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1.6: Visions of Emergency Management

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    This overview of emergency management in the United States has included a discussion of the kinds of organizations that operate within the emergency management system, the different patterns of responsibility and interaction among the components of that system, and the general time phases of emergency management. The development of a perspective on emergency management requires consideration of at least two additional topics. The first of these deals with the evolution of prevailing federal conceptions of how hazards are managed—especially the underlying assumptions that define what goals are important and that determine the creation and structure of emergency organizations. The second topic concerns the way in which hazards are conceptualized—whether one focuses upon the event itself or upon the demands that events place upon social systems.

    Alternative Conceptions of Managing Hazards

    As one might infer from the history of emergency management organizations, there is a separation of emergency functions that has emerged and persisted over the years. With only a few exceptions, federal organizations charged with addressing wartime attacks have been different from those charged with concerns about natural disasters. This separation of functions has also been reflected in the research by social scientists on human performance in the face of disasters. Historically, this is one of the earliest and, in terms of research and theory, one of the most fundamental distinctions in emergency management and research. Hence civil defense issues have been isolated, particularly since the advent of nuclear weapons. Although nuclear (or other wartime) attack involved functions—warning, protective action, emergency medical care, search and rescue, communications, and sheltering—similar to those addressed in natural disasters, the two were treated separately and usually under the auspices of different agencies. Indeed, Drabek (1991b, p. 3) concluded “the two principal policy streams that have shaped emergency management in the United States [are] responses to natural disasters and civil defense programs”.

    This separation of emergency management systems appears to have spawned what has been called the philosophy of “dual use”, a term that was first used officially when President Nixon created the Defense Civil Preparedness Agency in 1972 (Harris, 1975). At the federal level, this meant funding priority was given to research and planning that would be useful in coping with both natural disasters and nuclear attack. Perhaps the most persistent application of the dual use philosophy was found in the natural disaster research sponsored by the Defense Civil Preparedness Agency in the l970s. As part of contract fulfillment, researchers were required to include an appendix to reports describing how their results applied to the nuclear attack setting. Although the dual use philosophy implied basic comparability between natural and technological disasters, this had little impact on the way either emergency managers or researchers partitioned such events. Even under dual use, the comparability issue was addressed largely after the fact (in the case of research, after the data collection and analysis were completed). Conceptions of emergency management practice and disaster research continued to compartmentalize wartime threats and natural disasters. Of course, the compartmentalizing was not limited to this broad division; there was also a tendency to separate different types of natural disasters. Yoshpe (1881, p. 32) indicates that legislation sanctioned dual use by 1976: “[It was]…established as a matter of national policy that resources acquired and maintained under the Federal Civil Defense Act should be utilized to minimize the effects of natural disasters when they occurred.”

    Beginning with the classic study of the Halifax explosion (Prince, 1920), social scientists interested in disaster response sporadically studied events that were not products of the natural environment or wartime attacks. Although few in number, a 1961 catalog of disaster field studies compiled by the National Academy of Sciences listed 38 research studies on technological incidents (Disaster Research Group, 1961). By the mid-1960s, a third distinct body of research was developing with respect to technological threats. These studies generally reflected the body of research conducted in connection with natural disasters and wartime attack. At the federal level, President Nixon’s creation of the Environmental Protection Agency in 1970 (with a major emphasis on chemicals and chemical processes) solidified the concept of technological hazards as distinctly different phenomena.

    By the late 1960s, each type of hazard or disaster had begun to be treated differently by policymakers, federal agencies, emergency management practitioners, and researchers. The separations were not analytic but largely reflected differences in the threat agent. Thus, there were lines of research on hurricanes, tornadoes, floods, explosions, mine collapses, wartime attacks, and so on. These divisions were also reflected in public policy for dealing with disasters; different organizations focused on different threats. An important consequence of this approach was the concentration on the distinctiveness of disaster agents and events. The prevailing idea was that disaster agents differ qualitatively, rather than just quantitatively, and that each of these hazards required its own unique mode of understanding and management.

