The potential for terrorist activities directed against United States (U.S.) citizens and interests worldwide has become an increasingly serious threat. In an effort to counter this threat, the U.S. Government has implemented a number of measures to enhance the Nation's ability to deter, prevent, respond to, and recover from terrorist activities within the United States, its territories, and possessions. The establishment of the Weapons of Mass Destruction (WMD)-Civil Support Team (CST) program is one of the measures that has been implemented to support the defense of the Homeland. The WMD-CST program mission is to support civil authorities at domestic chemical, biological, radiological, nuclear, and high-yield explosives (CBRNE) incident sites by identifying CBRNE agents and substances, assessing current and projected consequences, advising on response measures, and assisting with appropriate requests for additional support. This includes the intentional or unintentional release of CBRNE and natural or man-made disasters in the United States that result, or could result, in the catastrophic loss of life or property. As the "state governors' 911 forces for WMD," WMD-CSTs provide direct support to the front lines of local, state, and federal emergency response organizations. WMD-CST operations are conducted primarily in civil environments-urban, rural, industrial, or suburban areas-and in hot or cold weather. WMD-CSTs currently operate within the United States, its territories, and possessions while in Title 10 U.S. Code (USC) or Title 32 USC status. This manual serves as the foundation for WMD-CST doctrine and focuses on the organization, mission, command and control (C2), and operations of the WMD-CST. It discusses employment concepts, planning considerations, capabilities, and the type of support that WMD-CSTs can provide during a response. This information should be shared with key decision makers at local, state, and federal levels.