity) of two chemical species becomes less relevant. Whatever the specific chemical involved, all releases progress through a similar series of stages (e.g., release, transport, diffusion, exposure). The release consequences will be affected by the source (e.g., release rate, release duration, and toxicity), meteorology (wind speed, wind direction, atmospheric stability, precipitation), and population (e.g., population distribution and structural protection; response action) factors. Similar opportunities for emergency response and similar consequences (casualties, property damage, and environmental insult) are possible. This provides the opportunity for investments in science and technology development that mitigate     speed and direction. The exposed area is likely to be only 25 percent (one quadrant) of the total vulnerable zone at most, and probably less. The number of people exposed in such an event depends on the size of the impact area and the size of the population remaining in that area. This might be only a small fraction of the total number of people living in the vulnerable zone, especially if they are able to take prompt protective action such as evacuation or sheltering in-place. 2   Belke, J. 2001. Chemical accident risks in US Industry—A preliminary analysis of accident risk data from US hazardous chemical facilities. Proceedings of the 10th International Symposium on Loss Prevention and Safety Promotion in the Process Industries. Stockholm, Sweden: Elsevier Sciences. 3   Lethal dose 50 (LD50) is the dose at which 50 percent of an exposed animal model population dies.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities against all risks in this hazard category. Continuing with the above example, highly toxic chemicals have the potential to cause thousands of casualties with a single release under the worst circumstances. DHS therefore could make investments in science and technology development that are specific to the methyl isocyanate risk, or it can make investments that mitigate the methyl isocyanate risk while also reducing risks from other highly toxic materials. In the absence of specific threat information, it will be most appropriate at this time for DHS to invest its research efforts, including technology development, for general classes of vulnerabilities. In the case of either casualties or economic loss, catastrophic levels of consequences are expected only where large quantities of chemicals with these properties are involved. However, social response may amplify the effects of an incident involving even small quantity of chemicals to the point where its economic effects, not its casualties, become catastrophic or at least of national concern. SUPPLY CHAIN CHARACTERISTICS OF CONCERN The model of the chemical supply chain presented in Chapter 2—which considers materials, infrastructure, pathways, links and nodes, and ownership and control of the network—leads to characteristics that, if present in any given case, could pose vulnerabilities. These characteristics include the following: Key materials without obvious substitutions; Single suppliers of key materials with no potential alternative source; A plant or production process that uses high volumes of toxic, flammable, or explosive materials; Dominant nodes or dominant paths between nodes; Vulnerable points of control where theft of or tampering with a chemical can occur; and Interdependencies in the supply chain. SITING CONCERNS The consequences of an event at a chemical plant or storage facility can be greater or lesser depending upon the local environment in which the facility exists. If a facility is located within a major population center, the number of potential casualties increases. If the facility is near a major trans-

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities portation corridor, disruption of that corridor and subsequent economic loss become possible. If the facility is near important public infrastructure, such as a water supply, potential consequences increase. SOCIETAL RESPONSE Societal response has the potential to transform the consequences of an event by either diminishing or amplifying them. For example, in the event of a hazardous material release, a community whose residents know how to shelter in-place and do so when instructed may suffer many fewer casualties than another community whose residents are not so prepared. Conversely, negative reaction can amplify the consequences of an event. One example of magnification is the loss of business faced by airlines in the weeks and even months after the September 11, 2001, events—many people refused to fly even though, arguably, flying was safer after that date with the implementation of new security rules. Amplification is most likely to affect economic consequences rather than casualties since, contrary to popular belief, people rarely panic in the face of disasters.4 Societal response and emergency planning are discussed in more detail in Chapter 5.5 PRIMARY ANALYSIS OF VULNERABILITIES Using the six categories of chemicals discussed in Chapter 2 and the supply chain characteristics and chemical properties of concern, it is possible to construct a matrix representing the primary vulnerabilities posed within each category (Figure 3.1). This matrix is not meant to be exhaustive; rather it is meant to represent those combinations of supply chain characteristics and chemical properties that could lead to catastrophic consequences. The number of boxes checked does not necessarily indicate that any one class of chemicals is inherently more or less vulnerable. The checked boxes identify the highest areas of priority in each chemical category that can be utilized to guide investment intended to mitigate vulnerability. 4   Clarke, Lee. 2002. Panic, myth or reality? Contexts 1(3):21-26. 5   See also National Research Council. 2002. Making the Nation Safer: The Role of Science and Technology in Countering Terrorism. Washington, DC: The National Academies Press. pp. 270-275.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities FIGURE 3.1 Primary vulnerabilities by chemical category.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities A red teaming type exercise determined situations in which their exploitation could lead to catastrophic consequences. Another way of presenting this information is given in Figures 3.2-3.4. These figures make it clear that the primary cases of concern can be narrowed to three general cases with potential catastrophic consequences: Key materials (shortage) (Figure 3.2) High-volume toxic, flammable, and explosive chemicals (Figure 3.3) Vulnerable points of control (theft or tampering) (Figure 3.4) The aspects of nodes and interdependencies as vulnerabilities of the chemical infrastructure are depicted in the vulnerable points of control flowchart (Figure 3.4). These are the only vulnerabilities in the flowcharts that are not discussed as a scenario in the next chapter. No single vulnerable node within the chemical supply chain was identified that if disrupted, would lead to catastrophic consequences. Targeting of multiple nodes is required to have catastrophic consequences. Similarly, the interdependencies that were identified were not of a high level of concern. Previous analysis based on records of terrorist attacks against the chemical infrastructure reached a similar conclusion: To do significant damage that truly impacts the U.S. critical infrastructure—rather than inflicting symbolic damage or causing large numbers of casualties—would require the large-scale targeting of select facilities, especially those that are key manufacturers of critical chemicals or single producers of raw chemicals. Most potentially catastrophic for the U.S. chemical critical infrastructure would be a coordinated attack on a number of facilities responsible for key precursors, the disruption of which would cause a bottleneck blockage. Fortunately, the selection of such facilities would require sophisticated knowledge of chemical manufacturers, industrial processes, distribution, and warehousing. It would also require a substantial effort by a relatively large, well-financed terrorist group with access to individuals with specific scientific or technical knowledge.6 Although there are other vulnerabilities, only the three cases identified above clearly have the potential for catastrophic consequences. These cases are examined further in illustrative scenarios in Chapter 4. The scenarios are used to test and illustrate the conclusions and observations derived from the analysis. 6   Monterey Institute of International Studies Center for Nonproliferation Studies. 2004. Assessing Terrorist Motivations for Attacking Critical “Chemical” Infrastructure. Monterey, CA. p. x.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities FIGURE 3.2 Flowchart leading to a high-volume storage scenario.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities FIGURE 3.3 Flowchart leading to a shortage scenario.

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Terrorism and the Chemical Infrastructure: Protecting People and Reducing Vulnerabilities FIGURE 3.4 Flowchart leading to a misuse scenario.