    This orientation was supported by the loosely coupled collection of federal agencies and programs that addressed emergencies through the 1960s and most of the 1970s. As public policy, difficulties began to arise with “dual use” as a philosophy and an organizational strategy. The difficulties became the basis for the beginning of a radical change in the way disasters were conceptualized. In retrospect, at least three forces guided the change in thinking. First, the persistence of “dual use” as a principle for justifying the support of disaster research by civil defense agencies pressed scientists to make explicit comparisons among disaster events. Such justification was based upon two rationales—generalizability and cost-effectiveness. The generalizability principle held that, in the absence of real war, natural disasters provided the next best approximation to study human disaster response. The cost-effectiveness rationale assumed that, by funding studies of one class of events, inferences could be made to other types of events at relatively small incremental cost—loosely described as “getting more knowledge for the research dollar”. The cost-effectiveness rationale was to ultimately play a significant role in subsequent changes in emergency management philosophy. It was clear, however, that “dual use” forced researchers to think about and conduct cross-disaster applications of various emergency functions—emergency assessment, hazard operations, population protection, and incident management. Without a conscious intention of doing so, these comparisons began to build an empirical body of evidence regarding dimensions along which events normally thought to be quite distinct could be compared.

    The second force that promoted changes in basic conceptions of emergency management was the rise of social scientific subdisciplines or specializations in disaster behavior. An important factor in this development was the growth of the Disaster Research Center (DRC—which was located first at The Ohio State University and later at the University of Delaware) under Quarantelli and Dynes beginning in 1963. This institution trained social scientists to study events caused by a diverse set of natural and technological hazard agents and complying with the dual use demands for comparisons with nuclear attack. These researchers focused not on the differences among disaster agents, but upon the social management of the consequences of disasters. They linked these diverse studies using a theoretical framework that was marked by the designation of a focal social system and discussions of generic management issues, such as the problems of resource mobilization, interactions of system components, and the interrelationships of the focal system with external systems. An early and important contribution of the DRC studies was to focus research and management attention upon the demands a crisis imposes upon a social system. These were conceptualized as agent-generated demands (i.e., tasks generated by a disaster as a function of impact—warning, search and rescue, emergency medical care) and response-generated demands (i.e., those tasks necessary to meet agent-generated demands—communication, resource mobilization). By focusing upon a disaster’s demands and not on the physical characteristics of the disaster agent itself, this line of research posed a significant challenge to both the theoretical and operational perspectives that differentiated events based on the agent involved. It is important to point out that DRC did not ignore the effects of different types of hazard agents; each agent was acknowledged to produce its own distinctive pattern of demands. Instead, DRC’s contribution lay in establishing a concern with social management of events within a systems perspective. This practice emphasized the problem of identifying and responding to different demands growing out of the crisis and set the stage for subsequent identification of generic or “common” management functions across disasters.

    The third force for change came well after DRC began its operation. This was the NGA’s emergency preparedness project. Primarily concerned with public policy associated with emergency management, these analysts focused first upon what they saw as the ineffective allocation of emergency management responsibilities among the federal agencies assigned to help states and localities cope with disasters. It was their contention that the presence of a bureaucratized and compartmentalized collection of federal disaster agencies made it difficult for lower levels of government to obtain necessary aid for both planning and recovery. Moreover, they emphasized the lack of cost effectiveness of the diverse constellation of federal programs and agencies. Another contribution of the NGA project was its perspective on disasters. As members of state government who were sensitive to the problems experienced by local governments, their view of disasters was less compartmentalized than that of their federal counterparts. States and localities had long been forced to plan for and respond to disasters without the benefit of a bureaucracy that had as many specialized agencies as that of the federal government. Among other reasons, their revenues simply could not support much specialization. The same people who were called upon to deal with floods also dealt with explosions, hurricanes, hazmat incidents, and tornadoes. Over the years, state and local emergency response personnel developed an approach based upon managing all types of disasters without regard to the precipitating agent. From a practical standpoint, their orientation meant that they focused on each disaster’s demands and sought to manage those, making specific procedures apply to as many types of events as feasible. In one sense, this produces an emphasis upon the idea of developing organizational systems to perform generic functions. For example, warning systems, emergency medical care systems, evacuation plans, damage assessment procedures, communication systems, and search and rescue plans may all be applicable to crises associated with floods, hurricanes, nuclear power plant accidents, volcanic eruptions, earthquakes, and others. Driven in part by economic need, the NGA project became strong advocates for an “all hazards” approach to emergency management—which they called comprehensive emergency management—and their efforts drew intellectual strength from the comparative research at the Disaster Research Center.

