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Monday, 15 April 2013

Poison Gas

Perhaps the most controversial military development during the First World War was the use of poison gas.  While no formal restrictions on its use existed prior to 1914, contemporaries widely considered such action morally unacceptable.  As the stalemate of trench warfare emerged along the Western Front, however, both sides searched for a weapon or tactic that could produce a 'breakthrough'.  In this situation, it is not surprising that combatants contemplated its use.

During the war's early months, both sides employed non-lethal gas in an attempt to gain a military advantage on the battlefield.  As early as August 1914, French troops used a form of tear gas against advancing German soldiers, hoping that the eye irritant would impair their fighting abilities.  German forces responded with a similar attack on British troops at Neuve Chapelle on October 1914.  In both instances, the gas proved largely ineffective.

As the year came to an end, Germany found itself in the predicament it had hoped to avoid - simultaneously fighting a war against French and British forces on the Western Front and Russian forces on the Eastern Front.  With its human and industrial resources stretched to the breaking point, German military commanders desperately sought a means to a quick victory on either front.  Thus, they advocated the use of poison gas, despite its moral implications.

The war's first large-scale gas attack occurred along the Eastern Front on January 31, 1915, when German forces fired 18,000 artillery shells filled with tear gas on Russian soldiers near Warsaw.  Cold temperatures caused the gas to freeze, rendering it largely ineffective.  Nevertheless, the scale of the attack set a precedent and suggested a significant change in strategy.

Poison gas attack on the Western Front.
This new direction was confirmed three months later at a strategic location on the Western Front.  The Ypres Salient extended more than eight kilometres into German front lines, containing sixteen kilometres of trench defended by French colonial, British and Canadian soldiers.  A German breakthrough at Ypres might end the impasse and lead to a decisive victory.  In retrospect, it is not surprising that poison gas made its debut at such a time and place.

On April 22, 1915, German artillery launched a morning barrage near Ypres.  By mid-day, the guns fell silent only to resume firing in late afternoon. A gentle breeze blew across "No Man's Land" toward an Allied section manned by French Algerian and Mauritanian troops.  Almost 6000 pressurized cylinders containing 168 tons of chorine gas lay along the parapet of the German trenches from Langemark to Poelkapelle, north of Ypres.  At 1730 hours, German soldiers opened the valves, releasing the gas into the air.

When Algerian sentries observed a yellow-green cloud drifting across "No Man's Land" toward their position, they initially thought it was a smoke screen for an infantry attack and roused their comrades to man the line.  As the gas floated into their trenches and men began coughing and gagging, those not affected dropped their weapons and fled in terror, creating a seven-kilometer gap in the Allied line.

Had the German infantry reacted quickly, the final outcome may have been different.  However, caught off-guard by the sudden withdrawal and fearful of the presence of poison gas on the battlefield, they advanced cautiously across No Man's Land.  Their hesitation allowed British and Canadian troops to counterattack and close the gap through the night.  However, the precedence was set - poison gas had been used in combat.  By war's end, it had become a major component of weapon supplies on both sides.

Soldiers wearing primitive gas masks.
German forces released chlorine gas on three more occasions during the Second Battle of Ypres - against soldiers of the 1st Canadian Division on April 24, and British troops on May 2 and 5, 1915.  It was also used against Russian troops near Warsaw on August 6, 1915, inflicting 9000 casualties and more than 1000 deaths. 

Chlorine gas was a by-product of dye manufacturing and Germany therefore had access to sizeable quantities.  The gas irritates the eyes, nose, throat and lungs upon contact.  High concentrations and prolonged exposure result in death by asphyxiation.  However, the coughing induced by contact reduces the amount of gas ingested.  In addition, chlorine is most effective at ground level, where it is most concentrated.  Soldiers in a standing position or on higher ground were less affected than individuals in a prone position, such as wounded or sleeping soldiers.

Several factors reduce chlorine's effectiveness as a weapon.  Its yellow-green color makes it easy to detect.  As the gas is water soluble, covering the mouth and nose with a damp cloth reduces its impact.  Soldiers at Ypres quickly discovered that a urine-soaked rag was particularly effective, as the chlorine reacted with urea and lost much of its effectiveness.

In addition, after its initial use, the element of surprise was lost as Allied commanders prepared for subsequent attacks.  Within days, soldiers in the front lines received gauge pads filled with cotton, accompanied by bottles of bicarbonate solution.  In the event of a gas attack, the pads were dipped into the liquid and held to the face.  By July 6, all British forces were equipped with a 'smoke helmet' designed by Major Cluny MacPherson of the Newfoundland Regiment.  It consisted of a flannel bag with a celluloid window and covered the soldier's entire head.  While it obscured their vision and was somewhat uncomfortable, it did protect their health.

Australian soldiers wearing advanced gas masks.
It was not long before Allied forces responded in kind.  Shortly after the Ypres attack, Britain organized Special Gas Companies consisting of 1400 personnel, assigning them to strategic locations along the front.  When the first British gas attack occurred several months later, however, its outcome illustrated the challenges faced in effectively using poison gas on the battlefield. 

At 5:20 am September 24, 1915, British troops released 140 tons of chlorine gas into an initially favorable wind near Loos, Belgium.  As the cloud crawled across No Man's Land, however, the wind shifted and within forty minutes portions of the gas blew back into sections of the British line.  In addition, the gas in some cylinders could not be released, as soldiers were not issued with the correct turning key.  Subsequent German artillery shells struck several full cylinders, releasing more gas into the British positions.  It is estimated that the number of British gas casualties may have actually exceeded the number of victims in the opposing trenches. 

