Chemical Warfare Agents

CHEMICAL WARFARE AGENTS (O. V.). Contents: I. Poisonous substances, their characteristics and military application............. 602 II. Pharmacology of poisonous substances. . . 611 III. General tasks and principles of chemical defense ......................620 Chemical warfare agents (O. V.) are chemical substances used as weapons. Since most of them are used in the form of gas, vapor, or mist, they are sometimes called "gases" and chemical warfare is called "gas warfare." The French call O. V. "gaz de combat" (combat gases), the Germans call them "chemische Kampf-stoffe" (combat chemical substances), and the English and Americans call them "toxic gases" or "poisonous gases." I. Poisonous substances, their characteristics and military application. The idea of using O. V. as a combat weapon belongs to ancient times. In descriptions of ancient wars, there are references to the use of smoke to drive the enemy out of fortifications by burning sulfur, arsenic, and resin, and the use of projectiles with chemical fillings. The so-called "Greek fire" consisted of resin, oil, sulfur, and quicklime. In the Middle Ages, a foul-smelling oil made from a mixture of turpentine, sulfur, asa foetida (stinking gum), feces, and blood was sometimes used during the siege of fortresses. Glauber proposed making chemical grenades. During the Napoleonic Wars, English chemists proposed using projectiles with hydrocyanic acid, and during the Crimean War, projectiles with arsenic compounds and the use of sulfur dioxide smoke. During the Franco-Prussian War, the possibility of using veratrine in projectiles was discussed. In 1899, the Hague Conference adopted a resolution not to use suffocating and poisonous gases in projectiles. The U.S.A., however, refused to sign this agreement, arguing that from a humanitarian point of view there is no difference between gas warfare and the sinking of ships by mines. Thus, chemical warfare was already on the agenda at the end of the 19th century, and military historians, in order to justify the violation of the convention in the imperialist war, are only arguing about which state first used O. V. during this war. In the imperialist war, for the first time in human history, O. V. received extensive and systematic military application, which was a logical consequence of the progress of engineering technology and the development of the chemical industry. The fortifications being built became so powerful that even heavy artillery was sometimes unable to overcome them. O. V., however, in the form of gases and vapors or smokes and mists, easily penetrate everywhere with the air, and depending on the concentration, they put people out of action or quickly kill them. Chemistry knows many substances with toxic properties, but only those O. V. that satisfy the following requirements are suitable for use in war: 1) toxicity even in small concentrations must be such that soldiers are put out of action; 2) the substance must not decompose during storage and must not act on the shell of the projectile or the cylinder in which it is contained; 3) the density of the substance must be large enough so that there is no rapid diffusion and evaporation upward; however, the vapor pressure must be large enough so that their concentration does not fall below the toxic level; 4) the substance should be, if possible, odorless, and its recognition should be difficult in order to catch the enemy by surprise; 5) the substance should quickly exhaust the enemy's gas masks; 6) the substance should be difficult to decontaminate (neutralize); 7) the production of the poisonous substance should not present great difficulties, and the raw materials or semi-finished products should be available in sufficient quantity to ensure production. The beginning of chemical warfare is considered to be April 22, 1915, when the Germans released gaseous chlorine from cylinders on the French front. In reality, however, the Germans had already used projectiles with tear gases in the fall of 1914; in addition, during this period, part of the German shrapnel had a filling with red phosphorus to prolong the healing period of wounds. Due to complete surprise and lack of protective means (gas masks, etc.), the front was broken through for several kilometers, and about 15,000 people were affected by the gas, of whom 5,000 died. Chlorine satisfied the above requirements for O. V. only in terms of toxicity, density, and ease of production, but its recognition and protection against it proved to be quite easy. Even a wet gas mask (with hyposulfite and soda) can protect against chlorine poisoning under field concentrations. this prompted the Germans to seek new O. V. Until the end of the war, the chemical initiative was in their hands. Just as the increase in armor power went in parallel with the increase in projectile power, so during the imperialist war there was a continuous struggle between gas and gas mask. The exceptionally wide development of chemical science and industry in Germany and its chemical monopoly allowed Germany to use O. V. of such a nature in combat purposes, which complicated the enemy's gas mask defense. In addition, Germany could count on the fact that the enemy would not have time to establish rapid production of O. V. due to the lack of developed chemical industry. Indeed, the Allied countries could only compete with Germany in the use of chemical weapons by 1918. When protection against chlorine was found, the Germans turned to new O. V. - After suffocating gases such as chlorine and phosgene, liquids and solids with tear-causing, blistering, and sneezing properties were used. Instead of releasing gases from cylinders, the Germans turned to throwing chemical bombs from gasometers and using chemical artillery projectiles. Protection became more complicated: instead of simple gauze bandages soaked with hyposulfite and soda, it was necessary to construct polyvalent dry gas masks, i.e. boxes filled with activated charcoal, special chemical mixtures, and antidust filters from felt, cotton, etc. There arose a need to protect the skin from blistering substances by means of special diving-type suits. If the war had continued, it might have given new chemical surprises. For example, Lefebur considers it possible to invent O. V. that selectively act on the fluid of the semicircular canals of the ear in order to cause loss of balance. To ensure the widespread use of O. V. for military purposes, a special military chemical organization is necessary, involving scientists, chemists, engineers, and doctors in its work. In Germany, the "Kaiser Wilhelm Institute" and large research laboratories of the Chemical Trust were at the head of military chemical research activities. There were military chemical schools in Berlin and Leverkusen. Haber and Nernst participated in this work. In France, the military chemical service in its scientific research activities relied on the municipal Paris laboratory headed by Klinge, and laboratories of higher educational institutions (Prof. Grignard, Moreau, Venson, Bertrand, etc.). In England, a gas service administration was created; scientists from the Chemical Society of London (Ramsay, Rayleigh, etc.) participated in the military chemical organization. In Italy, scientists Paterno and Villavecchia were involved in military chemical work. In the U.S.A., military chemical affairs were first organized at the Bureau of Mines, and then a special service was created with the famous Edgewood Arsenal and a network of chemical plants. In Russia during the war, the Commission for Suffocating Agents (U. S.) was first organized, and then the Chemical Committee under the Main Artillery Administration, under the chairmanship of Academician and Professor of the Artillery Academy V. N. Ipatiev. The committee included scientists, chemists, physicists, pharmacologists, doctors, engineers (Kurnakov, Zelinsky, Shaternikov, Spitalny, Chugaev, Likhachev, Khlopin, and others). The Chemical Committee contributed to the development of the chemical industry in Russia, supplied the army with chemical means of struggle and protection in contact with the Military-Industrial Committee and the All-Russian Zemstvo Union. O. V. can be classified from a physiological, chemical, and tactical point of view. From a physiological point of view, the following are distinguished: 1) suffocating, 2) poisonous, 3) tear-causing, 4) blistering, 5) sneezing O. V. Some O. V. can belong to several categories, since this classification is not entirely accurate. However, attempts at chemical classification have also not been successful to this day. One such classification was proposed by Chugaev: 1st group of O. V. - chlorine and bromine; 2nd group - acid chlorides (phosgene, sulfuryl chloride, etc.); 3rd group - derivatives of chlorine and bromine that are not affected by water (benzyl bromide, chloropicrin), and halogen-substituted ethers, ketones, etc.; 4th group - substances not containing halogens. From a tactical point of view, O. V. are divided into categories: 1) short-lived (volatile or subject to decomposition from moisture, heat, soil, etc., for example, phosgene), and 2) persistent, long-acting, such as, for example, mustard gas. The first substances are used, mainly, in cases where, following a chemical attack, the attacking troops intend to occupy the corresponding area. Substances of the 2nd category are useful for striking flanks or areas of rear reserves.

