The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments

The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments Emily Post, Eileen Morocho, Shaun Allen, Carly Cox, Kaitlin Rainwater-Lovett, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9271722/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background When large-scale disasters exhaust civilian federal agencies’ assets, the U.S. Federal Emergency Management Agency can issue mission assignments to the Department of War (DoW) to leverage its unique, self-sustaining logistical and operational capabilities. Despite the DoW’s critical role, empirical analyses characterizing military involvement in civilian-led disaster response remain scarce, limiting the potential for proactive strategic planning. This study aimed to provide a data-driven baseline of DoW contributions to domestic disaster relief. Methods This study characterized DoW contributions to U.S. disaster response by analyzing 4,065 Federal Emergency Management Agency (FEMA) mission assignments issued between 2012–2024. Mission assignments were analyzed by geographic location, disaster type, event timing, personnel types deployed, and associated Emergency Support Function. Results The DoW supported 37% of all original FEMA mission assignments during the study period. Activity peaked during the 2017 hurricane season and the COVID-19 pandemic. Tropical cyclones and hurricanes in low-lying coastal states and island territories, and biological incidents in densely populated areas, were the primary drivers for DoW assistance. The DoW primarily supported Emergency Support Functions relating to Public Works and Engineering, Logistics, and Information and Planning activities. The U.S. Army Corps of Engineers was the most active entity, involved in 38% of all DoW-supported mission assignments. Conclusion As an essential federal partner in managing increasingly complex, large-scale disasters, a data-informed picture of the DoW’s contributions is vital for strategically optimizing operational planning and resource deployments to protect the health and well-being of the American public. Department of War Humanitarian Assistance Disaster Relief Disaster Preparedness Figures Figure 1 Figure 2 Figure 3 Background Within the United States, natural events beyond human control and public health emergencies are increasing in scale, complexity, and severity [ 1 ]. National-level disaster events, such as Hurricane Katrina, Superstorm Sandy, and the COVID-19 pandemic, have demonstrated that robust federal interagency collaboration is necessary to respond to complex, large-scale emergencies, protect lives, and build national resilience to future catastrophic events. When a natural hazard or public health emergency occurs within the United States, governmental disaster response initially occurs at the state, tribal, local, and territorial levels. If the severity of an event exhausts a jurisdiction’s response capabilities, the governor of a state or territory, or tribal leader, can request federal assistance from the President of the United States. The President can then declare a disaster and authorize federal support through the Robert T. Stafford Disaster Relief and Emergency Act [ 2 ]. This law provides authority to the Federal Emergency Management Agency (FEMA) to coordinate various Emergency Support Functions (ESFs) and direct response activities by the federal entities involved [ 3 ]. Available under the National Response Framework (NRF), the 15 ESFs represent a framework for grouping functional areas of essential services, resources and capabilities that the federal government provides to support states, tribes, territories, local governments, and the public sector during a disaster or emergency response [ 4 ]. However, in situations where the scale of a disaster exhausts civilian federal agencies’ assets, FEMA can request support from the Department of War (DoW). The DoW possesses an array of unique resources - such as tactical air and sealift capabilities and extensive logistics, communications, and distribution networks - that can be rapidly mobilized and deployed at scale to support disaster response [ 5 ]. Additionally, the DoW typically deploys units as self-sustaining force packages, ensuring that already-strained community resources are not depleted. The increasing complexity of disasters in the domestic U.S. suggests that the DoW may continue, if not increase, its role in federal disaster response. Yet the capabilities provided by military involvement in disaster response and humanitarian aid remains poorly understood relative to civilian capabilities, limiting opportunities for proactive planning and strategic resource allocation. This lack of understanding arises partially due to the dearth of empirical analyses evaluating military involvement in civilian-led disaster response efforts [ 6 ]. Strengthening military contributions to disaster response efforts that complement the civilian sector requires empirical data with respect to geographic location, disaster type, timing of disaster and response activities, personnel deployments and supported ESF. To investigate the contexts in which the DoW contributes to disaster response activities in support of civilian responses receiving federal support following Stafford Act declarations, we characterized DoW support to domestic disaster response efforts among FEMA-issued mission assignments between the years of 2012 and 2024 [ 7 ]. Mission assignments represent work orders issued by FEMA to other federal agencies to leverage resources and capabilities to support disaster response efforts. Multiple, distinct mission assignments can be issued for one disaster and are assigned to each U.S. state, tribe, or territory. As such, mission assignments provide a verifiable record of requested support from the DoW for disaster response efforts. This analysis provides a foundational, data-driven understanding of how the DoW contributes to federal interagency disaster response, providing information to support operational planning and future research concerning military-civilian collaboration in disasters. Methods Details on the location, timing, disaster type, personnel, and ESFs provided by DoW domestic disaster response events were identified among data on FEMA mission assignments collected by FEMA’s Operations Capabilities Branch in the Department of Homeland Security (DHS). Mission assignments used for this report were extracted on May 14th, 2025 from the open source National Emergency Management Information System (NEMIS) [ 8 ]. Available data spanning from January 2012 to May 2025 were obtained and represented both originally issued mission assignments and any associated amendments prior to their initial issuance, which reflect adjustments in the work performed, funding, cost estimates, period of performance, or other terms of the assignment that unfolded during a disaster response. Of these, data were restricted to initial mission assignments and only those assigned from the years 2012 to 2024, to account for incompleteness of data logged in 2025 due to the ongoing nature of updates to mission assignments. We categorized the state, tribe, or territory for which a mission assignment was issued; the calendar year in which a mission assignment’s period of performance was requested to begin; the disaster or incident type generating a mission assignment; the specific DoW entity or Service branch assigned to execute the stated work; and the specific ESF associated with each mission assignment’s stated work. We then organized and visualized the data based upon observed trends. Data processing and analyses were conducted using Stata SE 18.0 [ 9 ]. Changes in the observed frequency of events over time were evaluated by simple linear regression. Results Of the 39,381 mission assignments and amendments captured in the initial dataset, 11,086 entries were original