16 Evolving chemical, biological, radiological and nuclear (CBRN) terrorism Intelligence community response and ethical challenges Patrick F. Walsh Introduction This chapter has three objectives. First it assesses briefly contemporary and emerging chemical, biological, radiological and nuclear (CBRN) threats from non-state actors. Secondly, it identifies capability challenges across “Five Eyes” intelligence communities (ICs) in managing CBRN non-state actor threats and how these can be addressed. Thirdly, noting the threat posed by CBRN terrorism and “Five Eyes” ICs capabilities to prevent, disrupt or mitigate them, the chapter outlines key ethical challenges for ICs in managing such threats. The chapter is divided into three sections: contemporary and emerging non-state actor CBRN threats, intelligence capability gaps and challenges, and ethical challenges. Contemporary and emerging non-state actor CBRN threats Defining CBRN The term “CBRN” includes a range of threats from the weaponization of chemi- cal, biological, radiological and nuclear agents by state and non-state actors. “CBRN” is a departure from the traditional nomenclature – “Weapons of Mass Destruction” (WMDs), “with all its Cold War connotations of massive effect and mutual deterrence” (Cornish 2007, 2). As discussed shortly, not all CBRN threats present an existential threat to humanity or even massive causalities – of the kind depicted during the Cold War; where the former Soviet Union or the United States might have deployed tactical or strategic WMDs (particularly nuclear weapons). A critical point of difference between “WMD” and “CBRN” weapons is the former’s principal objective of significant and predictable devastation. In order to achieve this objective, WMD weapons have to be reliable, safely deployable and able to result in major destruction of localities and in the deaths of hundreds of thousands in order to deter an adversary. Throughout the Cold War to the present, only a few threat actors have developed large-scale WMD programmes that could result in significant and reliable widespread destruction of an enemy. DOI: 10.4324/9781003164197-23