Chemical, biological, radiological and nuclear (CBRN) terrorism (depicted also as ultra- or superterrorism) is often reported as terrorism using mass destruction weapons or WMD terrorism. This is however not quite correct reducing thus the wide spectrum of terrorist means and methods falling under this term (CBRN) only to military weaponry of this art. There are also other terminological misunderstandings considering certain violent events occuring in wars and armed conflicts to be terrorism. Terrorism as a violence or threat with violence of individuals or/and groups based on racial, national, ethnic, political, religious, economic, ecologic, sexual and other ideology or motivation against individuals or social groups predestinates the choice of instruments of violence. Just the eve of the 21st century has marked escalation of violence in the shift from classical means ( silent weapons, incendiaries, fire-arms, explosives) to actual inclusion of toxic and biological agents into the arsenals of terrorists. Increasing brutality of contemporary terrorism under its proceeding internationalisation in globalised environment allows to anticipate further development of terrorism from its classical forms using incendiaries, light weapons and explosives towards its most destructive forms – to chemical, biological, radiological and nuclear terrorism. Assessment of actual and potential forms and sources of CBRN terrorism is a necessary point of outcome for combatting terrorism, effective preventive, repressive, protective, rescue and recovery measures and systems on national and global scale. This paper is aimed in the first line to categorise material sources and forms of CBRN terrorism. Differences between WMD and CBRN terrorism are elucidated. The former is considered to be no more and no less than one of the basic forms of the latter.

Main forms of CBRN terrorism in wide possible varieties are reviewed and portrayed, generally far exceeding the alternatively used term WMD terrorism.


Principal forms and their material sources can be shortly reviewed as follows (1,2):

The first and basic source for the CBRN terrorism ( to which it is often terminologically reduced) is the misuse of military means, i.e. WMD. Possibilities of non-authorised using chemical, bacteriological (biological), toxin and nuclear weapons are limited mainly in the connection with their strategic importance and ongoing implementation of existing arms control and disarmament agreements.

The second source (applied e.g. at all known terrorist chemical and biological attacks and threats that have occured till now) is the own manufacturing WMD components, i.e. supertoxic lethal compounds, highly lethal bacteriological agents and toxins as well as misusing industrial toxic agents, infectious materials and radionuclides. High attention is devoted to the possible misuse of fissile materials, mainly of weapon-grade plutonium and highly enriched uranium (HEU) for possible illicit manufacturing primitive nuclear device.

The third form, till now generally underestimated, is the violent pushing of secondary effects typical for striking industrial and social infrastructures of modern society (nuclear, chemical, petrochemical and like) with conventional weapons in wars and armed conflicts. Such disastrous terrorist strikes causing sudden release of toxic, inflammable and liquefied chemicals, radionuclides and infectious materials (often with explosive character, sometimes followed by burnings, in some cases with fireballs) differ in the pushing mechanism from the similar but much less dramatically proceeding peacetime incidents and accidents, caused by personal, material or system failure or by natural forces.

These forms and sources are portrayed in following chapters based on profound analysis (3).


CBRN Terrorism based on using WMD means any misuse or unauthorised use of existing military arsenals of WMD, i.e. of concrete chemical, bacteriological (biological), toxin and nuclear weapons or their key components, acquired as a result of stealing, robbery or illicit trade from military bases, storage sites, manufacturing facilities, transports etc. (similarly like conventional weapons and explosives) which is however much more uneasier because of items of strategic importance, strongly guarded. In this connection, the most probable is considered access to already commissioned chemical, biological and nuclear weapons determined to elimination pursuant to respective bi- or multilateral arms-control and disarmament agreements in the State Parties or to standard weaponry in the non State Parties (mainly in those in suspicion to support terrorist groups). In ongoing discussions, several reasons have been indicated why terrorists have not yet used WMD on mass scale, while during two decades (1979 – 1998) at least 12 conventional high-casualty assault cases are known involving more than 100 fatalities each, not to speak about the events of September 11, 2001. Among the reasons, there are e.g. general reluctance to experiment with unfamiliar weapons and lack of corresponding precedents, fear that the weapon would harm the producer or user, fear that it would not work at all, or only too well, fear of alienating relevant constituencies and potential supporters on moral grounds, fear of unprecedented governmental crackdown and retaliation, lack of a perceived need for indiscriminate, high-capacity attacks for furthering goals of the group, and lack of funds to buy e.g. nuclear material on the black market (4). Some of the reasons are however weakened due to increasing occurence of suicidal terrorist attacks. It is a question of time when the WMD terrorism actually emerges.