(See Table No. 1 on pp. 607-610.) There are 4 known methods of applying C.W.: 1) gas cylinder, 2) gas mortar, 3) artillery, and 4) bombing from airplanes. 1. Gas cylinder attack. For this purpose, chlorine and phosgene are suitable, sometimes with admixtures of liquid substances (tin tetrachloride, bromine, chloropicrin). Gas is released from cylinders - thick-walled steel cylinders holding from 20 to 60 kg of liquid chlorine. 3 kg of liquid chlorine can give about 1 cubic meter of gaseous chlorine. The cylinders have a siphon tube running from the bottom of the cylinder to the valve. Through this tube, the liquefied gas is ejected when the valve is opened. Usually, additional pressure is introduced into the cylinders by pumping air up to 25 atmospheres for more energetic ejection of the liquefied gas. Cylinders are connected into batteries by means of lead tubes, from which go discharge hoses with disk sprayers. To create a combat concentration (about 1:1,000 by volume), 1-2 cylinders with 40 kg of chlorine per linear meter of front are required, i.e., from 40 to 80 tons of chlorine per kilometer. In the January 1917 attack, the Germans released about 18,500 cylinders on a French front 97½ km long. Under favorable meteorological conditions (wind speed 2-3 m per second, early morning when there are no ascending currents under the influence of solar heat, appropriate terrain relief, etc.), the gas cloud can poison the area for 15-20 km from the line of the cylinders. The height of the wave is usually about 5-6 m. During the war, the gas cylinder method was significantly improved; by the end of the war, portable small cylinders were already being used, a system of crank keys was developed for simultaneous release of gases from a series of cylinders, and special mufflers were invented to destroy the hissing noise when gas escapes from the cylinder. The main disadvantage of the method is dependence on meteorological conditions, the bulkiness of installations on the forward position under enemy fire, and the inability to use liquid and solid C.W. 2. Gas mortar attack. The gas mortar was first introduced by the English. It is a steel tube about 1.2 m long with a wall thickness of about 1 cm and an internal diameter of 20 cm. One end of the tube is closed and rounded. The charge and projectile are separate. The igniter of the charge has a thin platinum wire connecting electrical wires, which come out of the muzzle of the gas mortar. The projectile is made in the type of a gas cylinder. The weight of an empty projectile is about 12 kg; the weight of C.W. is approximately the same. Gas mortars are installed in narrow trenches at an angle of 45°, connected in groups of 20 to 100 pieces. Such a battery explodes simultaneously with the help of an electric machine. The English fired a salvo at once from a battery of 4,500 gas mortars. The range of smooth-bore gas mortars reached 1,500 m, and of rifled ones up to 3 km. Gas mortars allowed any C.W. to be thrown; the dependence of the success of the attack on meteorological conditions is less compared to the cylinder method, a high concentration of C.W. on certain sections of the front is created more easily. In gas mortar projectiles, phosgene, diphosgene, chloropicrin, mustard gas, etc. are used primarily. 3. Artillery firing with chemical projectiles has great advantages over the two methods mentioned. It does not depend on meteorological conditions and allows for the creation of a poisoned atmosphere within the range of the artillery. In chemical projectiles, C.W. are placed either directly in the projectile if the C.W. does not act on metal, or enclosed in a glass or lead casing. The tube and primer cup are attached with mastic from magnesium oxychloride. In German chemical projectiles, they were marked with colored crosses - green, yellow and blue crosses; the first contained substances of volatile type (phosgene, diphosgene, chloropicrin), the second contained C.W. of prolonged action (mustard gas), and the third contained arsines (dichloroethylarsine and diphenylcyanarsine). According to German calculations, about 12,000 shells of 77 mm caliber were required per 1 sq. km, i.e., about 12 tons of C.W. In the summer of 1918, the number of chemical shells in German artillery parks reached 80% of the total number of shells (see Table No. 2 on pp. 611-612). 