
The horrors that man is capable of unleashing upon his enemy during warfare reached a pinnacle during World War I, when BOTH slides used Poison Gas against the other. World War I was the first conflict to devolve into stagnant trench warfare. This happened when the equally matched armies dug thousands of miles of trenches along the front lines. In between the trenches lay a “No Man’s Land,” snaked with barbed wire and obliterated by heavy artillery. After numerous high casualty battles that did nothing to move the front, both the Germany and Allies looked for any way to win campaigns.
Chlorine gas was first deployed by the German military at the Second Battle of Ypres on 22 April 1915. French, British and Canadian troops lined a 10 mile long front against the German army. At 17.00 hours, the day’s shelling ceased, and winds favorably blew toward the enemy in the west. German troops opened pressurized tanks of chlorine gas hidden at the front line trenches.
French sentries first noticed a strange, greenish-yellow cloud moving towards them. Thinking it was a smoke screen to cover a German advance, all troops were ordered to the ladders of their trenches. The gas’s impact was immediate and horrifying. It destroyed a man’s ability to breath in a matter of seconds. causing death by asphyxiation. The surviving French troops fled in terror. Even the Germans were so shocked by the deadly effect of their gas, they never followed through with a full assault.
Germany’s use of poison gas provoked immediate and widespread condemnation around the globe. Nevertheless, the poison gas ‘cat was out of the bag,’ so to speak. Its use escalated for the remainder of the Great War to End all Wars, by Both Sides.
The first Allies to respond was Britain in 25 September 1915. Newly formed Special Gas Divisions attacked German lines at Loos, France around 5 am with their new “Accessory.” They were forbidden, to use the word Poison Gas, else they be as guilty as the ‘Jerries.’ Unfortunately, along parts of the British front lines, the wind changed direction unexpectedly! The chlorine gas was blown back onto the British troops, causing over 2,000 casualties, more than inflicted on the Germans.
After chlorine came phosgene, a gas that induced less coughing, so more would be inhaled by the enemy, increasing the kill rate. But what was the average trench soldier to do? At first, they were instructed to hold a urine soaked kerchief over their face to protect against the effects! Needless to say, this failed miserably. Gas mask production lagged behind gas production. It took several ineffective versions before the troops were finally provided with a reliable full face model. Uncomfortable masks with round goggles and a single filter cartridge were effective if applied fast enough.
Made of sulphur dichloride, the oily, brown liquid gave off what survivors described as a garlicy, horseradish or mustard stench. Mustard gas was nearly invisible, and rather than immediately choking the victim, it caused large, severe and painful blisters, both in the mouth, lungs, and on the skin. Temporary blindness and pulmonary edema were induced. Mustard gas also remained potent in clothing and the soil for weeks, making infected trenches impossible to live in.
To the thousands of souls fighting in Flanders, it was hard to imagine how the hell of trench warfare could get any worse. On 12 July 1917, German gunners fired more than 50,000 artillery shells of mustard gas into the British and Canadian lines. Hospital tents up and down the front were soon bursting with more than 2,000 victims, suffering from excruciating blisters across their bodies. Most were blinded, others slowly suffocating, leaving the rest disfigured and writhing in agony.
By autumn, mustard gas was in use up and down the Western Front from Belgium to Switzerland, once again by both sides. By year’s end, the British were dropping mustard gas shells onto German trenches as well. When the U.S. entered the war in 1917, America’s Dow Chemical manufactured the poison for the troops.

Mustard gas so terrified soldiers because unlike phosgene, victims were initially unaware they were being gassed. Gas masks only protected the lungs; everything else burned and blistered, even skin beneath clothing. Since it was heavier than air, clouds would settle into bomb craters and trenches, remaining there for hours if there was no breeze.
The Germany military continued to develop a deadly array of delivery methods including artillery shells, mortar rounds, free falling bombs from bi-wing airplanes and even in land mines. The British army alone suffered 20,000 mustard gas casualties in just the last year of the war.
Although the use of poison gas was banned by the 1925 Geneva Convention, armies around the world continued to use it up through the 1930s. For example, the Japanese Empire gassed both Chinese armies and civilians in its invasion of Manchuria. During World War II, the Allies stockpiled millions of tons of mustard gas behind frontlines just in case the Nazis and Japanese decided to use it.
In modern times, mustard gas was used most recently in the 1980s Iran-Iraq War. Saddam Hussein ordered its use against the Iranian army, and even against Iraq’s own Kurdish population, where more than 5,000 civilians died.
Today, advanced post Cold War militaries have much more modern Nerve Agent Gases, like VX, Novichok and Sarin. They remain largely unused and stockpiled by both sides, kept as a deterrent only of course. Or until our enemies, extremists or terrorists, decide to use them against us first. Then, the deadly cycle of escalation seen during World War I might just begin again in modern times.