EDMG541Wk6

DISASTER MEDICINE/CONCEPTS

Electronic Mass Casualty Assessment and Planning Scenarios (EMCAPS): Development and Application of Computer

Modeling to Selected National Planning Scenarios for High- Consequence Events

James J. Scheulen, PA-C, MBA Meridith H. Thanner, PhD Edbert B. Hsu, MD, MPH Christian K. Latimer, BA Jeffrey Brown, BSME, MBA Gabor D. Kelen, MD

From the Department of Emergency Medicine (Scheulen, Thanner, Hsu, Kelen), Johns Hopkins Applied Physics Laboratory (Latimer, Brown), Johns Hopkins Office of Critical Event Preparedness and Response (Scheulen, Thanner, Hsu, Latimer, Kelen), and the National Center for the Study of Catastrophic Preparedness and Response (Scheulen, Thanner, Hsu, Latimer, Kelen), The Johns Hopkins University, Baltimore, MD.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not represent the policy or position of the Department of Homeland Security.

Few tools exist that are sufficiently robust to allow manipulation of key input variables to produce casualty estimates resulting from high-consequence events reflecting local or specific regions of concern. This article describes the design and utility of a computerized modeling simulation tool, Electronic Mass Casualty Assessment and Planning Scenarios (EMCAPS), developed to have broad application across emergency management and public health fields as part of a catastrophic events preparedness planning process. As a scalable, flexible tool, EMCAPS is intended to support emergency preparedness planning efforts at multiple levels ranging from local health systems to regional and state public health departments to Metropolitan Medical Response System jurisdictions. Designed around the subset of the National Planning Scenarios with health effects, advanced by the US Department of Homeland Security, the tool’s platform is supported by the detailed descriptions and readily retrievable evidence-based assumptions of each scenario. The EMCAPS program allows the user to manipulate key scenario-based input variables that would best reflect the region or locale of interest. Inputs include population density, vulnerabilities, event size, and potency, as applicable. Using these inputs, EMCAPS generates the anticipated population-based health surge influence of the hazard scenario. Casualty estimates are stratified by injury severity/types where appropriate. Outputs are graph and table tabulations of surge estimates. The data can then be used to assess and tailor response capabilities for specific jurisdictions, organizations, and health care systems. EMCAPS may be downloaded without cost from http://www.hopkins-cepar.org/EMCAPS/EMCAPS.html as shareware. [Ann Emerg Med. 2009;53:226-232.]

0196-0644/$-see front matter Copyright © 2008 by the American College of Emergency Physicians. doi:10.1016/j.annemergmed.2008.09.014

INTRODUCTION As part of comprehensive disaster preparedness planning,

regional planners and health care system administers must routinely conduct assessments of their response capabilities, including surge capacity and overall systems resources required for accommodating the influx of casualties after an event.1-5

Health care systems and response organizations must also assess their capability in the context of broader external factors, such as their location, populations served, and availability of outside resources. During a disaster with resultant mass casualties, all levels of responders are expected to provide the best possible care to the greatest number of victims; this can best be accomplished when a region or specific hospital medical system

knows in advance its capability to absorb and respond to the

226 Annals of Emergency Medicine

surge.4-6 Advance and directed planning, taking into consideration accurate scaling of a potential event and its consequent effect, allows emergency managers at all levels to act as more flexible and effective decisionmakers during the event.

To assist emergency planners, the Department of Homeland Security released a set of 15 National Planning Scenarios for use in federal, state, and local homeland security preparedness and response activities.7 Each scenario is described in terms of background, critical assumptions, and various effects (eg, medical, financial, logistical). The scenarios are intended to be used as the basis for exercises or as planning tools to help emergency planners better understand the nature and scope of natural and terrorist-induced hazards in their area and to guide

prioritization of preparedness expenditures. However, practical

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implementation must take into consideration regional or local components of response. For example, emergency medical services and health care systems are diverse because they differ considerably according to their locale, the populations they serve, and available resources.8 The effect, therefore, of a disaster may vary significantly according to these and various other conditions. Although the National Planning Scenarios form the basis for constructing disaster response exercises, they do not offer specific details, conditions, or casualty estimates, all of which would directly affect a system’s surge capacity demands.