4. The use of chemical bombs from airplanes, which was already recognized during the imperialist war, in view of the extraordinary development of aviation, will probably play a very large role in future wars. Airplane bombers can lift two-ton bombs. According to calculations by American General Fries, 100 airplanes armed with two-ton mustard gas bombs can poison an area of 14 sq. km. Thus, with the range of airplanes, the deep rear can be subjected to intensive shelling with chemical bombs. In the absence of proper organization of defense, disruption can be brought into the life of political, transport, industrial and other centers important for the country. To get an idea of the importance of C.W. for modern warfare, we will cite the capacity of the Edgewood Arsenal factories in the U.S.A. by the time of the armistice in 1918. The monthly output of the factory (in tons): titanium tetrachloride - 30, tin tetrachloride - 90, yellow phosphorus - 100, mustard gas (dichlorodiethylsulfide) - 900, benzyl bromide cyanide - 90, phosgene - 1,050, chloropicrin - 1,500, chlorine (gaseous) - 1,500, chlorine (liquid) - 895. Table No. 3 (p. 611) shows the amount of C.W. produced during the imperialist war in France and Germany. - The French equipped over 13 million 75 mm chemical shells, about 4 million large-caliber chemical shells, and more than 1 million hand chemical grenades. According to American data, out of 275,000 wounded of the American army, 75,000 suffered from C.W., which indicates the importance of chemical weapons. - At present, in all countries, the chemical industry is actively developing. Characteristics of chemical warfare agents. Table No. 1. Vapor pressure in mm of mercury Chemical Other Physical name or formula state at 10° 20° 30° Effect on Most essential method of protection C.W. name or designation Chlorine Bertholite Cl₂ Gas yellow-green color 1.4 (liquid) -102° -33.6° Suffocating Hyposulfite Activated charcoal 2. Bromine Br₂ Liquid red-brown 3.1 -7° +59° Activated charcoal 3. Phosgene Collongite COCl₂ Colorless gas +8° Activated charcoal Chem. absorbent urotropine 4. Chloromethyl Palite ClCOOCH₂Cl Liquid - - +105° 3.6 5.6 - Activated charcoal chloromethyl ester of formic acid K-Stoff 5. Trichloromethyl Diphosgene or ClCOOCCl₃ - 1.65 - +128° 10.3 16.3 Activated charcoal chloromethyl ester of surpalit or formic acid Perstoff 6. Chloropicrin Akrynit CNO₂Cl₃ - 1.69 - +112° 10.8 18.9 30.5 Suffocating and lachrymatory Activated charcoal 7. Tin tetrachloride Otsnitsin SnCl₄ - - - +114° 10.3 18.6 31.3 Smoke-forming and irritating Same and anti-smoke filter 8. Phenylcarbyl- Phenylimido- C₆H₅NCCl₃ - - - +209° - - - Suffocating Activated charcoal, permang. aminochloride phosgen grains 9. Bromcyanide CNBr Crystals +52° +61.3° 63.3 (15°) 119.5 (25°) Lachrymatory and vesicant Activated charcoal 10. Dichloromethyl (CH₂Cl)₂O Liquid - - +105° - - - Suffocating Alkalis, activated charcoal methyl ether of formic acid 11. Benzyl bromide Senzyl C₆H₅CH₂Br - 1.4 - +198° 1 mm at 25° Lachrymatory Activated charcoal 12. Xylyl bromide C₆H₃(CH₃)₂CHBr - 1.4 +216° Activated charcoal 13. Ethyl iodoacetate - - +180° 0.28 0.54 0.87 Activated charcoal 14. Bromoacetone Martonite CH₃COCH₂Br - 1.63 - +136° - - - Activated charcoal 15. Bromomethylethyl- Homomartonite CH₃BrCOCH₃ - - - +145° - - - Activated charcoal ketone and CH₃COCH₂BrCH₃ - - - - - Activated charcoal 16. Dibrommethyl- CH₃COCHBr₂ - - - - - Activated charcoal ethylketone CH₃CHBr₂ - - - - - Activated charcoal 17. Acrolein CH₂CHCOH - 0.9 -88° +52° - - - Activated charcoal 18. Methyl ether of SO₂OCH₃Cl - 1.5 - +132° - - - Lachrymatory chlorosulfonic acid and irritating 19. Dimethylsulfate SO₂(OCH₃)₂ - 1.3 - +188° - - - Vesicant and irritating - Activated charcoal 20. Sulfuryl chloride SO₂Cl₂ - 1.7 - +70° - - - Suffocating Activated charcoal 21. Chlorosulfo- - 1.8 - +156° Suffocating - Activated charcoal nic acid and vesicant Chemical name Other name or designation Chemical formula Physical state 2 2. Hydrocyanic acid 23. Hydrogen sulfide 24. Diphenylchloro-arsine 25. Diphenylcyan-arsine 26. Ethyldichloro-arsine 27. Methyldichloro-arsine 28. Dichlorodiethyl-sulfide 29. Chlorinated ortho-nitrobenzyl 30. N-ethylcarbazole 31. Benzyl bromide cyanide 32. Chloroacetophenone 33. Diphenylamine-arsine 34. Chlorovinylarsines 35.

