THREE new and powerful weapons of warfare were developed in the World War -- aëroplanes, gas and submarines. It is fortunate for the world that two of these -- aëroplanes and gas -- are bound up with the development of the industries of the world. It is axiomatic that every effort should be made to prevent war; but if war cannot be prevented, then it is very much better for the world that when it comes it should be fought with weapons that have not required an immense outlay of funds during years of peace. Mine fields, submarines and aircraft can now aid in giving protection to harbors, with the result that expensive coastal fortifications have become less necessary. Surprise attacks become more difficult, and modern transportation facilities enable both armies and armaments to be shifted rapidly to meet any new attack. In many cases the influence of local interests is the only factor preventing the closing of navy yards, fortifications and army posts no longer really needed for defensive purposes. If individuals and statesmen desire disarmament, and are willing to examine the facts carefully, then material reduction of expensive armaments can probably be secured without sacrifice of national security.

In order that our conclusions regarding chemical warfare may be sane, we must study the facts disclosed by experience.

During the World War a total of about 100,000 tons of gas was used by the various nations involved. The gas casualties produced have been estimated at 534,000 for France, Great Britain, the United States, Italy and Germany, and of those casualties approximately 4.2 percent resulted in death. As regards Russia the facts are very uncertain. Her troops were poorly protected against gas, however, and suffered heavily; the gas casualties in the Russian armies have been estimated at 475,000, of which 11.7 percent resulted in death.

Many different chemicals were used. These can be roughly divided, according to the effect produced, into four classes.

Lachrymatory compounds, commonly known as tear gases, force the closing of the eyes. Gas masks afford efficient protection, but a man without a mask is helpless. Effective tear gases are known which produce no casualties and no deaths. Such gases are efficient agents with which to control mobs or for use against an army without masks.[i]

Toxic smokes in exceedingly low concentrations cause severe irritation of the mucous membranes of the nasal passages and throat, the effect being much like that produced by red pepper. A very efficient mask is required for protection. Some casualties are caused and a few deaths. During the war the Germans manufactured about 14 million "Blue Cross" toxic smoke shell, and expected to secure great results because of the ineffective masks then in use by the Allies. Fortunately these shell, due to the manner of dispersion of the toxic smoke, were almost a total failure in so far as their gas content was concerned, though of course the heavy explosive charge which they carried was effective.

Mustard gas was, and is, the most efficient warfare gas known. Probably 12,000 tons of mustard gas were used during the World War and caused in the neighborhood of 350,000 casualties among the French, British, Americans and Germans. Of these casualties about 2.5 percent died. The gas mask provides protection for the eyes and lungs, but the gas or liquid penetrates the clothing and produces skin burns of a nature very hard to heal. At the time of exposure no pain is produced and no discomfort, so that it is exceedingly difficult to enforce wearing of masks. Mustard gas is persistent, and an area heavily treated with it may be untenable for two weeks or even longer.

The phosgene and chloropicrin type of gas produces a high rate of deaths in proportion to casualties. An unprotected army can be practically annihilated. Gas masks afford efficient protection and during the World War the importance of these gases decreased as the masks improved. Three cloud gas attacks against the Russians resulted in total casualties of 140 officers and 21,000 men dead and disabled. Probably none of these attacks lasted more than twenty minutes.

The total number of special gas troops in actual service at the front at any one time was very small, amounting to only about 17,170 men for the armies of France, Great Britain, the United States and Germany. The same nations used nearly 60 million gas shell, a figure representing probably between 5 and 10 percent of the total amount of shell which they used.

These facts enable us to draw some important conclusions. Gas cannot displace the older weapons. At the same time, the use of gas results in a large increase in casualties, and no one who understands the facts would dare send into the field an army which is unprotected against gas, relying for its protection upon a treaty signed years before the war began.

Moreover, we may question whether it is wise for any nation to agree that in time of national danger gas shall be discarded and that a more expensive weapon, and one in fact more brutal, shall be maintained in its place. A nation at war thinks itself in the right and is struggling for its life. Is there any sound reason why it should not use gas as a means of defense?