Recognizing the importance of greater detail in supporting planning functions, as well as the generation of estimates that are applicable to a broader emergency planning audience, a scalable tool to aid planners of medical surge capacity was conceived and designed. Notably, the Electronic Mass Casualty Assessment and Planning Scenarios (EMCAPS) tool was designed to be intuitive and readily usable, requiring almost no instruction for successful implementation. The development and application of this tool are described in the next sections, as well as in Appendix E1 (available online at http://www. annemergmed.com). EMCAPS may be downloaded without cost from http://www.hopkins-cepar.org/EMCAPS/EMCAPS. html as shareware.

EMCAPS: DEVELOPMENT, CAPABILITIES, AND APPLICATION

On review of the 15 Department of Homeland Security scenarios, EMCAPS developers selected 9 of the scenarios that could result in large-scale health effects to include in the tool (Table 1; Figure 1).9 The remaining 6 were excluded either because of insufficient modeling and scaling information within the Department of Homeland Security scenario documentation or because limited human casualties were anticipated as a result of the particular type of attack (eg, foreign animal disease spread

Table 1. Department of Homeland Security scenarios selected for inclusion in EMCAPS.

DHS scenarios Type of Attack

Scenarios included Biological Inhalational anthrax

Pneumonic plague Food contamination (anthrax) Disease outbreak: pandemic influenza

Chemical Blister agent (mustard) Nerve agent (sarin) Pulmonary agent (chlorine)

Radiologic Dirty bomb (RDD) Explosive Improvised explosive device (IED)

Scenarios excluded Biological Foreign animal disease Chemical Toxic industrial chemicals Nuclear Improvised nuclear device Natural disaster Major hurricane in port city

Major earthquake Technological Cyber attack

or cyber attack). All scenarios were then programmed

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specifically for EMCAPS, with the exception of the pandemic flu scenario, which links directly to the Centers for Disease Control and Prevention’s (CDC’s) FluSurge model.10 Each of the remaining threat scenarios, when launched, has a link that describes the detail of the scenario; the assumptions underlying the physics and other threat factors; calculation, methodology, and scaling; and scientific references.

The selected scenarios are each programmed to allow users to input options for certain variables that enable the best representation of the locale or jurisdiction of interest, along with corresponding regional risks, vulnerabilities, and hazards (these user-controlled variables also have links to guide input decisions). Using these inputs, the tool generates the anticipated resultant surge effect of the hazard-based scenario, including casualty estimates stratified by injury types where appropriate, as well as scenario-specific health care considerations.

EMCAPS is intended to allow users to model scenarios with a range of health and medical effect magnitudes applicable to a variety of jurisdictions, regions, types of agencies, and levels of government. To meet this goal, certain assumptions were made to develop reasonable scaling calculations for each of the scenarios. Most of these assumptions and calculations were taken directly from the documented Department of Homeland Security scenarios.7 In some cases, it was necessary to conduct further research and augment this information with additional data and previously developed threat-agent predictive models (eg, plume modeling).11,12 After an initial prototype of each scenario had been developed, following Maryland’s Department of Health and Mental Hygiene doctrine for categorizing health care resources (facilities, equipment, personnel), a group of subject matter experts was consulted to vet the inputs and outputs of each of the scenarios and validate the model effect. In total, a group of 8 individuals with expertise in weapons of mass destruction, agent model transport and delivery, and medical management of resultant casualties was consulted.

The tool also provides other scenario details such as mission areas and target capabilities addressed by each scenario, as well as key planning and assessment factors. The target capabilities were developed in accordance with guidance provided in the Department of Homeland Security target capabilities list7

(Appendix E1, available online at http://www.annemergmed. com). This capabilities-based planning approach seeks to identify and document target levels of capabilities that various entities (ranging from federal to local) must achieve to effectively perform critical tasks associated with homeland security missions. Specifically, the target capabilities list, composed of 37 specific capabilities, was developed by the federal government as guidance to help entities understand their respective roles, should a major event occur, as well as the capabilities required to perform specified sets of tasks and how to acquire additional needed resources.