Carbon monoxide Vincentite (mixture of HCN with tin tetrachloride, arsenic trichloride and chloroform) {Blue cross, sternite, Clark II {Blue cross, sternite, Clark II Mustard gas, yellow cross, mustard gas yellow cross, Lost Camite, phenyl-Sromuxus acid nitrile Adamsite, phenarsazine hydrochloride Lewisite (C,H,),AsCl (C.H.), AsCN C,H,AsCI, CH.AsCl, (CH,C1CH,),S C.H.NO.CH.Cl C,H,N(C.H,), C,H_sCHBrCN C_tH,COCH,Cl (C,H,),NHAsCl S iCHCl: § -CHAsCl,; к '(CHC1: g,'| CH),AsCl: & (CHC1CH), co I As . CO Liquid Gas Solid substance Liquid Solid body Crystals Liquid Gas (when shells burst) [of chemical warfare agents. Table No. 1 (continued). at -13° + 43 + 31° Boiling point -13° + 26.5° -61.8° + 333° + 300° with decomposition + 156° + 133" + 217° + 69° + 190/ 15 mm + 29° + 58° + 245° + 193° - - [ + 937 26 mm 1 + 1337 j 26 mm + 155°/ 1 28 mm -207° -190° Vapor pressure in mm Hg at 10° 455 at 15° 16,500 0.02 20° 30° Effect on the human body at 50° 0.03 0.06 0.15 Poisonous zU « 5.*-' Not so The most significant method of gas mask protection Sneezing Irritating and vesicant Vesicant and poisonous Lacrimatory Weak sneezing Lacrimatory Sneezing Vesicant Asphyxiating and poisonous 19 16 | Same, permanganate grains 1919 1917 1915 1918 Not tested in battle Same Active carbon with anti-smoke filter Active carbon and permanganate grains Same and protective clothing Activated carbon Same with anti-smoke filter Same Activated carbon, permanganate grains. Hopcalite, iodine anhydride, isolated gas mask Characteristics of German chemical shells. Table M g. №№ Designation on Weight of Weight of O.V. explosive substances in g according to shells Caliber O.V. kg Green cross (ordi- 7.7 cm 1 kg nary) Diphosgene with chloropicrin 10.5 » 2 » 10 » 2 » 50 g 90 or 6 3 15 » 6 » 25 » 90 or 63 21 » 16 » Green cross 1 Armored ketones or phenylcarbaminoyl chloride Similar to simple green cross Green cross 3 Ethyldichloroarsine 1 Ethyldibromoarsine 1 10.5 cm FROM 1 KZ 750 8 TO 2 KE50g 21 » 15 kg 50 g Yellow cross Mustard gas, with addition of 20% 7.7 » 0 » 760 » carbon tetrachloride, 7.7 » 0 » 610 > chlorobenzene, nitrobenzene 10.5 » 1 » 600 » and others 10 » 13 » 15 » 1 » 145 » 4 » 500 » 15 » 3 » 600 » 15 » 3 ► 800 » 17 » 5 » 500 » 21 » 12 » 400 » 24 » 11 > 50 » Blue cross Diphenylchloroarsine or di- 7.7 » 0 » 135 » phenylcyanarsine 10.5 » 0 » 350 » 10 » 0 » 37 » 15 » 1 » 350 » 15 » 1 » 00 » 21 » 3 » 850 » Double green Diphosgene or phosgene with chlor- cross picrine 15 » 3 » 240 » Double yellow Similar to shells with simple 10.5 » - cross yellow cross (see above) 15 » 21 » 2 » 800 » Note. The charge «Green cross 2» contains phosgene, diphosgene and diphenylchloroarsine. In combat supplies of 1918 this shell was no longer present. Table M 3. Amount of O.V., produced during the world war (in tons). Substance name Chlor............ Phosgene........... Diphosgen....... . . Brominated ketones . . Chloropicrin........ Aromatic arsines . . Fatty arsines . . Phenylcarbaminoyl chloride. Mustard gas........ Vincentite......... Germany approx. 50,000 France 24,000 15,800 481 493 2,000 4,160 creation of scientific chemical institutes and experimental chemical plants. The French define the situation with the following words: «the protection of the state and chemistry are one whole, and it is necessary to advance scientific and technical research». V. Ipatiev, E. Dengin. P. Pharmacology of poisonous substances. The effect of O.V. on the organism depends on their physico-chemical properties, with the following properties being important: 1. Ability to adsorption by free surfaces, which most of the substances under consideration possess to a high degree. Due to this ability, O.V. accumulate and are retained both on the outer surface of the human and animal body, and on the surfaces of their respiratory tract. 2. Solubility in lipoids, necessary for rapid penetration of substances into the cell. In this regard, O.V. belonging to the group of non-dissociating organic compounds can be contrasted with ionizing mineral acids and salts, for which the outer layer of the living cell represents an impermeable membrane. In addition to absolute solubility in lipoids, the relative solubility (so-called, according to the theory of action of narcotics Overton - Meyer's, the distribution coefficient expressing the ratio of solubility of a given O.V. in lipoid to the solubility of the same substance in water) is also important. 3. Chemical activity of O.V., causing corresponding reactions in the body, which in turn are the cause of the pharmacological effect. In a number of O.V. this activity depends on the presence in the molecule of groups with unsaturated means.-The toxic effect may be caused or enhanced by the fact that O.V. undergoes decomposition in the body, with poisonous products being formed. Thus, many, and moreover extremely active O.V., are distinguished by their ability to hydrolyze, with one of the products being hydrogen chloride (HCl). Therefore, naturally, an attempt was made to link the toxic effect of these substances with the formation of the latter. According to this hypothesis, O.V. penetrates into the cell, undergoes hydrolysis there, and the released HCl changes the hydrogen ion tension, and thereby violates one of the essential conditions for the normal life of the cell. Although the amount of active HCl in this case is very small - significantly lower than in poisoning with hydrochloric acid or chlorine (which turns into HCl in the body), the difference between both cases lies in the fact that in the form of a dilute acid HCl cannot penetrate into the cell from outside, as has already been indicated above. It should be noted, however, that the observed toxic effect is not always easily explained by the chemical properties of O.V. There are cases when the basis of the mechanism of action of the latter is not fully elucidated (e.g., chloropicrin). Apparently, here, at least in some cases, we have to admit the specific effect of the entire O.V. molecule on the cellular molecules of the body. The effect of O.V. on the body, like any poison in general, can be local and general. The first is understood as the effect of the toxic agent at the site of its direct application. When a person is in a poisoned atmosphere, such an effect may manifest on the skin and open mucous membranes, on the respiratory tract and to a lesser extent - on the mucous membrane of the digestive tract, since O.V. is swallowed. General (otherwise resorptive) action is called the action manifested by the poison after absorption and penetration into the blood. At the same time, since the blood is carried throughout the body, all cells of the body are to some extent exposed to the action of the poison, with the final effect depending on the functions of which cells are affected by this poison. The best-known strong poisons (such as alkaloids, hydrocyanic acid and its salts, phosphorus, arsenic) are, for the most part, poisons of general action. Conversely, all typical combat O.V. are, mainly, poisons of local action. The general effect, if observed, recedes into the background. This local action manifests itself in the form of irritation, inflammation and necrosis, with the local process proceeding differently in substances of different groups; thus, in asphyxiants, the inflammatory process in the lungs is complicated by edema, in vesicants blisters form on the skin, etc. The primary process is very often complicated by a secondary one, depending on secondary infections of the affected areas. The necrobiotic products formed in tissues can also play a certain role here, similar to what happens in burns, frostbite, the action of light, etc. In some cases, the damage is limited to local phenomena that are not of serious importance for the general economy of the body, in other cases this damage (such as lung damage in asphyxiants) disrupts the most vital functions of the body to such an extent that it dies. The degree of local tissue damage by various O.V. is disproportionate to the local irritation they cause. In some cases, irritation is extremely strong, while the local toxic effect is relatively weak (lacrimators, arsine smokes); in other cases, tissue damage can occur to a certain degree unnoticed. In addition to the strength of action of O.V., the speed of action also has considerable practical importance. With some substances, the effect occurs very quickly (with HCN, lacrimators), with others, a latent period precedes the effect of action, so that the action may manifest only after some time, sometimes after the action of O.V. has ceased. In the presence of this latent period and weak immediate irritating action of O.V., unnoticed poisoning can easily occur (for example, with mustard gas). A further factor contributing to unnoticed poisoning is the ability of O.V. to cumulation. Cumulation is understood as either the material accumulation of the poison with its prolonged introduction into the body in small doses, or the accumulation of effects from these successive small doses. In the case of O.V., in most cases we are dealing with the latter phenomenon.

