Main three categories of chemical, biological, radiological and nuclear (CBRN) terrorism (often depicted as ultra‐ or superterrorism) according to form and material source are suggested. Differences between terrorism using weapons of mass destruction (WMD) and CBRN terrorism are explained, the WMD terrorism being only one of the three categories of CBRN terrorism.

CBRN terrorism involves in the first line misuse of the WMD, in the second line use of non weaponised toxic,contagious and radioactive materials, or primitive nuclear explosive devices.The third category implies violent strikes against infrastructures of present civilised and industrialised societies causing accidents with release of toxic agents, highly infectious materials and radionuclides resembling the pushing mechanism of disastrous wartime strikes with conventional weapons rather than peace‐time accidents caused by personal, material or system failures.

Examples of already executed cases of CB‐terrorism support this approach and categorisation of these highest forms of terrorism.