    Comprehensive Emergency Management

    Operating together, these forces gave rise to Comprehensive Emergency Management (CEM) as a basic conceptual approach to disasters and to managing emergencies. In 1979, NGA issued a Governor’s Guide to Comprehensive Emergency Management (National Governors’ Association, 1979) that provided an articulate statement of the philosophy and practice of CEM. The approach was further legitimated through its adoption and promotion by FEMA in 1981. In 1993, when the US Congress repealed the Federal Civil Defense Act of 1950, a provision (Title VI) was added to the Stafford Act requiring the federal government to adopt the all-hazards approach inherent in CEM. In summary, CEM refers to the development of a capacity for handling emergency tasks in all phases—mitigation, preparedness, response, and recovery—in connection with all types of disaster agents by coordinating the efforts and resources of a wide variety of nongovernmental organizations (NGOs) and government agencies. CEM is distinguished from previous conceptualizations—particularly dual use—by two important characteristics. First, CEM emphasizes comprehensiveness with respect to the performance of all disaster relevant activities by dictating a concern for mitigation, preparedness, response, and recovery. The second distinguishing feature of CEM is its concern with the management of all types of emergencies whether technological, natural, or willful (including state sponsored and terrorist attacks). This characteristic is an outgrowth of the idea that an emergency may be seen as a disruption of the normal operation of a social system. To the extent possible, one would like to minimize the likelihood and magnitude of system disruptions in the first place and minimize their duration by creating the potential for quickly stabilizing the system and subsequently restoring it to its normal activities following an unpreventable disruption. In this context, the cause of the disruption is less important than the nature and magnitude of its effects upon the social system. The only reason to distinguish among disrupting agents rests on the extent to which different agents impose distinctive demands on the system. For example, hurricanes can be distinguished as events that provide long periods of forewarning when compared with earthquakes.

    In developing a framework for managing all phases of all types of disasters, CEM can be seen as an attempt to integrate emergency management by developing a body of techniques effective for managing the responses to multiple disaster agents. CEM represents an extremely significant departure from historical views of emergency management that make sharp distinctions among hazard agents and claim (either explicitly or implicitly) that a unique strategy must be developed for managing each of them. Furthermore, aside from the intuitive appeal of a more parsimonious theoretical approach, cost conscious officials at all levels of government are attracted to the more efficient use of resources promised by a comprehensive approach to emergency management (Quarantelli, 1992).

    Once state and local governments began to adopt some variant of CEM, FEMA introduced the concept of Integrated Emergency Management Systems (IEMS) in 1983. The initial goal of IEMS was to facilitate the development of disaster management functions and (at the time it was introduced) to increase congressional support for a larger civil defense budget (Perry, 1985, p. 130). When pressed to distinguish IEMS from CEM, the principal reply was: “CEM is the long term objective, IEMS is the current implementation strategy” (Drabek, 1985, p. 85). It appears that the meaning of IEMS on a practical level derives from the term “integrated”—identifying the goal of addressing all hazards and consolidating emergency actions into a single office or organization within a jurisdiction. However, CEM remains the primary vision of disaster management in the US.

    Classifying Hazard Agents

    An emergency management vision that addresses all hazards must by necessity focus upon the concept of generic functions while acknowledging that special functions will be needed in the case of hazard agents that present unique or singular challenges. CEM implies a basic comparability across all types of disasters. Moving from emergency management to the academic study of disasters, one implication of comparability is that one should be able to distinguish hazard agents in terms of a common set of characteristics. A typology of hazard agents is a system for classifying them into categories within which the social management demands are similar. On a practical level, implementing CEM involves identifying generic emergency response functions and then specifying circumstances (tied to the impact of different disaster agents) under which they will need to be employed. If one could use such functions as key characteristics of disasters, then one could begin to develop meaningful taxonomies.

