- Poison gas in World War I
The use of poison gas in
World War Iwas a major military innovation. The gases ranged from disabling chemicals, such as tear gasand the severe mustard gas, to lethal agents like phosgeneand chlorine. This chemical warfarewas a major component of the first global war and first total warof the 20th century. The killing capacity of gas was limited — only 4% of combat deaths were due to gas — however, the proportion of non-fatal casualties was high, and gas remained one of the soldiers' greatest fears. Because it was possible to develop effective countermeasures against gas attacks, it was unlike most other weapons of the period. In the later stages of the war, as the use of gas increased, its overall effectiveness diminished. This widespread use of these agents of chemical warfare, and wartime advances in the composition of high explosives, gave rise to an occasionally expressed view of World War Ias "the chemists' war". [cite web
last=Reddy | first=Chris | date=April 2, 2007
title=The Growing Menace of Chemical War
publisher=Woods Hole Oceanographic Institution
accessdate=2007-07-30 ] [cite web
last=Saffo | first=Paul | year=2000
title=Paul Saffo presentation
publisher=Woods Hole Oceanographic Institution
History of poison gas
1914: Tear gas
The early uses of chemicals as weapons were as a tear-inducing irritant (
lachrymatory), rather than fatal or disabling poisons. During the first World War, the French were the first to employ gas, using 26 mm grenades filled with tear gas ( ethyl bromoacetate) in August, 1914. The small quantities of tear gas delivered, roughly 19 cc per cartridge, were not even detected by the Germans. The stocks were rapidly consumed and by November a new order was placed by the French military. As brominewas scarce among the Entente allies, the active ingredient was changed to chloroacetone. [cite book
first=Ludwig Fritz | last=Haber | year=1986
title=The Poisonous Cloud: Chemical Warfare in the First World War
publisher=Oxford University press
id=ISBN 0198581424 ]
In October 1914, German troops fired fragmentation shells filled with a chemical irritant against British positions at Neuve Chapelle, though the concentration achieved was so small that it was barely noticed.cite web
last=Heller | first=Charles E. | date=September 1984
title=Chemical Warfare in World War I: The American Experience, 1917-1918
publisher=Combat Studies Institute
accessdate=2007-08-02 ] None of the combatants considered the use of tear gas to be in conflict with the Hague Treaty of 1899, which prohibited the launching of projectiles containing
asphyxiating or poisonous gas. [cite book
first=L. B. | last=Taylor | coauthors=Taylor, C. L.
year=1992 | title=Chemical and Biological Warfare
edition=Revised edition | publisher=Franklin Watts
1915: Large scale use and lethal gases
Germanywas the first to make large scale use of gas as a weapon when on 3 January, 1915, 18,000 artilleryshells containing liquid xylyl bromide tear gaswere fired on Russian positions on the Rawka River, west of Warsawduring the Battle of Bolimov. However, instead of vaporizing, the chemical froze, completely failing to have the desired effect.
The first killing agent employed by the German military was
chlorine. German chemical companies BASF, Hoechst and Bayer(which formed the IG Farbenconglomerate in 1925) had been producing chlorine as a by-product of their dyemanufacturing. [cite web
author=Legg, J.; Parker, G. | year=2002
title=The Germans develop a new weapon: the gas cloud
publisher=The Great War | accessdate=2007-08-06 ] In cooperation with
Fritz Haberof the Kaiser Wilhelm Institutefor Chemistry in Berlin, they began developing methods of discharging chlorine gas against enemy trenches. [cite web
author=Staff | year=2005
title=Fritz Haber | publisher=Chemical Heritage Foundation
accessdate=2007-08-06 ] [cite book
first=Werner | last=Abelshauser | year=2003
title=German Industry and Global Enterprise, BASF: The History of a Company
publisher=Cambridge University Press
id=ISBN 0521827264 ]
22 April, 1915, the German Army had 168 tons of chlorine deployed in 5,730 cylinders opposite Langemark-Poelkapelle, north of Ypres. At 17:00, in a slight easterly breeze, the gas was released, forming a gray-green cloud that drifted across positions held by French Colonial troops who broke ranks, abandoning their trenches and creating an 8,000 yard (4.5 km) gap in the Allied line. However, the German infantry were also wary of the gas and, lacking reinforcements, failed to exploit the break before Canadian and British reinforcements arrived. The Entente governments quickly claimed the attack was a flagrant violation of international law, but Germany argued that the Hague treaty had only banned chemical shells, rather than the use of gas projectors. [cite book
first=Jonathan B. | last=Tucker | year=2006
title=War of Nerves: Chemical Warfare from World War I to Al-Queda