mission assignments without amendments between the years 2012 and 2025. Data from 2025 were excluded due to it being an incomplete year, resulting in 10,946 original mission assignments between the years 2012 and 2024. Missions were assigned by FEMA to multiple U.S. Departments and Agencies (Table 1 ). The DoW was assigned to support disaster or public health emergency incidents in 4,065 (37%) missions. Table 1 Distribution of FEMA Mission Assignments Assigned to U.S. Departments or Agencies from 2012–2024. U.S. Department or Agency Number (%) of Total Mission Assignments DoW 4065 (37%) DHS 1228 (11%) HHS 966 (9%) USDA 742 (7%) GSA 631 (6%) EPA 495 (5%) DOT 425 (4%) DOJ 362 (3%) DOI 342 (3%) DOC 326 (3%) DOE 321 (3%) VA 262 (2%) DHUD 148 (1%) Other 633 (6%) Geographic Analysis The 4,065 mission assignments from this sample encompassed all 50 U.S. states and 6 districts/territories – the District of Columbia, Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands (Fig. 1 ). From 2012 to 2024, the state of Florida generated the most mission assignments assigned to the DoW of any U.S. state or territory, encompassing 514 distinct observations (13% of total). Additional states and territories that made up notable proportions of DoW mission assignments include Puerto Rico (n = 320 [8%]), Louisiana (n = 260, [6%]), the Virgin Islands (n = 203 [5%]), and Texas (n = 198 [5%]). The South Atlantic states generated the most DoW mission assignments compared to other U.S. regions (n = 1,057 [26%]). Note Visualized using MapChart ( https://mapchart.net ) [ 10 ]. Temporal Analysis From 2012 to 2024, the DoW averaged 312 distinct FEMA mission assignments per year. The DoW received the most requests for domestic disaster response support during the periods of 2017–2018 and 2020–2021, accounting for 29% (n = 1,154) and 31% (n = 1235) of mission assignments, respectively (Fig. 2 ). These peaks were associated with a strong hurricane season in 2017 and the COVID-19 pandemic response, respectively, although no statistically significant change was observed in the number of mission assignments to the DoW per year over time ( p = 0.20). Incident Type Analysis The majority of mission assignments requesting DoW support between 2012 and 2024 were in response to tropical cyclones and hurricanes (n = 2,309 [57%]) (Table 2 ). Additionally, biological incidents, defined by FEMA as events involving both naturally occurring or deliberately caused outbreaks of an infectious pathogen affecting people, accounted for 20% of DoW disaster response requests (n = 815). Overall, these two incident types accounted for over three-quarters of FEMA mission assignments involving DoW support within the observed time period. Mission assignments for tropical cyclones and hurricanes most commonly originated from Florida (n = 423 [18%]) and Puerto Rico (n = 282 [12%]), whereas biological disaster support requests to DoW most commonly originated from the District of Columbia (n = 63 [8%], California (n = 48 [6%]) and New York (n = 39 [5%]). Table 2 Most common U.S. incident types resulting in DoW-assigned mission assignment from 2012 to 2024. Incident Type Number (%) of Mission Assignments Most Commonly Impacted U.S. State/Territory Tropical Cyclone / Hurricane 2,309 (57%) Florida Biological 815 (20%) District of Columbia Severe Storm 234 (6%) Iowa Flood 212 (5%) California Fire 170 (4%) California Coastal Storm 129 (3%) Florida Winter Storm 47 (1%) Texas Tornado 38 (< 1%) Kentucky Earthquake 27 (< 1%) Puerto Rico Dam/Levee Break 12 (< 1%) California Volcanic Eruption 10 (< 1%) Hawaii Mud/Landslide 9 (< 1%) Washington Chemical 6 (< 1%) Ohio Unclassified 47 (1%) Hawaii Emergency Support Function and Personnel Analysis Of the 4,065 DoW-supported mission assignments, 59% of the available data identified the associated ESF (Table 3 ). The DoW most commonly supported ESF #3: Public Works and Engineering (n = 1,340 [33%]), followed by ESF #7: Logistics (n = 369 [9%]) and ESF #5: Information and Planning (n = 287 [7%]). Table 3 Emergency Support Functions and responding DoW agency for DoW-assigned mission assignments from 2012 to 2024. Emergency Support Function Number (%) of Mission Assignments Most Frequent Responding DoW Agency 3: Public Works & Engineering 1,340 (33%) U.S. Army 7: Logistics Management & Resource Support 369 (9%) Defense Logistics Agency 5: Information & Planning 287 (7%) U.S. Air Force 8: Public Health & Medical Services 128 (3%) Defense Logistics Agency 9: Search & Rescue 112 (2%) U.S. Coast Guard 10: Oil & Hazardous Materials Response 45 (1%) U.S. Coast Guard 6: Mass Care, Emergency Assistance, Housing, Human Services 43 (1%) U.S. Army 15: External Affairs 30 (< 1%) U.S. Coast Guard 1: Transportation 23 (< 1%) NA 13: Public Safety & Security 6 (< 1%) U.S. Army 2: Communications 4 (< 1%) NA 12: Energy 3 (< 1%) U.S. Air Force 4: Firefighting 1 (< 1%) NA 11: Agriculture and Natural Resources 0 NA 14: Long-Term Community Recovery 0 NA Missing/Unidentified 1,674 (41%) NA Additionally, 2,337 (57%) of observed mission assignments in the dataset identified the specific DoW entity or Service branch that was deployed to execute the assigned work (Fig. 3 ). The most commonly referenced organization was the U.S. Army, specifically the Army Corps of Engineers (USACE), which was involved in a total of 1,547 mission assignments (38% of total). The USACE supported the majority of Public Works and Engineering mission assignments (n = 1,327 [99% of ESF #3 mission assignments]), while the Defense Logistics Agency (DLA) was responsible for more than half of Logistics support (n = 194 [53% of ESF #7 mission assignments]). Information and Planning support was commonly provided by the U.S. Air Force (n = 109 [38% of ESF #5 mission assignments]), with additional support from the U.S. Coast Guard (n = 40 [14%]) and U.S. Army (n = 11 [4%]). Discussion This study assessed empirical evidence for military involvement in domestic disaster response operations. By analyzing more than a decade of data on FEMA mission assignments, this analysis provides evidence of substantial DoW contributions to civilian authorities during domestic disasters, highlighting its critical support in public works, logistics, and planning during large-scale, complex disaster events. This assessment of FEMA’s open source dataset shows that 37% of 10,946 original FEMA mission assignments issued between 2012 and 2024 were assigned to the DoW. Periods of peak activity during the 2017 hurricane season and the COVID-19 Pandemic illustrate DoW’s role in supporting U.S. government response to high-impact, catastrophic domestic disaster events. Responses to the COVID-19 Pandemic were largely concentrated in densely populated areas such as the District of Columbia, New Jersey, and California. Similarly, low-lying coastal states in the South Atlantic and small island territories were more likely to receive support than areas at higher altitude, specifically due to cyclones and hurricanes. Both event types represented large-scale, wide-ranging, and prolonged disaster events where local, state, and federal civilian agencies’ capacities were overwhelmed. While only ~ 60% of the available data identified the ESF and permitted classification of the type of support provided by the DoW, available results revealed that the DoW most commonly supported ESF #3: Public Works and Engineering, overwhelmingly through the USACE. Additional areas of frequency support were ESF #7: Logistics, most commonly provided by the DLA, and ESF #5: Information and Planning. The USACE’s critical role in ESF #3 and the relatively high frequency of response efforts illustrates DoW’s extensive infrastructure capabilities supporting civilian disaster response. This type of disaster response can include large-scale engineering projects after major destructive events, such as debris removal, infrastructure repair and water resource management, that