Thus, phosgene undoubtedly has a cumulative effect, as it immediately decomposes upon entering the organism and therefore cannot accumulate in it. For cumulative chemical warfare agents, Haber proposed the formula: W=c×t, where W is the effect, c is the concentration of the substance in mg per 1 cubic meter, and t is the time in minutes. Thus, if the toxic effect (W) for phosgene is 450 (the figure given by Laqueur and Magnus), this means that in an atmosphere containing 30 mg of phosgene per 1 cubic meter of air, the toxic effect will occur after an animal has remained in this atmosphere for 15 minutes. From the formula, it is clear that a long stay in an atmosphere with a low concentration gives the same result as a short stay in an atmosphere with a high concentration. Non-cumulative substances, which are simultaneously excreted or destroyed by the organism upon being absorbed, produce different results. With them, poisoning can only occur if the concentration of the chemical warfare agent in the atmosphere is not below a certain (and relatively high) level. The formula determining the magnitude of the toxic effect takes the following form: W=(c-e)×t, where e is the highest non-toxic concentration in mg per 1 cubic meter. When c=e, W equals zero, in other words, no poisoning occurs. According to the nature of their physiological action at the concentrations at which chemical warfare agents are used in war, they are usually divided into the following groups: 1) toxic, 2) suffocating, 3) vesicant, 4) lacrimatory, and 5) sternutatory. The toxic effect of substances in the first group depends on their general (resorptive) action; the toxic effect of all other groups depends primarily on local action. Substances of the first three groups are used in concentrations that cause poisoning, often leading to death or severe illness. The use of substances of groups 4 and 5—lacrimatory and sternutatory—is based on their irritating properties and aims only to cause irritation of the mucous membranes of the eyes and respiratory tract. - Toxic substances. These substances, which have a resorptive effect, include carbon monoxide, hydrocyanic acid, and its salts. The effect of the first depends on the binding of blood hemoglobin with the formation of carboxyhemoglobin, while that of the latter depends on the suppression of tissue respiration (see Hydrocyanic acid). Local action in poisoning with the aforementioned substances is of no importance. Among chemical warfare agents, arsines also have a resorptive effect, along with local action, which is of great importance in this case, to a lesser extent chloropicrin. - Suffocating substances. This group includes: chlorine (see), bromine, which acts relatively weakly, carbon oxychloride (COCl₂)—phosgene, chlorinated alkyl ethers of chloroformic acid, among which the trichloromethyl ether of the said acid—difosgene (see) (ClCO₂CCl₃)—deserves special attention. Some authors also include chloropicrin (CCl₃NO₂) in this group. Some of these substances—chlorine and chloropicrin—have pronounced irritating properties, while others (phosgene, difosgene) irritate much less even in lethal toxic concentrations. In this case, chlorine irritates the upper respiratory tract more strongly, while phosgene and difosgene, at sufficient concentration, act more strongly on the lungs themselves. Chloropicrin occupies an intermediate position. When inhaling chlorine and chloropicrin in strongly irritating concentrations, there is a temporary expiratory arrest of breathing, but then breathing is restored, although it remains difficult, so true reflexive suffocation never occurs. This arrest (or slowing of breathing) should be considered as a protective reaction of the body, hindering the penetration of the poisonous substance into the lungs. Such protective reactions are also bronchial spasms and expiratory arrest of breathing when the lower parts of the respiratory tract are irritated. In addition, strongly irritating gases cause a distressing cough and then shortness of breath, irritation of the eyes and vomiting (especially chloropicrin). The symptoms of poisoning with phosgene and formic acid ethers, which are more toxic but less irritating, do not appear immediately. The main toxic effect of all substances in this group, both strongly and weakly irritating, lies in the damage to the lungs with the formation of edema in them. The edema reduces the respiratory surface of the lungs, which causes shortness of breath. In addition, it causes thickening of the blood with an increase in its viscosity and creates an obstacle to the flow of blood through the pulmonary capillaries. The above conditions significantly burden the heart, as a result of which stagnation phenomena develop in the venous system. Unfavorable conditions of breathing and blood circulation cause a decrease in oxygen content in the blood and accumulation of carbon dioxide in it. Blood pressure, initially high (blue stage), then falls with the expansion of internal vessels and the outflow of blood from the surface (gray stage). In addition to edema, in the first days, phenomena of emphysema and atelectasis develop in the lungs. The edema progresses until the 2nd or 3rd day, after which, if death does not occur, resorption begins, and the first period of poisoning—asphyctic—passes into the second—pneumonic, with the development of inflammatory processes in the lungs, in which secondary infections play a significant role. The pneumonic period lasts for at least several weeks. In poisoning with substances that have irritating properties, along with damage to the lungs, inflammatory phenomena of the upper respiratory tract and eyes also appear in the first period. Among the less constant consequences of poisoning with suffocating substances should be noted thromboses and various lesions of the nervous system. Early deaths are characteristic of substances in this group: in the vast majority of cases of lethal poisoning, death occurs in the first 2-3 days. Vesicant substances. The most important substance in this group is dichlorodiethyl sulfide S(C₂H₄Cl)₂—otherwise known as mustard gas (or yperite, see Mustard gas). Also belonging to this group is lewisite, which exists in three fractions (the most important is the first—chlorovinyldichloroarsine CHCl=CHAsCl₂), discovered after the war and not tested in combat conditions. Other liquid arsines (e.g., ethyldichloroarsine C₂H₅AsCl₂), usually classified as sternutatory, can also be included in this group. Substances in this group have a pronounced effect: 1) on the skin, where in severe cases they cause an effect somewhat similar to a burn from X-rays: first, after a latent period of several hours, redness appears, and later, for example, after 15-24 hours or more, a blister forms, which then bursts, and the resulting ulcer heals very slowly; with weak exposure to vapors, the process is limited to redness with subsequent