Chemical Warfare

Chemical warfare is about using the toxin properties present in certain chemical substances as weapons of mass destruction. It contributes to one of the 3 major banned warfare’s acronymed NBC (nuclear, biological, chemical) which are prohibited by several treaties such as the Geneva protocol signed in 1925.

The Geneva protocol banned the use of asphyxiating or poisonous gases during warfare to protect people’s wellbeing as they are deemed cruel weapons. Certain chemical weapons can have lasting effects, changing the body’s chemistry or prolonged death with constant suffering. Before the signing of this protocol several poisonous gases were used to get the upper hand in world war one.

The first chemical weapon to be used in world war one was tear gas, contained within canisters during 1914. Tear gas is a lachrymatory agent which irritates the mucous in the respiratory system leading to coughing and breathing difficulties.  No one died using tear gas as it was mainly used to incapacitate briefly to get the advantage as the symptoms subsided after 30 minutes. 1

Chemistry 1

Figure 1: Tear Gas from WW1

In 1915 Chlorine gas was deployed which is a powerful irritant, damaging the respiratory system. Chlorine converts into hydrochloric acid when in contact with water in the body leading to chemical burns shutting down the lungs. Therefore, in high concentrations, death by asphyxiation is highly probably. Soldiers could see a chlorine attack coming due to its yellow – green colour and could equip a gas mask to prevent inhalation. However, during the start of the war soldiers did not carry a gas mask since gas attacks were thought to be inhumane. Chlorine is denser than air so remained in the trenches poisoning soldiers until it dissipated. 2

Chemistry 2

Figure 2: Reaction of Chlorine gas within the body

Due to chlorines defects, such as being water soluble, a deadlier gas recognised as phosgene was developed by French chemists. This was colourless, more effective at killing needing only 0.4ppm, and harder to detect but gave off an odour of musty hay. 85% of gas related fatalities from World War 1 were due to phosgene poisoning. Once again, phosgene reacted in the lungs causing asphyxiation but often symptoms were not apparent for hours, incapacitating soldiers on the battlefield long after the gas attack. 3 There is no known antidote for phosgene, so people exposed at high concentration would die.  Due to this and its hard detectability it resulted in the most deaths by gas attack in the war.

Chemistry 3

Figure 3: Phosgene

In 1917 mustard gas was introduced, which was the most effective gas. It was not a killing agent although in high concentration it could be fatal. It formed intermediates that could react with DNA resulting in cell death. 4 However, for the most part mustard gas was an irritant and a blistering agent which could incapacitate soldiers by damaging the respiratory system and producing chemical burns on the skin. It could also create internal and external bleeding resulting in soldiers needing medical care taking up more resources, transporting and treating than a dead soldier. Mustard gas has a yellow-brown colour and smelled of horseradish (mustard) so was easily detected. The gas was denser than air sinking to the ground forming a liquid where it could absorb into the soil. This could remain active for weeks causing blistering on the skin for any soldiers in the trenches. This even meant enemy forces could not advance immediately after launching a mustard gas attack without risk of exposure.

Chemistry 4

Figure 4: Mustard Gas

New gases were constantly developed but by the end of the war soldiers were well trained and equipped with counter measures reducing the gases effectiveness. After signing the Geneva protocol the use of chemical warfare wouldn’t have been expected but preparations were still made regardless. It became evident that some countries or groups were willing to break the Geneva protocol to gain power even before the war broke out. This can be seen in 1935 with the Italians using mustard gas in Abyssinia.

By the start of world war two the previous tear gas had been improved to a version called adamsite. This included all the previous respiratory problems but also caused nausea and vomiting. 5 Once again, no lasting harm was caused. This vomiting agent was very useful when combined with another gas as soldiers would have to take the gas mask off to vomit leading to poisoning by another gas.

Chemistry 5

Figure 5: Adamsite

Mustard gas also got improved to a deadlier version called lewisite which soaks through clothing to reach the skin creating blisters like mustard gas. This is a vesicant and lung irritant causing damage to the bronchia destroying their function leading to pneumonia and respiratory problems that could be fatal. For all the gases except mustard and lewisite mentioned above a gas mask can prevent major harm to the organs of the body. A gas mask covers the whole face making sure it is sealed tight and filters the air that can be breathed. 6

Chemistry 6

Figure 6: Lewisite

Nerve agents are organophosphates. Several nerve agents including Tabun(GA), Sarin(GB) and Soman(GD) were deployed during the second world war which affect the nervous system and disrupted bodily functions. Exposure to large portions of nerve agents can lead to convulsions, comas and even death. 7 These were G agents that are volatile and don’t require clean up as they evaporate into the atmosphere. VX is another nerve agent which is deadlier requiring milligrams to kill and requires clean up. 8 VX shuts off the signals in the nervous and muscular system leading to paralysis and death by asphyxiation. 9 However, gas masks cannot protect against vesicants/blistering agents or nerve agents that enter through the skin and don’t have to be inhaled. Vesicants can soak through clothing quite easily so full protective clothing is needed to prevent them. Luckily in the provided bag alongside the gas mask in world war two there was a uniform made from a water-soluble material that prevent the gas reaching the skin.

Chemistry 7

Figure 7: Tabun (GA)

 Chemistry 8

Figure 8: Sarin (GB)

 Chemistry 9

Figure 9: Soman (GD)

Chemistry 10

Figure 10: VX

Chemical warfare is a big threat even today as large organisations can produce their own poisonous gases. This week, the “worst chemical weapons attack in years” took place in north west Syria. The gas was believed to be sarin and the death toll at the time of writing is almost 60 with many more still battling the effects of the gas. 10 But several counter measures can be put in place to reduce the number of casualties from attacks. Some of these being antidotes, evacuation plans, early detection, and medical care.

Written By James Yarnall


[1] – “Chemical Warfare: Poison Gases in World War 1”, Compound interest, 17/05/2014 [Online] Available:

[2] – “Chemical Warfare: World War 1”, Compound interest, 17/05/2014 [Online] Available:

[3] – “Phosgene Gas WW1”, Prezi, 22/05/2013[Online] Available:

[4] – “Mustard gas”, Centers for Disease Control and Prevention, 18/11/2015 [Online] Available:

[5] – C N Trueman, “Poison Gas And World War Two”, The History Learning Site, 06/03/2015 [Online] Available:

[6] – J B Calvert, “Chemical Warfare”, 22/12/2002 [Online] Available:

[7] – “Chemical Warfare & Nerve Agents- Part 1: The G Series”, Compound interest, 07/10/2014 [Online] Available:

[8] – “Types of Chemical Weapons”, Federation of American Scientists, [Online] Available:

[9] Dina Esfandiary, “The Five Most Deadly Chemical Weapons of War”, 17/07/2014, [Online] Available:

[10] “Syria ‘chemical attack’ down to Assad, US says,” BBC News: Middle East, 04/04/2017, [Online] Available:


One thought on “Chemical Warfare

  1. Very interesting. It’s scary to think we still use these in humane methods in war! More must be done to prevent the use of such things.


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