publisher=Pantheon Books | isbn=0-375-42229-3 ]
In what became the
Second Battle of Ypres, the Germans used gas on three more occasions; on 24 April against the 1st Canadian Division, [cite web
author=Staff | date=
July 29, 2004
title=On the Western Front, Ypres 1915
publisher=Veteran Affairs Canada
accessdate=2008-04-08 ] on 2 May near Mouse Trap Farm and on 5 May against the British at Hill 60. [cite book
first=Victor | last=Lefebure | coauthors=Wilson, Henry
title=The Riddle of the Rhine: Chemical Strategy in Peace and War
year=2004 | publisher=Kessinger Publishing | isbn=1417935464 ] The British Official History stated that at Hill 60,
Chlorine is a powerful irritant that can inflict damage to the eyes, nose, throat and lungs. At high concentrations and prolonged exposure it can cause death by
Effectiveness and counter-measures
It quickly became evident that the men who stayed in their places suffered less than those who ran away, any movement worsened the effects of the gas, and those who stood up on the fire step suffered less—indeed they often escaped any serious effects—than those who lay down or sat at the bottom of a trench. Men who stood on the parapet suffered least, as the gas was denser near the ground. The worst sufferers were the wounded lying on the ground, or on stretchers, and the men who moved back with the cloud. [Edmonds and Wynne (1927): pp. 177-8.]
Chlorine was, however, less effective as a weapon than the Germans had hoped, particularly as soon as simple counter-measures were introduced. The gas produced a visible
greenish cloud and strong odor, making it easy to detect. It was water-soluble, so the simple expedient of covering the mouth and nose with a damp cloth was somewhat effective at reducing the effect of the gas. It was thought to be even more effective to use urine rather than water, as the ammonia would neutralize the chlorine, but it is now known that ammonia and chlorine can produce toxic fumes (NH3 + Cl2 —> HCl + NH2Cl). Even if the chemistry had been correct, the amount of ammonia in human urine is extremely small. However, it was known at the time that chlorinereacted readily with urea(present in large amounts in urine) to form dichlorourea. [For example, see: cite journal
last=Chattaway | first=Frederick Daniel
date=December 22, 1908
title=The Action of Chlorine upon Urea Whereby a Dichloro Urea is Produced
journal=Proceedings of the Royal Society of London
volume=81 | issue=549 | pages=381–388
Chlorine required a concentration of 1,000 parts per million to be fatal, destroying tissue in the
lungs, likely through the formation of hydrochloric (muriatic) acid when dissolved in the water in the lungs (2Cl2 + 2H2O → 4HCl + O2). [cite web
last=O'Leary | first=Donal | year=2000
title=Chlorine | publisher=University College Cork
accessdate=2007-08-02 ] Despite its limitations, however, chlorine was an effective psychological weapon—the sight of an oncoming cloud of the gas was a continual source of dread for the infantry.
Counter-measures were quickly introduced in response to the use of chlorine gas. The Germans had issued their troops with small gauze pads filled with cotton waste, and bottles of a bicarbonate solution with which to dampen the pads. Immediately following the use of chlorine gas by the Germans, instructions were sent to British and French troops to hold wetted handkerchiefs or cloths over their mouths. Simple pad respirators similar to those issued to German troops were soon proposed by Lieut.-Colonel N.C. Ferguson, the A.D.M.S. of the 28th Division. These pads were intended to be used damp, preferably dipped into a solution of
bicarbonate of sodakept in buckets for that purpose, though urine or other liquids were also used. Because such pads could not be expected to arrive at the front for several days, army divisions set about making them for themselves. The locally available muslin, flannel and gauze were used, and officers sent to Paristo buy additional quantities, and local French women were employed making up rudimentary pads with string ties. Other units used lint bandages manufactured in the convent at Poperinge. Pad respirators were sent up with rations to British troops in the line as early as the evening of April 24.
In Britain the
Daily Mailnewspaper encouraged women to manufacture cotton pads, and within one month a variety of pad respirators were available to British and French troops, along with motoring goggles to protect the eyes. By 6 July 1915, the entire British army was equipped with the far more effective "smoke helmet" designed by Major Cluny McPherson, Newfoundland Regiment, which was a flannel bag with a celluloid window, which entirely covered the head. The race was then on between the introduction of new and more effective poison gases and the production of effective counter-measures, which marked gas warfare until November 1918.Edmonds and Wynne (1927): p. 217.]
