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With hindsight we know that gas was not really used as an offensive weapon in WW2, although certainly the Allies held stockpiles for use on the south coast in case of 
invasion. Maybe each side realised its use would bring similar retaliation and it thought that High Explosive was a preferable way to produce casualties, although recently 
released documents have suggested that the Germans decided that as the quantity of stockpiled gas weapons of the Allies was far in excess of those they held it might 
be prudent not to start using them. Certainly many gas masks were discarded by soldiers in the ETO, I wonder at what stage they were really safe from the gas threat.

Seeing as we are reasonably sure that we aren't going to be attacked with gas I think the only effort most of us make to these precautions is to carry a bag, but maybe 
not with a mask in it! That doesn't mean we can't be aware of what the soldier's gas training covered so I submit a brief synopsis of a contemporary guide published for 
the US Army, 'Gas Warfare - The Chemical Weapon, its use, and Protection Against it', by Brigadier General Alden H. Waitt, published by The Infantry Journal in the 
Fighting Forces Series.


There is ancient evidence of the use of gas as a weapon of war, mainly by burning substances with elements such as sulphur in it. However the first large scale use was in 
the First World War by the Germans at Ypres in 1915, by releasing Chlorine from gas cylinders on a day when light winds would carry it into Allied trenches, who were 
entirely unprepared for this attack. The Allies retaliated at Loos, again by deploying Chlorine from gas cylinders. Grenades, Shells, Mortars, and devices such as the Livens 
Projector were later developed to deploy chemicals more effectively, sooner than having to rely on suitable wind. Protection against Chlorine was quite straightforward so 
other gases such as Phosgene were introduced. Both these gases just affected the lungs, the later introduction of Mustard Gas required more protection than a gas mask, 
as it also affected skin over the whole body. In 1918 the US Army First Division was attacked near Seicheprey, with Phosgene and Chlorpicrin, which resulted in heavy 
casualties. The scale of the First World War use makes its absence a contrast with the Second World War.


Chemical weapons can be argued to have advantages over high explosives and cold steel, they leave property intact, and can be more likely to only subdue an opponent 
sooner than take his life, thus still allowing a nation to impose its policies over another, without destroying it. In the First World War only 2% of American gas casualties died, 
but 25% of casualties from conventional weapons died. So the notion that the use of gas weapons is inhumane is maybe a bit misplaced.


Gas could exist in lethal concentrations, - a casualty agent - but it can also exist at lower concentrations. These could be thought of as an intolerable or harassing 
concentration - a harassing agent. Although this might not cause casualties, it would cause personnel in the affected area to have to wear gas masks, which would adversely 
affect their working efficiency.

Although we describe the substances as gases, many are liquids dispersed as a fine spray, or even smokes.

Gas can be effective over a long time (a persistent agent), or a short time (non persistent), if that is what is required. A persistent gas may soak into the ground as a liquid 
and cause problems in that area for some time. A non persistent gas would loose its effect, or become dispersed within 10 minutes. Clearly if we use gas in an area of land 
which we then intend to try to occupy, a persistent gas would also cause us problems. The Germans in the First World War gas shelled much of a section of the line, with a 
persistent gas, apart from one area, which they intended to attack. The Allies all relocated to this area clear from gas, in order to escape the gas, so were well prepared when 
the Germans attacked the best defended section! A persistent gas is denoted on a shell or bomb by two green bands, non persistent by one. The chemical in the device was 
labelled with a two letter code – CG being Phosgene, the letters derived from ‘CollonGite’, its French name, although it is a Choking Gas! Mustard gas was coded HS, though no 
one knew why, unless this was something to do with the British nickname ‘Hot Stuff’.

Although there are many thousands of poisonous substances, those suitable for warfare are few. Ideally they should possess the following characteristics :-

1.         Be effective in small concentrations. Chemicals like Mustard gas are effective in far smaller concentrations than Chlorine.
2.         Be unreactive - this makes the development of effective gas masks harder, and the gas more persistent.
3.         Easily manufactured.
4.        Composed of raw materials easily procurable on the North American continent.
5.         Cheap.
6.         Easy to transport, ideally compressed to a liquid.
7.         Stable in storage and against shock of explosion.
8.         Heavier than air.
9.         Effective against all parts of the body - lungs, skin, eyes.
10.        Odourless, tasteless, colourless.

