Sulfur mustard is a liquid blister agent which is colorless when pure, but which is more commonly yellowish, amber colored, or even black in color due to impurities. It evaporates about five times more slowly than water, and may persist for several months in cold conditions. When protected in soil, it has been known to persist for up to three years. Mustard is variously reported to have a sweetish odor, to smell like garlic, like mustard, or like horseradish. The odor can be detected at relatively low concentrations (threshold 0.0013 mg/L); however this is close to the level at which damage to the eyes can occur on prolonged (e.g., 1 hour or longer) exposure.

CHEMICAL AND PHYSICAL PROPERTIES

DETECTION

Mustard gas-sensitive chemical agent detectors (e.g., (e.g., CAM, M18A2, M256, etc.) and papers (e.g., M8, M9) may be used for detection.

SYMPTOMS AND EFFECTS

No laboratory tests exist for quantifying mustard intoxication. However, blood counts, serum electrolytes, and coagulation times should be monitored over the course of treatment. Methods do exist for identifying metabolites and degradation products of mustard for confirmation of agent use.

The eyes are particularly sensitive to exposure to mustard.

Depending on the degree of exposure, symptoms may include:

The appearance of symptoms is usually delayed, with a latent period of 4-6 hours being common. Onset of respiratory symptoms may be delayed by 24 hours. The length of the latent period may be related to the seriousness of exposure, with shorter latent periods indicating a larger exposure.

MEDICAL COUNTERMEASURES

Useful Drugs	Povidone-iodine ointment	Silver sulfadiazine cream

Remove victims from exposure as rapidly as possible. Victims must not be moved into clean treatment areas where unmasked/ungloved personnel are working until decontamination is complete.

Medical treatment should include decontamination of victims at as early a stage as possible to prevent further damage. See the section DECONTAMINATION.

Medical personnel treating casualties should avoid direct (skin-to skin) contact; protective gear including breathing protection should be worn when treating casualties prior to decontamination. Latex gloves are not adequate protection. Chemical protective (butyl rubber) gloves must be worn.

While it has not been verified in humans, recent experiments with guinea pigs (Wormser, U., et al, J. Appl. Toxicol. 20, S183-S185, 2000) suggest that rapid application of povidone iodine ointment (within 20 minutes of exposure) may provide some protection for skin against the vesicant effects of sulfur mustard.

Once decontamination has been completed, medical care is largely restricted to supportive and palliative measures.

Mustard burns should be treated in a manner similar to thermal burns (fluid replacement as needed while avoiding overhydration, analgesics, infection prevention). Silver sulfadiazine (1%) creams and ointments are known to produce good results. Blister fluids may be drained under sterile conditions; while blister fluids should not be dangerous (sulfur mustard reacts very rapidly), there have been anecdotal reports that suggest blister fluids can display vesicant action in rare cases. Therefore, contact with the fluid should be avoided, and areas exposed to it should be decontaminated. Dermal hypersensitivity which may develop may be treated using antihistimines or systemic or topical corticosteroids.

Eye injuries should be treated depending on severity. Atropinre eye drops (to induce mydriasis) may be useful. Topical steroids used within the first 24 hours may reduce inflammation. Dark glasses, rather than bandaging, should be used (e.g., for photophobia).

Inhalation injuries to the upper airway may be aided by cool steam inhalation and cough drops. More severe inhalational injuries will require oxygen-supplemented breathing support, including PEEP. Airway maintenance can be problematic due to blister formation; intubation should be initiated if there are indications of damage at the level of the larynx or below.

If administered promptly, activated charcoal may have some benefit in reducing damage caused by mustard in the GI tract (e.g., due to ingestion). Emesis should be avoided.

PHYSICAL COUNTERMEASURES

Protective equipment (self-contained breathing equipment or gas mask, barrier suit) must be used.

The combustion products produced by burning HD include hydrochloric acid and sulfur oxides. Sealed containers of HD pose a risk for BLEVE.

Also refer to 2004 Emergency Response Guidebook (ERG2004) Guide 153.

DECONTAMINATION

Victims

Decontamination of victims is accomplished by removing the victim from the contaminated area, removing clothing, cutting off contaminated hair, and removing or neutralizing agent present on the skin. Soap and water can be used to clean skin if it is already reddening, with rinsing using copious amounts of water for at least 15 minutes. For skin which is not yet displaying indications of injury, a 0.5% hypochlorite bleach solution may be used for decontamination, followed by rinsing, wiping or blotting, and rinsing again. Thickened agent may require scraping (e.g., using a tongue depressor or blunt knife).

Eyes should be lavaged with large amounts of water or saline for at least 15 minutes, making sure that the eyelids are kept open. If contamination was from droplets of the agent, irrigation must be begun within 5 minutes of exposure to be useful.

DO NOT cover eyes with bandages; protect eyes with dark glasses instead.