In reality -- the propaganda against it notwithstanding -- gas is the most humane weapon which exists today for use in actual warfare. More than 24 percent of the total American battle casualties resulted in death. Only 2 percent of the American gas casualties resulted in death. In the British Army, of all gas casualties only 3.3 percent died. The Surgeon General's report for 1920 showed conclusively that gassing does not increase tuberculosis in after years and that permanent injury of any kind from gas is comparatively rare. Gas does not mutilate the body, and it seldom causes extreme pain -- usually no pain whatever at the time it is breathed. Later on, in the hospital, a seriously gassed case can probably best be compared to a case of pneumonia. The first gas used in the war, chlorine, was extremely irritating and painful. The change to less painful chemical agents was not due to any humanitarian consideration. It was merely found that a gas which poisons without pain is far more effective, for the pain warns of danger and the soldier puts on his mask.

No attempt is being made here to argue that chemical warfare is humane. There is little humanity in any sort of actual combat. The facts are stated only to show that gas cannot be barred as a weapon of war on the ground that it is barbarous. There are antiaircraft installations that fire one thousand rounds per minute. Would it not seem a little absurd for the nations of the world to rule that the aviator could not drop tear gas to confuse the aim of his humanitarian opponent?

If we were to stop with the foregoing statement as to the relative inhumanity of gas and other weapons of war an injustice would be done to gas warfare, for there is a further important difference between them -- gas warfare can be made humane if the nation using it desires; other weapons cannot. Once the bullet or the shell has been started on its course all control over it is gone. There is no way of tempering the injury done. Whoever stands in the way will suffer mutilation and possible death. Gas is a weapon the effect of which can be controlled. Tear gas can be used to disperse a mob with the certainty that no one will be injured. If the tear gas is not sufficiently effective then a toxic smoke can be used. If the opposing force is so well trained and protected that these two gases are not sufficient, then it is not a mob but an organized army. Mustard gas may even then accomplish the purpose with a relatively small loss of life. Perhaps the time will come when it will be considered barbarous to use rifles, machine guns and explosives against a mob, or against some unorganized or uncivilized nation, when the situation could be controlled by the use of gas without loss of life. These facts make it improbable that any general agreement for the complete abolishment of gas warfare will ever be reached.

A nation fighting on the defensive generally fights at home. The use of chemicals, aëroplanes and submarines tends toward equalizing fighting ability among civilized nations. They are relatively cheap weapons; the raw materials required are abundant; and no large number of fighting men are required. For a variety of reasons, moreover, as the distance from a secure base increases there is a decrease in the possibility of using these weapons effectively. The diminution of the power to fight successfully at a distance seems likely to tend strongly towards peace among the nations. Thus it is possible to prophesy that the new and powerful weapons of war made possible by science may be a gain to the world.

Gas warfare is particularly powerful as a defensive weapon. This fact arises primarily because mustard and similar gases can be used to prevent the occupation of the homeland by a foreign foe. They also can be used by a retreating army, but their use by an army on the offensive would block that army's own advance.

These considerations require most careful attention at the hands of those who are dealing with the vexed question of arms limitation. If gas warfare were outlawed, a nation on the defensive would in all probability be the heaviest sufferer from such limitation in time of war. Moreover, any treaty requiring the signatories to array themselves against a nation using gas in warfare would be dangerous, for such a provision might easily require the signatories to join against a nation using gas only as a means of defense against some aggressor. No treaty should forbid a nation the right to use any weapon whatever within its own territory.

Is chemical warfare a menace to civilization? Terrifying pictures have been drawn of possible uses of gas against cities. It has been stated that twelve large bombs of Lewisite could annihilate the population of a city the size of Chicago or Berlin. As a matter of fact, Lewisite is not quite twice as toxic as mustard gas and is not today considered to be nearly so effective a warfare agent. This is because Lewisite is destroyed by moisture or by rain, and Lewisite vapor does not penetrate clothing to the same extent that mustard gas does. During the World War one ton of mustard gas caused on the average about thirty casualties. If the inhabitants showed proper care, twelve large gas bombs would probably injure few people more than a hundred yards distant from their bursts, while many close at hand could escape without any injury whatever. So let us temper imagination with reason.

The power of all chemical warfare gases to injure depends upon two entirely separate and distinct factors. One is the concentration of the gas in the air, and the other is the time of exposure. The injury is proportional to the product of the concentration and the time of exposure.

Warfare gases with high boiling points (low vapor pressure) cannot be obtained in the air in high concentrations, for according to well-established laws high concentrations of such gases condense out immediately and deposit as a liquid, which falls to the ground and evaporates slowly. Both mustard gas and Lewisite belong to this type of gas. The average mustard gas casualty reported to the First Aid Station about eight hours after exposure. Immediate danger with these gases arises only from the liquid or close to the shell or bomb burst.