The Loos incident illustrated one of the greatest challenges in using poison gas as a weapon - finding an effective delivery system.  For several months, both sides experimented with inserting gas into artillery shells, a tactic that eventually proved highly effective.  More significantly, chemists addressed chlorine's shortcomings by developing a new, more effective poison gas by year's end - phosgene.

First produced by French chemists, phosgene is colorless and almost odorless, making it much more difficult to detect.  It does not induce coughing, increasing the amount of gas inhaled.  Phosgene does not immediately incapacitate its victims, requiring 24 to 48 hours to take effect.  However, inhalation of small quantities causes death.  As it is a denser gas, phosgene was usually mixed with equal amounts of chlorine to enhance its ability to disperse.  Allied troops called this deadly combination 'White Star', a reference to the symbol painted on the shells used to deliver the gas.

Poster highlighting phosgene's properties and effects.
The Germans launched the first chlorine - phosgene attack on British troops at Willtje, Belgium on December 19, 1915.  A total of 88 tons of gas was delivered by artillery shells, inflicting 69 fatalities and 1009 casualties.  British troops used the same weapon and technique during the Somme offensive launched in July 1916.  While only 36,600 tons of phosgene were produced during the war in comparison to 93,900 tons of chlorine gas, it was far more effective in inflicting casualties.  Estimates credit phosgene with approximately 85 % of the deaths caused by chemical weapons during the war.

By 1917, both sides were capable of launching gas attacks on one another's front lines, supply lines, support trenches and gun placements by means of chemical artillery shells, projectiles and mortars.  That same year, another deadly weapon made its debut.  Mustard gas, a chemical compound developed by the Germans, was first used during the Third Battle of Ypres (July 1917) on the Western Front and against Russian troops near Riga, Latvia (August 1917) on the Eastern Front.  Called "Yellow Cross" by the Germans after the identifying symbol placed on the shell casings, mustard gas is virtually odorless and colorless.  To the British, it was "HS" - "Hun stuff" - while the French called it "Yperite" after the Belgian city where it was first used. 

Unlike chlorine and phosgene, mustard gas does not have to be ingested.  Simple physical contact produces skin blisters, sore eyes and vomiting in addition to internal bleeding if inhaled.  The gas strips the mucous membrane of the bronchial tubes, leading to a slow, painful death as long as five weeks after contact.  Survivors often suffer blindness due to eye contact.  While not particularly effective at killing enemy soldiers, it did severely inhibit their ability to fight.  The gas also remained active in the soil for several days, depending on weather conditions, making contaminated trenches 'uninhabitable'.

While poison gas never succeeded in breaking the stalemate on either front, it became a standard part of the weaponry employed by both sides throughout the conflict.  At war's end, 35 % of French and German, 25 % of British, and 20 % of American ammunition stockpiles consisted of poison gas shells.  It was particularly suited to the static trench warfare that dominated fighting on the Western Front and was regularly combined with artillery fire in support of infantry attacks during the war's later stages.  Had the war continued into 1919, both combatants planned to insert poison gas into 30 to 50 % of newly manufactured artillery shells.

Artillery shells filled with poison gas.
While the Germans used the largest quantity of gas during the war - an estimated 68,000 tons - British forces actually launched more gas attacks during the last two years of the war than their opponents.  In comparison, French forces used 36,000 tons and British forces 25,000 tons of poison gas throughout the war.  During the war's later stages, Germany was unable to keep pace with Allied stockpiles, due to the cost of production and the entry of the United States into the war, an event that significantly increased Allied resources. 

In the final analysis, poison gas did not prove to be an effective weapon.  While it was deployed in 25 % of the artillery shells fired during the war, it caused only 3 % of its casualties.  This was due in large part to the development of filter respirators utilizing charcoal or chemical antidotes, although the masks remained cumbersome. 

Nevertheless, gas was responsible for thousands of casualties and deaths.  British forces suffered 188,706 casualties and 8,109 fatalities due to contact with poison gas.  An estimated 12,000 Canadian soldiers suffered from its effects.  Many victims never reported minor contact with gas and therefore were unable to obtain compensation if its effects produced health problems later in life.  Russian soldiers were most affected, suffering 419,340 casualties and 56,000 fatalities, although this was largely due to their military's failure to implement suitable precautions.

In total, poison gas accounted for 1,250,000 casualties and 91,000 fatalities, half of which occurred on the Eastern Front.  While significant, these figures represent only 10 % of the total number of casualties during the war, demonstrating its overall ineffectiveness as a weapon.  After the war, concern over future use of poison gas led to the creation of the 1925 Geneva Protocol.  This international agreement, eventually adopted by all of the war's major combatants, specifically prohibited the use of lethal gas and bacteriological weapons in combat, although production and stockpiling were permitted.  As a result, with the exception of a few isolated incidents, poison gas was not used to any extent during World War II or subsequent 20th century military conflicts.



Chemical Weapons in World War One.  Wikipedia: The Free Encyclopedia.  Available online.

Poison Gas.  Canada and the First World War.  Canadian War Museum.  Available online.

Poison Gas and World War One.  History Learning Site.  Available online.

Poison Gases.  Spartacus Educational.  Available at

Weapons of War: Poison Gas. - A Multimedia History of World War One.  Available online.

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