It was April 22, 1915. It was World War I and thousands of soldiers from Germany and France were fighting each other to win what many believed would be an easy war. It had been a long day, but the fight was barely beginning. Suddenly, the unexpected happened. Greenish-yellow colored clouds covered the air over the Allied troops. This cloud reached thousands of soldiers, causing them to abruptly choke to death.¹ Many tried to escape this cloud of horror, but the movement of the fog was too fast, wounding approximately 4,000 French and Algerian soldiers.² After seeing all of this, officials and scientists couldn’t help wonder what this cloud was made of and how it was able to kill so many soldiers?

Both the French and British hurried to collect whatever information they could from this suspicious cloud. Within days, French scientists had proven that the Germans had used Chlorine gas.³ They had launched their first successful gas attack against their enemy in Ypres, France. They had opened the valves of more than 6000 steel cylinders that released 168 tons of chlorine gas.⁴ The idea of an easy war had now shifted. But how did German officials come to have such technology and how were they able to proficiently kill thousands of enemy soldiers? There must have been an expert behind this, a mastermind, someone who had studied chemicals and their effects on humans. This scientist was Fritz Haber, also known as the “father of chemical warfare.”⁵

During World War I, entomology practices were introduced into chemical-warfare in Germany.⁶ Fritz Haber created a nitrogen-based fertilizer to help feed an exploding human population that came with Germany’s industrialization. These chemical advances were at first targeted toward pest control in agriculture and forestry.⁷ At the same time, German soldiers were looking for ways to be ahead of their enemies. They were looking for a force multiplier that would give them an edge or advantage. Haber saw this search for an advantage in the war zones as an opportunity for his studies. Government officials approached Haber because of his work in toxicology and chemistry. He suggested that increasing the studies made on small insects to large animals would be useful for both advances in agriculture and forestry. For this strategy to be successful, the knowledge of entomologists and botanists needed to be combined with that of chemists. The resulting knowledge could turn into the most important development of chemical warfare.⁸

After the first use of chlorine gas by the Germans in Ypres, France, the Allies too were looking for ways to catch up to their enemies and be stronger than them. The British began employing it in September of the same year.⁹ But their approach to it was different from the Germans and was started because of hate. They were attacked with a form of warfare that the Army wasn’t ready to combat: they had no masks, no gas canisters, no policy with regard to chemicals, nothing.¹⁰ Britain responded with outrage. Britain was morally repulsed and their forces were militarily vulnerable. Government officials began to buy from factories anti-gas helmets. These were then distributed to the soldiers, providing them with more technologically advanced weapons.

As the war continued, scientists continued their research, and were able to produce a range of chemicals, from simple chlorine to sophisticated and elaborated mustard gas.¹¹ But the issue wasn’t on the creation of chemical weapons. Britain instead was facing the dilemma of whether or not they should use it offensively. They believed that they had a higher level of civilization and even believed they were able to restrict themselves from using such inhumane war elements such as chemical weapons.¹² If they were to use these weapons, Britain would be seen as hypocritical after they had condemned Germany for using these weapons. They decided to use gas weapons as self-protection and only use gas after the other had used them first. They also were not allowed to use the word “gas” in their operations, because of the stigma that came with it. Instead, the British used these “accessories” on September 24, 1915, where around 400 chlorine gas emplacements were established along the British line around Loos. The next morning, the gas was released.¹³ By releasing gas like this, the soldiers had to be very cautious of wind conditions, since the gas could drift over the enemy or turn and drift over their own trenches. This is exactly what happened. It is estimated that there were more British casualties than German that morning.¹⁴

Just as scientists in Britain worked to find ways to match the same technological level as their German counterparts, France funded laboratories and factories to come up with innovative ways to deploy chemical weapons in the war. French research on poison gas began in January 1915, after the Grand Quartier Général learned that the Germans had begun doing research the month before. He ordered a large number of engins suffocants (tear-gas rifle grenades) to replace the weapons that the French had marched to war. Additionally, 90,000 protective goggles would be sent to be used primarily by infantry attacking an enemy position that had been gassed.¹⁵ These changes started to help the French soldiers increase their strength at the war zones. But still, more research had to be made in order to get to the same level as the Germans.