As for chemical weapons (CW) concerned, among the State Parties to the Convention on general and comprehensive prohibition of chemical weapons (CWC) (from 1993, that entered into force in 1997), main possessors are Russia and the USA and in the second line India and South Korea having declared small amounts of CW. Possession of CW is anticipated in some signatory states which have not yet ratified (e.g. Israel) and in others (mainly Arabic neighbours of Israel and their sympatisants) that have even not yet signed, binding their signature on Israel´s cancelling its nuclear programme. Iraq´s CW are blocked at present.

In the case of bacteriological (biological) and toxin weapons (BTW), the situation is far less clear. On the one hand, there exists the Convention on prohibition, development, production and stockpiling BTW and on their destruction (BTWC) (from 1972, that entered into force 1975, by the way the first disarmament document outlawing one class of WMD) but on the other hand with the lack of any verification mechanisms. The State Parties only have declared elimination of the BTW stockpiles and transformation of corresponding R&D and production facilities to peaceful purposes. This Convention was signed in the time of ending classic era of BW (lasting for about six centuries) and starting rapid development of biotechnologies shortly after its signature. This is why some countries were continuing in the R&D of new BTW and defence against them. It is to be noted, that the use of BTW (similarly like the use of CW) in wars is prohibited by the Geneva Protocol (from 1925 that entered into force in 1928). As for toxin weapons (TW), their development, production, stockpiling and use are prohibited also by the above mentioned CWC, committing to their verified destruction. The long feeling absence of mechanisms for verification of eliminating BTW stockpiles will be solved by strengthening the régime of BTWC amending it by a Protocol on implementation, elevating it on the similar level like CWC. The aim of this Protocol is to prove objectively and under international verification system that the stockpiles have been actually destroyed and any new ones are not being developed. This Protocol is a matter of very complicated negotiations proceeding from the early 1990s. It is a pity that the ongoing negotiations have entered a deadlock recently. From the point of view of potential targets of terrorism it can be added that while CW are only defined as antipersonnel means, BTWC are defined also as means against animals and plants. (Practice of use of toxic agents however involved also multiple intentional use of phytotoxic agents as a method of warfare e.g. in Malaysia and mainly in the Second Indochina War).

Radiological weapons (RW), i.e. intentional dissemination of radioactive materials in armed conflicts are not covered by any international agreement yet. During negotiations on this issue in Geneva Conference on Disarmament, this problem was withdrawn from the agenda in 1984 because the group of neutral and non aligned countries had required to combine this problem with the issue of nuclear weapons ban. Even from the military point of view such weapons were not considered actual ( Their massive use gives neither quick effect like CW nor high delayed one like BTW). There is a general opinion that such weapons do not exist in military arsenals of WMD at all, even if the UNSCOM inspectors concluded in the early 1990s that Iraq had tried to develop such weapons.

Nuclear weapons (NW) as the most effective WMD are also subject of efforts aimed to their reduction and total ban as a final goal. Beside multilateral agreements involving testing and deployment in various environmental compartments and geographis zones, the most important is the Treaty on non proliferation of NW (NPT) (from 1968) closely connected with the system of IAEA safeguards. The core of nuclear arms control and partial disarmament are represented in the first line by bilateral agreements between USA and USSR (Russia respectively). Previous bilateral agreements concluded in the Cold War era on the strategic nuclear arms, such as nuclear bombers, ICBMs, SLBMs (including MIRVs) i.e. mainly SALT-I, SALT-II, did not reduce numbers of weapons, but only regulated bilaterally balanced increase (limitation). This was the reason why the overall number of nuclear explosive devices gradually reached about 60 thousand (including nuclear charges of other NW states) worldwide in the mid-1980s. This was considered as actual nuclear multi-overkill and the nuclear status of the major Powers created then the situation characterised as Mutual Assured Destruction (MAD) which is not a strategy of any side as it has been sometimes reported but an objectively existing threat for both sides and for the whole mankind.

