On April 22, 1915, a regiment of German pioneers opened a series of gas cylinders near Ypres, releasing clouds of chlorine gas. These clouds drifted in the wind toward the positions being held by troops drawn from France’s colonial possessions. The affected troops broke, but reserve troops from Canada held the Allied positions long enough to prevent the Germans from exploiting the confusion. This event is often considered the first use of poison gas in World War I, and in several particulars it was typical; it was sudden, it was terrifying and in the end, it was ineffective.
Poison gas was a feature of the First World War, and generally not of other conflicts, for two reasons; availability and perceived need. In the former category, it should be observed that the technological developments that made the use of chemical weapons possible only began in the late nineteenth century. The second wave of the Industrial Revolution was characterized by developments in steel and chemicals, and both were used extensively during World War I. Poison gas was a side-effect of developments in chemical research.
As for perceived need, it was trench warfare that made both sides desperate for a weapon that could break the stalemate. A secondary consideration was the fact that poison gases were heavier than normal air, which allowed the gases to sink into trench positions and even into protective tunnels. Of course, the heavy concentration of men in the trench systems made them an attractive target for gas attacks, assuming that the prevailing winds permitted a reasonably accurate deployment.
Like many other new technologies, the first efforts to use poison gas were tentative and weak. As early as October 1914, the Germans attempted to use an irritant against the French near Neuve Chapelle, but without any appreciable effect. The effort seemed not to have been noticed by the targeted enemy, and is rarely noted in the literature as well. Better attested, but hardly more effective, was the use of tear gas (specifically, xylyl bromide) against the Russians at Bolimov in January 1915. In this case, winter weather on the Eastern Front foiled the German effort. The gas condensed rather than spreading and, again, the enemy failed to note its use.
The attack at Ypres in April 1915, changed the circumstances. Clearly, weather played a very different role, given the place and time of its use. The weapon was also different: this time it was chlorine gas, another irritant that could be deadly in large doses. Chlorine gas reacted with water by forming hydrochloric acid, with disastrous results in the lungs. The German Chief of Staff, Falkenhayn, had permitted its use on a trial basis, but without much expectation.
Falkenhayn’s pessimism proved warranted, but other trends came into play that ensured that the project did not die. Firstly, sentiment on the Allied side militated for retaliation; many felt that the use of such an inhumane weapon by the Germans demonstrated just how barbarous they were, and so, for precisely that reason, the Allied armies needed to use the same inhumane weapon. Secondly, it was never clear during the war whether the concept had failed, or simply the combination of a given agent and its method of deployment. Under continuing circumstances of stagnation, the concept of poison gas could not be discarded as long as the possibility remained that the right combination could prove effective.
Thus, development continued, with the Germans, French and British (in that order) taking the lead. In terms of deployment, one alternative to trusting the wind presented itself: in 1916, the belligerents mastered the process of encasing poison chemicals in liquid form inside artillery shells. The chemicals would become gas when exposed to the air after the shell detonated. This technique allowed a force to project the poison gas deeper into the enemy ranks, and at a somewhat safer distance from one’s own troops. It also offered a higher level of control over the distribution of the gas effect. Even so, a change in the wind could still return the gas to the side that had projected it in the first place.
It was in the creation of new gases that the most ingenuity was demonstrated. Tear gas and chlorine gas were the first weapons used, and several variations of chlorine gas were eventually employed. Phosgene was developed later in 1915, and proved to be one of the more insidious gas weapons. Like chlorine, it attacked the respiratory system, but its effects were often delayed by as many as two days. Cyanide was used in a variety of compounds, especially by the French, and these gases were effective killers, but they were more difficult to deploy. Later in the war, mustard gas (dichlorethylsulphide) caused external and internal burns. Diphenylchloroarsine, or “blue cross,” distinguished itself as a powder with small grains that could penetrate many gas masks; it induced vomiting.
Many other specific varieties were engineered, but they resembled one or more of these main types. More generally, they included gases that killed immediately, like the cyanide gases; gases that attacked the respiratory system, like chlorine; gases that attacked the eyes, like tear gas, gases that created convulsions in the thorax, from sneezing to vomiting, like blue cross and gases that created burns or blisters, like mustard gas. They could also be used in combination, as long as the two chemicals involved did not react directly with each other. Often, a gas that caused convulsions (known as a sternutator) was used in connection with one of the irritators. The sternutator might hinder efforts to put a gas mask on, or if it was already on, might require its removal to avoid vomiting into it; with the enemy soldiers thus exposed, the other gas would create its normal effects.
Naturally, efforts to combat poison gas were undertaken as soon as the weapon revealed itself on the battlefield. During the course of the war, protective techniques advanced even as gas technology did so. In early 1915, with tear gas and chlorine gas as the primary dangers, improvised protection came in the form of goggles and wet handkerchieves, moistened with water or sterile and ever-plentiful urine. Gradually, gas masks with built-in goggles and provisions for replacing spent filters, came into use. Such masks did not protect against all dangers; mustard gas and blue cross are notable exceptions. Still, they saved many lives and prevented a great deal of disorder in the ranks.
At the war’s end, it was determined that gas was fairly ineffective as a weapon. Between its intrinsic flaws and the advances in protective gear, gas was seen to have a surprisingly low level of lethality. Roughly three percent of gas victims were killed by the attack, in contrast to 33% or more for those injured by bullets and shells. Not all military planners were dismayed by the low lethality rates; some showed a surprisingly contemporary view, considering the drain on enemy resources involved in dealing with the wounded to be worth more than a clear kill. Certainly, the threat of a gas attack inspired fear and raised the possibility of disorder.
It should be noted, however, that these potential tactical benefits remained true during World War II, but gas was never used on the battlefield. Nor has it been used in most subsequent conflicts. Pious statements about inhumane weapons are not enough to explain the lack of use; similar views were held before World War I, and yet poison gas enjoyed considerable use during that conflict. Rather, it was the unique strategic reality of World War I that made gas an attractive weapon. Weapons technologies had favored the defense to the point that no attacker could achieve more than a pyrrhic victory. Armies were desperate to find technologies and tactics that could break the impasse, and gas was one option among many. Subsequent wars have not been characterized by such stalemate, and so, the usefulness of poison gas has largely dissipated in standard military contexts.
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