Clearly no chemical has all these properties.

The chemicals can be categorised, with examples.

Many gases have secondary effects – mustard gas is classed as a vesicant as casualties are mainly caused by its effect upon the skin. However, it also irritates the lungs and 
is a tear gas.

Most chemical agents affect the lungs. Phosgene (CG) was effective even in low concentrations, where its effects aren’t immediate so if undetected it may be breathed for 
sometime before a gas mask is deployed. A casualty may suffer little effect for some hours, but exposure could still be fatal. Larger concentrations can produce immediate 
effects with coughing, choking, inability to expand the chest, pain in the chest, then blueness of the lips and a red or ashen face. Phosgene smells like new mown hay. 
Phosgene is denser than air so the gas will flow down into foxholes and trenches. It is non-persistent as it is a gas, and reacts quickly with water forming acids, so its 
deployment on a rainy day will produce little effect. Soda lime was used in gas mask canisters to absorb phosgene. Chlorine is also a choking gas but was not likely to be 
encountered, as it is so reactive protection was easy. Chlorpicrin (PS) is a lung irritant and tear gas, less poisonous but more persistent than Phosgene. It maybe smells like fly 
paper. It is relatively unreactive so difficult to protect against with a gas mask – usually they relied on charcoal to absorb it.

Mustard gas (HS) was the most famous blister gas which saw much use in WW1. Lewisite (M1) is another. They will cause severe blistering upon any part of the body. This 
effect is unfortunately not immediate so if detected precautions must be taken even if combatants are not yet in any discomfort. Low concentrations are not easily smelt but 
it will affect the eyes after about an hour. The gas brassards were used to detect this gas, they should turn red. Clearly use of a gas mask is not enough so modifications to 
clothing, and avoiding contact with ground and vegetation that are contaminated are necessary. The persistent vesicant is useful where there was ground that they did not 
wish to occupy themselves, eg in retreat. Mustard gas deploys as a mist hence the liquid can remain for some time on the ground and foliage. The odour of mustard gas is 
somewhere between mustard, garlic, and onions. Mustard gas will produce many casualties but few deaths, Lewisite is much more lethal, Lewisite’s odour resembles 

Very small concentrations of tear gases cause discomfort and hence cause personnel to put on their gas masks. This reduces their effectiveness. Tear gases tend not to 
cause permanent casualties, so are more harassing agents – those affected will recover. In some situations eg riots, or training, this is useful. Tear gases have been used to 
good effect in combination with high explosives. CN and CNS solution were standard tear gases, with an odour that resembles locust blossom.

Blue Cross (German WW1 shell markings) (DA) or Adamsite (DM) were liberated in the air as a smoke, with very fine particles, this must be mechanically filtered by gas 
masks, and the finer the particles the more difficult this is. Irritant smokes generally don’t have toxic effects, though they can, and just result in sneezing and nausea. 
German tactics in WW1 included the deployment of DA in a HE shell, this caused affected troops to remove their gas masks as the fine DA particles penetrated the filters and 
they were suffering from sneezing and nausea. The Germans could then follow this up with much more deadly Phosgene. Adamsite was the standard irritant smoke of the US 

White Phosphorous (WP) is very reactive and produces clouds of white smoke when burned, igniting on exposure to oxygen. Burning particles are very hazardous due to
temperature, creating fires and injuring personnel, but the smoke is harmless.  A safer solid screening smoke was HC, this was the standard WW2 US Army screening smoke. 
Smoke might result from spraying a liquid into the air, FS was designed to deploy by spraying from aircraft, shells or static installations. Burning crude oil has also been used to 
create screening smoke. Screening smoke is used to conceal potential targets, air currents obviously controlling its effectiveness. The use of screening smoke is a two edged 
sword though as its use would alert the enemy, and it potentially interferes with the users visibility as well as the enemies.

These had yet to be used successfully in warfare up to WW2 but were a potential threat. The French used hundreds of thousands of hydrogen cyanide shells in WW1 to
effect. There is also an odourless tasteless gas that has killed more than all other gases together, however carbon monoxide is less dense than air so disperses rapidly.

