In the second half of the 20th century, chemical products used in homes instead of military materials were increasingly used in the construction of explosive devices. The most popular ones come from agriculture and chemical industry. In general, improvised explosive devices can be built using commonly available materials; components for the construction are becoming easier to obtain. Unconventional means, such as chemical substances, may be used to enhance the effect of the explosive device. However, they are not necessary for its operation.
Improvised explosive devices come in many forms – starting with simple ones and ending with very complicated and hard-to-detect devices. They are seen not only as an effective physical weapon (generating destruction and human casualties) but also as an effective tool in influencing state authorities and societies. After 2001, the terms “improvised explosive device”, “explosive device” or “bomb” have became more widely known all over the world. Growth in the global media interest during the wars in Iraq, Afghanistan and Syria has popularized mainly the term “improvised explosive device”.
In order to create an explosive with the desired properties, terrorists and criminals combine different substances, receiving a variety of explosive mixtures. The example is the terrorist attack of 22 July 2011 made by Anders Breivik who used a car containing an improvised explosive device which was in the form of a pyrotechnic mixture – ANFO [Ammonium Nitrate Fuel Oil]. Breivik had been preparing the attack for several years – among others he established a business related to agriculture, which allowed him to purchase components for the manufacture of the explosive. Producing ANFO in house conditions is simple and does not require specialized skills or knowledge. Information available online describes potential effects of an explosion of a certain amount of the mentioned explosive.
In conclusion, improvised explosive devices can be used differently, most often as conventional loads. They may contain chemical, biological or radiological material as a component of destruction. The risks posed by them may have two main sources:
- chemical or biological missiles containing a factor of destruction in the form of chemical or biological weapons, including explosives for dispersion [Dispersion – the state of fragmentation of a diffuse substance in solutions].
- explosive device containing chemical, biological or radiological material.
Improvised explosive devices containing chemical substances
An explosive device containing a dangerous chemical substances can be used in two ways. Firstly to disperse chemical missiles by initiating an explosion that will damage the shells of typical ammunition and will continue to release [disperse] the chemical substances. Secondly, by using an explosive device which contains combat poisonous agents or toxic industrial agents.
It is likely to use easy-to-synthesize chemical substances such as mustard gas in basic laboratories. Toxic industrial agents such as chlorine and ammonia can also be used. These chemical substances are characterized by high toxicity. An explosive device is used here to leak transport containers and release [dispersion] chemical material of corrosive and irritating vapours and aerosols.
According to the European Union Terrorism Situation and Trend Report 2017 there are indications that terrorist organizations have sufficient knowledge to build an explosive devices containing chemical substances. The possibility of carrying out attacks using them is the crucial part of terrorist propaganda. On various social media platforms, attack tactics are shared and potential targets are described. [https://www.europol.europa.eu/activities-services/main-reports/eu-terrorism-situation-and-trend-report-te-sat-2017]
The choice of the type of explosive device, its quantity intended for explosives and its design will depend on parameters such as temperature, pressure which could cause a chemical to decompose. Toxic properties of chemical materials are most harmful when are used in closed spaces. The use of an improvised explosive device containing a chemical substances will also depend on the potential perpetrators of terrorist acts, especially on their knowledge and the availability of chemicals and explosives. In view of the current solutions used in explosives technology, they are expected to have several times increased parameters of destruction, while reducing their size several times. Such development of explosives can cause significant difficulties in detecting and identifying explosive devices.
The improvised explosive device is designed to disperse chemical substances on humans for poisoning, incapacitating or killing. As a result of energy emission in the form of shock wave, heat and mass, chemical materials depending on their properties will also pose a threat to the environment.
The use of explosive devices containing chemical substances is the example of asymmetric actions that take unconventional strategy and tactics into account. Their use is due to existing the possibility of buying products and technology available to the public. This condition forces great flexibility in the continuous improvement of international airport security elements.
Nowadays there is a wide range of instruments of detection or identification of all types of chemical substances. It is possible to detect: chemical substances such as chemical warfare agents, toxic industrial chemicals and explosives, as well as poisonous, commonly used, chemical substances at all phases (gas, liquid and solid).
Taking into account the different concentrations of chemicals and various equipment of their detection or identification, the next article will set out the methods of detecting chemical substances to ensure effective protection of international airports.