Edward Harrison, who gave his life developing protection against poison gas

I was very pleased to be asked by the Oxford Dictionary of National Biography to write the entry for one of the lesser-known heroes of the First World War who died one week before the Armistice as a result of poisoning and overwork while developing protection against poison gas.

Edward Harrison

Edward Frank Harrison (Wikimedia Commons)

Harrison, Edward Frank (1869-1918), analytical chemist and soldier, was born on 18 July 1869 in Camberwell, London, the third child of William Harrison, a Home Office clerk and his wife Susannah, a school teacher.   His father died when he was aged nine and his mother opened a small school which enabled the education of her sons at the United Westminster Schools.  At the age of 14 Harrison was apprenticed to a pharmaceutical chemist in north London, following which he was an assistant pharmacist in Croydon.  In 1890 he gained a Pharmaceutical Society Bell Scholarship and entered the School of Pharmacy in 1891.  He spent long hours in the research laboratories of the Society and made ends meet by working at a pharmacy each evening and as an assistant lecturer at the School.  Hard work, seriousness and a strong moral purpose were features from an early age.  His parents were Particular Baptists but his scientific education and a rigorous critical discernment meant that he found such religious conviction wanting to be replaced by a belief in research for its own sake.  He retained however a strong sense that life must have a moral purpose.

In 1894 he was made a Fellow of the Royal Chemical Society but the desire to earn enough to marry caused him to take a position with Brady and Martin pharmaceutical chemists of Newcastle upon Tyne which lasted five years.  In 1895 he married Edith Helen Wilson, a school teacher and sons Noel Stuart and Douglas Frank were born in 1897 and 1900.  In about 1899 he was appointed head of the analytical department of Burroughs, Wellcome and Company at Dartford.  During this time he also prepared for his B.Sc. at the University of London and graduated in 1905.  In that year he formed a partnership with Charles Edward Sage as an analytical and consulting chemist and to teach at Sage’s Central School of Pharmacy.  The partnership was dissolved in 1906 and Harrison took up independent practice in Chancery Lane, London.  He was assisted by Percy Arthur William Self and by 1914 traded as Harrison and Self.  A reputation for careful and thorough research led the British Medical Association to commission Harrison to analyse a variety of proprietary medicines to prevent deception of the public, and the results were published in 1909 as Secret remedies: what they cost and what they contain, followed in 1912 by More secret remedies.  That year he gave highly effective evidence to the Select Committee of the House of Commons on Patent Medicines as chief witness for the BMA.

Secret Remedies

Secret Remedies, written by Edward Harrison for the British Medical Association in 1909 to expose fake medicines.

Following the outbreak of the First World War, Harrison made repeated attempts to enlist in the forces.  He succeeded in May 1915 in joining the 23rd (1st Sportsman’s) Battalion, Royal Fusiliers, reducing his stated age by two years to meet the limit of 45.  The Germans in April having carried out an attack in Belgium using chlorine gas, in July he transferred to the Royal Engineers following the formation of a Chemists’ Corps and was immediately commissioned temporary Second Lieutenant in order to work on anti-gas research.  Like most of his profession, he was motivated in particular by detestation for what was seen as the prostitution of chemical science by the Germans in the use of poison gas but he also had no doubt that the Allies should reply in kind.

Harrison joined the staff of the Anti-Gas Department, initially at the Royal Army Medical College at Millbank, London, which had the task of devising protection.  The situation was one of the utmost urgency, the Allies having been caught with no form of respirator.  The design and production of masks to protect against chlorine was comparatively simple but by July 1915 the problem was to devise a single mask which could keep out a potentially very large number of gases which at one point exceeded 70.  Hydrogen cyanide and phosgene emerged as the most likely to be used.  Harrison’s experience and intuition enabled him to make rapid decisions when scientists with a purely academic background tended to be overly cautious and deliberate in their investigations.  There was a high degree of self-experimentation and all the scientist during this most critical phase were at times incapacitated, often to the point of unconsciousness.

GasDrill Purfleet1915

British troops train in gas helmets, 1915. (c) Simon Jones.

The War Office wished improved protection to be through modification of the existing chemically impregnated flannelette hood.  Although these hoods had some success against phosgene, they were penetrated by high concentrations and were not suitable for adaptation to meet new threats.  Almost immediately in July 1915, Harrison and a small team began developing a respirator in which the protective chemicals were layered in a filter box, initially an adapted army water bottle.  Soda lime permanganate granules, developed by Bertram Lambert at Oxford University, were capable of providing protection against a very wide range of substances but broke down into a dust which choked the wearer.  Hardening the granules rendered them ineffective until, after forty-nine attempts, Harrison discovered a successful formula.  Initially known as ‘Harrison’s Tower’, the respirator developed by the end of 1915 comprised a filter box connected to a facepiece with inlet and exhalation valves.  Adopted by the Army as the Large Box Respirator, 200,000 were issued to artillerymen and machine gunners between February and June 1916.  A compact version, the Small Box Respirator, was made a universal issue from August 1916.  The design meant that the filter box could be modified to protect against new agents; regarded as the most effective gas mask of the war it was adopted by the USA in modified form.  Harrison emerged as the most able in solving the complex problems of both design and production and made frequent visits to France to meet with chemists working at the front.  In January 1917 Harrison became Head of the Anti-Gas Department and in June was appointed a Companion of the Order of St. Michael and St. George.  On 1 November 1917, the Anti-Gas Department became part of the Chemical Warfare Department (CWD) of the Ministry of Munitions and Harrison was appointed an Assistant Controller of the CWD responsible for anti-gas apparatus.   In July 1918 he was appointed Deputy Controller and, in October, Controller of the CWD; in the same month he was appointed Officer of the French Légion d’Honneur.

Officers in Small Box Respirators

British officers in Small Box Respirators, 1917-1918. (c) Simon Jones.

His eldest son was killed in action age 19 on 30 July 1916 during the Battle of the Somme.  By October 1918, Harrison was weakened by two and a half years of constant work and the gas inhaled during the early stages.  He succumbed to influenza and died at the premises of Harrison and Self at 57 Charing Cross Road on 4 November 1918.  He was buried with full military honours at Brompton Cemetery.  Lengthy tributes emphasised his abilities, personality and organisational genius.  Memorials to Harrison were unveiled by the Pharmaceutical Society, Bloomsbury Square, and the Chemical Society, Burlington House, and both organisations continue to award prize medals in his memory.

Harrison Medal

The Harrison Medal awarded by the Royal Society of Chemistry. A large version of the medal forms the Society’s war memorial in Burlington House, London.

Contact me for details of sources. This article is available for download as an Oxford Dictionary of National Biography podcast.

I have also written about the Edward Harrison for The Guardian.