British gas attacks
The British expressed outrage at Germany's use of poison gas at Ypres but responded by developing their own gas warfare capability. The commander of
British II Corps, Lt.Gen. Ferguson (officially) said of gas:
Quote|It is a cowardly form of warfare which does not commend itself to me or other English soldiers.... We cannot win this war unless we kill or incapacitate more of our enemies than they do of us, and if this can only be done by our copying the enemy in his choice of weapons, we must not refuse to do so. [cite book
title=No Place to Run: The Canadian Corps and Gas Warfare in the First World War
pages=37 | id=ISBN 0774807407 ]
The first use of gas by the British was at the
Battle of Loos, 25 September 1915but the attempt was a disaster. Chlorine, codenamed "Red Star", was the agent to be used (140 tons arrayed in 5,100 cylinders), and the attack was dependent on a favorable wind. However, on this occasion the wind proved fickle, and the gas either lingered in no man's landor, in places, blew back on the British trenches.
The British Army had realized that the use of gas was needed, and mounted more gas attacks than the Germans in 1917 and 1918 due to marked increase in production of gas from the Allied nations. Germany was unable to keep up with this pace despite creating various new gases for use in battle, mostly due to very costly methods of production. Entry into the war by the
United Statesallowed the Allies to increase mustard gas production far more than Germany. [cite book|last=Crowell|first=Benedict|authors=Robert Forrest|title=The Armies of Industry: Our Nation's Manufacture of Munitions for a World in Arms, 1917-1918|vol=5|publisher=Yale University Press|year=1921|pages=491, 500] Also the prevailing windon the Western Front was from the west, [cite book
author=Lockwood, John C. | editor=Hewitt, C. N.; Jackson, A. V.
year=2003 | chapter=Chapter 3. The Earth's Climates
title=Handbook of Atmospheric Science: Principles and Applications
pages=pp. 72–74 | id=ISBN 0632052864 ] which meant the British more frequently had favorable conditions for a gas release than the Germans.
1915: More deadly gases
The deficiencies of chlorine were overcome with the introduction of
phosgene, first used by France under the direction of French chemist Victor Grignardin 1915.Fact|date=March 2008 Colorless and having an odor likened to "mouldy hay," phosgene was difficult to detect, making it a more effective weapon. Although phosgene was sometimes used on its own, it was more often used mixed with an equal volume of chlorine, the chlorine helping to spread the denser phosgene.cite web
author=Staff | year=2004
title=Choking Agent: CG | publisher=CBWInfo
accessdate=2007-07-30 ] The Allies called this combination "White Star" after the marking painted on shells containing the mixture.
Phosgene was a potent killing agent, deadlier than chlorine. It had a potential drawback in that some of the symptoms of exposure took 24 hours or more to manifest. This meant that the victims were initially still capable of putting up a fight; although this could also mean that apparently fit troops would be incapacitated by the effects of the gas on the following day. [cite web
author=Staff | date=
February 22, 2006
title=Facts About Phosgene
publisher=CDC | accessdate=2008-05-23 ]
In the first combined chlorine/phosgene attack by Germany, against British troops at
Nieltjenear Ypres, Belgiumon 19 December 1915, 88 tons of the gas were released from cylinders causing 1069 casualties and 69 deaths. The British P gas helmet, issued at the time, was impregnated with phenate hexamine and partially effective against phosgene. The modified PH Gas Helmet, which was additionally impregnated with hexamethylenetetramineto improve the protection against phosgene, was issued in January 1916.
Around 36,600 tons of the gas were manufactured during the war, out of a total of 190,000 tons for all chemical weapons, making it second only to chlorine (93,800 tons) in the quantity manufactured:Fact|date=August 2007
* Germany 18,100 tons
* France 1,125,700 tons
* United Kingdom 1,400 tons (although they also used French stocks)
* United States 1,400 tons (although they also used French stocks)
Although it was never as notorious in public consciousness as
mustard gas, it killed far more people, about 85% of the 100,000 deaths caused by chemical weapons during World War I.
Many of those who survived a gas attack were scarred for life. Respiratory disease and failing eye sight were common post-war afflictions. Of the Canadians who, without any effective protection, had withstood the first chlorine attacks during 2nd Ypres, 60% of the casualties had to be repatriated and half of these were still unfit by the end of the war, over three years later.
In reading the
statisticsof the time, one should bear the longer term in mind. Many of those who were fairly soon recorded as fit for service were left with scar tissue in their lungs. This tissue was susceptible to tuberculosisattack. It was from this that many of the 1918 casualties died, around the time of the Second World War, shortly before sulfa drugs became widely available for its treatment.
