Some chemical, biological, radiological, and nuclear agents, whether naturally, accidentally, or intentionally released, can be very damaging and pose a high risk to national security, owing to their potential for economic and social disruption. Efficacious pharmaceutical research and development could protect populations against such agents via new prophylactic drugs and vaccines or post-exposure treatment with antidotes and antimicrobials. However, because of the unpredictable nature of when, if ever, the health risks of specific chemical, biological, radiological, and nuclear agents might be realized, the development of medical countermeasures against these agents carries less promise of free market rewards to entice investment, and thus this development necessitates public funding or incentives. In terms of defining the level and targets of such public funding, the potential economic impact of any realized threat must be determined. This article first examines the specific components of market failure—research and development efforts vs. market rewards—associated with medical countermeasures against chemical, biological, radiological, and nuclear agents. Then, the latest natural outbreak of the Ebola virus disease is used as a case study to illustrate the risks that such biological agents can pose to social and economic structures. Rather than addressing risks associated with exposure from terrorist events, this case study highlights the potential to strengthen the case to fund relevant medical countermeasures for naturally occurring diseases with epidemic potential that could also impact Western countries owing to the consequences on their armed forces operating in the area of the outbreak, on trade, or even travelers who may disseminate the disease. To that end, causal factors that led to a lack of medical countermeasures prior to the 2014 outbreak are identified, then opportunities that could have triggered a re-evaluation as a threat worthy of high actionable concern are probed.< Réduire