    There have been few attempts to make systematic comparisons of human response to different disaster agents. Indeed, there has been a tendency among researchers to avoid examining relationships among different disaster agents, partly on the assumption that each “type” of event was simply unique. For example, the matter of comparing natural with technological threats rarely appeared in the professional literature at all until the 1970s. In part, this condition reflects the state of disaster research. For many years disaster studies were very descriptive in nature (Gillespie & Perry, 1976). Hence, attention often focused upon the event itself—the hurricane or the earthquake—and upon descriptions of specific consequences for disaster victims. Therefore, the research literature provided illustrative accounts of earthquake victims crushed under rubble, fire victims plucked from rooftops, and hurricane victims drowned in the storm surge. In this context, researchers argued that different agents have different characteristics and impose different demands on the social system and as a result probably must be explained using different theories. A typology is actually a form of theory created through taxonomy or reasoning (Perry, 1989). Thus, human reactions to different disaster events were expected to be different.

    In one sense, it is entirely correct to consider each disaster agent, as well as each impact of each agent, to be different. Floods present obvious differences from earthquakes and, indeed, the eruption of the Mt. St. Helens volcano on March 27, 1980, was very different from its eruption on May 18, 1980. Such comments reflect an essentially phenotypic classification system, focusing upon the surface or visible properties of an event. Emergency managers and disaster researchers are not so much interested in classifying disasters in these terms, however, because their goals are associated primarily with the behavior of the affected social system. It is human response to the natural environment, technology, or other humans that produces the disasters of hurricanes, tornadoes, hazmat releases, or wartime attacks. Thus, the goal is to distinguish among social causes, reactions, and consequences, not necessarily to distinguish hurricanes from chemical plants. There has been an increased concern with the development of conceptual schemes for explaining human behavior in disasters. This theoretical concern directs one to identify characteristics of disasters that determine the nature and types of agent-generated and response-generated demands imposed upon stricken communities. This leads to the creation of a classification system that characterizes disasters, not in phenotypic terms, but in terms of features that will have an impact on the kinds of assessment, preventive/corrective, protective, or management actions that might be used in disaster response. To pursue such a goal, one might begin by choosing a given function—population warning, for example—and examine the ways in which performance of that activity varies across disaster events as a function of differing agent characteristics such as the amount of forewarning provided by detection and forecast systems.

    There has been much discussion and only limited consensus among academic disaster researchers regarding either definitions of disaster or classification schemes for distinguishing among different types of disasters. However, as Perry (1998) has pointed out, most definitions of disaster contain many common elements—disagreements among definers tend to lie in minor aspects of definition or in the logic that is used to develop a definition. From the standpoint of practicing emergency managers, such minor variations pose few operational difficulties. Most events that are characterized as disasters, whether they arise from natural forces, technology, or even deliberate attacks, fit most of the academic definitions of the term. As defined by Fritz (1961, p. 652), a disaster is any event:

    concentrated in time and space, in which a society or a relatively self-sufficient subdivision of society, undergoes severe danger and incurs such losses to its members and physical appurtenances that the social structure is disrupted and the fulfillment of all or some of the essential functions of the society is prevented.

    From this classic definition (as well as from the definitions discussed previously in this chapter) one can surmise that disasters occur at a distinguishable time, are geographically circumscribed and that they disrupt social activity. Barton has proposed a similar definition, but chose to focus upon the social system itself, arguing that disasters exist “when many members of a social system fail to receive expected conditions of life from the system” (1969, p. 38). Both Fritz and Barton agree that any event that produces a significant change in the pattern of inputs and outputs for a given social system may be reasonably characterized as a disaster. The important point to be derived from these definitions is that events precipitated by a variety of hazard agents—floods, chemical spills, volcanoes, nuclear power plant accidents, terrorist attacks—all fit equally well into these definitions as disasters. At this level of abstraction, there is no compelling reason to differentiate among natural, technological, or other types of hazard agents. Given the breadth of most definitions of disasters, the analytic problem becomes one of determining the characteristics by which to distinguish among the events that do satisfy the definition. As noted earlier, such dimensions should not be restricted to physical characteristics of the hazard agent and its impact, but should also include attributes relevant to the effects of the event upon the social system and its consequences for management.

