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Gas and Chemical Warfare

Updated: Jan 18, 2023


Had gas warfare in the First World War been as effective and devastating as the myth states then the war would have been over after its first use.


Gas warfare was anything but as reliable and effective as the myths suggest, indeed, gas was never decisive and the casualties from gas have always been overstated. This fact does not lessen the agonies of the victims. The use of chemical or biological weapons in warfare was not restricted to the First World War as this form of warfare had been in use for centuries. From hurling dead horses into besieged castles to spread disease to pouring hot oil onto attackers. The use of poison gas and other chemical weapons had been something that the military had seen the potential of for some time.


It’s use had been outlawed by the Hague Declaration of 1899 and of the Hague Convention 1907 both of which had been signed by the European powers however, the earlier draft had not been signed by Britain and the United States of America but they did sign the later version. Therefore, at the outbreak of the First World War gas and chemical weapons had been outlawed. That said, it was the First World War that presented the ideal opportunity for gas to be used for the first time.

It was the French who first used gas in a limited scale in September 1914, using tear gas grenades, which the French police had already deployed in 1912 at Choisy-le-Roi. The first successful use of poison gas was by the Germans on 22 April 1915 at Langemarck in Flanders during what became known as the Second Battle of Ypres. The Germans had made a huge effort to deploy over 6,000 pressurized cylinders containing chlorine gas. The allied line was held by the French 45th Algerian and 87th Territorial Divisions, Canadian and British units with the German attack being against the French who held the left of the line.


At 5.10pm on 22 April, the German barrage ceased and the French reported seeing a large greenish cloud drifting towards their lines across no-man’s land. It was presumed that this was a smoke screen to hide a German attack and the French had gone to Stand To! As the gas enveloped the French lines the soldiers began to feel the gas burning their eyes and throats and had difficulty in breathing. The French lines broke with as many as 1,500 men succumbing to the gas. It took much heavy fighting over the next month to secure the line and hold the Salient. With a gap of some 8,000 yards in the line the Germans had forced the allies to shorten their lines and reduce the size of the Salient.

Falkirk Herald, 24 April 1915, mentions the use of gas at Langemark

The Germans had proved that poison gas could be used effectively but it was never a decisive weapon.


British Retaliation

After the attack at Ypres the British prepared a retaliatory attack of their own and the task fell to a hastily assembled unit of some 1,500 men under the leadership of Major Charles Foulkes who was to become the main adviser on chemical warfare. This unit was to eventually to reach a total of 6,000 men recruited and trained from the Royal Engineers. These were in the main chemists and were formed into Special Gas companies and they prepared for their first gas attack at the Battle of Loos in September 1915. In addition to mastering gas attacks these special Gas Companies also trained in the use of flame-throwers, smoke-screens, gas projectors, and mass train discharges. Except for gas shells that were fired by the artillery, it was these small units that managed the British gas retaliation.


Porton down established

Sanctioned by Kitchener and established in 1915 shortly after the attack at Ypres, Porton Down was the centre for Britain’s chemical-warfare research and development. The research was led by the Royal Engineers and Porton Down was not only to be the centre for research into gas on the battlefield but also testing the anti-gas equipment used by the British for the next forty years. Before we look at the counter measures it is important to get a basic understanding of the different types of gas.

Types of Gas encountered by troops in Ypres

Lachrymators (Tear Gas) - This type of gas causes the eyes to swell and water which produces temporary blindness. In addition, the nose runs uncontrollably and the victims throat becomes sore and inflamed which causes coughing fits.

Asphyxiant Gas - This type of gas is highly toxic and causes the victim to choke as the chemicals attack the respiratory system. Chlorine, used at Ypres in 1915, by the Germans and by the British at Loos. Chlorine attacks the alveoli in the lungs which then fill with fluid and the victim literally drowns. Phosgene, used by the Germans at Ypres on 19 December 1915. This gas prevents oxygen transfer in the blood stream which means the victim suffocates. Diphosgene, used by the Germans at Verdun in 1916, is a more deadly version of Phosgene. The British used a mixture of both chlorine and Phosgene known as ‘White Star’ with the chlorine helping to spread the denser but more toxic phosgene.

Blistering/Vesicant Gas - better known as ‘Mustard Gas’ which contained the chemical dichlorethyl sulphide. This gas got its name because of the pungent smell and colour. Vesicants include the alkylating agent which means the vapour will stick to moist areas and start to break down the membrane resulting in terrible burns and blisters, the most common being to hands, face, eyes and if inhaled it slowly destroyed the lungs .Mustard Gas lingered for days after and it was not uncommon for troops taking shelter in shell holes or craters to become victims of this gas.