pigmentation and loss of hair in the affected area; 2) on the mucous membrane of the eyes, where irritation phenomena appear earlier than on the skin and then pass into inflammation, which tends to take a purulent, sometimes ulcerative, character; 3) on the respiratory organs, where both the upper respiratory tract, especially the larynx (edema), and the lungs are affected. The process consists of redness, passing into inflammation, which soon takes on a purulent character. False membranes form on the mucous membrane, which can block the bronchial lumen. Subsequently, purulent bronchopneumonia develops, in which secondary infections play a very important role. In general, as a rule, poisoning proceeds more slowly than with suffocating agents. Among lesions of other organs should be noted lesions of the gastrointestinal tract and (in severe poisoning) of the central nervous system, which is expressed in phenomena of depression, sometimes replaced by attacks of anxiety, as well as in nausea, vomiting, a drop in temperature and a drop in blood pressure. The resorptive effect of the chemical warfare agents under consideration plays a certain role in the origin of many of the listed symptoms, as well as in causing lethal poisoning. Unlike suffocating agents, delayed deaths up to 14 days and even a month constitute a fairly significant percentage of all lethal poisonings here. - Lacrimatory substances (lacrimators), due to their irritating effect on the eyes, become intolerable at extremely low concentrations (for example, bromobenzyl cyanide and chloroacetophenone). According to Frey, this concentration, requiring the wearing of masks, is 500-1,000 times lower than with phosgene. Frey gives the following table of the action of lacrimators: Substance name Concentration in mg per 1 liter of air causing lacrimation Cyanobromobenzyl...... Martonit.......... Ethyliodoacetone ....... Bromoacetone..... Bromoxylene..... Bromoketone.......... Chloroacetone......... 0,0003 0,0012 0,0014 0,0015 0,0018 0,0040 0,0110 0,0180 0,0190 It should be noted that some arsines belonging to the sternutatory group (adamsite, diphenylchloroarsine) also have a strong lacrimatory effect. Sternutatory substances. These include solid and liquid arsines acting in the form of smoke or mist.

The most important substances of this group are diphenylchloroarsine (C₆H₅)₂AsCl, diphenylaminochloroarsine (adamsite) (C₆H₄)₂NHAsCl and diphenylcyanoarsine (C₆H₅)₂CNAs. Symptoms of poisoning: strong irritation of the nose, pharynx, larynx and trachea with abundant nasal discharge, accompanied by sneezing, secretion of viscous saliva, vomiting, nausea and difficult breathing; irritation of the eyes with tearing; later pains in the abdomen, sometimes numbness of the limbs, which can be replaced by very severe pain. These phenomena of irritation occur after a very short latent period (minutes) and are so severe that in some cases they cause mental disorders in the poisoned person. As consequences of poisoning, dizziness, burning in the eyes, nose and throat, nausea and neuralgic pains are observed. These symptoms pass quickly, so that patients recover in 2-3 hours. Concentration limits of some irritating substances, not tolerated by humans for more than 1 minute (according to F. Flury). Irritating substances Content in 1 cubic meter Diphenylcyanoarsine ..... Paranitrophenyldichloro- 0.25 mg 1-2 » 2.5 » 5-10 cubic mm 10 » » 25 » 30 - » 35-40 » » 60 » » 70 » » 75 » » > 100 o » > 100 » > 150 » » 500 » » Phenyldichloroarsine ..... Formaldehyde........ Bromoacetone . . . .... Benzyl bromide..... Diphosgene.......... Chloroacetone......... Arsenic trichloride . . The principles of first aid and therapy for poisoning with C.W. are as follows-for all C.W.: 1. It is necessary to remove the poisoned person from the contaminated area as soon as possible. If C.W. is easily adsorbed-change clothing, linen, wash the patient; for particularly strongly adsorbed substances (mustard gas)-cut the hair. 2. When evacuating the patient, every effort should be made to spare his strength (transport in a comfortable position) in order to protect his heart. This has special significance in poisoning with suffocating agents, when breathing is unsatisfactory and the patient suffers from anoxemia-any muscular strain sharply increases oxygen consumption. 3. Inhalation of oxygen: in poisoning with carbon monoxide it promotes the faster dissociation of carboxyhemoglobin. In poisoning with suffocating and vesicant agents, when breathing is unsatisfactory, oxygen brings subjective relief and improves the course of poisoning. It is recommended to first inhale pure oxygen for up to 8 hours, then in a mixture with air 60-40% O₂. The best but expensive method is to place patients in special chambers. Nasal probe and inhalation through a mask, mouthpiece or funnel are also used. 4. Symptomatic treatment-prescription of cardiac drugs, camphor, digitalis and caffeine for heart weakness, expectorants for bronchitis. Prescription of morphine for suffocating agents-is contraindicated due to the depressed state of the respiratory center. 5. Do not overlook that with all lesions from C.W. secondary infections of the lungs, as well as skin and mucous membranes, very easily develop. Therefore, special attention must be paid to the cleanliness of the room, the air in it, the sterility of dressing material, etc.-Special measures for poisoning with substances of individual groups:- A. In poisoning with suffocating agents: 1. Bloodletting up to 500 cubic cm (can be repeated) in the blue but not gray stage, with the aim of causing blood thinning, reducing edema and easing the heart. 2. Introduction into the blood of a solution of calcium chloride 1-5-10% at the rate of 0.5-1.0 calcium chloride pro dosi up to 4.0 pro die to reduce the permeability of pulmonary capillaries and reduce edema. 3. The introduction into the blood of a hypertonic solution (25%) of glucose has also been proposed, with the aim of reducing edema. Hypertonic salt solutions, used for the same purpose, gave unfavorable results.- B. In poisoning with vesicant agents: to prevent the development of skin lesions-immediate intensive washing with solvents of the poisonous substances: for mustard gas-soapy alcohol, kerosene, gasoline, during which it is recommended to rub the affected area for half an hour, changing the washing fluid. Another method consists in the use of agents that destroy C.W.-solutions of potassium permanganate, 5% solution of NaHO. The recommended use of bleaching powder for mustard gas can itself cause irritation. The success of the use of solvents and destroyers of C.W. depends mainly on how soon after the injury the mentioned measures will be applied. Further skin lesions are treated with solutions of Da-kin's (see Antiseptics) and chloramines in the form of washes and compresses. Weak solutions of potassium permanganate and a 3.5% solution of silver nitrate have also been proposed, which not everyone considers advisable. When blisters form-incision of them, aseptic dressing and application of solutions of Da-kin's and chloramines.-C. For lacrimators, as well as for eye lesions from the vapors of vesicant or sneezing agents-irrigation of the eyes with physiological solution of NaCl, 7% solution of soda, weak solutions of Da-kin's. Further-usual ophthalmological remedies: atropine, cocaine. With ulcers-usual treatment.-D. For sneezing agents, it is especially necessary to take care of changing linen and clothing, since negligible amounts of these substances in clothing maintain the poisoning. Otherwise, treatment is symptomatic, all the more so since in the overwhelming majority of cases all phenomena pass quickly and without treatment.