The first document on actual nuclear disarmament is the bilateral agreement (USA – USSR) on the elimination of nuclear missiles with the range of 500 – 5500 km (IMF) signed in December 1997. In the early 1990s both sides commenced with actual reduction of NW what is reflected in the START-I and START-II agreements. Recent developments, mainly refusal of ratifying the latter agreement and unilateral withdrawal from the ABM treaty of 1972 again have stopped ongoing reductions of NW arsenals. Moreover, recent orientation towards mininukes gives bad signal also from the point of view of nuclear terrorism.Contemporary estimated number of nuclear explosive devices is slightly over 20 thousand on the global scale. Simultaneously with growing number of NW states (USA, Russia, UK, France, China, India, Pakistan, Israel, Iraq) and rising number of states with missile technologies, the possibility of misusing NW increases. NW belong to the strategic interest of highest importance, well protected against non-authorised use. Even the simplest arial bombs are fitted with up to 5 independent systems to prevent it from unauthorised or accidental explosion, the highest levels controlled by the Command of Strategic Nuclear Forces and Presidents (USA, Russia) personally, in order to prevent accidental outburst of nuclear war.


Due to expected complications with stealing, robbery, illicit trade etc. of standard WMD from above mentioned sources, some already executed terrorist attacks have shown the ability of potent terrorist groups to develop and manufacture supertoxic lethal chemicals and highly contagious biological agents (5). This is enabled by the scientific and technological development and open access to information contributing also to the scientific and technological level of well organised terrorist groups. Growing dissemination of information mainly by means of the global computer network enable quick global communication without risk of being disclosed. Database of Incidents Involving Chemical, Biological, Radiological and Nuclear Materials, Since 1900 till Present in the Centre for Non-Proliferation Studies at the Monterey Institute of International Studies marked 329 cases till 1999. Most of them are connected with chemical and biological materials with clearly shown terrorist motivation.

Among chemicals, beside manufacturing of toxic agents, in the first line the most effective supertoxic lethal chemicals (standard chemical warfare agents, like GB and VX), also misuse of stolen riot-control agents and of toxic industrial chemicals like chlorine, phosgene, hydrogen cyanide, cyanogen chloride etc. can be considered for direct mass-casualty or mass incapacitation attacks (to evoke panics). Much wider possibilities in the choice of chemicals are given in indirect strikes (or threat with strikes), i.e. through contaminated water or food. Beside stable supertoxic agents (like VX, HD etc.) many other chemicals like persistent pesticides, cyanides, arsenous cmpounds, heavy metals, oil products etc. can be expected.

Biological agents of many types and origin, accessible e.g. from banks at medical and university institutes can be taken in consideration, including the misuse of infectious materials from foci of proceeding epidemies, both human and animal, not to speak about manufacturing of some toxins.

Similarly, radionuclides from several peacetime sources including radioactive wastes, disseminated by various mechanisms, most probably through explosion could be used in terrorist attacks.

At the time being, diverse views have been expressed concerning the posibility of nuclear terrorism. Even if the construction of nuclear explosive device seems theoretically very simple, there are obviously large very qualified teams and very specific conditions necessary to develop and manufacture such device. Taking into consideration material and technological requirements including own safety, this is generally considered as hardly possible without state involvement. From strategic reasons, R&D and many manufacturing steps belong to a best guarded state secrecy, moreover localised in strongly guarded areas. Nevertheless, taking in consideration proceeding nuclear horizontal proliferation, extent of the respective parts of the military-industrial complex in growing number of countries, partial escaping of information, material and brains are not excluded.