Two images from 2020, when a battlefield visitor picked up an unexploded chemical weapon.



The Methods of Protection from Gas

The British were not equipped for chemical warfare and following the gas attack on 22 April the BEF headquarters issued an order that handkerchiefs were to be soaked in bicarbonate of soda, an alkaline, to neutralize the chlorine gas until a more permanent solution could be found. Two scientists, at the request of Kitchener, were rushed to Flanders, Professor John Scott Haldane and Professor Herbert Brereton Baker.

Article that appeared in the Falkirk Herald on 1 May 1915

Both had specialised in the effects of gas in the mining industry, indeed Haldane had introduced the use of small animals in mines to warn against the presence of carbon monoxide.


As chlorine was confirmed as the gas that was used at Ypres, Haldane had also suggested that in the absence of bicarbonate of soda that the handkerchief should be soaked in urine, it has a high density of urea which reacts with the chlorine producing dichlorourea which crystallizes and supposedly protects the wearer. In the absence of handkerchiefs the troops were told to urinate on shell dressings which should then be tied around the nose and mouth. Many units arranged for these to be made by local townsfolk and the Daily Mail famously launched a campaign for the women of Britain to make 1,000,000 cotton-wool respirator pads in a day. These masks, although made with good intentions, were totally useless. When the mask was soaked in bicarbonate or urine the close knit fibres swelled so making an air tight seal that was impossible to breath through. It is estimated that some 30,000 of these masks had been issued before the fault had been discovered. On the 5 May 1915, an order was issued to dispose of these masks.


Types of protection

The Black Veil Respirator - This was the first official respirator issued to the British Army. It was made of more loosely woven material such as cotton waste of horse hair that could absorb the protective solution of hyposulphate, a salt derived from hyposulphuric acid that neutralized the chlorine, and enable the wearer to breathe. The solution was found in a German mouth-pad respirator taken from a prisoner. Developed by Haldane and Baker who worked alongside a Colonel Cummins of the Royal Army Medical Corps the name comes from the black mourning veil used in its production. The excess material could be pulled up to cover the eyes to protect against tear gas, this was before the issue of gas goggles. The problem of the mask drying out was solved by the simple expedient of supplying a waterproof wallet in order that the veil could be stored wet in the soldier’s kit. Also, should the gauze pad start to dry out when in the trenches there were buckets of sodium hyposulphate mixed with sodium carbonate, glycerine and water provided in the trench. Between May and July 1915, 2,500,000 were produced with all the work carried out by women, except the treatment of the gauze pads.

The Hypo or Smoke Helmet - was the idea of Dr Cluny MacPherson a medical officer with the Newfoundland Regiment. The idea is said to have come to him after he had met a Canadian soldier who had pulled a wet canvass bag over his head during a gas attack. The Smoke Hood was dipped in the same chemical solutions as the Veil Respirator and the ‘helmet’ was tucked into the tunic collar forming a seal. Clear mica was added to allow the wearer to see and this was replaced by cellulose in later production as the mica had a tendency to crack when partially dried out and then redipped in the solution. This helmet was easy to make although with no inlet/outlet valve it was very basic. At the testing stage the cloth was replaced by flannel to improve the retention of the solution and breathing. The flannel was sourced by the Royal Army Clothing Depot located at Pimlico in London and was grey in colour the same as the soldiers ’greyback’ shirts but khaki coloured Viyella was also used. The hoods were initially sprayed with the solution before this was changed to dipping them in large vats. They were stored in a waterproof satchel before be issued.

(Types of Protection from 1915 to 1918)


There were 2,000,000 produced between June and August 1915. The helmet did have its faults, the viewing piece steamed up as moisture gathered on the surface, after long periods of exertion sweat would cause the solution to seep from the helmet onto the wearers face causing irritation of the skin and also lessen the effectiveness of the helmet against gas, and there was a build up of carbon monoxide inside the helmet. The Army HQ referred to them as ‘Smoke Helmets’ and the Anti-Gas Department called them ‘Hypo Helmets.’