As an example of the design and capabilities of EMCAPS, we highlight the Chemical/Toxic Gas (Chlorine) scenario. This

scenario was selected because it has relevance to regional

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and

Computer Modeling for High-Consequence Events Scheulen et al

planning, particularly in light of the previous occurrence of a local transportation-related hazardous material incident involving a hydrochloric acid leak. Chlorine is known to be very toxic, is often shipped through cities, and is a heavy gas that, when released, will stay close to the ground and thus pose more danger to pedestrians than a lighter chemical that would tend to rise.13 Furthermore, our selection was informed by the fact that much work is being done in the simulation modeling field, using a chlorine leak as the focus of the scenario, given the high probability of this type of occurrence and the detrimental effects a chlorine exposure can have on local hospitals in particular and a city more generally.13 With regional hazard vulnerability assessment priorities in mind, this scenario was ultimately selected to highlight the capabilities and range of user inputs that are available with the EMCAPS tool.

The chlorine scenario built into EMCAPS is a scaled version of that presented by the Department of Homeland Security in the National Planning Scenarios. Because the National Planning Scenarios were developed for broad use, each is documented at magnitudes that would require a large-scale response at the regional or state level, thus limiting their utility for local or smaller-scale planning and assessment. Thus, although the scenario in the National Planning Scenarios describes the infiltration of an industrial facility that stores a large quantity of chlorine gas (liquefied under pressure), with the use of secondary devices set to affect first responders, the scenario presented in EMCAPS describes a limited-scale situation (a bomb attached to a tractor-trailer tanker carrying compressed liquid chlorine, which, on detonation, disseminates a toxic chlorine gas plume to the surrounding area).

Users are able to scale (input) appropriate settings for their geographic location, wind speed, outdoor temperature, and

Figure 1. EMCAPS home page

population density (Figure 2). The particular values selected for

228 Annals of Emergency Medicine

inclusion offer reasonable coverage of the conditions expected to be applicable and useful across a range of geography, seasons, and weather. Population density is defined as the average number of people per square mile, assuming a homogeneous distribution within the area of the event location. EMCAPS provides a table of population densities, based on US census records, for a variety of US cities to aid the user in defining this particular variable (Figure 2). Although not all US cities are listed, planners are able to select a city with a similar population density to their own.

Table 2 presents the output results for 3 localized settings with various population densities, ranging from a low of 1,021 persons per square mile to a high of 26,686 persons per square mile: Jacksonville, Baltimore, and New York City (with adjustments to outdoor temperature and wind speed included). With inputs of outdoor temperature� -1.11°C (30°F), wind speed�3 miles per hour, and population density�8,059 persons per square mile (for Baltimore, MD), 555 fatalities would be anticipated, with approximately 4,000 low-exposed, ambulatory persons; 1,800 moderately exposed persons; and 1,700 persons in the severely exposed group.

Application of EMCAPS as Part of a Directed Planning Approach

The ability for a community/region or its health system(s) to mitigate the effect of a high-consequence event depends on the level of advance planning.2,14 However, planning must be appropriately directed and hazard specific to be most effective. Responsible officials should engage in directed planning, taking into account specific community or regional issues such as population densities, vulnerabilities based on previous occurrence, and the presence of target risks or hazards (ie,

display of included scenarios.

chemical storage facilities, proximity to high profile targets,

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with

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earthquakes, etc). These considerations help to direct an entity’s planning efforts so they are more efficient, effectual, and cost- effective.2

Although response strategies are now typically produced as “all-hazards” plans, different hazards present different health outcomes, with each requiring an appropriately tailored response or a different scale of response. Thus, a proper all- hazards plan includes reviews and analyses of unique situational risk (by way of a local hazard vulnerability analysis or threat assessment) and identifies the hazard-specific capacities and capabilities required to respond to particular incidents of given strengths. This directed type of planning is likely to be the most effective in resource determinations and deployments because it can allow planners to prepare a singular response method for most anticipated events. The EMCAPS tool provides a more

Figure 2. Chlorine gas release scenario page

accurate assessment of likely population health effects estimates,

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allowing for the development of directed response plans based on realistic and localized scenarios.