are often beyond the scope or immediate capacity of civilian agencies. The USACE, however, has a long-standing civil works mission to develop and maintain civilian infrastructure [ 11 ]. This inherent expertise combined with a region-specific organizational structure allows units to maintain a local geographic presence and almost institutionalizes their involvement in any federal-level disaster response requiring surge capacity and capabilities. Beyond infrastructure support, ESF #7 (Logistics) and ESF #5 (Information and Planning) were the second and third most frequent response activities by the DoW, respectively, illustrating the importance of the DoW’s capacity to coordinate and execute the movement of life-sustaining resources in disaster zones when normal supply chains are disrupted. Interestingly, while the DLA’s primary mission focuses on global supply chain logistics during conflict, the agency’s capabilities clearly have the capacity to be adapted for large-scale commodity distribution in domestic disaster events [ 12 ]. Additionally, this work is often coordinated with the U.S. Air Force and U.S. Coast Guard, leveraging air and sea supply transport, reconnaissance, and structured planning capabilities. Overall, the proportion of FEMA mission assignments to the DoW in the observed data portray DoW capabilities as critical contributions to federal-level disaster response. This appears true for certain types of high-magnitude, complex disaster incidents that result in substantial disruption to physical infrastructure and local supply chains. Should a complex disaster occur simultaneous with wartime obligations, it is unclear how these capabilities would be provided during domestic disaster response. Further assessment of civilian dependencies on the military as well as potential alternative solutions when DoW is unable to respond are needed. High-impact disaster incidents in cyclone/hurricane-prone areas are associated with higher numbers of requests for DoW assistance, and the emergence of biological disasters will likely continue to require DoW’s extensive logistics and planning capabilities. Our analysis clearly indicates DoW maintains capabilities that are essential for responding to a variety of disaster-level events, especially those of a complex or large-scale nature. While this study provides an analysis of DoW support through FEMA mission assignments, several limitations warrant consideration. First, the focus on mission assignments sourced from NEMIS program records may not capture the full range of DoW disaster response assistance, such as immediate response actions or support provided outside the Stafford Act framework. Second, while the dataset is extensive, approximately 40% of mission assignments were incomplete regarding specific ESFs and deployed personnel, and the 2012–2024 timeframe may not capture longer-term historical shifts in DoW involvement with disaster response. Third, the methodological decision to exclude amendments made after initial issuance may not capture the full scope, duration, or nature of the work performed, which may evolve significantly during a response. Despite these constraints, this research offers an initial data-driven baseline of formally requested DoW support, identifying crucial trends that are foundational for potential planning adjustments. These adjustments may include strengthening of DoW capability in areas of likely future use or the development of civilian capabilities in areas where DoW dependence creates risk, especially in wartime. Future research should aim to complement these findings through examining mission assignment amendments to understand evolving needs and investigate methodologies to capture the full spectrum of DoW domestic disaster support beyond formal mission assignments, potentially including an analysis of DoW's internal data sources. A more holistic assessment of DoW support to disaster response simultaneous with other wartime requirements is also warranted. Conclusion This study underscores the necessity for proactive and refined partnerships between the DoW and civilian federal agencies tasked with domestic disaster response operations. Given the operational significance of DoW capabilities in disaster response to the National Response Framework, potential efficiency gains could likely occur through more deeply embedded coordination mechanisms and unified miliary-civilian training exercises. The increasing scale and complexity of domestic disasters and public health emergencies in the U.S. necessitates a precise, data-informed picture of the DoW’s contributions for both civilian and military organizations to ensure operational planning and resource deployments are strategically aligned to best protect lives and property. Declarations Ethics approval and consent to participate: Not applicable Consent for publication: Not applicable Availability of data and materials: Data that support the findings of this study are available upon reasonable request to the authors and pending approval for distribution by program leadership. Competing interests: The authors declare that they have no competing interests Funding: I. Award No. HU00012120098: The Office of the Assistant Secretary of War for Health Affairs, 77000 Arlington Blvd., Suite 5101, Falls Church, VA 22042-5101, is the awarding office and the Uniformed Services University of the Health Sciences (USUHS), 4301 Jones Bridge Road, Bethesda, MD 20814, is the administering office. II. This project is sponsored by USUHS; however, the information or content and conclusions reported in this work do not necessarily represent the official position or policy of, nor should any official endorsement be inferred on the part of, USUHS, the U.S. Department of War, the U.S. Government, or the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. Authorship Contributions: Conceptualization – JF and JC; Methodology – EP, EM, KR, JF; Software – EP, EM; Data Curation – SA, EP, EM; Formal Analysis – EP, EM; Resources – EP; Writing – Original Draft, EP, EM, SA, CC, KR; Writing – Review & Editing, EP, EM, SA, CC, KR, JC, JF; Visualization – EM, EP; Project Administration – EM, EP; Supervision – KR, JF, CC. All authors were involved in manuscript writing and approved the final manuscript. Acknowledgements: The authors acknowledge the support of NDMS Pilot leadership. Disclaimer This project is sponsored by the Uniformed Services University of the Health Sciences (USUHS); however, the information, content, and conclusions reported in this work do not necessarily represent the official position or policy of, nor should any official endorsement be inferred on the part of USUHS, the U.S. Department of War, the U.S. Government, or the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. Institutional Clearance Approved by USUHS Office of the Vice President for External Affairs and HJF Regulatory Affairs. References National Centers for Environmental Information. U.S, Billion-Dollar Weather, Disasters C. https://www.ncei.noaa.gov/access/billions/ (2025). Accessed 30 Sept 2025. Federal Emergency Management Agency, Robert T. Stafford Disaster Relief and Emergency Assistance Act. https://www.fema.gov/disaster/stafford-act (2023). Accessed 30 Sept 2025. Federal Emergency Management Agency. National Response Framework. https://www.fema.gov/emergency-managers/national-preparedness/frameworks/response (2024). Accessed 30 Sept 2025. United States Department of Homeland Security. National Response Framework (4th Ed). 2019. https://www.fema.gov/sites/default/files/documents/NRF_FINALApproved_2011028.pdf Accessed 30 Sept 2025. United States Department of Defense. DoD Manual 3025.01, Vol. 2, Defense Support of Civil Authorities: DoD Incident Response. 2017. https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodm/302501_vol02.pdf Accessed 30 Sept 2025. Grace R, Center for Human Rights and Humanitarian Studies. Surmounting Contemporary Challenges to Humanitarian-Military Relations. Brown University,. 