 |
| The Gas Alarm Is Sounded |
James Patton
An enduring hallmark of WWI, along with the trenches and the mud, is the large-scale use of chemical weapons, commonly called simply "gas." Although chemical warfare caused less than one percent of the total deaths, the treatment of many thousands of gassed soldiers was a significant drain on manpower. The "psy-war." or fear factor, was itself a formidable weapon. Chemical warfare was subsequently prohibited by the Geneva Protocol of 1925. Chemical warfare has been occasionally used since then but never in WWI-scale quantities. Although deployable inventories have been largely eliminated, production of some of the subject chemicals continues as they have peaceful uses—for example, phosgene is an industrial reagent, a precursor of pharmaceuticals (including some anti-cancer drugs), certain plastics, and other important organic compounds.
Several chemicals were weaponized in WWI. It began in August 1914 when France deployed gas grenades against the Germans. The Germans followed, gassing the Russians in January 1915. The agents used by the French was ethyl bromo acetate (BrCH2CO2CH2CH3 ) described as "fruity and pungent," while the Germans used xylyl bromide ( C6H4(CH3)(CH2Br)). which is described as smelling "pleasant and aromatic." Both are colorless liquids and have to be atomized. Both are lachrymatory agents ("tear gas"); they irritate the eyes and cause uncontrolled crying. Large doses can cause temporary blindness. If inhaled they can cause gasping. These symptoms usually resolve within 30 minutes after contact.
The German set up a gas warfare program, headed by future Nobel Laureate Fritz Haber (1868–1934), who had previously developed the process by which nitrates could be made from atmospheric nitrogen. Haber’s first chemical weapon was chlorine gas (Cl₂,) which was debuted in April 1915. Chlorine gas is diatomic, about two and a half times denser than air, pale green in color and with an odor which was described as a "mix of pineapple and pepper." If inhaled, it will react with moisture in the lungs to form hydrochloric acid (HCl), which will quickly lead to death. Even at lower concentrations, it can still cause coughing, vomiting, and eye irritation.
 |
| Early Depiction of Gas Attack at Second Ypres, 1915 |
Chlorine can be deadly against unprotected soldiers, and it’s estimated that over 1,100 were killed in the first use during the Second Battle of Ypres. But that day the Germans weren’t prepared for how effective the gas would be and were therefore unable to exploit the gap in the line that was created.
Chlorine’s usefulness was short-lived. Its color and odor made it easy to spot, and since chlorine is water-soluble, even soldiers without gas masks could reduce its effects by placing water-soaked rags over their mouth and nose. It was reported that Canadian soldiers at 2nd Ypres used urine-soaked hankies for protection, but the chemistry of the chlorine reacting with the ammonia in the urine produces two additional irritants: chloramines (such as NH2Cl), which can cause coughing, nausea, and even trigger asthma attacks, and cyanogen chloride (CNCl), which irritates the eyes, nose, and bronchial tract. Releasing the chlorine gas as a cloud was very hard to manage, as the British learned to their detriment when they released chlorine gas at Loos in September 1915. The wind shifted on them, carrying the gas back onto their own men.
Phosgene, carbonyl dichloride (COCl2), was Haber’s next product, probably first used by the Germans in December 1915 at Ypres. Phosgene is a colorless gas, with an odor likened to that of "musty hay," but for the odor to be detectable, the concentration has to be at least 0.4 parts per million, or several times the level at which harmful effects will occur. Phosgene is highly toxic due to its ability to react with proteins in the alveoli of the lungs, disrupting the blood-air barrier and causing suffocation.
 |
| Aftermath of Actual Gas Attack at Fromelles, 1916 |
As a weapon, phosgene was much more effective and deadly than chlorine, though one drawback was that the symptoms could sometimes take up to 48 hours to manifest. The immediate effects are lachrymatory. Subsequently, it can cause the build-up of fluid in the lungs, leading to death. It’s estimated that as many as 85 percent of the estimated 91,000 gas deaths in WWI were a result of phosgene or a similar agent called diphosgene trichloromethane chloroformate ( ClCO₂CCl₃), which is a liquid at ambient environmental temperatures, so has to be deployed as an aerosol.
