https://www.centerforhealthsecurity.org/our-work/events-archive/2001_dark-winter/about.html

Dark Winter
About the Exercise

On June 22-23, 2001, the Center for Strategic and International Studies, the Johns Hopkins Center for Civilian Biodefense Studies, the ANSER Institute for Homeland Security, and the Oklahoma City National Memorial Institute for the Prevention Terrorism, hosted a senior-level war game examining the national security, intergovernmental, and information challenges of a biological attack on the American homeland.