One notable poison gas casualty of World War I was
Adolf Hitler, who was temporarily blinded. As a result, Hitler adamantly refused to authorise the use of poison gas on the battlefield during World War II, for fear of retaliation. [cite web
last=Bernstein | first=Barton J. | year=2006
title=Why We Didn’t Use Poison Gas in World War II
accessdate=2007-08-02 ] However, poison gas agents such as
carbon monoxideand Zyklon Bwere extensively used against civilians in extermination camps.
None of the First World War's 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.
Even at Second 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 chlorineand recommended that the troops urinate on a cloth and hold it over their mouth and nose, the theory being the uric acidwould crystallize 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 neutralize the gas — however, the chemical would wash out into the soldier's eyes whenever it rained. 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. The first British version was the Hypo helmet, the fabric of which was soaked in sodium hyposulfite (commonly known as "hypo"). The British P gas helmet, partially effective against phosgeneand with which all infantry were equipped with at Loos, was impregnated with phenate hexamine. A mouthpiece was added through which the wearer would breathe out to prevent carbon dioxidebuild-up. The adjutantof the 1/23rd Battalion, The London Regiment, recalled his experience of the P helmet at Loos:
Quote|The goggles rapidly dimmed over, and the air came through in such suffocatingly small quantities as to demand a continuous exercise of will-power on the part of the wearers. [cite book
title=The Battle of Loos
pages=103 | id=ISBN 1840222298 ]
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 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
artillerygun crews but the infantry were supplied with the "Small Box Respirator" (SBR).
The Small Box Respirator featured a single-piece, close-fitting
rubberized 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 Offensiveof 1918, it was found that while some troops had discarded their rifles, hardly any had left behind their respirators.
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.
mustard gas, which did not need to be inhaled in order to inflict casualties, no effective countermeasure was found during the war. The kilt-wearing Scottish regiments were especially vulnerable to mustard gas injuries due to their bare legs. At Nieuwpoort in Flanderssome Scots battalions took to wearing women's tightsbeneath the kilt as a form of protection.
The Canadian soldiers are said to have found a way to minimize the effects of the mustard gas. Since the gas was sent by the wind towards them, they understood that it would minimize the exposure to the gas if the Canadians not only did not flee but ran through the gas. The French, conversely, when the gas was first used against them, fled, and therefore spent more time in the gas, suffering greater casualties.Fact|date=May 2008
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 (14 km) 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
coalor carborundumdust was tried. A proposal was made to equip front-line sentries with diving helmets, air being pumped to them through a 100 ft (30 m) hose.
However, the effectiveness of all countermeasures is apparent. In 1915, when poison 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.
The first system employed for the mass delivery of gas involved releasing the gas from cylinders in a favourable
windsuch that it was carried over the enemy's trenches. The main advantage 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, as was the case at Loos, 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.
left|thumb|250px|German gas attack onthe eastern front.A British
chlorinecylinder, known as an "oojah", weighed 190 lb (86 kg), of which only 60 lb (27 kg) was chlorine gas, and required two men to carry. Phosgenegas was introduced later in a cylinder, known as a "mouse", that only weighed 50 lb (23 kg).
Delivering gas via
artilleryshell overcame many of the risks of dealing with gas in cylinders. The Germans, for example, used convert|5.9|in|mm|sing=on artillery shells. 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 odorless phosgene — there are numerous accounts of gas shells, landing with a "plop" rather than exploding, being initially dismissed as dud HE or shrapnelshells, giving the gas time to work before the soldiers were alerted and took precautions.
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 convert|8|in|mm|sing=on diameter tube sunk into the ground at an angle, a propellantwas ignited by an electrical signal, firing the cylinder containing 30 or 40 lb (14 or 18 kg) of gas up to 1,900 meters. By arranging a battery of these projectors and firing them simultaneously, a dense concentration of gas could be achieved. The Livens was first used at Arrason 4 April, 1917. On 31 March, 1918the British conducted their largest ever "gas shoot", firing 3,728 cylinders at Lens.