Isaac Rosenberg

My ‘War Poets’ Battlefield Tour with The Cultural Experience, 26-29 July 2019


My ‘First & Last Shots’ Battlefield Tour with The Cultural Experience, 20-23 August 2019

Sawyer Spence (1)

Understanding Chemical Warfare in the First World War

IWM Q3999

The Lochnagar Mine: how and why it was blown and who were the men who dug it


Understanding chemical warfare in the First World War

In August 1918, while waiting to advance east of Amiens, Sergeant Sawyer Spence lay in a shell hole contaminated with mustard gas. Feeling no ill effects he only reluctantly agreed to be evacuated; only after 24 hours did medics realise that his uniform had been saturated by the oily liquid. By the time he reached a hospital twelve days later, in the converted pavilion of Nottingham’s Trent Bridge Cricket Ground, the whole of one side of his back and legs was septic and discharging pus, the result of massive blistering. He was the worst mustard gas case that the hospital had ever seen.

Sawyer Spence suffering extensive mustard gas blisters, Trent Bridge Hospital, Nottingham, 1918. © Jon Spence, used with permission.

Sawyer Spence suffering extensive mustard gas blisters, Trent Bridge Hospital, Nottingham, 1918. © Jon Spence, used with permission.

Sawyer Spence was one of an estimated half a million chemical warfare victims of the First World War. The first were on 22nd April 1915 when the Germans released 150 tonnes of chlorine gas from their front line trenches north of Ypres in Belgium and allowed it to drift towards the French positions. It inspired some of the most powerful works of art and literature to come out of the First World War yet, since its shocking debut, our understanding of chemical warfare remains surrounded by a miasma of fear, emotion and propaganda.

Chemical weapons were outlawed at arms control conferences at the Hague in 1899 and 1907; despite being signatories, Germany, France and Britain all carried out research before the outbreak of war. When trench warfare atrophied into a vast linear siege, chemicals were high on the list of solutions to break the deadlock; substances that would not cause permanent injury, such as tear gas, were favourites. Germany was first, adding an irritant to shrapnel shells, and thus technically not breaking the Hague Agreement, but the British-Indian troops they were used against in October 1914 failed even to notice. In a second attempt, Germany fired tear gas in shells against the Russians near Bolimow in Poland in January 1915, was equally ineffective when in the cold the liquid failed to vaporise. France followed by issuing instructions in February 1915 for the use of an anti-riot tear gas cartridge at the front, again without particular success. Britain adopted a tear gas, ethyl iodoacetate, in January 1915 after it was identified by Jocelyn Thorpe, professor of organic chemistry at Imperial College, University of London, which was codenamed ‘SK’ after the South Kensington location. Thorpe claimed that the War Office was only convinced of SK’s effectiveness after a small boy was given a shilling to stand in a trench into which it had been released; in April 1915 the British government was still pondering its legality.

Fritz Haber, in the uniform of the 35th Pioneer Regiment.

Fritz Haber, in the uniform of the 35th Pioneer Regiment.

Germany took the lead in chemical weapons thanks to her developed chemical industry and universities, but also because of the remarkable genius of Fritz Haber. The son of a dyestuff manufacturer, six years before the outbreak of war Haber made perhaps the single greatest chemical discovery of the twentieth century, for which he was to receive the Nobel prize for chemistry: the means of converting atmospheric nitrogen to ammonia. Fertiliser made using the Haber-Bosch process has produced food to increase the world’s population by an estimated one billion people; it has also facilitated the bulk production of explosives. Haber was the first Director of the Kaiser Wilhelm Institute for Physical Chemistry and in 1914 threw his immense energy and talent into his nation’s war effort. Vigorous and persuasive, he was responsible more than any other individual for the development of chemical weapons during the First World War. After the failure of the earlier attempts, Haber made a simple and direct proposal: readily available chlorine gas should be released from cylinders to be carried by a breeze over the enemy positions. If it was successful, the Germans believed that the Allies could not respond owing to their limited capacity for chemical production. Despite moral and military objections by two senior German commanders, the chief of the general staff, von Falkenhayn, decided that it should be tried at Ypres. A simple idea, in practice it was anything but. Carrying the heavy cylinders of chlorine into the trenches and concealing them was dangerous and difficult; when some were hit by shell fire the gas killed three of their own men and injured 50. The prevailing westerly wind placed the Germans at a disadvantage; it refused to blow in the right direction, or changed just as the attack was about to be launched. After a fruitless two week wait, the Germans had to reinstall 6,000 cylinders from the south of Ypres to the north but again twice more postponed when the wind was wrong.

German troops carry poison gas cylinders to be installed in trenches.  © Simon Jones

German troops carry poison gas cylinders to be installed in trenches. © Simon Jones

Finally, the order was given to release when it was ‘half-way favourable’; the troops assembled packed in the trenches throughout the 22nd April until, late in the afternoon, a southerly wind arose and orders were hurriedly issued to attack. The gas hissed from hundreds of pipes placed over the trench parapets and greenish-yellow clouds drifted across no man’s land towards the French positions; in most places, the gas quickly engulfed the trenches and the field guns close behind them. Reservist and North African troops had no means of protection; a powerful odour of bleach and fumes which stung the eyes were quickly followed by choking as they inhaled the gas. Most fled for their lives but the unlucky ones fell to the ground where the gas pooled. As the gas entered their lungs the mucous membranes produced fluid to flush away the irritation, oxygen transference was severely hindered and the victims began to drowned.

A French victim of the first chlorine gas attack. © Simon Jones

A French victim of the first chlorine gas attack. © Simon Jones

It should not have been a surprise to the Allies. At least two German soldiers deserted to the French before the gas attack, revealing detailed information and even producing rudimentary gas masks. Chemical weapons had achieved such negligible results that it was assumed the effects would be equally insignificant but it is cited as one of the great intelligence failures of history; when the name of one of the deserters was published in 1933, he was imprisoned by the Nazis and ultimately sent to Dachau concentration camp.

The Germans, moving cautiously for risk of succumbing to their own gas, gained two and a half miles by nightfall. It was the largest advance since the onset of trench warfare; but lack of troops and resistance on the flanks by Canadians and Belgians prevented them from exploiting the attack. In the captured French positions the Germans took thousands of prisoners, and found gas victims lying on their backs with fists clenched; but their own reports state that they found few dead. A doctor was told by a German officer, himself injured by chlorine, that he saw few French dead and most ‘had run away like a flock of sheep’. The number killed by the first attack, impossible to calculate, may still be somewhere between 800 and 1,400; a figure of 5,000 dead, grossly exaggerated by the Allies for propaganda purposes, is still reported as fact.

The response of the Allies was a mixture of real and artificial outrage; there was genuine anger that a barbarous and unchivalrous method should be used against their troops, and breaking the spirit if not the letter of the Hague Agreement. Chemical weapons nullified the romantic chivalric contest of equals that war was supposed to be but never has been. In this confused notion, to have an agreement and then break it almost seemed worse than if there had been no agreement at all. Paradoxically, an unrealistic notion of the degree to which warfare could be governed by humanitarian considerations may even have made matters worse by bringing about a swifter abandonment of restraint once the system collapsed. The Hague Agreement failed to prevent the use of chemical weapons because it did not anticipate what the war was becoming: a war of nationalism and ideologies, a war of hatred, a war to the death. There was also much inflated indignation to influence neutral American opinion; in this respect the chlorine attack was a propaganda gift to the Allies, as was the sinking of the liner Lusitania just 16 days later.