2020. https://watson.brown.edu/chrhs/files/chrhs/imce/research/Surmounting%20Contemporary%20Challenges%20to%20Humanitarian-Military%20Relations_Grace.pdf Accessed 30 Sept 2025. Federal Emergency Management Agency. Federal Agency Mission Assignments. https://www.fema.gov/partnerships/mission-assignments (2024). Accessed 30 Sept 2025. Federal Emergency Management Agency. National Incident Management System. https://www.fema.gov/emergency-managers/nims (2025). Accessed 30 Sept 2025. StataCorp, Stata. Version 18.0. 2023. https://www.stata.com/stata18/ Accessed 30 Sept 2025. MapChart. Create your own custom map. 2025. https://mapchart.net Accessed 30 Sept 2025. United States Army Corps of Engineers. Mission Overview. https://www.usace.army.mil/Missions / (2025). Accessed 30 Sept 2025. Defense Logistics Agency. About the Defense Logistics Agency. https://www.dla.mil/About-DLA / (2025). Accessed 30 Sept 2025. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9271722","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":616621692,"identity":"b938ff11-c5de-4e6b-914e-ca05c7d5c191","order_by":0,"name":"Emily Post","email":"","orcid":"","institution":"Henry M. 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Jackson Foundation","correspondingAuthor":false,"prefix":"","firstName":"Kaitlin","middleName":"","lastName":"Rainwater-Lovett","suffix":""},{"id":616621702,"identity":"ead58fc8-7aac-4e38-b77f-41b71a4e4b36","order_by":5,"name":"James Chambers","email":"","orcid":"","institution":"United States Department of War","correspondingAuthor":false,"prefix":"","firstName":"James","middleName":"","lastName":"Chambers","suffix":""},{"id":616621703,"identity":"2785c5e8-3efa-4d4d-9da0-1257adb193d4","order_by":6,"name":"Jeffrey Freeman","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFUlEQVRIiWNgGAWjYBACxgbGBx9ADPYGiIAcELNBZHBqYTacAWLwHIAIGBPUwsCApiWxgZAW5vZmxuaKisMMPNKHDz66UXMnfcP5M2YPfzDYyG44gMNhPYcZG8+cAWrhS0s2zjn2LHfDjRxzYx6GNGOcWmbkH3/Y2HaYwZ6Hx0w6h+0wUAuQwcBwOBGnlvmPGRsb/wFt4eH//jvn3+F0A6DDJH8w/MetZQYzUEsDSAsPG3Nu2+EEgwM5ZhI8DAdwa+lJZmxsOJYO0mEsndt32HDmjbQyaR6DZOOZOLQYtgO931BjLcfDw/zwc863w/J85w9vk/xRYSfbh0tLA5hq5kETN8CuHATkIVQdbhWjYBSMglEwCgB5y2DKwGWX/AAAAABJRU5ErkJggg==","orcid":"","institution":"Uniformed Services University of the Health Sciences","correspondingAuthor":true,"prefix":"","firstName":"Jeffrey","middleName":"","lastName":"Freeman","suffix":""}],"badges":[],"createdAt":"2026-03-30 20:23:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9271722/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9271722/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106114173,"identity":"05241cde-2207-48bb-b0cc-3e3aa09134db","added_by":"auto","created_at":"2026-04-03 15:49:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":108297,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency of DoW-assigned mission assignments to U.S. states and territories from 2012 to 2024.\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote\u003c/strong\u003e: Visualized using MapChart (https://mapchart.net) [10].\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9271722/v1/c7519e0427e3f7b238b32c49.png"},{"id":106114171,"identity":"5e187a5d-160b-486d-a5fa-d3a4f9f5d256","added_by":"auto","created_at":"2026-04-03 15:49:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":26204,"visible":true,"origin":"","legend":"\u003cp\u003eFrequency of DoW-assigned mission assignments from 2012-2024.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9271722/v1/4332af9ee62130421083cb36.png"},{"id":106402052,"identity":"912b2048-dbfe-491c-9b67-3ccbb238b1a1","added_by":"auto","created_at":"2026-04-08 09:10:47","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":72217,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9271722/v1/1274a67a4ed2360dc9f9280d.png"},{"id":106787115,"identity":"6683c0ad-ba13-4fb6-8f18-64b47908dfaa","added_by":"auto","created_at":"2026-04-13 12:44:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":827473,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9271722/v1/a26e9baf-d23f-4a0b-83fc-954f9ccfb082.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments","fulltext":[{"header":"Background","content":"\u003cp\u003eWithin the United States, natural events beyond human control and public health emergencies are increasing in scale, complexity, and severity [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. National-level disaster events, such as Hurricane Katrina, Superstorm Sandy, and the COVID-19 pandemic, have demonstrated that robust federal interagency collaboration is necessary to respond to complex, large-scale emergencies, protect lives, and build national resilience to future catastrophic events.\u003c/p\u003e \u003cp\u003eWhen a natural hazard or public health emergency occurs within the United States, governmental disaster response initially occurs at the state, tribal, local, and territorial levels. If the severity of an event exhausts a jurisdiction\u0026rsquo;s response capabilities, the governor of a state or territory, or tribal leader, can request federal assistance from the President of the United States. The President can then declare a disaster and authorize federal support through the Robert T. Stafford Disaster Relief and Emergency Act [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. This law provides authority to the Federal Emergency Management Agency (FEMA) to coordinate various Emergency Support Functions (ESFs) and direct response activities by the federal entities involved [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Available under the National Response Framework (NRF), the 15 ESFs represent a framework for grouping functional areas of essential services, resources and capabilities that the federal government provides to support states, tribes, territories, local governments, and the public sector during a disaster or emergency response [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, in situations where the scale of a disaster exhausts civilian federal agencies\u0026rsquo; assets, FEMA can request support from the Department of War (DoW). The DoW possesses an array of unique resources - such as tactical air and sealift capabilities and extensive logistics, communications, and distribution networks - that can be rapidly mobilized and deployed at scale to support disaster response [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Additionally, the DoW typically deploys units as self-sustaining force packages, ensuring that already-strained community resources are not depleted. The increasing complexity of disasters in the domestic U.S. suggests that the DoW may continue, if not increase, its role in federal disaster response. Yet the capabilities provided by military involvement in disaster response and humanitarian aid remains poorly understood relative to civilian capabilities, limiting opportunities for proactive planning and strategic resource allocation. This lack of understanding arises partially due to the dearth of empirical analyses evaluating military involvement in civilian-led disaster response efforts [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Strengthening military contributions to disaster response efforts that complement the civilian sector requires empirical data with respect to geographic location, disaster type, timing of disaster and response activities, personnel deployments and supported ESF.