If a volatile gas such as phosgene or hydrocyanic acid were used in an attack upon a city, high concentrations from a chemical warfare standpoint could be produced, not indeed by a few bombs, but by the use of many tons of gas. A gas concentration of only one part by weight in ten thousand parts by weight of air, over an area five miles by five miles, to a depth of thirty feet, would require eighty tons of gas. Gas in this concentration would be fatal if breathed continuously by an unprotected man for about an hour. Many immediate fatalities would indeed result and there is no intention of minimizing the horror of such an attack. But the bulk of the population could save themselves by going at the first intimation of danger into any ordinarily tight room and closing the doors, windows and ventilators, for a volatile gas is blown away by the wind and even a four-mile-an-hour wind takes the gas away very quickly and dissipates it into the upper regions of the air.

Certain and complete evacuation of the civilian population of a city could be compelled by the use of tear gas, without the production of any casualties. There is no military necessity for the use of lethal gas against civilian populations, and those who are tempted to make such use of it will probably be dissuaded by the fear of retaliation and the fear of the condemnation of all right-thinking and civilized peoples. As Professor Nolf, President of the Belgian Red Cross, said at the opening of the International Congress of the Red Cross at Brussels in January 1928: "I believe it my duty to declare that the principal safeguard of civilian populations appears to me always to be that primordial rule that the operations of war between civilized peoples must be limited to the armed forces alone. If in the future a belligerent nation breaks this rule and attacks the population of defenseless cities back of the front, and submits them to the horrors of death by asphyxiating gases, it deliberately places itself under the ban of civilized peoples and exposes itself to the harshest and most justifiable reprisals."

Nevertheless we should consider whether it is possible to take effective steps to limit the manufacture of lethal gas and its use in war. Certain technical facts must first of all be understood. Table salt, water, coal, sulphur and starch or sugar are the only raw materials needed for the production of two of the most powerful war gases. Add to these lime, phosphate rock, arsenic ores, bromides and bauxite, and you have almost completed the list of materials needed for the manufacture of chemical warfare agents. The list should also include titanium and zinc compounds, which are used in the production of smoke screens. All of these raw materials find numerous uses in everyday commerce. To supervise or limit their production or sale is obviously impossible.

In the process of manufacturing the actual gas a number of so-called "intermediates" are produced. The list of intermediates is rather long, but the most important will be mentioned here because it has been proposed to limit or supervise the production of such intermediates "for use in war." The list includes chlorine, sulphuric acid, hydrochloric acid, caustic soda, benzol, alcohol, acetic acid, acetone, calcium carbide, bleaching powder, aluminium chloride, sodium nitrate, sodium cyanide, chlorhydrin, diphenylamine, thiodiglycol, sulphur monochloride and arsenic trichloride. Every compound mentioned except the last three is an important industrial compound and is in large everyday use. No industrial expert would consider it remotely possible to control their manufacture or sale. The last three compounds are, or may be, used in the manufacture of mustard gas and Lewisite; but no gain would result from an agreement to regulate their manufacture.

The whole situation is well illustrated by the history of mustard gas. This compound had been known for years before the war, but large-scale manufacture was considered impossible until the Germans produced it from chlorhydrin, which they used in making indigo. The Allies had no supply of chlorhydrin and only after strenuous effort lasting a year did they succeed in the manufacture of mustard gas. Two new processes were found; neither of them required chlorhydrin. Thiodiglycol and sulphur monochloride may be used in the manufacture of mustard gas but they are not necessary. Arsenic trichloride is so easily manufactured that regulation of its production in time of peace would have no effect on the supply available in time of war.

After the war, an inter-Allied commission of chemists visited Germany to learn her secret processes for the manufacture of chemical warfare agents; they were shown the factories, but they learned almost nothing new. The factories were the same factories that for years had manufactured harmless products, such as dyes, perfumes and medicines. "It took forty years and more to develop these factories. Yet forty days saw many of their plants producing huge tonnages of poison gas, and as many hours were sufficient for others." Whether a chemical factory is to turn out beneficial medicines or death-dealing poisons depends upon the will of the operator. Generally speaking, the same retorts, filters, stills, centrifugals, boilers and machinery are as necessary and as useful for the one as for the other, and almost the same raw materials. In fact, the task of producing containers such as shell and bombs for use with gas would in all probability cause more delay in preparing for extensive chemical warfare operations than would the task of adapting chemical factories to the manufacture of war gases.