Many would subsequently express a more detached view on the relative distinction between chemical and so-called conventional weapons. The wartime officer, C. R. M. F. Cruttwell, later principal of Hertford College, concluded that ‘there is little to choose in horror and pain between the injuries inflicted by modern war. The extent to which the human body can be mangled by the splinters of a bomb or shell, without being deprived of consciousness, must be seen to be believed.’ J. B. S. Haldane, future Professor of Genetics at University College London, went further: injured by chlorine developing the first protective masks and shortly afterwards wounded in action, he maintained that the pain and discomfort from gas were ‘utterly negligible compared to those produced by a good septic shell wound’. A weapon which temporarily incapacitated such as tear gas, Haldane said, was ‘the most humane weapon ever invented’. Yet such views ignore the fact that there was nothing irrational about the terror felt by soldiers at being gassed; even the Army pathologist who specialised in gas cases felt that there was something particularly terrible about dying of suffocation from gassing. Coupled uneasily with outrage was the belief that the Allies must adopt such an apparently effective method without hesitation and not be hindered by misguided notions of honour if the enemy was not abiding by them. Five days after the first chlorine attack the British cabinet gave its consent for the Minister for War, Lord Kitchener, to fall ‘to the level of the degraded Germans’ and instructed him to ‘use anything he could get invented’. 

The method used at Ypres turned out to be of limited military value. Nine subsequent German chlorine attacks during the month-long Second Battle of Ypres were thwarted by the desperate resistance of British soldiers protected by rudimentary mouth pads soaked with neutralising solutions, including urine, which limited German gains to a few short lengths of front line trench. The Germans themselves suffered heavy casualties when the wind changed, which worsened when they tried it on the Eastern Front, and on one occasion 1,450 of their own men were gassed with 138 killed. But the chlorine attacks had a profound impact on the British, seemingly unaware of the difficulty of coordinating the massed troops to exploit the gas with a favourable wind to blow it onto the enemy. Britain’s first attack with chlorine gas was to be made in the wrong place for the wrong reasons. Sir Douglas Haig, commanding the British 1st Army, was a sceptic about the value of gas. However, ordered by the government to carry out an attack around Loos over terrain which was utterly unsuitable and for which he had insufficient guns and shells, his view was altered by a demonstration of chlorine gas at Runcorn when it appeared to move so effectively to the Manchester ship canal that bargees had shouted abuse. The gas seemed the means to carry out this unwanted attack and even achieve a rapid advance like that of the Germans at Ypres. Confounding the German belief that the Allies lacked the capacity to do so, Britain managed to stage a chlorine gas attack on 25 September 1915, five months after the German attack; the Battle of Loos however was a failure. On the morning of the attack, Haig took the decision to release the gas on the advice of a meteorologist and the drift of the smoke from the cigarette of his ADC but when the wind appeared to change it was impossible to countermand the order. The British troops encountered exactly the same problems as the Germans but on a larger scale: the wind was wrong and panic that the gas induced in the attackers is recorded by Robert Graves in Good-Bye to All That. The Germans, in strong defensive positions, all had gas masks and the machine gunners had breathing apparatus. Over two and a half thousand British soldiers were hospitalised as gas cases, although two-thirds were more terrified than badly injured. Seven British soldiers, and no Germans, were reported killed by the gas. As a result, the British almost never again used gas directly to assist an attack. Instead British chemical weapons were used to kill, injure and demoralise enemy troops in sectors away from main attacks; in other words for attrition not break-through.

Personnel practicing for the first British gas attack.

Personnel practicing for the first British gas attack.

The escalation of chemical warfare was limited solely by the restraints of research, development and production rather than any questions of morality. The first attacks had shown that chlorine was not poisonous enough and too easily protected against; the Germans led in the introduction of new chemicals owing to their ability to produce chemicals in bulk. Both sides raced to deploy new and more poisonous chemicals and to issue masks to their own troops to protect against a range of potential substances. Phosgene, about one hundred times more toxic than chlorine, was the most prominent threat and a German phosgene attack against the British in December 1915 was thwarted by the rapid issue of an improved gas helmet. The Germans were soon able to penetrate these impregnated cloth helmets with higher concentrations and the British were forced to replace them with a complex but effective mask in which a box filter was connected by rubber hose to a face piece. These ‘Small Box Respirators’ began to be issued in autumn 1916 and within five months every man at the front possessed one. The unsung scientist responsible for coordinating this triumph of design and production, Edward Harrison, weakened by overwork and gas inhalation, died of influenza one week before the war’s end.

Edward Harrison, who gave his life in the development of protection from poison gas.

Edward Harrison, who gave his life in the development of protection from poison gas.

In 1916 the gas shell became the favoured means of overcoming the problem of the wind but a very large number of shells had to be fired to build up a concentration sufficient to penetrate a gas mask, especially after the British introduced Harrison’s Small Box Respirator. The tactic shifted to forcing men to wear their masks for long periods and thereby impede their ability to fight and chemical weapons became particularly important as a counter-battery weapon to silence the opponents’ guns. The aim was also to catch soldiers by surprise before they could adjust their masks and gas shells contained a charge just large enough to break open the shell with a distinctive dull plop. Wilfred Owen’s poem ‘Dulce et Decorum est’ describes his recurring nightmares of a man dying of gas poisoning after soldiers are surprised by phosgene shells which drop softly behind them. Troops easily recognised the sound and in 1918 the Germans increased the size of the charge, rendering them harder to distinguish from high explosive shells. The one major British innovation in chemical weapons, highly effective but also technologically the most crude, was a means of projecting a dense cloud of gas instantaneously onto enemy positions. Inspired by the desire of William Livens to avenge his wife whom he thought had perished on the liner Lusitania (it turned out she hadn’t sailed), each Livens Projector hurled a drum containing 11 litres of liquefied gas, when up to 800 were fired simultaneously, it either gassed the German soldiers before they could get their masks on or penetrated the filters owing to the high density. It was so effective that after its first use Livens boasted that he could kill Germans at 16 shillings per head. The Germans copied the Livens projector and, on the Italian front at Caporetto in October 1917, used it to drench low-lying Italian positions with phosgene; they followed it up with an advance far more substantial and dramatic than that at Ypres in 1915, and the resulting panic formed the central sequence of Hemingway’s A Farewell to Arms.

The first German lethal gas shell, containing 0.285 litres of diphosgene.

The first German lethal gas shell, containing 0.285 litres of diphosgene.