\u003c/p\u003e \u003cp\u003eTo investigate the contexts in which the DoW contributes to disaster response activities in support of civilian responses receiving federal support following Stafford Act declarations, we characterized DoW support to domestic disaster response efforts among FEMA-issued mission assignments between the years of 2012 and 2024 [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Mission assignments represent work orders issued by FEMA to other federal agencies to leverage resources and capabilities to support disaster response efforts. Multiple, distinct mission assignments can be issued for one disaster and are assigned to each U.S. state, tribe, or territory. As such, mission assignments provide a verifiable record of requested support from the DoW for disaster response efforts. This analysis provides a foundational, data-driven understanding of how the DoW contributes to federal interagency disaster response, providing information to support operational planning and future research concerning military-civilian collaboration in disasters.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eDetails on the location, timing, disaster type, personnel, and ESFs provided by DoW domestic disaster response events were identified among data on FEMA mission assignments collected by FEMA\u0026rsquo;s Operations Capabilities Branch in the Department of Homeland Security (DHS). Mission assignments used for this report were extracted on May 14th, 2025 from the open source National Emergency Management Information System (NEMIS) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Available data spanning from January 2012 to May 2025 were obtained and represented both originally issued mission assignments and any associated amendments prior to their initial issuance, which reflect adjustments in the work performed, funding, cost estimates, period of performance, or other terms of the assignment that unfolded during a disaster response. Of these, data were restricted to initial mission assignments and only those assigned from the years 2012 to 2024, to account for incompleteness of data logged in 2025 due to the ongoing nature of updates to mission assignments.\u003c/p\u003e \u003cp\u003eWe categorized the state, tribe, or territory for which a mission assignment was issued; the calendar year in which a mission assignment\u0026rsquo;s period of performance was requested to begin; the disaster or incident type generating a mission assignment; the specific DoW entity or Service branch assigned to execute the stated work; and the specific ESF associated with each mission assignment\u0026rsquo;s stated work. We then organized and visualized the data based upon observed trends. Data processing and analyses were conducted using Stata SE 18.0 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Changes in the observed frequency of events over time were evaluated by simple linear regression.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eOf the 39,381 mission assignments and amendments captured in the initial dataset, 11,086 entries were original mission assignments without amendments between the years 2012 and 2025. Data from 2025 were excluded due to it being an incomplete year, resulting in 10,946 original mission assignments between the years 2012 and 2024. Missions were assigned by FEMA to multiple U.S. Departments and Agencies (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The DoW was assigned to support disaster or public health emergency incidents in 4,065 (37%) missions.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution of FEMA Mission Assignments Assigned to U.S. Departments or Agencies from 2012\u0026ndash;2024.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eU.S. Department or Agency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber (%) of Total Mission Assignments\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDoW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4065 (37%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDHS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1228 (11%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHHS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e966 (9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUSDA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e742 (7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGSA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e631 (6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEPA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e495 (5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDOT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e425 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDOJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e362 (3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e342 (3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDOC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e326 (3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDOE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e321 (3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e262 (2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDHUD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e148 (1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOther\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e633 (6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eGeographic Analysis\u003c/h3\u003e\n\u003cp\u003eThe 4,065 mission assignments from this sample encompassed all 50 U.S. states and 6 districts/territories \u0026ndash; the District of Columbia, Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). From 2012 to 2024, the state of Florida generated the most mission assignments assigned to the DoW of any U.S. state or territory, encompassing 514 distinct observations (13% of total). Additional states and territories that made up notable proportions of DoW mission assignments include Puerto Rico (n\u0026thinsp;=\u0026thinsp;320 [8%]), Louisiana (n\u0026thinsp;=\u0026thinsp;260, [6%]), the Virgin Islands (n\u0026thinsp;=\u0026thinsp;203 [5%]), and Texas (n\u0026thinsp;=\u0026thinsp;198 [5%]). The South Atlantic states generated the most DoW mission assignments compared to other U.S. regions (n\u0026thinsp;=\u0026thinsp;1,057 [26%]).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eNote\u003c/strong\u003e \u003cp\u003eVisualized using MapChart (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://mapchart.net\u003c/span\u003e\u003cspan address=\"https://mapchart.net\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e\n\u003ch3\u003eTemporal Analysis\u003c/h3\u003e\n\u003cp\u003eFrom 2012 to 2024, the DoW averaged 312 distinct FEMA mission assignments per year. The DoW received the most requests for domestic disaster response support during the periods of 2017\u0026ndash;2018 and 2020\u0026ndash;2021, accounting for 29% (n\u0026thinsp;=\u0026thinsp;1,154) and 31% (n\u0026thinsp;=\u0026thinsp;1235) of mission assignments, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). These peaks were associated with a strong hurricane season in 2017 and the COVID-19 pandemic response, respectively, although no statistically significant change was observed in the number of mission assignments to the DoW per year over time (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.20).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eIncident Type Analysis\u003c/h3\u003e\n\u003cp\u003eThe majority of mission assignments requesting DoW support between 2012 and 2024 were in response to tropical cyclones and hurricanes (n\u0026thinsp;=\u0026thinsp;2,309 [57%]) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Additionally, biological incidents, defined by FEMA as events involving both naturally occurring or deliberately caused outbreaks of an infectious pathogen affecting people, accounted for 20% of DoW disaster response requests (n\u0026thinsp;=\u0026thinsp;815). Overall, these two incident types accounted for over three-quarters of FEMA mission assignments involving DoW support within the observed time period. Mission assignments for tropical cyclones and hurricanes most commonly originated from Florida (n\u0026thinsp;=\u0026thinsp;423 [18%]) and Puerto Rico (n\u0026thinsp;=\u0026thinsp;282 [12%]), whereas biological disaster support requests to DoW most commonly originated from the District of Columbia (n\u0026thinsp;=\u0026thinsp;63 [8%], California (n\u0026thinsp;=\u0026thinsp;48 [6%]) and New York (n\u0026thinsp;=\u0026thinsp;39 [5%]).