DISCUSSION Scenario modeling by emergency preparedness planners is an

accepted practice that is endorsed by the Department of Homeland Security.7 Computer modeling and simulation has shown promise in supporting disaster planning activities and is increasingly used.3,13,15-17 However, there are few programs currently available that allow users to input local or regional data to estimate hazard effects or potential surge needs. The Bioterrorism and Epidemic Outbreak Response Model, developed by Weill Medical College researchers supported by the Agency for Healthcare Research and Quality, allows customizable inputs to estimate staffing needs (number and

display of detailed information by hyperlinks.

type) for community mass prophylaxis after an infectious disease

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Computer Modeling for High-Consequence Events Scheulen et al

outbreak or attack.18 There are also proprietary developed models that have an online user interface, such as CleerImpact (developed by Keigan Systems, Inc., Ontario, Canada). This program/applet determines plume dispersion from chemical or toxic hazards by using Google Maps and Google Earth19 but does not give outcome estimates. Recently, Abramovich et al20

developed a spreadsheet-based tool for pandemic planning; population inputs can be made and the effect of surge resource augmentation (eg, ventilators, staff) on health outcomes, particularly death, can be determined.

EMCAPS provides planners with the capability to determine the health and medical effect magnitudes of a subset of the 15 Department of Homeland Security National Planning Scenarios, which cover biological, chemical, radiologic, and explosive events, as well as natural disasters. Output figures can be translated into practical terms for planners as they draft an appropriate and directed response plan by suggesting resources, including personnel and particular supplies, planning entities may need (or not need) to effectively respond during such an event. In addition, EMCAPS can serve as a complementary component of the newly required National Incident Management System training for health care workers by providing an understanding of the likely surge to be encountered after various critical events—a practical application of the tool by hospital planners responsible for implementing

Table 2. EMCAPS outputs by user inputs for 3 geographic area

Inputs Geographic

Area 1

Location: urban setting (population density, persons/mile2)

Baltimore (8,059 p/mi2

Outdoor temperature, °C(°F) �1.11(30) Wind speed, miles/h 3 Outputs Fatalities 555 Low-exposed group (treatment and

release; mostly supportive care) 4,285 Symptoms Eye irritation, headache, throat irritation, coughing, and skin irritation

Moderately exposed group (treatment and observation; potential need for airway support) 1,795 Symptoms Eye pain and swelling, headache, throat irritation, rapid breathing, co

Severely exposed group (advanced treatment; probable need for airway support or mechanical ventilation) 1,702 Symptoms Eye pain and swelling, headache, throat irritation, restricted airflow: d bloody sputum, vomiting, skin irritation, and possible chemical burns

Health care considerations Large numbers of respiratory distress cases requiring positive-pressu Large demand for decontamination facilities; Appropriate PPE required for responders and health care workers; an Psychologically distressed but uninjured population reporting to hosp chlorine.

and tracking such Joint Commission accreditation standards.

230 Annals of Emergency Medicine

To the best of our knowledge, EMCAPS is the only readily available computer software program that allows locally tailored estimates of a variety of hazards. EMCAPS is an applet developed specifically for emergency response planners in the public sector or in the health and medical disciplines to assist them in understanding the nature and scope of the hazards for which they must prepare. In particular, the ability to use local estimates helps them specify and prioritize enhancements to their directed preparedness program. As an example, beyond use by those within and affiliated with the Johns Hopkins planning community, EMCAPS was used by emergency planners in the Boston area as part of their attempt to estimate the blood supply needed for their local area in response to a potential mass casualty event.21 The ultimate success of this type of tool, however, will be evident through further evaluations of its use by and usefulness for organizations involved in emergency planning, the documentation of which we plan to track in a future version of the tool. To date, however, more than 125 CD-ROM versions of the program have been distributed to health care and government officials, and there have been more than 1,000 hits to our EMCAPS Web page.

There are several limitations about the development of EMCAPS. First, EMCAPS was developed assuming that the conditions and calculations contained in the Department of Homeland Security scenarios were accurate. Second, the same

Geographic Area 2

Geographic Area 3

Jacksonville (1,021 p/mi2)

New York City (26,686 p/mi2)

15.56 (60) 32.22 (90) 9 15

21 692

362 10,961

154 6,505

g, chest pain, and skin irritation.