Incendiary devices use spontaneously or easily combustible materials to cause fires. Many of them also contain chemicals that will produce oxygen when burning, to increase 
the temperature of the fire. Many incendiaries are based on Thermites. Gasoline and other oil based compounds also found use, for instance in flamethrowers. Oils were also 
used in incendiary bombs and shells though, sometimes with the addition of sodium particles, so if water was used to try to quench the oil fire, its contact with sodium would 
soon reignite the fire. Many incendiary shells or bombs used magnesium in the casing, which burnt well itself. Fires are also useful for defensive means, fires lit on the outskirts 
of cities could draw bombers off their real targets.


Lung irritants or choking gases
Eg Phosgene

Non persistent, casualties

Vesicants – blister gases
Eg Mustard Gas

Persistant, casualties

Lacrimators – tear gases
Eg Tear Gas Solution        
semi persistant, harassing

Irritant Smokes
Eg Adamsite
non persistent, harassing

Solid Smokes
Eg, White phosphorous
screening agent

liquid smokes
Eg Smoke or FS
Screening Agent

Nerve & blood poisons
Eg Hydrogen, Cyanide
non persistent, casualties

Eg Thermites



These were designed for releasing gas at points close to the enemy. Wind strength and direction obviously had to be factored into their use. The standard US Army WW2 
portable gas cylinders were around 19” high and 8 ¼” in diameter and two could be carried on a mans back by means of two metal hooks. The valve could either be
manually or electrically.

A simple mortar-like weapon that could throw large containers filled with incendiary or toxic chemicals. It was created by the British army officer Captain William H. Livens in 
WW1. The projectors were part buried in the earth for support, and had little accuracy.

Unlike artillery, mortars are high angle weapons better able to penetrate trenches. The standard US Army WW2 Chemical mortar had a calibre of 4.2”, chemical mortar 
battalions attached to U.S. Infantry divisions were also called the "Four-deucers". They were readily transportable to support infantry with the help of a hand cart or vehicle 
trailer, and could fire gas, smoke or HE projectiles. For amphibious operations chemical mortars were either mounted on a landing craft, or carried in jeep and trailer.

The US Army in WW2 developed chemical shells to use from field guns and howitzers. To contaminate a given area with the same weight of chemical a larger number
shells from a smaller calibre weapon were more effective than a smaller number from a high calibre weapon, in creating effective dispersal.

These were developed to contaminate ground being vacated in retreat with Mustard gas.

Used for screening, candles lit, grenades
thrown, smoke pots were larger devices. Tear gas grenades were produced as well as smoke screening grenades. Tanks were often 
equipped with smoke generators, the simplest injecting oil into the exhaust.

The US Army in WW2 was equipped with a portable one man flamethrower that will throw flame around 55 yards. Powered by diesel oil, pressure from compressed nitrogen 
and a small tube of propane to provide ignition. A larger version is fitted to tanks. Their main application was on fixed emplacements (when the flamethrower team can get 
close enough!) where the flame can fill enclosed spaces.

The use of aircraft to spread chemical weapons expanded their threat to a much wider area. Deployment could be by
bombs, or sprayed from an aircraft. Incendiary bombs 
also found much use in WW2. Generally smaller size bombs were used than for high explosive, in the hope that one would land on something combustible.




Much effort was made to protect troops from the possible use of gas. The CC-2 anti-gas paste used to treat the uniforms to make them less permeable to gas resulted in 
greasy and foul-smelling clothing that many of the men were forced to wear for many weeks after the invasion. Cuffs and collars were made so that they could be made 
tightly fitting, shirts were equipped with an extra flap behind the front. An impervious cellophane cover was issued to protect against blister gases sprayed by aircraft and two 
were contained in the Lightweight service gas mask bag. These also contained an Anti Dim stick used to try to prevent mask lenses fogging. Ointments were provided which 
reduced injury after exposure to blister gases.