The quest to find toxic chemicals which did not disperse as quickly as a gas led the Germans to a liquid, dichlorodiethyl sulphide, commonly called ‘mustard gas‘ by the British owing to its odour of mustard or horseradish. The most effective chemical agent of the First World War, it would inflict on soldiers a new dimension of horror and suffering. Ironically, after testing on cats in 1916, the British rejected mustard on the grounds that it was not sufficiently lethal. German trials on monkeys demonstrated that it caused eye and respiratory injury but again there were doubts about its lack of toxicity. It was noted that the liquid took much longer to disperse than gas; a detonating shell spread droplets which slowly evaporated in daylight, prolonging its harmful effects. This quality prompted Haber to propose its use to the German High Command when he learnt of the requirement for a chemical weapon to forestall Allied attacks expected in the summer of 1917. However, Haber is said to have warned that it should only be used if Germany was certain of winning the war within a year; once the Allies had the ability to bulk produce their own, Germany would not be able to produce sufficient replacement uniforms needed for decontamination. On the night of 12 July 1917, the Germans fired 50,000 shells containing 125 tonnes of mustard into the ruins of Ypres; it was the first of a series of intense bombardments to target British attack preparations. Within 24 hours, over two thousand British soldiers had been admitted to Casualty Clearing Stations, many suffering intensely painful inflammation of the eyes which effectively blinded them, they were led in files, each holding on to the man in front. After several hours many developed severe throat and lung irritation which in some turned into fatal broncho-pneumonia. A third prominent symptom, not anticipated by the Germans, was large skin blisters, especially on the buttocks, genitals and armpits. Mustard caused injury by skin contact, especially the sweaty parts of the body, either with the vapour as it evaporated in daylight or sitting where the liquid had been splashed by the bursting shell. The predictions that it would have a low mortality rate were correct: of the 2,143 cases admitted to Casualty Clearing Stations after the first bombardment, 95 died, a comparatively small number; put crudely it had taken 500 mustard gas shells to cause each death. But the Germans reported that the British guns were all but silent for two days afterwards. The effectiveness of mustard did not lie in the death rate, rather the large numbers injured, many of whom, by the standards of the time, recovered after several months in hospital. Many, however, such as those nursed by Vera Brittain on the French coast, suffered serious infection and pneumonia, ‘burnt and blistered all over with great mustard coloured suppurating blisters, with blind eyes… and always fighting for breath, their voices a mere whisper…’ A German mustard gas bombardment of the still partially inhabited town of Armentières later the same month, an operation called ‘Totentanz’ (‘Dance of Death’), caused 675 civilian casualties of which 86 died; a high proportion, many elderly, were unable or unwilling to leave the contaminated area. Yet, paradoxically, for some soldiers injury by mustard gas actually saved their lives by taking them out of the fighting for an extended period; in September 1917, a Canadian Chemical Advisor claimed that soldiers were deliberately exposing their eyes to mustard gas in order to escape the front line.

German troops demonstrate their gas mask at a gas alarm post. © Simon Jones

German troops at a gas alarm post. © Simon Jones

The International Red Cross appealed for an end to gas warfare in February 1918 but neither side was willing. The Allies were beginning to rival the Germans in production capacity and also did not trust the Germans to abide by such an agreement. The German use of chemical weapons during their offensives in the spring and summer of 1918 was lavish, comprising 50% of all shells fired, and sophisticated. Shells were colour coded according to their effect: non-persistent lung irritant gas phosgene shells were designated Green Cross and fired in combination with ‘Blue Cross’ shells designed to penetrate respirator filters and cause sneezing, forcing the soldier to remove his mask. Mustard gas, ‘Yellow Cross,’ was fired into the rear and flanks to block reinforcements from reaching the attack zone and to silence the artillery; as many as 80% of the shells fired into these areas were mustard. British mustard decontamination could not cope and at one point in 1918 the British had about thirty thousand men in hospital suffering from the effects. In August 1918, the sight of lines of men blinded by mustard gas inspired society painter John Singer Sargent to produce his monumental canvas ‘Gassed‘ which remains for many the most powerful artistic representation of the First World War. Pushed back by Allied offensives, mustard was initially the ideal defensive weapon for the Germans and the British suffered up to 4,000 mustard casualties per week during September and October. But the effectiveness of German chemical weapons declined as their forces became disorganised and Allied troops learnt to avoid the worst effects of mustard. As Haber had warned, the Allies managed to produce their own mustard within a year of the German use; American production in particular threatened to overwhelm the German ability to decontaminate. By November 1918 the Americans could produce 1,600 tonnes of chemical warfare agent each month, enough for 2.7 million shells. If Germany hadn’t requested an Armistice she would have been overwhelmed by Allied chemical weapons in 1919.

German respirators for man and horses.

German respirators for man and horses.

Was Germany ultimately defeated by chemical weapons? She was already beaten militarily in the field and starved at home by the blockade: chemical weapons did not have a decisive impact on the outcome. Deaths during the war from chemical weapons are estimated at about 18 thousand, or less than 0.2 per cent of battlefield deaths. Even allowing for the effectiveness of mustard in causing injury rather than death, this was a negligible contribution. Herein lies the reason why gas was not used on the battlefield during the Second World War: chemical warfare wasn’t as effective as other methods of warfare developed and refined during the First World War. With the end of the war, efforts were made to limit the use of chemical weapons. Under the Treaty of Versailles, Germany was forbidden chemical weapons, along with tanks, aircraft and submarines, and in 1925 the Geneva Protocol aimed at a global prohibition of chemical and bacteriological weapons. Between the wars the use of such weapons from the air on towns and cities dominated public anxieties and in the late 1930s most European nations embarked on the mass supply of gas masks to their civilian populations. Whilst the masks were not particularly good, informed opinion was aware that the concentration achievable with aircraft payloads would be low and thankfully the threat never materialised; however, since 1919 chemical weapons have been used almost exclusively against unprotected victims, usually non-combatants, and favoured by rogue states and terrorists. During the lead up to both Gulf wars the term ‘weapons of mass destruction’ encouraged an entirely false equivalence with nuclear weapons; ‘weapons of mass terror’ has been suggested as a more appropriate term.

In the hospital at Trent Bridge Cricket Ground, antiseptic dressings had little effect on Sawyer Spence’s septic mustard gas blisters and caused him such pain that they were abandoned; instead a treatment was begun with a new paraffin medication developed by Boots the Chemist. By early November 1918 he was at home recovering; he died, age 81, in 1973.

Sawyer Spence suffering extensive mustard gas blisters, Trent Bridge Hospital, Nottingham, 1918. © Jon Spence, used with permission.

Sawyer Spence suffering extensive mustard gas blisters, Trent Bridge Hospital, Nottingham, 1918. © Jon Spence, used with permission.