A. Likhachev. General Tasks and Principles of Chemical Defense. The task of chemical defense is the rapid and as complete as possible protection from chemical warfare agents (CWA) used by the enemy. Protection from CWA must be carried out in any situation with the least possible disruption to the normal life and activities of the population, and in relation to troops—with the least possible restriction of their freedom of movement, firing, maneuver, and command. In developing methods of chemical defense, the following are considered: a) preventing the enemy from using CWA as a weapon of war, b) if a chemical attack could not be prevented and has occurred, poisoning the air, soil, bodies of water, various structures, and objects—protecting people and animals from the effects of the poisoned environment and decontaminating this environment, degassing it (see), and c) restoring the health of those affected by a chemical attack. Chemical defense can be active, when it is based on the active actions of the armed forces (active actions of troops, armed resistance of aircraft, shelling by anti-aircraft artillery, etc.), undertaken for the purpose of preventing a chemical attack as well as to reduce its effects, or passive, when the enemy does not encounter armed resistance and defensive measures are exclusively of a protective nature. In relation to the protected contingents, defensive measures are either individual, when the protection of individual persons is intended, or collective, undertaken for group protection. The objectives of chemical defense are achieved through the use of appropriate technical means and the implementation of proper organizational measures. The technical means of chemical defense are based on mechanical, physico-chemical, and biological principles. A. Among defensive means based on mechanical principles are those aimed at mechanically blocking CWA access to living organisms and other protected objects (for example, warehouses, bodies of water, etc.). For mechanically blocking access to enemy military aircraft carrying aerial bombs to threatened populated areas and other important points, special nets were used, raised with the help of balloons to a height of up to 2 km. The purposes of mechanical protection for groups of troops and the population are also served by hermetic shelters (see Gas Shelters), i.e., specially constructed or adapted rooms with a constant volume of air, protecting against the impact and fragmentation effect of shell fragments and against the dispersion of molecules, dust, smoke particles, and fog, as well as against liquid CWA. For mechanical protection of the body surface, special suits, boots, and gloves for people, and special boots for horses have been introduced into use. The principle of design of such suits is hermetic sealing to prevent mustard gas from coming into direct contact with the skin. For the purpose of mechanical protection (mainly from CWA of the mustard gas type), drinking water, food supplies, fodder, medical supply items, etc., hermetically sealed, CWA-impermeable containers, receptacles, casings, and vessels are used. For example, first aid dressing packets (individual packets) are enclosed in a metal, hermetically sealed box that opens like a sardine box. The mechanical principle is also the basis of many methods for removing CWA adsorbed in the pores of clothing, accumulated in trenches, rooms. Removal of CWA here is reduced to the mechanical displacement of CWA molecules by molecules of some neutral and harmless gas, for example, air. These are: a) ordinary ventilation of rooms and clothing, b) artificial ventilation, for example, Norton trench fans, c) fires creating air movement, d) special beaters, e) blowing clothing in special chambers with a stream of air, etc. The listed means of chemical defense, based on mechanical principles, are in many respects unsatisfactory: they are either very bulky (barrier net), or although they provide sufficient protection, at the same time create abnormal physiological conditions for existence when using them (for example, hermetic gas shelter and protective clothing), or, without neutralizing chemical warfare agents, merely drive them from one place to another. Nevertheless, mechanical methods of chemical protection have a certain practical importance in the overall system of chemical defense. B. Means of chemical defense based on physico-chemical principles are especially numerous. Among means of chemical defense based on physical principles (sound, heat, light, electricity), the following deserve attention: 1. Special devices, so-called sound detectors, designed to detect sounds generated by the movement of propellers and bearing surfaces of enemy aircraft, from tens of kilometers away from the expected attack site. The use of such devices makes it possible to prepare for defense in advance. Sound detectors are designed in two types: as large resonators and as devices that collect sound waves at a focal point. 2. Signal devices for informing the population of threatening danger, such as bells, gongs, whistles, clappers, sirens, etc., as well as devices and equipment for light, color, etc. signaling of alarm. 