Over convert|16000000|acre|km2 of France had to be cordoned off at the end of the war because of unexploded ordnance. About 20% of the chemical shells were duds, and approximately 13 million of these munitions were left in place. This has been a serious problem in former battle areas from immediately after the end of the War until the present. Shells may be, for instance, uncovered when farmers plough their fields (termed the '
iron harvest'), and are also regularly discovered when public works or construction work is done. [cite book
first=Eric | last=Croddy | year=2002
title=Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen
publisher=Springer | id=ISBN 0387950761 ]
An additional difficulty is the current stringency of environmental legislation. In the past, a common method of getting rid of unexploded chemical ammunition was to detonate or dump it at sea; this is nowadays prohibited in most countries.Fact|date=March 2008
The problems are especially acute in some northern regions of France. The French government no longer disposes of chemical weapons at sea. For this reason, piles of untreated chemical weapons accumulated. In 2001, it became evident that the pile stored at a depot in
Vimywas unsafe; the inhabitants of the neighboring town were evacuated, and the pile moved, using refrigerated trucks and under heavy guard, to a military camp in Suippes. [cite web
author=J. C. | date=April 17, 2001
title=Sécurité. Les 55 tonnes d’obus chimiques sont stockées au camp militaire de Suippes.
publisher=L'Humanité | language=French
accessdate=2007-07-30 ] The capacity of the plant is meant to be 25 tons per year (extensible to 80 tons at the beginning), for a lifetime of 30 years.cite web
author=J. C. | date=April 17, 2001
publisher=Sénat | language=French
Effect on World War II
In the Geneva Gas Protocol of the
Third Geneva Convention, signed in 1925, the signatory nations agreed not to use poison gas in the future, stating "the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices, has been justly condemned by the general opinion of the civilised world." [cite web
author=Third Geneva Convention | date=June 17, 1925
title=Text of the Biological and Toxin Weapons Convention
publisher=Brigham Young University
accessdate = 2007-08-04 ]
Nevertheless, precautions were taken in
World War II. In both Axis and Allied nations, children in school were taught to wear gas masks in case of gas attack. Italy did use poison gas against Ethiopia in 1935 and 1936, and the Empire of Japanused gas against China in 1941. Germany developed the poison gases tabun, sarin, and somanduring the war, and, infamously, used Zyklon Bin Nazi extermination camps. Neither Germany nor the Allied nations used any of their war gases in combat, despite maintaining large stockpiles and occasional calls for their use, [The U.S. reportedly had about 135,000 tons of chemical warfare agents during the WW II; Germany had 70,000 tons, Britain 40,000 and Japan 7,500 tons. The German nerve gasses were deadlier than the old-style suffocants ( chlorine; phosgene) and blistering agents ( mustard gas) in Allied stockpiles. Churchill, and several American Generals reportedly called for their use against Germany and Japan, respectively (Weber, 1985).] possibly heeding warnings of awful retaliation.
* cite book
title = Trench warfare | last=Bull | first=S.
year = 2003 | id = ISBN 1-85648-657-5
publisher = PRC Publishing
* cite journal
last=Chattaway | first=F. D.
title=The Action of Chlorine upon Urea Whereby a Dichloro Urea is Produced
journal=Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character
year=1908 | volume=81 | issue=549 | pages=381–388
first=James Edward | last=Edmonds
coauthors=Wynne, Graeme Chamley | year=1927
title=Military Operations: France and Belgium, 1915, volume 1.
publisher=Macmillan and co., limited
* cite news
last=Fassihi | first=F. | date=
October 27, 2002
title=In Iran, grim reminders of Saddam's arsenal
publisher=The New Jersey Star-Ledger
* cite book
title =The Poisonous Cloud; Chemical Warfare in the First World War
first=L. F. | last=Haber | year = 1986
id = ISBN 0198581424
publisher = Oxford University Press
* cite book
title = A Higher Form of Killing : The Secret History of Chemical and Biological Warfare
first=R. | last=Harris | coauthors=Paxman, J.
year = 2002 | id = ISBN 0-8129-6653-8
publisher = Random House Trade Paperbacks (first published 1982)
* cite book
first=Albert | last=Palazzo | year=2000
title=Seeking Victory on the Western Front: The British Army & Chemical Warfare in World War 1
publisher=U of Nebraska press | id=ISBN 0803287747
* [http://www.cbwinfo.com/History/WWI.html Chemical Weapons in World War I]
* [http://www.worldwar1.com/arm006.htm Gas Warfare]
* [http://www.vlib.us/medical/gaswar/chlorine.htm Gas-Poisoning, by Arthur Hurst, M.A., MD (Oxon), FRCP 1917] effects of chlorine gas poisoning
* [http://www.english.emory.edu/LostPoets/Dulc.html Dulce Et Decorum Est] -
Wilfred Owen's famous WWI poem on a chlorine gas attack
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