The use of poison gas was a major
military innovation of the First World War. The gases
used ranged from tear gas to disabling chemicals such as mustard gas and killing agents
like phosgene. The killing capacity of gas was limited - only 3% of combat deaths were
due to gas - however, the proportion of non-fatal casualties was high and gas remained
one of the soldier's greatest fears. Unlike most other weapons of the period, it was
possible to develop effective countermeasures to gas and hence in the latter stages of
the war, as the use of gas increased, in many cases its effectiveness was diminished.
History of poison gass attacks in WW1
The early uses of chemicals as weapons were as a tear-inducing irritant (lachrymatory),
rather than fatal or disabling poisons. The French were the first to employ gas, using
grenades filled with tear gas (xylyl bromide) in August 1914. Germany retaliated in kind
in October 1914, firing shrapnel shells filled with a chemical irritant against French
positions at Neuve Chapelle though the concentration achieved was so small it was barely
noticed.
Germany was the first to make large scale use of gas as a weapon. On 31. January 1915
18,000 artillery shells containing liquid xylyl bromide tear gas (known as T-Stoff) were
fired on Russian positions on the Rawka River, west of Warsaw during the Battle of
Bolimov. Instead of vaporizing the chemical froze, completely failing to have an impact.
Australian troops wearing SBR, Ypres 1917 |
Chlorine became the first killing agent to be employed. German chemical conglomerate
IG Farben had been producing chlorine as a by-product of their dye manufacturing. In
cooperation with Fritz Haber of the Kaiser Wilhelm Institute in Berlin, they began
developing methods of discharging chlorine gas against enemy trenches.
By 22. April 1915,
the German Army had 160 tons of chlorine deployed in 5,730 cylinders opposite Langemarck,
north of Ypres. At 17:00, in a slight easterly breeze, the gas was released, forming a
grey-green cloud that drifted across positions held by French Colonial troops who broke,
abandoning their trenches and creating an 8,000 yard gap in the Allied line. However,
the German infantry were also wary of the gas and failed to exploit the break before
Canadian and British reinforcements arrived.
In what became the Second Battle of Ypres, the Germans used gas on three more occasions.
At this stage, defences against gas were non-existent.
Chlorine was inefficient as a weapon. It produced a visible greenish cloud and strong
odour, making it easy to detect. It was water-soluble so the simple expedient of
covering the mouth and nose with a damp cloth was effective at reducing the impact of
the gas. Chlorine required a concentration of 1,000 parts per million in order to be
fatal, destroying tissue in the lungs. However, despite its limitations chlorine was an
effective terror weapon and the sight of an oncoming cloud of the gas was a continual
source of dread for the infantry.
Refinement of gas attacks
British infantry advancing through gas |
The British expressed outrage at Germany's use of poison gas at Ypres but responded by
developing their own gas warfare capability. In the end, the British Army embraced gas
with enthusiasm and mounted more gas attacks than any other combatant due partly to the
fact that the British spent most of the latter years of the war on the offensive. Also
the prevailing wind on the Western Front was usually from the west which meant it was
more frequent for the British to have favourable conditions for a gas release than the
Germans.
The first use of gas by the British was at the Battle of Loos, 25. September
1915 but the attempt was a disaster. Chlorine, codenamed Red Star, was the agent to be
used (150 tons arrayed in 5,500 cylinders) and the attack was dependent on a favourable
wind. However, on this occasion the wind proved fickle and the gas either lingered in no
man's land or, in places, blew back on the British trenches.
The deficiencies of chlorine were overcome with the introduction of phosgene, first used
by Germany in December 1915. Phosgene was a potent killing agent, 18 times more powerful
than chlorine, and difficult to detect, being colourless and having an odour likened to
"mouldy hay". Phosgene's disadvantage was that it was light-weight and readily dissipated
so it was initially mixed with the heavier chlorine. The other "problem" was that the
symptoms of exposure took 24 hours or more to manifest meaning that the victims were
initially still capable of putting up a fight.