If in writing regulations for the manufacture of chemical warfare agents and intermediates we insert the words "for use in war," how could we discover the use which is really intended? The task would be hopeless. Often the manufacturer does not know who his customer will be and often he could only guess at the use to which the product is to be put.

This whole technical discussion is rendered almost useless by the fact that nations do not in the least care to manufacture and store chemical warfare agents in time of peace. Storage is troublesome and expensive; and it is easy enough to arrange to manufacture them beginning with the date of mobilization. Any nation with a well-developed chemical industry possesses ipso facto the means to manufacture chemical warfare agents. The size and character of the factories will be determined by the extent and nature of the nation's industries and not by treaty. Statesmen may decree that the product of these factories shall not be used in war, but they cannot diminish the size or equipment of the factories themselves. In other words, neither statesmen nor treaties can limit the real weapon -- the power to manufacture gas.

Nor is it possible by abolishing chemical warfare to limit research for new poisonous compounds. They are a necessity of modern civilization. They play a necessary part in the development of insecticides, fungicides, germicides, disinfectants, preservatives, fumigants and medicinals. It has been estimated that the destruction caused by insect and animal pests in the United States reaches the astounding total of more than two billion dollars a year. The bubonic plague in India alone cost 8,000,000 lives in the first ten years of this century. Eliminate the rat, mosquito, flea and louse, and such diseases as malaria, bubonic plague, yellow fever and typhus would disappear from the face of the earth. It is certain that the death toll inflicted by these pests has far exceeded that of all the wars of all the centuries. Poisons form the chief weapons used in combating them, and we may therefore conclude that research upon poisonous compounds will certainly continue, and that it is essential that it should continue. Why fear increasing knowledge? It brings new powers as well as new responsibilities.

Efforts to agree to limit peace-time expenditures for chemical armament seem futile. For the fiscal year 1931 the total appropriation for the military establishment of the United States was $341,050,664, of which sum the Chemical Warfare Service's allotment was $1,295,215. Thus only 0.38 percent of the total appropriation of the army was given by special appropriation to the Chemical Warfare Service. During the World War 19.39 percent of the total casualties produced in the American army were gas casualties. The appropriations for chemical warfare made throughout the world today are probably actually insufficient to provide adequate protection for the armed forces now maintained by the nations, and therefore could not wisely be subjected to further limitation.

Certain clauses in the Treaty of Washington and the Geneva Protocol are purposely worded so as to prevent the use of tear gas. But since it is now generally recognized that tear gas is a humane weapon, and can be effectively used to control mobs or an enemy not equipped with gas masks, it has been suggested that the term "poisonous gases" be substituted, apparently with the idea of permitting the use of tear gas. At this point it is necessary to make one of those statements which appear so contradictory to readers who are not familiar with chemistry. Most tear gas compounds are in themselves very toxic and poisonous. The most effective and harmless tear gas known is probably equally as poisonous, weight for weight, as phosgene, one of the most deadly of warfare compounds. The fact that the tear gas never produces fatalities or serious casualties is due to its physical properties, which are such that only very low concentrations can be obtained in the air under field conditions of use. These low concentrations are irritating to the eyes, but do not cause serious injury.

There is an old argument that any treaty which forbade the use of gas, and which would be observed and could be enforced, should be extended to other weapons, with the result that war itself would be prevented. Without answering this argument, which has some merit, the writer suggests that a treaty attempting solely to limit the use of gas should, if adopted, be worded somewhat as follows: "The signatory powers bind themselves not to use beyond the limits of their own territory gases or other chemical agents capable of producing fatalities in the concentrations used." This would permit the use of tear gases and also would allow a nation to use any chemical warfare agent whatever within its own territory. The use of chemicals as a means of defense would not be prohibited. And since no nation would use gas in a way to injure its own non-combatant population, a provision so worded would protect civilian populations against gas to the extent that such protection can be afforded by treaty.

[i] Some lethal gases also produce lachrymation. In this article the term "tear gas" refers to gases which will not poison in the field concentrations used. The lethal tear gases are classified with the phosgene-chloropicrin gases.

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  • JAMES E. MILLS, Professor of Chemistry, University of South Carolina; Chairman of the Division of Chemistry and Chemical Technology, National Research Council
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