Fritz Haber, who used science to create life and to end it, is surrounded by myths. His wife, Clara, herself a doctor of chemistry, was opposed to his chemical warfare work but it remains unknown whether this was the reason, as has been claimed, for her suicide shortly after the first chlorine attack. The oft-quoted description of chemical warfare as ‘a higher form of killing’ attributed to him is almost certainly apocryphal. It is clear however that when the Nazis took power Haber, a Jew who had converted to Christianity, was unable to retain his post as head of the Kaiser Wilhelm Institute for Physical Chemistry. His friend Albert Einstein had concluded many years before that his own future did not lie with identifying himself with the German state. Haber realised this too late; leaving Germany in 1934 he died soon afterwards. A method of pest control using hydrogen cyanide gas invented in 1918 under Haber’s direction and marketed as ‘Zyklon B’ was used by the Nazis to kill over a million people.

Dr Clara Haber (née Immerwahr) committed suicide on 2 May 1915 while her husband was home on leave after the first gas attack.

Dr Clara Haber (née Immerwahr) committed suicide on 2 May 1915 while her husband was home on leave after the first gas attack.

See below for bibliography including online sources.

Text © Simon Jones

1st Shots Memorial Mons 1914 Simon Jones

My ‘First & Last Shots’ Battlefield Tour with The Cultural Experience, 20-23 August 2019

Isaac Rosenberg

My ‘War Poets’ Battlefield Tour with The Cultural Experience, 26-29 July 2019

Harrison Medal

Edward Harrison, who gave his life developing protection against poison gas

IWM Q3999

The Lochnagar Mine: how and why it was blown and who were the men who dug it


Yellow Cross: the advent of mustard gas in 1917

Yellow Cross: measures to protect against mustard gas

The First Gas Attacks, a Century On

Understanding the 1914 Christmas Truce

Contact me



Where did Vera Brittain serve in France during the First World War?

Vera Brittain when a VAD nurse.

Vera Brittain when a VAD nurse. (Literary Executors for the Vera Brittain Estate, 1970 &The Vera Brittain Fonds, McMaster University Library)

From early August 1917 until the end of April 1918 Vera Brittain served as a Voluntary Aid Detachment nurse at No 24 General Hospital, Étaples. She wrote about this experience in her acclaimed and powerful memoir Testament of Youth in the chapter entitled ‘Between the Sandhills and the Sea’.  Étaples is a fishing port fifteen miles from Boulogne, and just to the north the British established a large infantry training camp and a complex of nine major hospitals, almost entirely comprised of huts and tents.

A plan of the Étaples Base Bamp and hospital complex with No 24 General Hospital marked.

A plan of the Étaples Base Camp and hospital complex with No 24 General Hospital marked.

The area of the Étaples Base Camp and hospital complex today. The area occupied by No 24 General Hospital is now covered by housing.

The area of the Étaples Base Camp and hospital complex today. The area occupied by No 24 General Hospital is now covered by housing.

She was first assigned to the ward for acute German cases and then treated mustard gas cases suffering severe skin blistering and temporary or sometimes permanent blindness.

A Canadian victim of mustard gas at No.7 Canadian General Hospital, Etaples, c. 1917 (Library and Archives Canada/ Wikimedia).

A Canadian victim of mustard gas at No.7 Canadian General Hospital, Etaples, c. 1917 (Library and Archives Canada/ Wikimedia).

No 24 General Hospital was not in the ‘front line’, as the fighting was never less than fifty miles from Étaples, nor was it a Casualty Clearing Station but it was bombed several times in 1918. The hospitals were hit by bombs because they were built alongside the Boulogne to Paris railway and were adjacent to the major complex of training camps, both of which were targeted. Vera experienced over a month of night-time air raids which left her exhausted and ‘more frightened than I had ever been in my life’. She left Étaples before the worst bombing raids of May, June and August 1918 when patients and nurses were killed in No 24 General and neighbouring hospitals.

A First Aid Nursing Yeomanry driver with an unexploded German aerial bomb at a British hospital in Calais, 1918.

A First Aid Nursing Yeomanry driver with an unexploded German aerial bomb at a British hospital in Calais, 1917.

Isaac Rosenberg

My ‘War Poets’ Battlefield Tour with The Cultural Experience, 26-29 July 2019


My ‘First & Last Shots’ Battlefield Tour with The Cultural Experience, 20-23 August 2019


Where and how did Edward Brittain die?

Protection against Mustard Gas

The advent of Mustard Gas

‘Anon.’ no longer: the author of the ‘Menin Gate’ poem revealled

Contact me



Yellow Cross: Measures to protect against Mustard Gas

As a follow-up to my post on the introduction of mustard gas I have provided some details of the means that could be taken to protect against the weapon.

During the first three weeks after its first use on 12-13 July 1917, around 14,000 British soldiers were admitted to Casualty Clearing Stations affected by mustard gas. Of this number, 7,797 were Fifth Army casualties from the Ypres Salient.  This was more casualties than had been suffered by the British from gas shelling during the entire previous year.  Owing to the length of time required for recovery, more than three quarters had to be evacuated to hospitals on the lines of communication.

Mustard Victim 1

A British victim of the first mustard gas attack, recorded five days after exposure, this man was suffering from slight laryngitis and bronchitis but his eyes and skin were affected, the latter in areas of perspiration. W. G. MacPherson (ed.), History of the Great War Medical Services Diseases of the War, Vol. II, plate VI.

The British found unexploded shells marked with a yellow cross the morning after the first bombardment and within three days scientists, at the British Expeditionary Force’s (BEF) Central Laboratory at Helfaut, identified the contents as mustard gas.  Rapid treatment and secrecy prevented mustard from having a fatal effect on British morale.  Limited detection was possible from the smell of garlic or mustard and, until the Germans modified the shells, the distinctive ‘plop’ sound of their bursting.  Mustard gas evaporated in sunlight and, after a night bombardment, might not be noticed until sunrise when the vapour became dangerous.  In winter it could lie dormant for several weeks.  Those affected might not know they were contaminated for several hours, feeling no pain until conjunctivitis and skins lesions appeared, the sweaty parts being affected worse.

Mustard Victim 2

A British mustard gas victim recorded eleven days after exposure showing the effects of sitting on contaminated ground. This man’s injuries healed in three weeks. W. G. MacPherson (ed.), History of the Great War Medical Services Diseases of the War, Vol. II, plate VII.

Powdered chloride of lime became the standard means of removing mustard gas and was scattered over the shell craters and areas where the shells had burst.  The chloride of lime then had to be covered with clean earth both to camouflage it and because the smell prevented the detection of further mustard.  It was used in solution to wash guns, trees, etc which had been splashed.  Clean uniforms had to be issued immediately.

The French had already attached a pharmacist to each unit for anti-gas duties and in response to mustard created battalion and battery decontamination squads.  However, the affected areas were often so extensive that there was insufficient chloride of lime: the teams therefore had to choose the key points to treat, and prohibit access to others.  In late August fatigue uniforms impregnated with oil were issued while special overalls treated with boiled linseed oil and dyed horizon blue, impregnated gauntlets, and trench boots were developed.  The British were unimpressed by the French anti-mustard gas clothing, finding that neither the gloves nor the boots would keep out mustard.  They devised hooded overalls of black oiled cloth but the BEF Army Chemical Advisers did not consider that the amount of injury suffered from mustard gas warranted special clothing and concentrated instead on training and discipline.  Skin blistering could sometimes be prevented by directly applying chloride of lime and Britain, Germany and France all developed anti-mustard gas ointments, the French version Pommade Z comprising 10% chloride of lime in Vaseline.