Mustard gas
The most famous and effective gas of the First World War was mustard gas, a vesicant,
which was introduced by Germany in July 1917 prior to the Third Battle of Ypres. Known
to the British as HS (or Hun Stuff), mustard gas was not intended as a killing agent
(though in high enough doses it was fatal) but instead was used to harass and disable
the enemy and pollute the battlefield. Delivered in artillery shells, mustard gas was
heavier than air, settled to the ground as an oily sherry-looking liquid and evaporated
slowly without sunlight.
The polluting nature of mustard gas meant that it was not always suitable for supporting
an attack as the assaulting infantry would be exposed to the gas when they advanced.
When Germany launched Operation Michael on 21. March 1918, they saturated the
Flesquières salient with mustard gas instead of attacking it directly, believing that
the harassing effect of the gas, coupled with threats to the salient's flanks, would
make the British position untenable.
Gas never reproduced the dramatic success of 22. April 1915. However, it became a
standard weapon which, combined with conventional artillery, was used to support most
attacks in the later stages of the war. The Western Front was the main theatre in which
gas was employed. The static,
confined trench system was ideal for achieving an
effective concentration.
However, Germany made use of gas against
Russia on the Eastern Front,
where the lack of effective countermeasures would result in deaths of thousands
of Russian infantry, while Britain experimented with gas in Palestine during the Second
Battle of Gaza. The universal horror with which gas was viewed led to a post-war ban on
the use of lethal gas which came into effect in 1925. No subsequent conflict has made
such large-scale use of poison gas as the First World War.
Countermeasures
None of the
First World War combatants
were prepared for the introduction of poison gas
as a weapon. Once gas had appeared, development of gas protection began and the process
continued for much of the war producing a series of increasingly effective gas masks.
German infantry with improvised
gas masks, 1915 |
Even at 2nd Ypres Germany, still unsure of the weapon's effectiveness, only issued
breathing masks to the engineers handling the gas. At Ypres a Canadian medical officer,
who was also a chemist, quickly identified the gas as chlorine and recommended that the
troops urinate on a cloth and held it over their mouth and nose, the theory being the
uric acid would crystallise the chlorine. The first official equipment issued was
similarly crude; a pad of material, usually impregnated with a chemical, tied over the
lower face. To protect the eyes from tear gas, soldiers were issued with gas goggles.
The next advance was the introduction of the gas helmet - basically a bag placed over
the head. The fabric of the bag was impregnated with a chemical to neutralise the gas.
Whenever it rained, the chemical would wash out into the soldier's eyes. Eye-pieces,
which were prone to fog up, were initially made from talc. When going into combat, gas
helmets were typically worn rolled up on top of the head, to be pulled down and secured
about the neck when the gas alarm was given.
Self-contained box respirators represented the culmination of gas mask development
during the First World War. Box respirators used a two-piece design; a mouthpiece
connected via a hose to a box filter. The box filter contained granules of chemicals
that neutralised the gas, delivering clean air to the wearer. Separating the filter
from the mask enabled a bulky but efficient filter to be supplied. Nevertheless, the
first version, known as the Large Box Respirator (LBR) or "Harrison's Tower", was
deemed too bulky - the "box" canister needed to be carried on the back. The LBR had no
mask, just a mouthpiece and nose clip; separate gas goggles had to be worn. It continued
to be issued to the artillery gun crews but the infantry were supplied with the
"Small Box Respirator" (SBR).
Gas masks and other reliefs
The Small Box Respirator featured a single-piece, close-fitting rubberised mask with
eye-pieces. The box filter was compact and could be worn around the neck. The SBR could
be readily upgraded as more effective filter technology was developed. The
British-designed SBR was also adopted for use by the American Expeditionary Force. The
SBR was the prized possession of the ordinary infantryman; when the British were forced
to retreat during the German Spring Offensive of 1918, it was found that while some
troops had discarded their rifles, hardly any had left behind their respirators.