106 4,375

lty breathing, coughing, chest pain, lung inflammation and edema,

ntilation;

could be as high as 9 times the actual number of people affected by

s.

)

.

ughin

ifficu .

re ve

d itals

conditions, assumptions, and calculations were used in the

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Scheulen et al Computer Modeling for High-Consequence Events

scaling of each of the scenarios, and thus any errors or inaccuracies in the scenarios as published by the Department of Homeland Security will be reflected in EMCAPS; no independent validation of the scenarios has been conducted. Third, in considering population density, average population distribution is used for purposes in calculations; some jurisdictions, however, may have considerable variability within a given area. Fourth, in the scenario example, the outcome was limited to a 1-hour exposure, although, as noted, this is a commonly accepted figure. Still, in subsequent iterations of the tool, exposure time will be made a scalable variable. Finally, EMCAPS does not estimate the number of “worried well” persons related to individual scenarios who can add to the surge burden experienced by elements of the health system. EMCAPS, however, will be refined in a future version, with the inclusion of more models and increased data elements, including, in part, to address identified limitations and to further broaden its applicability (ie, the transformation of current discrete variable options to variables that are more scalable; the ability to examine in greater detail the release of other toxins, biologic agents, etc). Additionally, in future versions, we will include mathematical modeling to allow sensitivity analysis, although some sense of variability can be ascertained by the minor manipulations of the scalable variables in the current version.

Despite these limitations, EMCAPS provides casualty estimates for selected Department of Homeland Security planning scenarios according to variable user inputs that have not been previously widely available. In particular, as a flexible, scalable tool, EMCAPS, which is portable and easily shared, can help emergency response planners better understand and prioritize readiness needs and response efforts according to their unique, localized situation. Furthermore, by generating a packaged set of scenario outputs, EMCAPS is specifically formatted to foster collaborative, capabilities-based discussions, exercises, and training as part of an overall preparedness planning process.

Supervising editor: Jonathan L. Burstein, MD

Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article, that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. Supported in part by a Maryland Special Projects Grant through the Health Resources and Services Administration (HRSA) FY 2005 Bioterrorism Hospital Preparedness Program and by the US Department of Homeland Security through a grant (N00014- 06-1-0991, awarded to the National Center for the Study of Catastrophic Preparedness and Response). Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not represent the

policy or position of the Department of Homeland Security.

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Publication dates: Received for publication May 15, 2008. Revision received August 19, 2008. Accepted for publication September 16, 2008. Available online November 4, 2008.

Reprints not available from the authors.

Address for correspondence: Meridith H. Thanner, PhD, Johns Hopkins Office of Critical Event Preparedness and Response, 5801 Smith Avenue, Davis Bldg 3220, Baltimore, MD 21209; 410-735-6442, fax 410-735-6440; E-mail mthanne1@ jhmi.edu.

REFERENCES 1. Barbisch DF, Koenig KL. Understanding surge capacity: essential

elements. Acad Emerg Med. 2006;13:1098-1102. 2. Baker D, Refsgaard K. Institutional development and scale

matching in disaster response management. Ecol Econ. 2007;63: 331-343.

3. Kaji A, Koenig KL, Bey T. Surge capacity for healthcare systems: a conceptual framework. Acad Emerg Med. 2006;13:1157-1159.

4. Kelen GD, McCarthy M. The science of surge. Acad Emerg Med. 2006;13:1089-1094.

5. Kaji AH, Langford V, Lewis RJ. Assessing hospital disaster preparedness: a comparison of an on-site survey, directly observed drill performance, and video analysis of teamwork. Ann Emerg Med. 2008;52:195-261.

6. Bonnet CJ, Peery BN, Cantrill SV, et al. Surge capacity: a proposed conceptual framework. Am J Emerg Med. 2007;25:297- 306.

7. Department of Homeland Security. National preparedness guidelines, September 2007. Available at: http://www.dhs.gov/ xlibrary/assets/National_Preparedness_Guidelines.pdf. Accessed March 27, 2008.

