ABSTRACT
Introduction Since September 11, 2001, public debate in the United States has combined, and often confused, the notions of fighting terrorism and the proliferation of weapons of mass destruction (WMD). The actions of al Qaeda on September 11, the subsequent anthrax mailings, infections and deaths after October 2001, and the wars in Iraq and Afghanistan, have unforgettably intertwined terrorism and the concept of WMD. During the Cold War, the term WMD meant only nuclear weapons: something that could produce truly mass destruction, that is, hundreds of thousands or even millions of deaths. But 9/11 caused the bar to be lowered to something that could cause a few thousand deaths, a few hundred, or even fewer. In September 2002, the State of California passed a law that would define an ordinary school bus as a weapon of mass destruction if used for terrorism. But generally, today, a weapon of mass destruction is thought to be either a nuclear bomb, or chemical, biological, or radioactive materials dispersed by a bomb or by some other apparatus. Terrorist threats are categorized as Chemical, Biological, Radiological, or Nuclear (CBRN) according to the type of hazard each presents. In this chapter we discuss the characteristics of each in the increasing order of their likely severity if used by terrorists.