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMost common U.S. incident types resulting in DoW-assigned mission assignment from 2012 to 2024.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIncident Type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber (%) of Mission Assignments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMost Commonly Impacted U.S. State/Territory\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTropical Cyclone / Hurricane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,309 (57%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFlorida\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiological\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e815 (20%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDistrict of Columbia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSevere Storm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e234 (6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIowa\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlood\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e212 (5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCalifornia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFire\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e170 (4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCalifornia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoastal Storm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129 (3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFlorida\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWinter Storm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47 (1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTexas\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTornado\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eKentucky\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEarthquake\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePuerto Rico\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDam/Levee Break\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCalifornia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVolcanic Eruption\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHawaii\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMud/Landslide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWashington\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChemical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOhio\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnclassified\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47 (1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHawaii\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eEmergency Support Function and Personnel Analysis\u003c/h3\u003e\n\u003cp\u003eOf the 4,065 DoW-supported mission assignments, 59% of the available data identified the associated ESF (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The DoW most commonly supported ESF #3: Public Works and Engineering (n\u0026thinsp;=\u0026thinsp;1,340 [33%]), followed by ESF #7: Logistics (n\u0026thinsp;=\u0026thinsp;369 [9%]) and ESF #5: Information and Planning (n\u0026thinsp;=\u0026thinsp;287 [7%]).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEmergency Support Functions and responding DoW agency for DoW-assigned mission assignments from 2012 to 2024.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEmergency Support Function\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumber (%) of Mission Assignments\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMost Frequent Responding DoW Agency\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3: Public Works \u0026amp; Engineering\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1,340 (33%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Army\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7: Logistics Management \u0026amp; Resource Support\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e369 (9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDefense Logistics Agency\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5: Information \u0026amp; Planning\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e287 (7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Air Force\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8: Public Health \u0026amp; Medical Services\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e128 (3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDefense Logistics Agency\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9: Search \u0026amp; Rescue\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e112 (2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Coast Guard\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10: Oil \u0026amp; Hazardous Materials Response\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45 (1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Coast Guard\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6: Mass Care, Emergency Assistance, Housing, Human Services\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43 (1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Army\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15: External Affairs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Coast Guard\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1: Transportation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13: Public Safety \u0026amp; Security\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Army\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2: Communications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12: Energy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eU.S. Air Force\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4: Firefighting\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (\u0026lt;\u0026thinsp;1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11: Agriculture and Natural Resources\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14: Long-Term Community Recovery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMissing/Unidentified\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1,674 (41%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNA\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAdditionally, 2,337 (57%) of observed mission assignments in the dataset identified the specific DoW entity or Service branch that was deployed to execute the assigned work (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The most commonly referenced organization was the U.S. Army, specifically the Army Corps of Engineers (USACE), which was involved in a total of 1,547 mission assignments (38% of total). The USACE supported the majority of Public Works and Engineering mission assignments (n\u0026thinsp;=\u0026thinsp;1,327 [99% of ESF #3 mission assignments]), while the Defense Logistics Agency (DLA) was responsible for more than half of Logistics support (n\u0026thinsp;=\u0026thinsp;194 [53% of ESF #7 mission assignments]). Information and Planning support was commonly provided by the U.S. Air Force (n\u0026thinsp;=\u0026thinsp;109 [38% of ESF #5 mission assignments]), with additional support from the U.S. Coast Guard (n\u0026thinsp;=\u0026thinsp;40 [14%]) and U.S. Army (n\u0026thinsp;=\u0026thinsp;11 [4%]).\u003c/p\u003e "},{"header":"Discussion","content":"\u003cp\u003eThis study assessed empirical evidence for military involvement in domestic disaster response operations. By analyzing more than a decade of data on FEMA mission assignments, this analysis provides evidence of substantial DoW contributions to civilian authorities during domestic disasters, highlighting its critical support in public works, logistics, and planning during large-scale, complex disaster events.