    Distinguishing disasters, accidents, and attacks

    There has been some discussion among researchers regarding the lines along which natural disasters, technological accidents, and willful attacks might be meaningfully distinguished. While there remains much disagreement in the research community about which dimensions are meaningful, it is possible to begin to identify dimensions from the research literature. Much of this work can be traced to the staff of the Disaster Research Center who attempted to draw parallels between natural disaster response and possible response to nuclear attack (particularly between 1963 and 1972; see Kreps, 1981). Barton (1969) developed a scheme for identifying distinguishing features of disasters that characterize the nature of social system stress. Barton’s system defined four basic dimensions—scope of impact, speed of onset, duration of impact, and social preparedness of the threatened community. These dimensions have been used by a number of researchers in developing classification schemes (Lindell & Perry, 1992) and can be briefly explained here. Scope of impact is usually defined as the absolute geographic area (e.g., in square miles) affected by a disaster but, as will be described in Chapter 5, it also can be defined in terms of the affected percentage of a jurisdiction’s area (geographic scope), population (demographic scope), or economic production (economic scope). Aside from sheer size, this dimension has implications for resource mobilization within the affected social system and for the availability of supporting resources that might be drawn from nearby communities or higher levels of government. Speed of onset refers to the interval of time between a physical event’s first manifestation of environmental cues until its impact on a social system. Speed of onset varies both by the inherent nature of the hazard agent and the level of technological sophistication of the detection system. For example, earthquakes have a very rapid onset (there are often no detectable environmental cues before the initial shock), whereas droughts have a very slow onset (some take years to develop). In other cases, the technology to forecast meteorological hazards such as hurricanes has developed considerably over the course of the past 50 years so events, such as hurricanes, that could at one time occur with little or no forewarning are now routinely monitored and forecast days in advance. Duration of impact refers to the time that elapses between initial onset and the point at which the threat to life and property has been stabilized. This can be a few minutes (short) in the case of a tornado, a few hours or days (moderate) in the case of riverine floods, persistent for years in the case of drought, or intermittent for years in the case of volcanoes. Finally, social preparedness is a dimension that attempts to capture the ability of the social system to anticipate the onset of an event, control its impact, or cope with its negative consequences. Obviously, this social preparedness dimension is precisely the objective of emergency management.

    Anderson (1969b) contributed another comparative dimension from his research on the functioning of civil defense offices (now more commonly called emergency management departments) during natural disasters and attempted to extrapolate to the nuclear attack environment. In developing his analysis, Anderson (1969b, p. 55) concluded that in spite of obvious differences between nuclear threats and natural disasters:

    [these differences] can be visualized as primarily ones of degree. With the exception of the specific form of secondary threat, i.e. radiation, and the probability that a wider geographic area will be involved, a nuclear [threat] would not create essentially different problems for community response.

    Anderson’s analysis introduced the issue of secondary impacts of disaster agents as an important defining feature. It should be remembered that virtually all hazards, whether natural or technological, accidentally or deliberately caused, entail some secondary impacts. Indeed, the secondary threat can be more devastating than the initial threat. Riverine floods tend to deposit debris and silt that persists long after the water has receded. Earthquakes often produce urban fires, and volcanic eruptions can melt glaciers or ignite forest fires.

    By assembling lists of distinguishing characteristics such as those discussed above, one can compare or classify an apparently widely differing (in terms of superficial features) range of disaster events. As an example of how such comparisons might work, Table 1-1 compares three disaster agents—riverine floods, volcanic eruptions, and nuclear power plant accidents—in terms of the five distinguishing characteristics.

    Table 1-1. Classification of Selected Hazard Agents.