After the use of gas by the Germans on Ypres on April 24, 1915, the French war minister, Alexandre Millerand, appointed André Kling, the director of the Paris municipal laboratory, to lead the research on poison gas. Kling mobilized three laboratories, Amiens, Châlons-sur-Marne, and Nancy, and he specialized their research in toxicology and medicine in relation to poison gas.¹⁶ These French scientists then discovered that chlorine was water-soluble and came up with a solution for the camps. They created gas masks using cotton but later realized that their masks weren’t very effective compared to the British masks. They adopted the British’s gas masks, which consisted of a large pad of cotton impregnated with sodium thiosulphate. Then, it would be urinated, thus increasing its ability to absorb and neutralize chlorine gas.¹⁷

Besides working on ways that would neutralize the effect of Chlorine gas, the French were also looking for ways to advance their chemical weapons and get ahead of Germany. The French first tested chlorine gas in May 1915 at the military camp at Satory, which allowed them to create a basis to develop more concrete theories for the offensive use of gas. They discovered that for a gas attack to be successful, a necessary density of gas was needed for it to be carried to the enemy trenches. But one of the most interesting projects that the French initiated was the creation of poison gas shells.¹⁸ By the end of May, the efficiency of these shells had been tested. By the 9th of June, 10,000 shells were ready for deployment and were launched for the first time on June 16, 1915.¹⁹ The use of chemical weapons in France just boomed. In fact, the French even accepted and embraced the use of these weapons for the neutralization of their enemies. This became a key component as armies of the Western Front shifted their tactic of destruction towards neutralization as a guiding principle when preparing trench offensives.²⁰

The creation of chemical weapons during World War I proved that it was effective to combine both science and military and be ahead of everyone else. But chemical weapons were not the only means for obtaining a force multiplier. Other attempts to find a force multiplier included advancements in submarine warfare, uses of the airplane and tank, as well as gas warfare. Advances in weaponry included new rifle cartridges that traveled at higher velocities, and the improvement of machine guns, among others.²¹ World War I was also the first war to witness the first tank raid on a large scale, which included nearly 400 tanks from Britain used at the Battle of Cambrai against the Germans.²² Germany also contributed to the advancements in warfare. During 1916, Germany had a rather effective system of submarines that were destroying about 300,000 tons of British and Allied shipping per month. In just one year, this grew to 875,000 tons. Great Britain then began to develop warfare that would aid them against the Germans. They adopted a system that included warships, destroyers, submarine chasers, and the use of hydroplanes to spot submarines and destroy them.

As the war advanced, Britain’s fleets became stronger and more numerous than the Germans, making the German attacks less and less effective. By 1918, Germany’s efforts with submarines were proven a failure.²³ World War I also provided great encouragement for the production and use of aircraft that was used for two purposes: observation and bombing. Small tethered balloons were used to observe the enemy and locate their troops and defenses. Big balloons would then be used to bomb and attack these previously located troops and enemy centers. At the beginning of the war, Germany dominated the sky. They were, in fact, the ones who participated in the first airplane raids, which happened in August 1914 in Paris with the airship Zeppelin. These raids then became relatively frequent, with the objective of eliminating British planes from the western front, to handicap the British industry, and to destroy the morale of the civilian population.²⁴ But this supremacy in the air later passed to the British, proving Germany’s efforts here a failure as well.

