What are chemical weapons

What is a chemical weapon?

The official definition of chemical weapons is very technical, but important nonetheless. According to Article II of the Convention on the Prohibition of Chemical Weapons, the term "chemical weapon" comprises three points:

1. Toxic chemicals, i.e. chemicals that can cause death, temporary incapacity or permanent damage in humans and animals through their chemical effects, as well as their precursors, i.e. all chemical reaction components that are involved at any stage in the production of a toxic chemical .

2. Ammunition or equipment specifically designed to cause death or other physical harm by releasing toxic chemicals.

3. Any equipment specifically designed to be used in close conjunction with the above ammunition or devices


The OPCW distinguishes three categories of chemicals that have to be declared and whose production facilities are inspected, depending on the production volume:

1. Chemicals and their direct starting materials, which have almost no other production goal than to be processed into weapons of mass destruction. They are subject to very strict restrictions in terms of production, the production limit is set at one ton per year and per country and an exemption is required, and in terms of their transport.

2. Chemicals that are raw materials for chemical weapons, but which are also used in conventional industry, such as in the synthesis process of some drugs or in the production of lubricants, insecticides or pesticides. For example, chlorine is also a chemical that can be used in two ways.

3. The chemicals, which are mainly used in industrial applications with peaceful intentions, as pesticides, insecticides, lubricants, in paints, plaster or textiles.


Here is an overview of the toxic gases most commonly used as chemical weapons:

Nerve agents: Originally, they are derivatives of pesticides, which because of their structure are also called organophosphorus compounds. These are colorless, tasteless and odorless liquids. If they are inhaled or absorbed through the skin, these nerve gases block the human nervous system and gradually paralyze the respiratory muscles. Sarin, soman and tabun, the best-known nerve agents, were synthesized by the German chemical industry in the 1930s. The VX warfare agent was developed by an English chemist after the Second World War.

Lung warfare agents: These highly volatile substances such as phosgene, diphosgene, chlorine and chloropicrin can be released in gaseous or liquid form. The asphyxiating gases block the flow of oxygen into the body, causing toxic pulmonary edema. The victim dies from suffocation.

Skin warfare agents: If they come into contact with the skin, these oily liquids cause severe chemical burns and burns immediately or a few hours later. Blisters often form on the skin. Contact with the eyes leads to severe irritation and can lead to severe eye inflammation or even blindness. The damage to the respiratory tract can be similar to that of lung warfare agents. The best-known tissue-damaging substances are yperite, also known as mustard gas, which was used en masse, especially during the First World War, as well as other nitrogen mustards and Lewisites.

Blood warfare agents: These very unstable compounds usually enter the body through the airways or skin and act very quickly. They lead to death by suffocation. These include hydrogen cyanide and cyanogen chloride, as well as arsine and hydrogen cyanide (Zyklon B).

Neutralizing irritants: These chemicals cause irritation to the skin and respiratory tract, severe chest pain, and temporary incapacity. The neutralizing substances are mainly used to put down unrest, but have also been used in acts of war. The most common irritants used are CS and CN tear gas and adamsite, which causes nausea and nausea. The Chemical Weapons Convention enables the use of neutralizing irritants as a means of combating unrest at home in order to maintain domestic political order. They are therefore not considered deadly chemical weapons in the strict sense. The use of tear gas against demonstrators has already resulted in deaths from asphyxiation, particularly in Egypt, Bahrain, Palestine and Turkey. Activists have therefore created a website on which they try to trace the origin of the gas cartridges. They want to draw attention to their deadly effect and consequently their illegal use.

Psychological warfare agents: These lesser-known psychogenic substances temporarily incapacitate people by acting on the central nervous system and incapacitating the victims physically or mentally. They attack the psyche of people and can trigger hallucinations. The best known psychological warfare agent is benzilic acid ester (BZ). For the Organization for the Prohibition of Chemical Weapons, psychological warfare agents are among the permitted means of combating unrest in Germany, so their use is permitted under certain conditions.

Sources: United Nations Office for Disarmament Affairs / Organization for the Prohibition of Chemical Weapons (OPCW)



Ralf Trapp is a former inspector with the Organization for the Prohibition of Chemical Weapons (OPCW). He was part of the German delegation at the first international negotiations on lethal weapons. These negotiations finally led to the signing of the Chemical Weapons Convention in Paris in 1993. The trained chemist and toxicologist now works as an independent advisor on disarmament issues. He describes the various warfare agents that make up a chemical military arsenal.