Parallel to proceeding decrease of numbers of operational nuclear devices paradoxically increases possibility of terrorist misuse due to growing volume of fissile material from nuclear weapons decommissioned mainly according to above mentioned agreements (IMF, START-I) as well as due to routinely proceeding upgrading of nuclear arsenals. It is in the first line the weapon-grade plutonium but more probably the highly enriched uranium (HEU) due to its extremely high amount and possibility to construct primitive types of nuclear explosive devices with the yields typical for mininukes (in order of t – kt) resembling large conventional demolition charges. While there has long been concern about nuclear material being acquired by non-state groups, recent reports indicate that NW may now, or soon will be, availabe to terrorist groups. Large quantities of HEU that are poorly controlled and otherwise unaccounted in the former USSR and some other countries could be a very attractive source. This fissile material (only in the former USSR is enough to build about twenty thousand nuclear charges). HEU can, however, be readily diluted with natural uranium to a low-enriched level where it has high commercial value as proliferation-proof fuel for nuclear energetic reactors (6).


In various assessments of terrorist threats, this mechanism is more-or-less aside of analysing CBRN terrorism in spite of its high probable and even actual occurence and under certain circumstances also of very high effectiveness, sometimes less targetable, in other cases with large extent (which also belongs to the terrorist aims).

The principle lies in violently evoked secondary effects of accident acts, analogically as in cases of intentional and unintentional strikes with conventional weapons on infrastructures of modern civilised societies (7,8,9) such as chemical, petrochemical, nuclear, energetic, cooling and other facilities including social and hygienic installations. These terrorist strikes are aimed to release toxic, inflammable and liquefied chemicals, radionuclides, highly infectious materials ( frequently accompanied with explosions, implosions, blast waves, fires with the effects of toxic products of burning, sometimes also with a fireball). These acts are similar to peacetime incidents and accidents caused by material, personal or system failures or to phenomena caused by natural forces (lightning, earthquake, earth shift, tsunami ) but differ very significantly in the extent and velocity of occurence of destructive factors due to pushing mechanism. So, e.g. a rupture in welding joint of the stationary or mobile tank filled with chlorine of other liquefied or highly volatile chemical or petrochemical or a leakage in large cooling equipment (food industry, ice-hockey arenas) filled with liquefied ammonia will be considerably different from hiting with e.g. anti-armour missile or demolition explosive charge. In the first case, typical for peacetime incidents, a longtime-acting point source with slow generating toxic plume is being formed. This enables rather effective protective and rescue measures. The latter disastrous event, occuring in armed conflicts and in potential terrorist attacks, is represented by sudden dramatic creation of a momentum volume source with very quick evolution and proliferation of a plume possessing extremely toxic to lethal effects (depending on toxic chemical) within the close neighbourhood.

It is obvious that this category of terrorist attacks is applicable in the first line for chemical terrorism as mentioned above.

One can however imagine also biological attack evoked through strike e.g. on storage of infectious waste or simply on the communal waste water purification facilities aimed to contaminate water supply etc.

Very dangerous seem in this respect strikes against nuclear installations (hydrochemical uranium mining, enrichment and reprocessing facilities, nuclear reactors, storage sites for spent nuclear fuel and institutional radioactive waste, waste water and waste sludge reservoirs etc.), representing an extremely deleterious form of radiological terrorism with extensive and long-lasting contamination. This would be especially in case of a destroyed nuclear reactor much worse than the contamination following a nuclear attack (due to presence of nuclei with long half-time of radioactive decay in the reactor´s inventory).

To the category of evoked accident belongs as a matter of fact even the shocking scenario from the September 11, 2001. Intended accident of three Boeings 757 with suicidal steering towards the twin WTC towers in New York and the Pentagon in Washington had the character of terminal phase of guided missile trajectory with extremely destructive power due to combination of kinetic energy of heavy objects flying a speed of about 500 km/hr and mainly of thermic energy of several tons of burning jet fuel from nearly full tanks of aircrafts on the route to the eastern shore after relatively short flight from the Lugan airport in Boston.


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 peacetime accidents caused by personal, material or system failures. Examples of already executed cases of CBRN terrorism support this approach and categorisation of these highest forms of terrorism.

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4. UN Office for Drug Control and Crime Prevention, Vienna (2002), 12 April.
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6. Pugwash Council (2001) Statement on the dangers of nuclear terrorism, 11 November.
7. Matousek, J. (1989) Scientific World 33, No 1, 24-29.
8. Matousek, J. (1989) New Perspectives 19, No 4, 6-7.
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