3. Utilization of radiant energy in the form of sunlight to accelerate the degassing of contaminated objects, heat to accelerate the evaporation of liquid CWA, etc. 4. Lighting devices, such as searchlights, designed to detect the location of enemy attacking air forces at night, and many others. Defense means based on chemical principles are primarily aimed at neutralizing CWA itself by converting it into another chemical state, harmless to living organisms. All chemical reactions of combination, exchange, decomposition, etc., leading to this goal, can be used in defense if they can be carried out with the help of substances that are inexpensive, easily obtainable, and producible. An example of a CWA neutralization reaction is the reaction of phosgene with sodium phenolate in the presence of free caustic soda [C_eH₅ONa+NaOH + + COCl₂ = C_eH₅(OH)+2NaCl + C0₂], as well as the reaction between chlorine and a solution of sodium hyposulfite. Such and similar solutions were used to moisten layers of gauze that served as wet respirators for people and animals (see Respirators). Corresponding solutions were also poured and sprayed using hydro-pumps and sprayers in rooms and trenches to neutralize CWA (see Degassing). The principle of replacing chlorine with hydrogen in the ethyl groups of mustard gas is the basis for the use of chlorine for neutralizing water, clothing, etc., poisoned with mustard gas. Chemical methods are also widely used to detect the presence of CWA in the environment; for this purpose, a number of special devices (gas detectors) have been proposed, such as Prokofiev's gas detector. This device consists of a glass tube divided into two chambers and containing reactive papers for chlorine and phosgene that change color when air containing these gases is drawn through with a rubber bulb. Americans (according to Frey) have invented special paints, enamel and oil-based, that instantly change color from yellow to dark red from the vapors of mustard gas. Special devices based on the use of gas adsorption phenomena on the surfaces of finely porous bodies should also be classified as physico-chemical defense means (see Adsorption). Such substances include, for example, wood charcoal, which is subjected to special treatment, so-called activation, to increase its adsorption capacity. For the purpose of increasing the absorbing capacity with respect to gases, especially acidic ones, a chemical absorbent in the form of grains from a mixture of: a porous body—kieselguhr, soda lime, and potassium permanganate, the latter for oxidizing organic CWA, is used. For filtering poisonous smokes and mists not absorbed by the above-mentioned absorbents, anti-smoke filters made of felt, special types of paper, etc., were constructed during the world war. Many reactions that neutralize CWA but proceed very slowly under normal conditions require an increase in the speed of these reactions through accelerators (catalysts) to ensure practical results of CWA neutralization. Such a catalyst, for example, for the conversion of carbon monoxide, CO, into carbon dioxide, C0₂, is so-called hopcalite (see)—grains of a mixture of oxides of certain metals, prepared in a special way (Mn0₂, CuO, Co₂0₃, Ag₂0). Adsorbers, chemical absorbents, and anti-smoke filters are used in filtering and purifying air poisoned with CWA and are the main component of the filling of respiratory boxes for filtering respirators, as well as filters for shelters with variable air volume, equipped in a chemical defense manner. C. Biological methods in chemical defense are used for the purpose of detecting the presence of traces of CWA.

(most often mustard gas) in the air and on objects, for which purpose, for example, the following are used as gas detectors: a) the sense of smell of specially trained people in recognizing odors (so-called "sniffers"), b) the skin or conjunctival reaction of rabbits, guinea pigs, and other experimental animals. The organization of chemical defense in wartime consists in general of: a) organizing proper reconnaissance to obtain timely information about the enemy's preparation for a chemical attack; b) establishing air observation; c) meteorological observations; d) organizing an "alarm service" in case of threatening danger; e) applying active defense means (active actions of troops, fighter squadrons, anti-aircraft artillery, etc.); f) applying camouflage of fortifications and other technical devices (such as special shelters with constant and variable air volume, special protective equipment for warehouses, water bodies, etc.); g) providing troops and the population with means of individual protection (gas masks, protective clothing, etc.); h) ensuring timely decontamination work; i) sanitary-preventive measures carried out in the form of medical-sanitary supervision over the condition and use of protective means, over the implementation of decontamination work, over the condition of food, clothing, and other items in terms of suitability for consumption that have been exposed to C.W. or are suspected in this regard, and conducting corresponding laboratory research; k) ensuring timely medical assistance to victims of C.W. When organizing medical-sanitary service for victims of C.W., health authorities must provide for: a) prompt delivery of first aid; b) possible bringing of medical assistance to the site of chemical casualties; c) sorting of victims of C.W. according to the nature and degree of poisoning; d) as prompt and careful evacuation as possible; e) preparing forward evacuation stages to receive large groups of poisoned and those suspected of poisoning simultaneously; f) providing forward evacuation stages with transportation means for victims of C.W.; g) appropriate equipment of medical aid points and medical institutions and supplying them with necessary medical and preventive means; h) establishing and maintaining the closest connection with the chemical service. In the USSR's preparation for chemical defense, alongside state bodies, Soviet public society participates widely-through the Ossoaviakhim, Red Cross and Red Crescent societies, and others, which is expressed in the following main organizational forms: a) organizing special courses on chemical defense for doctors, engineers, etc.; b) organizing circles, cells, and detachments of Ossoaviakhim, Red Cross and Red Crescent; c) disseminating relevant information on military-chemical affairs among the broad masses of the working population of the USSR by organizing lectures, reports, conversations, publishing relevant literature, and other measures aimed at involving the broad masses of the population in chemical defense work. When assessing the degree of danger of chemical weapons, one must proceed from the current situation that scientific research work on C.W., the presence of sufficiently developed corresponding types of industry in the country, the organized use of protective means, the preparedness of the personnel participating in defensive actions, and the consciousness and discipline of the population protect troops and the population from C.W. or weaken the results of a chemical attack. The general attitude of the Soviet government and Soviet public toward the use of chemical weapons for military purposes is sharply negative. This attitude was manifested in a number of international proposals by the USSR and the signing of the Geneva Protocol by the Soviet government on March 7, 1928. The Combat Charter of the Red Army states:-"Being opposed to the use of chemical means of warfare, the Workers' and Peasants' Red Army will resort to them only in the event that the bourgeois opponents fighting us use them first." However, the evasion of foreign states from giving guarantees of renunciation of the use of C.W. in wartime necessitates, in the interests of the security of the USSR, extensive anti-chemical defensive measures.