    Hazard Agent Characteristic

    Riverine Flood

    Volcanic Eruption

    Nuclear Power Plant Accident

    Scope of impact

    Highly variable long, and narrow

    Highly variable broad area

    Highly variable broad area

    Speed of onset

    Rapid: flash flood

    Slow: main stem flood



    Duration of impact




    Health threat

    Water inhalation

    Blast, burns ash inhalation

    Ingestion, inhalation, direct radiation

    Property threat




    Secondary threats

    Public health danger from water/sewer inundation

    Forest fires, glacial snowmelt

    Secondary contamination




    Variable ability to predict releases after accident onset

    It is interesting to note that, at this analytic level, volcanic eruptions and nuclear power plant accidents are similarly classified. Both threats involve variable scopes of impact that are potentially widespread. Usually, a volcanic eruption’s threats to human safety are limited to within a few miles of the crater. Life threatening levels of radiation exposure from a nuclear power plant accident is likely to be confined to the plant site or a few miles downwind from it (US Nuclear Regulatory Commission, 1978). Under special conditions, however, either type of event might involve a considerably greater scope of impact. The May 18, 1980, eruption of Mt. St. Helens volcano spread a heavy layer of volcanic ash over a three state area and the Chernobyl nuclear power plant accident spread radioactive material over an entire region. The speed of onset for volcanic eruptions and nuclear power plant accidents is likely to be rapid, although each of them has the potential for a significant degree of forewarning prior to the onset of a major event. These two events are also similar with respect to the duration of impact of the primary threat to human safety. In both cases, a volcanic eruption and a release of radioactive materials, the event could last from hours to days. Persistence of secondary impacts could, in each case, last for years, although the long-term health effects of volcanic ash are less significant than radiation. To the extent that volcanic eruptions continue in an eruptive sequence that lasts for years, the duration of impact can be said to be long. A nuclear power plant accident would be expected to be of moderate length although so few actual accidents have occurred that the empirical data are extremely limited. The accident at the Three Mile Island nuclear power plant, which is more accurately labeled as an emergency than as a disaster, involved a danger period that lasted for about six days. However, the Chernobyl accident severely contaminated areas that are still uninhabitable two decades later.

    Both volcanic eruptions and nuclear power plant accidents generate secondary threats. The sheer number of secondary threats associated with volcanoes is quite large; ultimately they involve long-term threats to public health, to the stability of man-made structures, and to plants and animals in land and water ecosystems. The most probable secondary threat of a nuclear power plant accident is associated with the effects of residual radiation exposure arising from ground deposition and water contamination by radioactive materials. In addition to the potential exposure by way of external gamma radiation and inhalation of radioactive materials, there is the threat of exposure by means of ingestion of contaminated vegetation or animal products (meat or milk).

    Finally, the state of technology is such that neither volcanic eruptions nor nuclear power plant accidents can be forecast accurately far in advance. There is in both cases, however, a technology for detecting and monitoring events once they are in progress. In the case of some volcanoes, once an eruptive sequence has begun either seismic or geochemical cues can be used to make approximate forecasts of eruptive events. With nuclear power plants, monitoring instruments are designed to detect even minor aberrations early in order to facilitate the implementation of corrective action before more serious difficulties arise. Thus, although one might not be able to predict a power plant accident, instruments are designed to detect problems in their early stages before they can escalate to an atmospheric release of radioactive material.

    Riverine floods differ from the other two hazard agents primarily in terms of two characteristics. First, floods are frequently predictable, often days in advance. Second, speed of onset typically is gradual (by definition requiring a minimum of six hours to reach a flood crest, although more rapid onset can occur during flash floods in mountainous areas). Another general point of distinction is the frequency with which floods occur; they are the most common geophysical hazard in the United States (Perry, Lindell & Greene, 1981). Thus, from the standpoint of both emergency managers and the public, riverine floods are a familiar threat. Moreover, the duration of the primary flood impact is much shorter than a volcanic eruptive sequence or a nuclear power plant accident. Secondary impacts of floods include both public health threats and dangers to man-made structures, but in general the extent and duration of the effects of their secondary threats are less than either of the other two disaster agents. Finally, like a volcanic eruptive sequence or a nuclear power plant accident, the scope of impact of riverine floods is highly variable. Usually the scope of flood impacts is narrower than either of the other hazards, but there is a potential for widespread scope.

