RESUMEN
The Strategic National Stockpile (SNS) serves as a repository of materiel, including medical countermeasures (MCMs), that would be used to support the national health security response to a chemical, biological, radiological, or nuclear (CBRN) incident, either natural or terrorism-related. To support and advance the SNS, the National Institutes of Health (NIH) manages targeted investigatory research portfolios, such as Countermeasures Against Chemical Terrorism (CounterACT) for chemical agents, that coordinate projects covering basic research, drug discovery, and preclinical studies. Project BioShield, managed by the Biomedical Advanced Research and Development Agency (BARDA), guides and supports academia and industry with potential MCMs through the Food & Drug Administration's approval process and ultimately supports the acquisition of successful products into the SNS. Public health emergencies such as the COVID-19 pandemic and the ever-increasing number of MCMs in the SNS present logistical and financial challenges to its maintenance. While MCMs for biological agents have been readily adopted, those for chemical agents have required sustained investments. This paper reviews the methods by which MCMs are identified and supported for inclusion in the SNS, the current status of MCMs for CBRN threats, and challenges with SNS maintenance as well as identifies persistent obstacles for MCM development and acquisition, particularly for ones focused on chemical weapons.