P (Phenate) and PH (Phenate Hexamine) Helmets - With the development of Phosgene Gas, which was harder to detect than chlorine as it was colourless and with an odour similar to that of musty hay, the Anti-Gas Department supported by the Royal Army Medical College at Millbank in London, began to look at how the Smoke Helmet could be improved. After various experiments it was discovered that sodium phenate offered the best protection and the new helmet was fitted with a rubber outlet valve that had previously been suggested for the Smoke Helmet. This valve tube had to be held in the mouth which allowed the wearer to breathe in through their nose and exhale the carbon monoxide out via the valve. The new helmets were dipped in a solution of sodium phenate, caustic soda, glycerine, industrial spirit and water. The cellulose viewing piece was replaced by two eye pieces with the eyepieces being made of coated glass which were held in place by screw bezels and a rubber gasket added between the glass and bezel to improve the seal. They became known as ‘P’ Helmets and around 9,000,000 were manufactured unfortunately, the P Helmet proved to be unreliable against high concentrations of phosgene and as with the Smoke Helmet the wearer developed sores as a result of the chemicals seeping onto the face. Following a message from the Russians in October 1915 that Hexamine, white crystal like in appearance, was effective against phosgene the British, on 20 January 1916, ordered the dipping of the P Helmets in the new solution and these helmets became known as the PH Helmet. From 1916 to when production ceased in February 1918 over 14,000,000 of these helmets were produced. To accompany the Veil Respirator the troops had been issued with rubber drivers’ goggles to help them see during a chlorine gas attack, the veil being pulled over the eyes meant the soldier could not see and this led to panic and confusion, in two instances on the Menin Road and at Sanctuary Wood in May 1915. The goggles were good in situations where the concentration of chemical used in the attack only affected the eyes and the respiratory system. The new helmets proved ineffective against such attacks and the troops took to wearing the goggles underneath their helmet. By 1916, the British soldier was now carrying three types of anti-gas protection, the Smoke Helmet, gas goggles and the PH Helmet.


A further development of the PH Helmet was the PHG (Phenate Hexamine Goggle) Helmet this replaced the need for troops to wear gas goggles by simply incorporating the gas goggles into the helmet design. The effect of this change was minimal with the helmets being issued to men in static positions such as artillery and machine gun units. Approximately 1,765,000 of this type of helmet was produced. With the introduction of the Large Box Respirator the PHG helmet was withdrawn.

Large Box Respirator - the LBR was the idea developed by a senior chemistry lecturer at Oxford University Bertram Lambert following trials in the summer of 1915. The idea being that the LBR would be effective against a range of gases and the British had identified at least eighty gases that the Germans could potential deploy. It was the Russians once again that had identified that activated charcoal,


Large Box Respirator


essentially grains of charcoal that had been treated with steam to give their surface tiny holes and making them extremely porous so making them effective in filtering gas. It should be noted that the Box Respirator did not offer any eye protection this role was filed by pairing the respirator with the gas goggles. The filter was made from a standard Army water bottle that was filled two-fifths with lime permanganate and pumice stone treated with sodium sulphate and the rest was charcoal. A collapsible rubber tube connected the filter to the facepiece which was made of up to forty layers of muslin sewn together and treated with a zinc-hexamine solution. This had been developed by Edward Harrison of the Royal Army Medical College at Millbank and another officer, John Sadd, developed the breather tube that was held in the soldiers mouth by using elasticated straps worn around the back of the head. The size and weight of the filter was a problem and it had to be carried over the shoulder in a haversack and the filter hung down by the hip. The LBR was introduced in February 1916 and was again issued as a priority to the artillery, machine gun units and later to the Heavy Branch if the Machine Gun Corps who operated the new weapon, the tank. Only 250,000 were ever produced.


At the same time as they were working on developing the LBR Harrison and Sadd were also working on the Small Box Respirator (SBR) which was of s similar construction to the LBR however, the SBR was to be lighter and easier to carry and the plan was to make it available en masse. The SBR had a full canvas facepiece which contai8ned a nose clip and mouthpiece allowing breathing through the mouth and also meant that facepiece did not have to be gas tight around the wearers face all the time. An initial order was placed in June 1916 for 100,000 however, following the gas attack on the British at Wulverghem opposite the German lines at Messines Ridge, this was revised to 500,000. The SBR was further revised and updated in 1917 and again in September 1918 and saw service until 1924.


Warning of a gas attack - To warn the troops of a gas attack the British had various devices. The simple gas rattle, gongs or bells, some made their own out of used shell casings. Later there were klaxons and Strombos. These were air powered horns that were operated by the gas sentry. The Strombo had two small compressed air cylinders, one a spare, and would last for approximately one minute. They had a sound range of two miles which meant those troops not affected by a gas attack would also don their respirators.


Making the masks that saved men’s lives’ The New Illustrated, 1919. This shows the manufacturing process of the SBR


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