The most commonly used gas was "mustard gas," (bis(2-chloroethyl sulfide) (C₄H₈Cl₂S). When pure, this is colorless, but in WWI impure forms were used, which had the mustard-like color. There is no chemical relationship between mustard gas and the condiment, although mustard gas has an odor reminiscent of garlic or horseradish. Mustard gas is an irritant and a strong vesicant (blister-forming agent); it causes chemical burns on contact, with the blisters oozing yellow fluid. Initial exposure is symptomless, and by the time skin irritation begins, it is too late to take preventative measures. Like diphosgene, it is a liquid and has to be deployed as an aerosol, but it can linger on surfaces such as clothing for a long time. The mortality rate from mustard gas was only two to three percent of cases, but those who suffered chemical burns and respiratory problems required long hospitalizations and, even if they recovered, UK sources say they turned out to be at higher risk of developing cancers during later life.
Akin to mustard gas, the U.S. Chemical Warfare Service had developed the vesicant aerosol chlorovinyldichloroarsine (C2H2AsCl3 ), known as "Lewisite." Often referred to as "the dew of death," it smelled like geraniums and exposure caused massive skin blistering, eye damage and severe respiratory distress, and if it was absorbed, it could cause systemic arsenic poisoning. In 1940, it was discovered that injections of dimercaprol (C3H8OS2 ) are an effective antidote.
 |
| German Medic Equipped for Gas Warfare |
German-developed chloropicrin (Cl3CNO2), diphenylchlorarsine (code-named Clark 1) ((C6H5)2AsCl), and diphenylcyanoarsine (C13H10AsN) (code-named Clark 2), both colloquially known as "sneezing oil," plus the American-developed diphenylaminechlorarsine (C12H9AsClN), familiarly called Adamsite or DM, were aerosols widely used as "mask-busters"—irritants that could get through the gas mask filters, thus making soldiers have to remove their masks, thereby exposing themselves to the phosgene barrage that would shortly follow. Today DM remains present in the inventories of riot control agents.
After the mostly unsuccessful and sometimes disastrous releases of gas from pressure tanks, such as at Loos, chemical attacks were delivered in artillery shells or by projectors that ejected canisters that burst on contact. The gaseous agent(s) were in liquid form under pressure in glass bottles inside the warhead, which would break on contact, and the liquid would quickly evaporate. The aerosols used a small explosive charge to disperse the liquid as drops.
Different types of gas were often used in combinations, so to enable their appropriate use, the artillery shells were color-coded: green cross shells had the pulmonary agents—chlorine, phosgene, and diphosgene; white cross had the tear gases; blue cross had the "mask-busters; gold (or yellow) cross had the mustard gas; and red stripe was for the Lewisite.
 |
| Imperial War Museum's Collection of WWI Gas Respirators |
Although mustard gas was never used in combat in WWII, all sides had inventories available. On 3 December 1943, a German air raid on the port of Bari, Italy, destroyed 28 Allied ships. One of these was the American Liberty Ship S.S. John Harvey, whose cargo of munitions included 2,000 M47A1 mustard gas bombs, each holding 60–70 lbs of the agent. The munitions on the Harvey detonated, causing a huge release of mustard gas in both liquid and aerosol forms. There were 628 cases of mustard gas poisoning of U.S. personnel, 83 of which were fatal. No figures are available for Italian civilian casualties. The incident was covered up; all of the official records were sealed until 1958.
While we’re on the subject of gas in WWII, it should be made clear that Zyklon B, the agent used to kill millions at Auschwitz (and other sites) wasn’t used in WWI. It hadn’t even been invented yet. Chemically, Zyklon B is a gaseous version of hydrogen cyanide (HCN), commonly known as prussic acid, which blocks respiration by inhibiting the production of adenosine triphosphate (ATP). It wasn’t discovered by Haber (it was first isolated in France in 1752), but it was developed in the 1920s by men who had worked in Haber’s chemical weapons lab during WWI. Zyklon B was first patented (for use as a pesticide) in 1926. HCN (not in the form of Zyklon B) is still used today as a precursor in the production of certain plastics and pharmaceuticals.
Souces include the BBC magazine http://www.bbc.com/news/magazine-31042472 Some of this material was previously published by the author at the University of Kansas Medical Center’s Webpage Medicine in the First World War, now archived at https://www.kumc.edu/school-of-medicine/academics/departments/history-and-philosophy-of-medicine/archives/wwi.html
No comments:
Post a Comment