8. Committee on the Future of Emergency Care in the United States Health System, Institute of Medicine of the National Academies. Emergency Medical Services at the Crossroads. Washington, DC: National Academies Press; 2006.

9. Latimer CK, Brown JC. Electronic Mass Casualty Assessment & Planning Scenarios (EMCAPS) Development Project, Maryland HRSA Bioterrorism Hospital Preparedness Program, Special Projects Grant, FY 2005. Laurel, MD: Johns Hopkins Applied Physics Laboratory; 2006. JHU/APL Report, NSAD-R-2006-057.

10. Centers for Disease Control and Prevention. FluSurge V2.0. Available at: http://www.cdc.gov/flu/tools/flusurge. Accessed July 7, 2008.

11. National Oceanographic and Atmospheric Administration. ALOHA V5.3.1. Available at: http://www.epa.gov/emergencies/content/ cameo/index.htm. Accessed July 7, 2008.

12. Segal E, Lang E. Toxicity, chlorine gas [WebMD Web site]. Available at: http://www.emedicine.com/emerg/topic851. htm. Accessed March 14, 2008.

13. Coolahan JE, Kane MT, Schloman JF, et al. Design of an urban chemical disaster simulation federation for preparedness and response, technical paper No. 07S-SIW-077. Presented at: Fall Simulation Interoperability Workshop; September 16-21,2007; Orlando, FL.

14. Kaji AH, Koenig KL, Lewis RJ. Current hospital disaster preparedness. JAMA. 2007;298:2188-2190.

15. Hoard M, Homer J, Manley W, et al. Systems modeling in support of evidence-based disaster planning for rural areas. Int J Hyg Environ Health. 2005;208:117-125.

16. Xinzheng L, Ning Y, Jianjing J. Application of computer simulation technology for structure analysis in disaster. Automat Construct.

2004;13:597-606.

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Computer Modeling for High-Consequence Events Scheulen et al

17. Asher H, Stein M, Raphael W. Surgical resource utilization in urban terrorist bombing: a computer simulation. J Trauma Injury Infect Crit Care. 1999;47:545-550.

18. Agency for Healthcare Research and Quality. Computer staffing model for bioterrorism response, BERM V2.0. Available at: http:// www.ahrq.gov/research/biomodel.htm. Accessed July 7, 2008.

19. Keigan Systems. CLEER Impact: emergency impact simulator. Available

at: http://cleerimpact.keigansystems.com. Accessed July 7, 2008.

232 Annals of Emergency Medicine

20. Abramovich MN, Toner ES, Matheny J. Panalysis: a new spreadsheet-based tool for pandemic planning. Biosecur Bioterror. 2008;6:78-92.

21. Brinsfield, K. Reserve donor strategies [Department of Health and Human Services Web site]. PowerPoint presented to: Advisory Committee on Blood Safety and Availability. Available at: http:// www.hhs.gov/ophs/bloodsafety/presentations/brinsfield0807.pdf.

Accessed July 7, 2008.

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APPENDIX E1. Design details of EMCAPS. Each of the EMCAPS scenarios was prototyped in Excel and the algorithms and formulas were converted to C# code with Visual Studio (Microsoft Corporation, Seattle, WA). Standard Windows forms (Microsoft Corporation) controls were used for the user interface, and EMCAPS is compatible with any Windows-based system. Formatting of scenario results was completed with Crystal Reports (Business Objects, San Jose, CA). All references, assump- tions, conditions, and calculations for each scenario are described in the “Calculation Methodology” and “Scaling” hyperlink sec- tions in the EMCAPS tool itself, allowing the user to conduct independent validation and make adjustments as desired.

As an example of the design and capabilities of EMCAPS, we highlight the Chemical/Toxic Gas (Chlorine) scenario within the article. EMCAPS uses ALOHA (Areal Locations of Hazardous Atmospheres) hazardous plume modeling software to derive cal- culations for each combination of user-defined conditions (eg, outdoor temperature, wind speed, setting, and population densi- ty).1 Within the ALOHA software program, 3 variables were de- termined to have a significant effect on the plume dispersion: outdoor temperature, wind speed, and setting. A discrete set of options was chosen for each of these variables, and each permuta- tion of variable combinations was calculated. The options pro- vided in EMCAPS for each of the variables are shown in Figure 2.