Various gas masks were provided. Generally the filters contained charcoal to absorb some gases, and soda lime to react with gases like Phosgene which charcoal doesn’t hold 
so well, and a fine filter to absorb smokes. The US WW1 mask had a facepiece, giving one seal before the eyes, but then a noseclip and separate mouthpiece giving a 
second seal before the lungs. Unfortunately these took time to put on and were uncomfortable so one piece facemasks were developed. There is an excellent guide to gas 
masks at, but briefly, the ones that infantry might be issued within the years that we attempt to portray -

The M2 Service Gas Mask, with a separate canister held in a large kidney shaped bag normally lettered MIVA1 and 'ARMY SERVICE GAS MASK', which was carried on the 
side were current from 1940. Although the first US troops that landed in the UK were issued with these they were replaced by the time of most of the impressions that we 
do. There are many of these bags around that have had one strap removed and are re-labelled ‘Training Use’.

The M3 (1942) and M4 (1944) Lightweight Service Gas Mask. This had a smaller canister as technology of filters had improved. The bag is different being smaller 
and  rectangular, normally lettered with the US Army Chemical warfare symbol and lettered 'ARMY LIGHTWEIGHT SERVICE MASK'. These were issued in tan or OD, with a 
shoulder strap and waist strap to allow them to be carried normally on the left hip, opening at top. Frequently the waist strap has been cut off. This is the bag we should be 
carrying for most events, and although a reproduction has been on the market, originals can be seen from around £30.

The M5 Assault Mask was issued to first wave D Day troops, and with an integral canister was maybe a bit more lightweight, but perhaps not with the same capacity as 
those with a separate canister. Its M7 rubber bag isn't just somewhere dry for your sarnies, but was also a flotation device. This bag was carried on the front, opening to the 
top, with straps to cross behind the back, although this position wasn't that popular as it made crawling and getting close to the ground more difficult.

Effective training in the fitting of, and working while wearing a gas mask was important, so the mask could be quickly and effectively deployed, and hinder the user to a 
minimum while he was wearing it. Training was also provided into how to recognise gases by their sense of smell, and their concentrations by smell. Arm brassards, made of 
a chemically impregnated brown wax like paper were provided that fastened to the shoulder. They would turn red if exposed to mustard gas, which in low and still dangerous 
concentrations was difficult to smell. At the time the book was written it was thought that this paper would take the form of an arm band, and maybe also be used as paper 
ground detectors, and as a painted area on a vehicle.

Other variations of gas mask existed for use in training, by non combatants, some with a diaphragm to allow speech, some to allow better vision, and others even for dogs 
and horses.

Chemical defense squads were trained, these might carry chemicals such as brush cutting tools that would be used to clear vegetation contaminated with a persistent agent 
such as mustard gas (a liquid remember). They might also carry chloride of lime (bleach) which should render Mustard gas inert, it might be used to treat troops’ boots for 
instance after passing through a contaminated area. They also help to locate and sign gassed areas.

Gas proof shelters were also developed.


Each different chemical agent requires different treatment. Early first aid is as beneficial as it is to other injuries, so generally the following first aid was recommended.

1.        Remove the casualty to an area free from gas contamination, preferably in the open air.
2.        Remove any contaminated clothing, and replace with clean clothes or blankets, loosen any uncontaminated clothing.
3.        Put the patient to rest in a comfortable position, lying down or propped up.
4.        Apply warmth to the body and if possible keep in fresh air.
5.        Neutralise the chemical, wash surfaces with soap and water to remove the chemical. Send for an ambulance, litter or other transportation to convey the patient to a 
hospital or aid station where he can receive proper attention.
6.        Keep the patient quiet, and do not allow him to move unnecessarily.
7.        If the patient has been burned by phosphorus keep the burned areas covered with water.

There are some specifics given the different types of gas. For choking gases and lung irritants like Phosgene the patient will suffer oxygen starvation so if oxygen is available 
that would be beneficial. Otherwise keep the patient quiet and still to minimise oxygen use. With blister gases like Mustard gas the gas slowly penetrated the skin and destroys 
cells in the process, causing burns, blistering and reddening of the skin. It can do this in small concentrations that cannot be smelt, and can destroy the sense of smell. Oil 
based products like gasoline will wash off mustard gas splashes better than soap and water, bleach is also effective at neutralising it.

So, after all that, has anyone got a 4.2” Chemical Mortar?

Article written by Pfc. Harvey Coppock


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