German soldier and horses with gas masks |
It was not only humans that needed protection from gas; horses and mules, which were the
main means of transport, were also vulnerable to gas and needed to be provided with
protection. As animals were never used near the front-line, protection from gas only
became necessary when the practice of firing gas shells into rear areas was adopted.
For mustard gas, which did not need to be inhaled in order to inflict casualties, no
effective countermeasure was ever found. The kilt-wearing Highland regiments of Scotland
were especially vulnerable to mustard gas injuries due to their bare legs. At Nieuport
some Scots battalions took to wearing women's pantyhose beneath the kilt as a form of
protection.
Gas alert procedure became a routine for the front-line soldier. To warn of a gas attack,
a bell would be rung, often made from a spent artillery shell. At the noisy batteries of
the siege guns, a compressed air strombus horn was used, which could be heard nine miles
away. Notices would be posted on all approaches to an affected area, warning people to
take precautions.
Other British attempts at countermeasures were not so effective. An early plan was to
use 100,000 fans to disperse the gas. Burning coal or carborundum dust was tried. A
proposal was made to equip front-line sentries with diving helmets, air being pumped to
them through a 100-ft hose.
However, the effectiveness of all countermeasures is apparent. In 1915, when gas was
relatively new, less than 3% of British gas casualties died. In 1916, the proportion of
fatalities jumped to 17%. By 1918, the figure was back below 3%, though the total number
of British gas casualties was now nine times the 1915 levels.
Delivery systems
Poison gas release |
The first system employed for the mass delivery of gas involved releasing the gas from
cylinders in a favourable wind such that it was carried over the enemy's trenches. The
main advantages of this method was that it was relatively simple and, in suitable
atmospheric conditions, produced a concentrated cloud capable of overwhelming the gas
mask defences.
The disadvantages of cylinder releases were numerous. First and foremost,
delivery was at the mercy of the wind. If the wind was fickle,
the gas could backfire, causing friendly casualties. Gas clouds gave plenty of warning,
allowing the enemy time to protect themselves, though many soldiers found the sight of
a creeping gas cloud unnerving. Also gas clouds had limited penetration, only capable of
affecting the front-line trenches before dissipating.
Finally, the cylinders had to be emplaced at the very front of the trench system so that
the gas was released directly over no man's land. This meant that the cylinders had to
be manhandled through communication trenches, often clogged and sodden, and stored at
the front where there was always the risk that cylinders would be prematurely breached
during a bombardment. A leaking cylinder could issue a telltale wisp of gas that, if
spotted, would be sure to attract shellfire.
Delivering gas via artillery shell overcame many of the risks of dealing with gas in
cylinders. Gas shells were independent of the wind and increased the effective range of
gas, making anywhere within reach of the guns vulnerable. Gas shells could be delivered
without warning, especially the clear, nearly odourless phosgene. There are numerous
accounts of gas shells, landing with a "plop" rather than exploding, being initially
dismissed as dud or shrapnel shells, giving the gas time to work before the soldiers
were alerted and took precautions.
Loading of Livens gas projectors |
The main flaw associated with delivering gas via artillery was the difficulty of
achieving a killing concentration. Each shell had a small gas payload and an area would
have to be subjected to a saturation bombardment to produce a cloud to match cylinder
delivery. Mustard gas, however, did not need to form a concentrated cloud and hence
artillery was the ideal vehicle for delivery of this battlefield pollutant.
The solution to achieving a lethal concentration without releasing from cylinders was
the "gas projector", essentially a large-bore mortar that fired the entire cylinder as a
missile. The British Livens projector (invented by Captain W.H. Livens in 1917) was a
simple device; an 8-inch diameter tube sunk into the ground at an angle, a propellant
was ignited by an electrical signal, firing the cylinder containing 30 or 40 lbs of gas
up to 1,900 metres. By arranging a battery of these projectors and firing them
simultaneously, a dense concentration of gas could be achieved.
Please see some Banknotes from WW1
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