In each case, the source of the toxic gas is a standard tractor-trailer that is attacked, resulting in a 3-foot hole in the lower portion of the tanker. The dimensions of the tanker and hole were also analyzed with ALOHA to determine the quantity and dynamics of the gas release. The effects of the gas on the exposed population were deter- mined by referencing independent research on chlorine toxicity,2 and the overall effect of the gas on human populations was determined by evaluating the chlorine gas concentration regions identified by ALO- HA.1 The referenced study2 outlines research conducted to deter- mine the probable effects that each of these concentration levels would have on humans. The total casualty population (as an EM- CAPS output) is then determined by comparing the concentration areas to the user-defined population density.

When the plume was modeled in ALOHA, the total length of time of the gas release was set at 1 hour and the chemical concen- tration rings were identified within the generated dispersion path. The 1-hour period for detailing the plume dispersion path is a default setting within the ALOHA model and is used here as the length of time when persons within the target area would be most severely affected. The use of this particular period is also consistent with other research examining the effect of a toxic gas release— when defined as a finite duration event—on a local area where chemical concentrations have a 60-minute implied exposure time.3-5 The base assumptions built into EMCAPS for this sce- nario (assumptions more in line with a smaller-scale event and based on information used in the National Planning Scenarios, in independent research, and in ALOHA) are as follows (Figure 2):

● 4,850-gallon tank, all contents released through 3-foot

hole

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● partly cloudy, no precipitation ● 50% of people in plume area are indoors ● first effects on humans at concentration�10 ppm ● minimum lethal dose�430 ppm for 30 min ● median lethal dose (short-term exposure)�1,000 ppm

DEPARTMENT OF HOMELAND SECURITY TARGET CAPABILITIES LIST Common

● Planning ● Communications ● Risk management ● Community preparedness and participation

Prevent Mission Area

● Information gathering and recognition of indicators and warnings

● Intelligence analysis and production ● Intelligence/information sharing and dissemination ● Law enforcement investigation and operations ● CBRNE detection

Protect Mission Area

● Critical infrastructure protection (CIP) ● Food and agriculture safety and defense ● Epidemiologic surveillance and investigation ● Public health laboratory testing

Recover Mission Area

● Structural damage and mitigation assessment ● Restoration of lifelines ● Economic and community recovery

Respond Mission Area

● Onsite incident management ● Emergency operations center management ● Critical resource logistics and distribution ● Volunteer management and donations ● Responder safety and health ● Public safety and security response ● Animal health emergency support ● Environmental health ● Explosive device response operations ● Firefighting operations/support ● Weapons of mass destruction/HazMat response and

decontamination ● Citizen protection: Evacuation or in-place protection ● Isolation and quarantine

● Urban search and rescue

Annals of Emergency Medicine 232.e1

● Emergency public information and warning ● Triage and out-of-hospital treatment ● Medical surge ● Medical supplies management and distribution ● Mass prophylaxis ● Mass care (sheltering, feeding, and related services) ● Fatality management

REFERENCES 1. National Oceanographic and Atmospheric Administration. ALOHA

V5.3.1. Available at: http://www.epa.gov/emergencies/content/

cameo/index.htm. Accessed July 7, 2008.

232.e2 Annals of Emergency Medicine

2. Segal E, Lang E. Toxicity, chlorine gas [WebMD Web site]. Available at: http://www.emedicine.com/emerg/topic851.htm. Accessed March 14, 2008.

3. Moussa, MI, Eid T. Risk management for chlorine producing factory in Egypt. Australian J Basic Appl Sci. 2007;1:239-248.

4. Chitumalla PK, Harris D, Thuraisingham B, et al. Emergency response applications: dynamic plume modeling and real-time routing. Crisis Management. 2008;January/February:38-44.

5. Texas Department of State Health Services. Chlorine facts: Hazardous Substances Emergency Events Surveillance (HSEES) System [Texas Department of State Health Services Web site]. Available at: http://www.dshs.state.tx.us/epitox/fact_sheets/chlorine.

pdf. Accessed March 27, 2008.

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