Member of a French mustard gas decontamination squad, with oil impregnated overalls, ARS respirator and Vermorel sprayer containing chlorine of lime. © Simon Jones

German mustard shelling became intense with the series of offensives beginning in March 1918, and during the period of withdrawal of September – October when the British suffered 3-4,000 casualties per week.  Special clothing was again issued by the British from March but it was seldom possible to have it available when needed.  The USA ultimately developed the most extensive measures for both protection and decontamination in the form of mobile shower units.  Germany lacked the resources to produce either adequate protective clothing or replacement uniforms.  As the Allies began to use mustard, this presented Germany with a potentially disastrous situation.


Memorandum by the Chemical Advisor to the Canadian Corps, 27 September 1917, expressing concern that men were deliberately contaminating themselves with mustard gas. (Library and Archives Canada http://data2.collectionscanada.ca/e/e062/e001540690.jpg)

Chemical weapons added novel ways to the already horrific means of injury and death during the First World War.  Morale, discipline and training were major factors in combating mustard gas.  The non-permanent nature of mustard injury led the Chemical Advisor to the Canadian Corps to report at the end of September 1917 that he believed men were deliberately exposing their eyes to mustard in order to gain a few weeks rest in hospital.  Tens of thousands of Allied soldiers were hospitalised for months with mustard gas.  Yet mustard gas presents a paradox because the mortality rate was far lower than for any other weapon and, by being kept away from the fighting at a time when casualty rates were extremely high, mustard gas will actually have saved the lives of many of its victims.


British troops temporarily blinded by mustard gas at an Advanced Dressing Station at Béthune, 10 April 1918. The Germans bombarded areas north and south of the Lys attack area on 7 – 9 April to cut off support from the flanks. Note the soldiers in the background staring at the casualties (Wikimedia Commons/ Imperial War Museum).

Further reading

Simon Jones, World War I Gas Warfare Tactics and Equipment, (Osprey, London 2007).

W. G. MacPherson (ed.), History of the Great War Medical Services Diseases of the War, Vol.  II, (HMSO, London, 1923).

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Medics & Padres battlefield tour: Ypres & the French Coast, 2nd-5th August 2018

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Walking the Five Battle of Ypres, 28th September – 1st October 2018

German Yellow Cross mustard gas shell for 105mm howitzer.

Yellow Cross: The advent of Mustard Gas in 1917


Sawyer Spence (1)

Understanding Chemical Warfare in the First World War

Simon Jones, World War I Gas Warfare Tactics and Equipment

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Yellow Cross: the advent of Mustard Gas in 1917

In July 1917, on the eve of the Third Battle of Ypres, the Germans introduced two new chemical weapons to the battlefield.  One was a failure, the other a spectacular success.  The story of their use illustrates one of the lessons of chemical weapons from the First World War: the impossibility of predicting how they would behave in the field.[1]While gas played a comparatively minor role on the battlefield in 1916, it would become ubiquitous by the end of the following year.  Chemical warfare in 1917 was characterised by the British introduction of a new and effective means of delivery for chemical agents, the Livens projector, and by the German introduction of a new agent for artillery shells, mustard gas.  This article focuses on the introduction and impact of mustard gas.

All the combatants used colour-coded markings on their shells, and the Germans used a system to simplify the complex varieties of chemical fillings according to their function.  The existing diphosgene shells and others containing lethal lung irritant gas, which might dissipate in a few hours and was regarded as non-persistent, were marked with a green cross.  In July 1917 as the preparations for the Third Battle of Ypres were underway, the Germans introduced two new chemical agents, neither of which can accurately be described as a gas.

Blue Cross Shell

German Blue Cross shell for the 77mm field gun, showing the glass bottle containing the chemical embedded in the explosives.

The first was diphenyl chloroarsine, or Blue Cross.  The concept of these shells was not in themselves to cause death or injury, but to penetrate the respirator filters using a fine particulate dust, causing uncontrollable sneezing and coughing which would force the wearers to remove their respirator and succumb to lethal diphosgene shell.  The ‘mask-breaker’ shells were coded with a blue cross.  If effectively disseminated, the arsenic dust could cause intense pain to the sinuses and mental depression.  However, two factors served to diminish the effect of these shells.  Firstly the Germans chose as their method of dissemination to embed a glass bottle containing the powder in a high explosive shell and this rarely produced particles fine enough to penetrate the British respirator filters.  Secondly, the British had already introduced this concept with stannic chloride and between April and June 1917 had issued a particulate filter as an extension for their respirator to protect their own troops in the Ypres Salient.  Moreover, they had under development a new filter box incorporating the filter which they began issuing in July.  The Blue Cross shells however had the advantage of being effectively indistinguishable in flight and detonation from normal high explosive shells, thus soldiers had no warning of the bursting of the shells and might succumb before they could adjust their masks.

Strandfest: the first use of Blue Cross at Nieuwpoort, 10 July 1917

The Germans introduced Blue Cross shells during their operation to retake the bridgehead at Nieuwpoort (Nieuport) from which they rightly suspected that the recently arrived British were to launch an operation along the Belgian coast.  They amassed 146 batteries for this small, local action, under the codename Strandfest (which might roughly translate as ‘Beach Party’).  Because of bad weather the attack date was shifted several times, until early on 10 July orders were issued for a ten-hour preparatory bombardment to commence at 10am.  In addition to diphosgene (Green Cross) and tear gas shells, the British reported another type which burst like a high explosive shell but caused sneezing, slight irritation of the nose and eyes, and tightness of the chest.  At 8pm the German 3rd Marine Division stormed the British positions and threw them back over the Yser.  Despite taking 1,250 British prisoners, the Germans were apparently unable to establish how useful the new Blue Cross shells had actually been in achieving the success.[2]

In order to obtain evidence of the effectiveness of both the Blue Cross shells and the method of combining them with Green Cross, the Germans staged a major raid on 28 July at Wytschaete, south of Ypres.  Code-named, Heuernte or ‘Hay Making,’ the operation involved bombarding British positions at 10.40pm for six minutes by nine light field howitzer batteries with 100 rounds each of Blue Cross ammunition.  This was followed by 14 minutes of high explosives after which five raiding parties entered the British trenches.  They found however that the British had withdrawn from the shelled area and no prisoners were obtained.

British investigations following the 10 July attack where also inconclusive.  There were reports of the new symptoms but they were unable to recover an unexploded shell in order to identify the filling until early August.  The more dramatic use of mustard gas shortly afterwards also delayed investigation of the Blue Cross shells.  This occurred on the night of 12-13 July.