    The preceding discussion demonstrates that it is possible to classify diverse disaster agents in terms of an underlying set of dimensions and then to discuss the agents in terms of functional emergency management activities. Such dimensions could include the physical characteristics of the hazard agent and its impact, as well as attributes relevant to the effects of the event upon the social system and its consequences for management. The characteristics derived from the disaster research literature have provided a systematic set of attributes that could be used to examine and compare riverine floods, volcanic eruptions, and nuclear power plant accidents. As indicated above, the differences between classification schemes in the academic literature tend to rest on differences between researchers regarding exactly which dimensions and how many dimensions are optimal in creating the typology. The 21st Century has seen no more agreement than the 20th Century did, although there are two discernable trends in the literature. One trend, followed by only a few, involves attempts to elaborate on the analytic approach described here, adding or subtracting dimensions or otherwise changing the complexity of the approach (Kreps, 1989; Tobin & Montz, 1997). By far most disaster researchers have continued to ignore the issue of analytic typology and remained with some sort of phenotypic classification, most commonly with the classic categories of “natural disasters”, “technological accidents” and “willful attacks” (Cutter, 2001; Drabek, 1986).

    Without regard to the low level of consensus among researchers, analytic classification systems are more than an abstract intellectual exercise. They provide an opportunity to demonstrate how, by means of careful examination, one can begin to identify differences among disaster agents with respect to their demands upon the emergency response system. From the information listed in Table 1-1, an emergency manager might conclude that two protective measures might be used in all three events: population evacuation and the imposition of access controls to the threatened area. Because a volcanic eruption or a nuclear power plant accident could present a health threat resulting from inhalation of airborne materials (volcanic ash or radioactive gases and particulates, respectively), taking shelter indoors and using respiratory protection is feasible. Ad hoc measures for respiratory protection could be as simple as folding a wet towel and breathing through it.

    The importance of developing a comparative perspective structured by disaster agent characteristics lies in the prospect of identifying a profile of disaster demands that, in turn, define the functions that the emergency response organization must perform. Thus, classifying hazard agents with respect to defining characteristics allows emergency managers to better define the ways in which generic functions (e.g., emergency assessment, hazard operations, population protection, and incident management) should be implemented to achieve comprehensive emergency management. That is, the reason for identifying distinctive aspects of hazard agents is not to define each of them as “unique”, but rather to highlight the ways in which generic functions must be adapted to the needs of a particular type of emergency. By adopting this approach, emergency managers are better able to identify the range of hazard agents for which a particular emergency response action is appropriate or to identify the ways in which an emergency response action must be adapted to the constraints of a given hazard agent. For example, evacuation is an appropriate protective action in response to a wide range of hazards such as floods, hurricanes, and volcanic eruptions. However, authorities recommend sheltering in-place rather than evacuation during tornadoes because of the rapid onset and unpredictable track of the funnel cloud. In some cases, especially hazmat releases, the hazard agent’s speed of onset is so variable from one incident to another that there is no general rule regarding evacuation versus sheltering in-place. Moreover, evacuation was listed as a protective measure in nuclear power plant accidents and it was noted that the primary health threat to citizens in such events was radiation exposure. Research indicates that radiation hazard is feared as much or more than other natural and technological hazards (Lindell & Earle, 1983; Slovic, 1987). Assuming the conditions were appropriate for an evacuation warning, the emergency manager would be well advised of the possibility for a high level of spontaneous evacuation (people evacuating from areas that emergency managers consider to be safe). In turn, this alerts the emergency manager to a need for timely dissemination of information to the public about the characteristics of the impact and the potential personal consequences of exposure, thereby reassuring those who are not at risk that they are indeed safe.

    The Remaining Chapters

    1.6: Visions of Emergency Management is shared under a Public Domain license and was authored, remixed, and/or curated by LibreTexts.

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