The development of these force multipliers provided a shift of the armies from having traditional equipment and tactics to a more sophisticated and aggressive equipment and tactics. But this also proved the enormous role that mathematics and science had in the war that is often referred to as “the war of chemists.”²⁵ The development of chlorine gases contributed to this, but it also involved the manufacturing and deployment of other chemical weapons such as phosgene and mustard gas.²⁶ Phosgene was first used by the French in retaliation for the Germans using chlorine. This new weapon was stronger than chlorine, which caused the soldiers to cough out green bile, have shortness of breath and experience suffocation, and, if exposed to a greater dose, have heart failure.²⁷ Mustard gas was introduced into the war in the summer in 1917, bringing in a new horror. Soldiers were protected with gas masks and goggles that could protect their lungs, but this new gas could now burn the exposed skin and blind them before they were able to put their respirators on.²⁸ Mustard gas became known as a blister agent because it would burn the skin, eyes, windpipe, and lungs. Winston Churchill, Prime Minister of the United Kingdom at the time, labeled this gas as a “strange but formidable weapon” since it killed over four percent in comparison to about 25 percent for conventional weapons. This was considered a very low death rate of soldiers, which left the rest alive and able to fight.²⁹ Despite the horrific effect this chemical weapon caused and because of the low deaths it produced, it came to be considered a more humane weapon.³⁰

World War I finally came to an end on November 11, 1918. Russia had earlier signed a treaty with Germany to pull out of the war. This seemed like the harbinger of victory for Germany, but that all changed when the United States decided to ally with France and Britain. American troops came in large numbers, outnumbering Germany’s army. The Allies were then able to push up from Italy, the Balkans, and the Middle-East putting Austria-Hungary, Bulgaria, and the Ottoman Empire out of the war. Germany then called for an armistice to stop the fighting.³¹ The Treaty of Versailles was then signed on June 28, 1919, formally ending the war. This allowed for the assessment of the war and the agreement on terms for future wars.

At the end of the war, both sides had used massive quantities of chemical weapons, causing an estimated 1,300,000 casualties, including 91,000 fatalities. The Russian army suffered about 500,000 of these casualties, and the British had 180,000 wounded or killed by chemical arms. One-third of all U.S. casualties in World War I were from mustard and other chemical gases, roughly the ratio for all participants combined. Altogether, the combatants employed more than twenty-four different chemical agents, including mustard, which caused as many as 90 percents of all of the chemical casualties.³² The question regarding the use of chemical weapons rose again and the people from Europe wondered if it was humane to use them or not. Additionally, states who participated in the war realized that the unpredictability of the wind when using gas was an enormous challenge since many of the casualties had been caused by the same government who had utilized the gas. An agreement of some sort or a treaty had to be signed.

Previously, there had been a number of treaties that had been signed regarding wars and the treatment of combatants. The Hague Convention of 1899 banned the use of “projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases.”³³ But there was a problem with this Declaration. Even though it prohibited the use of projectiles to diffuse fatal gases, it suggested some leeway regarding the types of weapons it covered. The Declaration banned projectiles but gave no additional information about other methods of delivery nor banned them. For example, the attack at Ypres consisted of cylinders of compressed chlorine gas released into the wind by nozzles, but regardless, this was technically not a violation of the specific language of the Declaration, though it clearly went against the Declaration’s intent.³⁴ By the end of the war, it was clear that the Hague Conference was completely ineffective in preventing the use of chemical weapons not just because of the wording, but because it was unclear of the possible punishment or what would happen if the ban was violated. Additionally, the Hague Declaration IV required only that the Contracting Powers “abstain” from using asphyxiating gases, a word that did little to prevent the proliferation of chemical gases on both sides.³⁵ The wording of this Declaration left a lot of information unstated and unclear, leading to the use of this chemical warfare. The Geneva Protocol was signed to answer a few of these questions.

The Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or other Gases, and of Bacteriological Methods of Warfare, of the Geneva Protocol was signed on June 17, 1925. France was the first country to ratify the Geneva Protocol on May 10, 1926. Liberia ratified it the next year. Austria, Belgium, Egypt, Italy, Russia, and Venezuela followed in 1928. Germany, Finland, Iran, Poland, and Spain signed it in 1929. The United States ratified the protocol in 1975.³⁶ The protocol prohibits the use of “asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices” and “bacteriological methods of warfare.”³⁷ Although this Protocol was able to address the use of chemical weapons in the war, it failed to address the issue of manufacturing, production, storage, or transfer of these weapons. Lastly, the Protocol did answer many of the questions regarding the use of these weapons, but it ultimately failed to eliminate the use of these chemical weapons as we saw their resurgence during World War II and have seen their use recently in Syria. Will we ever address the use of these silent killers?