\u003c/p\u003e \u003cp\u003eThis assessment of FEMA\u0026rsquo;s open source dataset shows that 37% of 10,946 original FEMA mission assignments issued between 2012 and 2024 were assigned to the DoW. Periods of peak activity during the 2017 hurricane season and the COVID-19 Pandemic illustrate DoW\u0026rsquo;s role in supporting U.S. government response to high-impact, catastrophic domestic disaster events. Responses to the COVID-19 Pandemic were largely concentrated in densely populated areas such as the District of Columbia, New Jersey, and California. Similarly, low-lying coastal states in the South Atlantic and small island territories were more likely to receive support than areas at higher altitude, specifically due to cyclones and hurricanes. Both event types represented large-scale, wide-ranging, and prolonged disaster events where local, state, and federal civilian agencies\u0026rsquo; capacities were overwhelmed.\u003c/p\u003e \u003cp\u003eWhile only\u0026thinsp;~\u0026thinsp;60% of the available data identified the ESF and permitted classification of the type of support provided by the DoW, available results revealed that the DoW most commonly supported ESF #3: Public Works and Engineering, overwhelmingly through the USACE. Additional areas of frequency support were ESF #7: Logistics, most commonly provided by the DLA, and ESF #5: Information and Planning.\u003c/p\u003e \u003cp\u003eThe USACE\u0026rsquo;s critical role in ESF #3 and the relatively high frequency of response efforts illustrates DoW\u0026rsquo;s extensive infrastructure capabilities supporting civilian disaster response. This type of disaster response can include large-scale engineering projects after major destructive events, such as debris removal, infrastructure repair and water resource management, that are often beyond the scope or immediate capacity of civilian agencies. The USACE, however, has a long-standing civil works mission to develop and maintain civilian infrastructure [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This inherent expertise combined with a region-specific organizational structure allows units to maintain a local geographic presence and almost institutionalizes their involvement in any federal-level disaster response requiring surge capacity and capabilities.\u003c/p\u003e \u003cp\u003eBeyond infrastructure support, ESF #7 (Logistics) and ESF #5 (Information and Planning) were the second and third most frequent response activities by the DoW, respectively, illustrating the importance of the DoW\u0026rsquo;s capacity to coordinate and execute the movement of life-sustaining resources in disaster zones when normal supply chains are disrupted. Interestingly, while the DLA\u0026rsquo;s primary mission focuses on global supply chain logistics during conflict, the agency\u0026rsquo;s capabilities clearly have the capacity to be adapted for large-scale commodity distribution in domestic disaster events [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Additionally, this work is often coordinated with the U.S. Air Force and U.S. Coast Guard, leveraging air and sea supply transport, reconnaissance, and structured planning capabilities.\u003c/p\u003e \u003cp\u003eOverall, the proportion of FEMA mission assignments to the DoW in the observed data portray DoW capabilities as critical contributions to federal-level disaster response. This appears true for certain types of high-magnitude, complex disaster incidents that result in substantial disruption to physical infrastructure and local supply chains. Should a complex disaster occur simultaneous with wartime obligations, it is unclear how these capabilities would be provided during domestic disaster response. Further assessment of civilian dependencies on the military as well as potential alternative solutions when DoW is unable to respond are needed. High-impact disaster incidents in cyclone/hurricane-prone areas are associated with higher numbers of requests for DoW assistance, and the emergence of biological disasters will likely continue to require DoW\u0026rsquo;s extensive logistics and planning capabilities. Our analysis clearly indicates DoW maintains capabilities that are essential for responding to a variety of disaster-level events, especially those of a complex or large-scale nature.\u003c/p\u003e \u003cp\u003eWhile this study provides an analysis of DoW support through FEMA mission assignments, several limitations warrant consideration. First, the focus on mission assignments sourced from NEMIS program records may not capture the full range of DoW disaster response assistance, such as immediate response actions or support provided outside the Stafford Act framework. Second, while the dataset is extensive, approximately 40% of mission assignments were incomplete regarding specific ESFs and deployed personnel, and the 2012\u0026ndash;2024 timeframe may not capture longer-term historical shifts in DoW involvement with disaster response. Third, the methodological decision to exclude amendments made after initial issuance may not capture the full scope, duration, or nature of the work performed, which may evolve significantly during a response. Despite these constraints, this research offers an initial data-driven baseline of formally requested DoW support, identifying crucial trends that are foundational for potential planning adjustments. These adjustments may include strengthening of DoW capability in areas of likely future use or the development of civilian capabilities in areas where DoW dependence creates risk, especially in wartime. Future research should aim to complement these findings through examining mission assignment amendments to understand evolving needs and investigate methodologies to capture the full spectrum of DoW domestic disaster support beyond formal mission assignments, potentially including an analysis of DoW's internal data sources. A more holistic assessment of DoW support to disaster response simultaneous with other wartime requirements is also warranted.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study underscores the necessity for proactive and refined partnerships between the DoW and civilian federal agencies tasked with domestic disaster response operations. Given the operational significance of DoW capabilities in disaster response to the National Response Framework, potential efficiency gains could likely occur through more deeply embedded coordination mechanisms and unified miliary-civilian training exercises. The increasing scale and complexity of domestic disasters and public health emergencies in the U.S. necessitates a precise, data-informed picture of the DoW\u0026rsquo;s contributions for both civilian and military organizations to ensure operational planning and resource deployments are strategically aligned to best protect lives and property.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData that support the findings of this study are available upon reasonable request to the authors and pending approval for distribution by program leadership.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eI. Award No. HU00012120098: The Office of the Assistant Secretary of War for Health Affairs, 77000 Arlington Blvd., Suite 5101, Falls Church, VA 22042-5101, is the awarding office and the Uniformed Services University of the Health Sciences (USUHS), 4301 Jones Bridge Road, Bethesda, MD 20814, is the administering office.