The development of Mustard Gas

While Blue Cross was developed as an attack ammunition for use in conjunction with Green Cross, mustard was adopted as a defensive agent which was suitable for the continuous poisoning of an area.  Mustard gas, dichlorodiethyl sulphide, is in fact an oily liquid with a low boiling point, given the name mustard gas by the British owing to its odour of mustard or horseradish in its impure form.  It was to become the most effective chemical agent used during the First World War owing not to the numbers which it killed but to the temporary effects of skin blistering and severe conjunctivitis and to its ability to render ground uninhabitable owing to the time which it took to evaporate.  Its effect on the skin was noted by Viktor Meyer in 1886 but both the British and French considered adopting mustard in 1916 but rejected it on the grounds of its lack of toxicity.  Professor Ernest Starling, in charge of British anti-gas research, had ordered experiments on cats in 1916.  However, the persistency of mustard, the way that it continued to poison for hours or days after release, was not noticed and the range being only that of a bursting shell it was turned down.

The Germans named it ‘Lost’ after the names of the proposers: Dr Wilhelm Lommel at the Bayer research laboratories and Dr Wilhelm Steinkopf at the Kaiser Wilhelm Institute.  Trials were carried in September and October 1916 out by Doctors Ferdinand Flury and Curt Wachtel, toxicologists at the Kaiser Wilhelm Institute.  Their tests results on monkeys demonstrated eye and respiratory injury but made no mention of skin symptoms.  Wachtel later described how, in late 1916, mustard came to be adopted. [3]  The head of the Kaiser Wilhelm Institute for Physical Chemistry and also head of the German chemical warfare programme, Fritz Haber, learnt from the German commanders Hindenburg and Ludendorff that they required a defensive gas suitable for preventing Allied attacks expected in the summer of 1917.  Haber was able to propose the newly tested mustard gas which would remain dangerous for long after the gas shell then in use had dissipated and industrial production was initiated.  Haber’s son, L F Haber, however suggests that, while mustard was selected because of its persistency, its effect was still expected to be as a lethal lung-irritant rather than the non-lethal casualty producer that it in fact turned out to be: ‘No one appears to have remembered that Meyer, thirty years earlier, had written of its blistering action.’[4]

The lack of lethal effect was in fact noted before it was used in the field, according to Wachtel, following a serious explosion at the Adlershof gas shell filling plant, near Berlin, in the spring of 1917.  Occurring after the first 1,200 77mm shells had been prepared, this explosion delayed the first use of mustard by several weeks.  But a lack of casualties during the fire fighting and cleanup led to claims that it was not sufficiently toxic which had to be refuted with further toxicology tests.  A trial was conducted in which 500 mustard shells were fired on a test range on which several hundred cats and dogs were tethered.  Before its use in the field, mustard was dismissed by most gas warfare experts as being the best means to kill cats but not as a war gas. [5]

German Yellow Cross mustard gas shell for 105mm howitzer.

German Yellow Cross mustard gas shell for 105mm howitzer.

The First Mustard Gas Bombardment, 12-13 July 1917

The new shells were marked with a yellow cross to indicate their persistency.  The first bombardments which the Germans carried out at Ypres were clearly intended to forestall the British offensive.  From the start, mustard was a defensive agent, used to poison areas of ground over which the Germans had no intention of attacking over in the foreseeable future.  Some 50,000 shells containing 125 tonnes of mustard were used on this first night. [6]  The bombardment, with 77mm and 105mm shells, was in three phases apparently reflecting the way that non-persistent gas clouds were created and topped up using shells: starting at 10.10pm for twenty minutes, it resumed at 1230, again for twenty minutes, followed by a third phase at 1.55am for twenty-five minutes.[7]

On detonation the shells, bursting with a dull plop, sprayed the liquid in a seven metre radius in the case of the 77mm and about 10 metres in the case of the 105mm.[8]  Contact with either the liquid or the vapour, which evaporated in sunlight, caused injury.  However, the lack of any immediate symptoms meant that troops did not keep their masks on and did not appreciate the danger of being present in the vicinity of the shells.  At first those in the bombardment suffered only slight irritation of the nose which caused some sneezing (perhaps the result of Blue Cross shells).  However, in an hour or two they suffered painful inflammation of the eyes, vomiting, followed by reddening of the skin and blistering.

45 Bde WD 12 July 1917

The first mustard gas bombardment reported in the War Diary of the 45th Infantry Brigade, 12 July 1917. (The National Archives, WO95/1943)

Large numbers of casualties began to report to medical units.  The first were admitted to Numbers 47 and 61 Casualty Clearing Stations at Dozinghem (near Poperinge) and Numbers 46 and 64 at Mendinghem (near Proven) and on 13-14 July a total of 2,143 were admitted to these four units.  By the time they reached the Casualty Clearing Station the conjunctivitis had developed so rapidly that they were virtually blind and had to be led in files, each man holding on to the man in front, guided by an orderly or lightly wounded man.  In the first few hours the symptoms were in strong contrast to those usually found in gas cases, with only one or two casualties suffering from symptoms of acute pulmonary oedema (again this was possibly caused by Green Cross shells mixed with the new shells).  The majority suffered little distress to their breathing, although some exhibited a husky voice and a hard cough.  After a few more hours symptoms of laryngitis, tracheitis and bronchitis became more definite in a large number of the cases and some developed grave or fatal broncho-pneumonia. [9]

c080027 C-080027

Canadian victim of mustard gas at No.7 Canadian General Hospital, Etaples, c. 1917 (Library and Archives Canada/ Wikimedia).

Men developed blisters on their buttocks, genitals and armpits.  Within two days many were suffering from bronchitis and some had died from inflammation of the lungs.  By the sixth day the conjunctivitis which caused the blindness had disappeared but the breathing difficulties were still severe and the blistering had been replaced by skin rashes.

Of the 2,143 cases admitted to the four Casualty Clearing Stations, a comparatively small number, 95, or 4.4%, died.  German unit histories report that the British guns were all but silenced for up to two days.

Up to the end of July, the Germans bombarded the Ypres area every night with mustard, during which the Germans gunners had to surround their own gun positions with chloride of lime as a precaution against leaks or premature bursts of the shells.  In addition, a series of set piece gas shoots were conducted.  On 15 July a ‘multi-coloured’ shoot of a thousand rounds was carried out, which despite barrel bursts was repeated the following day.  Then on 17th and again on 21st more extensive gas shoots were carried out on tracks, shelters and accommodation at Zillebeke Lake.

On the night of 20-21 July Blue and Green Cross were again tried in combination in an operation called Britentod or ‘British death,’ postponed from the previous night owing to strong winds.  British battery positions at Voormezele were targeted, each German field battery having been issued with 900 rounds of Green Cross and each howitzer battery 350 rounds of Blue Cross.  The bombardment, from 1am to 3am, completely silenced the British batteries although no mention is made of mustard having been used.