\u003c/p\u003e\n\u003cp\u003eII. This project is sponsored by USUHS; however, the information or content and conclusions reported in this work do not necessarily represent the official position or policy of, nor should any official endorsement be inferred on the part of, USUHS, the U.S. Department of War, the U.S. Government, or the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthorship Contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization \u0026ndash; \u0026nbsp;JF and JC; Methodology \u0026ndash; EP, EM, KR, JF; Software \u0026ndash; EP, EM; Data Curation \u0026ndash; SA, EP, EM; Formal Analysis\u0026nbsp;\u0026ndash; EP, EM; Resources \u0026ndash; EP; Writing \u0026ndash; Original Draft, EP, EM, SA, CC, KR; Writing \u0026ndash; Review \u0026amp; Editing, EP, EM, SA, CC, KR, JC, JF; Visualization \u0026ndash; EM, EP; Project Administration \u0026ndash; EM, EP; Supervision \u0026ndash; KR, JF, CC. All authors were involved in manuscript writing and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the support of NDMS Pilot leadership.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eDisclaimer\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis project is sponsored by the Uniformed Services University of the Health Sciences (USUHS); however, the information, content, and conclusions reported in this work do not necessarily represent the official position or policy of, nor should any official endorsement be inferred on the part of USUHS, the U.S. Department of War, the U.S. Government, or the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eInstitutional Clearance\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eApproved by USUHS Office of the Vice President for External Affairs and HJF Regulatory Affairs.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNational Centers for Environmental Information. U.S, Billion-Dollar Weather, Disasters C. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.ncei.noaa.gov/access/billions/\u003c/span\u003e\u003cspan address=\"https://www.ncei.noaa.gov/access/billions/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2025). Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFederal Emergency Management Agency, Robert T. Stafford Disaster Relief and Emergency Assistance Act. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fema.gov/disaster/stafford-act\u003c/span\u003e\u003cspan address=\"https://www.fema.gov/disaster/stafford-act\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023). Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFederal Emergency Management Agency. National Response Framework. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fema.gov/emergency-managers/national-preparedness/frameworks/response\u003c/span\u003e\u003cspan address=\"https://www.fema.gov/emergency-managers/national-preparedness/frameworks/response\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024). Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUnited States Department of Homeland Security. National Response Framework (4th Ed). 2019. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fema.gov/sites/default/files/documents/NRF_FINALApproved_2011028.pdf\u003c/span\u003e\u003cspan address=\"https://www.fema.gov/sites/default/files/documents/NRF_FINALApproved_2011028.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUnited States Department of Defense. DoD Manual 3025.01, Vol. 2, Defense Support of Civil Authorities: DoD Incident Response. 2017. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodm/302501_vol02.pdf\u003c/span\u003e\u003cspan address=\"https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodm/302501_vol02.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrace R, Center for Human Rights and Humanitarian Studies. Surmounting Contemporary Challenges to Humanitarian-Military Relations. Brown University,. 2020. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://watson.brown.edu/chrhs/files/chrhs/imce/research/Surmounting%20Contemporary%20Challenges%20to%20Humanitarian-Military%20Relations_Grace.pdf\u003c/span\u003e\u003cspan address=\"https://watson.brown.edu/chrhs/files/chrhs/imce/research/Surmounting%20Contemporary%20Challenges%20to%20Humanitarian-Military%20Relations_Grace.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFederal Emergency Management Agency. Federal Agency Mission Assignments. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fema.gov/partnerships/mission-assignments\u003c/span\u003e\u003cspan address=\"https://www.fema.gov/partnerships/mission-assignments\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2024). 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Create your own custom map. 2025. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://mapchart.net\u003c/span\u003e\u003cspan address=\"https://mapchart.net\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUnited States Army Corps of Engineers. Mission Overview. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.usace.army.mil/Missions\u003c/span\u003e\u003cspan address=\"https://www.usace.army.mil/Missions\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e/ (2025). Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDefense Logistics Agency. About the Defense Logistics Agency. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.dla.mil/About-DLA\u003c/span\u003e\u003cspan address=\"https://www.dla.mil/About-DLA\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e/ (2025). Accessed 30 Sept 2025.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Department of War, Humanitarian Assistance, Disaster Relief, Disaster Preparedness","lastPublishedDoi":"10.21203/rs.3.rs-9271722/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9271722/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eWhen large-scale disasters exhaust civilian federal agencies\u0026rsquo; assets, the U.S. Federal Emergency Management Agency can issue mission assignments to the Department of War (DoW) to leverage its unique, self-sustaining logistical and operational capabilities. Despite the DoW\u0026rsquo;s critical role, empirical analyses characterizing military involvement in civilian-led disaster response remain scarce, limiting the potential for proactive strategic planning. This study aimed to provide a data-driven baseline of DoW contributions to domestic disaster relief.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis study characterized DoW contributions to U.S. disaster response by analyzing 4,065 Federal Emergency Management Agency (FEMA) mission assignments issued between 2012\u0026ndash;2024. Mission assignments were analyzed by geographic location, disaster type, event timing, personnel types deployed, and associated Emergency Support Function.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe DoW supported 37% of all original FEMA mission assignments during the study period. Activity peaked during the 2017 hurricane season and the COVID-19 pandemic. Tropical cyclones and hurricanes in low-lying coastal states and island territories, and biological incidents in densely populated areas, were the primary drivers for DoW assistance. The DoW primarily supported Emergency Support Functions relating to Public Works and Engineering, Logistics, and Information and Planning activities. The U.S. Army Corps of Engineers was the most active entity, involved in 38% of all DoW-supported mission assignments.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eAs an essential federal partner in managing increasingly complex, large-scale disasters, a data-informed picture of the DoW\u0026rsquo;s contributions is vital for strategically optimizing operational planning and resource deployments to protect the health and well-being of the American public.\u003c/p\u003e","manuscriptTitle":"The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-03 15:49:19","doi":"10.21203/rs.3.rs-9271722/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"965ef728-0ef4-43bd-ba7b-55c0e603cc87","owner":[],"postedDate":"April 3rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-13T12:41:55+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-03 15:49:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9271722","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9271722","identity":"rs-9271722","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}