On the same night 20-21 July, in an operation called Totentanz, or ‘Dance of Death,’ Armentières was first targeted with mustard gas, injuring about 6,400.  The following night 21-22 July, Nieuwpoort was heavily bombarded with mustard, thus the south and north flanks successively of the expected British attack area were rendered impassable.  The casualties were worse overall than those suffered at Ypres as the troops here had not yet received adequate warning and instructions regarding mustard gas.

On 23-24 July Britentod was repeated, then on 26-27 gas bombardments in the Wytschaete sector named Schlesien and Apolda.  On 28-29 July renewed gas bombardments of Armentières and Nieuwpoort was carried out between 1am and 4.30am.  The civilian casualties from mustard gas in Armentieres totalled 675, of which 86 had died by 18 August, a high mortality due in part to the number of elderly citizens, many living in cellars, who were either unable or reluctant to leave the area while the shelling was in progress.

From July, Blue and Yellow Cross shells were used in very large numbers with a reduction only coming in the winter of 1917-18.  Once the Germans had identified the improved protection afforded by the British respirator against Blue Cross, they came to use these shells at the beginning of a gas bombardment, as the shells could not be distinguished from HE shell.  The sneezing symptoms would therefore affect men before they could adjust their masks and then cause them to succumb to Green Cross shells used subsequently.  HE or Blue Cross shells were used to disguise the distinctive bursting sound of Yellow Cross mustard gas shells.

During August and September 1917, the Germans used mustard to defeat French attacks on either side of the river Meuse, causing 13,158 to be poisoned and 143 killed.  Losses were so great in the affected areas that it has been claimed that the French were forced to abandon the attack.[10]  The combination of Green and Blue Cross shells, used for the first time to support the attack at Nieuwpoort on 10 July, was later used for the successful German assault across the Daugava river on 1 September 1917 which lead to the fall of Riga.  The artillery fire plan was the work of Colonel Georg Bruchmüller and the publicity accorded it has led some to assume incorrectly that Bruchmüller invented this combination of gas shells, called Buntschiessen or ‘colour shoots’.

Mustard gas caused serious casualties to the British in July 1917 but there seems to be no evidence to support the claim by Beumelburg and Hanslian that it caused the start of the 3rd Battle of Ypres to be postponed for a fortnight.[11]  Hanslian and Seesselberg claimed also that it prevented a British break-though during the offensive.  Whilst mustard continued to be used throughout the battle, it was not used to cover the withdrawal of German forces as it would be in 1918, as they could not contaminate ground which they would wish immediately to recapture.  Although the Germans improved slightly the effectiveness of their Blue Cross shells, the Allies regarded them as a wasted effort, something that post-war German writers could not accept.

Conclusion: Yellow Cross in 1918

The year 1918 was to see the development of German gas tactics, in particular the use of the persistent mustard gas to block the flanks of areas attacked. The Germans used gas shells in unprecedented numbers and they were integral to their spring and summer offensives.  Against infantry, the Green Cross diphosgene and Blue Cross combination was 50% of the total shells used.  Against artillery the ratio was as high as 80% mustard to high explosive.  Areas outside the attack zone were heavily shelled with mustard to prevent counter attacks.  Mustard was extremely effective as a counter-battery weapon and British decontamination measures broke down.  At one point in 1918 the British had the equivalent to two divisions in hospital suffering from mustard gas injuries.  However, gas was less effective during the June – July offensives: attacking in gas masks behind a gas barrage was especially fatiguing for the Germans while Allied casualties were decreasing.

For the remainder of the year, the Germans were in retreat and mustard was to prove far more suited to defence than attack.  On 31 July 1918 they used 340,000 mustard gas shells to forestall a Franco-American attack west of Verdun.  During September – October British mustard gas casualties were 3 – 4,000 per week but as the British advanced continued, German bombardments became less effective and poorly targeted.  It was impossible for the Germans to create their complex fire plans as supply and command became disorganised.  When the Allied advances began, the Germans discovered that French troops were less hindered by mustard having learnt to minimise casualties when passing through affected areas.  Supplies of mustard were less plentiful by September and during October gas ceased to be a factor in halting the Allied advance.

The cases of both Blue Cross and Yellow Cross shells demonstrate that chemical weapons rarely behave on the battlefield in ways predictable in the laboratory or on the firing range.  Nevertheless, the German use of mustard was rightly regarded as a military success.  Despite apparently intending its effect to be as a lethal lung irritant rather than a non-lethal casualty producer, mustard revolutionised chemical warfare, and introduced an agent which alone amongst the chemical weapons of the First World War has continued application into the 21st century.  Until the introduction of mustard, the artillery arm, by far the most flexible means of using gas, had been handicapped by the lack of an agent effective enough in the smaller quantities delivered by shell.  By its persistent nature mustard provided this.  The German unity of research, production and military expertise, embodied in the person of Fritz Haber, meant that the right substance was available to meet the military demand.

The introduction of mustard gas however was a gamble for Germany.  A physicist at the Kaiser Wilhelm Institute, Wilhelm Westphal, claimed that when Haber described mustard gas to General Ludendorff, he warned against its use unless the war was certain to be won within the year.  Otherwise the Allies would produce mustard for themselves and Germany lacked the Allies’ ability to replace contaminated uniforms.  This alone he said could lose the war for Germany.  It did take the Allies a year to produce their own mustard gas, achieved by the French through accepting casualties in their factories comparable to those at the front.  Westphal’s anecdote may be apocryphal but when the Germans identified French-produced mustard in August 1918, this awareness that the Allies would probably soon be using it on a large scale was one more reason why the Germans would be unable to continue fighting in 1919.

Text (c) Simon Jones.  See below for Notes.

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Understanding Chemical Warfare in the First World War

Notes on Yellow Cross: the advent of Mustard Gas

[1] This article is an extract from a paper delivered at the In Flanders Fields Museum in 2007 and is partially referenced. Contact me if you require more information on sources.

[2] W. Volkart, Die Gasschlacht in Flandern im Herbst 1917, (E S Mittler & Sohn, Berlin, 1957) p.46.  The British Official History, J. E. Edmonds, Military Operations France and Belgium 1917 Vol. II, (HMSO. London, 1948), p. 119, mistakenly states that the Germans used mustard gas in the bombardment prior to this assault.

[3] Curt Wachtel, Chemical Warfare, (Chemical Publishing Co., Brooklyn, 1941), pp. 226-7.

[4] L. F. Haber, The Poisonous Cloud, (Clarendon Press, Oxford, 1986), p. 117.

[5] Wachtel, op. cit., pp. 221-2.

[6] Volkart, op. cit., citing Rudolf Hanslian, Der Chemische Krieg, (E S Mittler & Sohn, Berlin, 1937).

[7] Hanslian, op. cit., pp. 132-141.

[8] Volkart, op. cit., p.40.

[9] W. G. MacPherson (ed.), History of the Great War Medical Services Diseases of the War, Vol. II, (HMSO, London, 1923), pp. 292-293.

[10] Hanslian, op. cit., pp. 132-141.

[11] Hanslian op. cit., p. 140.