Property

Surface decontamination may be accomplished using hypochlorite bleach slurries, STB, or DS2 decontaminating solution.

Decontamination of papers, if essential, may be accomplished by exposing the papers to ammonia vapor in a closed container over a period of several days.

HD is of limited solubility in water (0.09% at 22°), but is very soluble in organic solvents (e.g., acetone, carbon tetrachloride, etc.). Hydrolysis occurs rapidly (half-life 16 minutes), but the rate-determining step is dissolution, and the low solubility of sulfur mustard will hinder this route of decontamination if large amounts are present. Additionally, the hydrolysis proceeds with the production of hemimustard, also a vesicant (which is further hydrolyzed) and hydrochloric acid.

SELECTED PRECURSORS

• 2-Chloroethanol
• Ethylene
• Hydrochloric acid
• Sodium sulfide
• Sulfur dichloride
• Sulfur monochloride
• Thiodiglycol

COMMENTS

Particulated sulfur mustard

Sulfur mustard has been investigated as a particulated agent (sulfur mustard adsorbed on a powdered carrier material such as silica, alumina, or Fuller's earth) on several occasions. Particulated agents are more persistent and harder to detect since there is a lower vapor concentration. Additionally, the particulated agent may be capable of mechanical penetration of protective clothing.

Particulation of sulfur mustard was explored by the Germans during World War II. Their interest may have been sparked by reports that the Soviets had investigated particulation.

A material known as Dusty Mustard or Dust Mustard, which is a particulated sulfur mustard (sulfur mustard 65% adsorbed on silica particles with diameters in the 0.1-10 micron range) was used by Iraq during its war with Iran. It produced somewhat different initial effects (e.g., a rash rather than a generalized erythema) than conventional forms of mustard. Onset of symptoms, especially respiratory symptoms, was also reported to occur more rapidly than for mustard vapor (however, it has been suggested that the early symptoms may be a result of the mechanical effects of the particles rather than the chemical effects of the agent).

In 1991, during the Gulf War, Dusty Mustard was thought to pose a particular penetration hazard for the Coalition's chemical protective suits ("MOPP gear"), but a rapid investigation determined that using the poncho over the overgarment to provide an additional barrier to mechanical penetration could be expected to provide nearly complete protection. Fortunately, this expectation was never tested.

Sulfur mustard-containing mixtures

Sulfur mustard has been used as a component in a number of vesicant mixtures. The mixtures were usually designed to produce a desired change in the properties (e.g., lowering the freezing point for cold weather use; adjusting viscosity to improve persistence) and/or toxic effects.

Anthrax in sulfur mustard

In 1942, research undertaken under the auspices of the M-1000 Committee of the Canadian National Research Council established that anthrax spores could survive in sulfur mustard. The research had been undertaken with the goal of developing a combined biological and chemical weapon, the idea being that the blisters caused by the mustard agent would facilitate infection by the anthrax. The program was terminated without proceeding to weaponization.

Radiomimetic effects of sulfur mustard

The damage caused by sulfur mustard is in some ways similar to that produced by ionizing radiation (e.g., burns similar to those produced by x-rays, effects on bone marrow leading to leukopenia, as well as mutagenic and carcinogenic effects). As a result, sulfur mustard is classed as a radiomimetic agent.

Historical Notes

Sulfur mustard was probably first synthesized by M. Depretz in 1822, again in 1854 by Richie, and possibly yet again in 1859 by F. Guthrie, who is credited with being the first to report (in the Quarterly Journal of the Chemical Society) that blisters formed if the liquid was allowed stand on the skin. A bit later, in 1860, a report by A. Niemann describes the synthesis of a compound that he identified as a relative of mustard, but which displays the characteristic vesicant effects of sulfur mustard to such an extent that it is generally thought that he didn't really know what he had made.

All of these early reports have in common that the chemists carried out reactions that actually produced mixtures of a variety of related compounds, making it difficult to be sure what the predominant component of the mixture might be. However, in 1886, V. Meyer published a paper titled (in translation from the German) Compounds of Thiodiglycol. In this paper he disclosed a synthesis that allowed the production of reasonably pure sulfur mustard in reasonably good yield.

No great attention was paid to sulfur mustard until the Great War, when the German cylinder attacks with chlorine gas set off a race to identify and weaponize chemical agents. In early 1916 Harold Dudley of Britain suggested that the compound might be useful; at almost the same time in Germany Lommel was testing the material for its possible utility as a war gas. The studies in Britain convinced Major Starling, head of the Anti-Gas Department of the Royal Army Medical College of Millbank, to recommend its use in April of 1916, but the recommendation was rejected because it was felt that sulfur mustard was not sufficiently lethal. In Germany, Lommel's recommendation went to Professor Steinkopf of the Kaiser Wilhelm Instute for Physical Chemistry, who gave it a strong recommendation. According to some accounts, the recommendation was influenced by an accident prior to the war in which a visiting British scientist was exposed to the material accidently and took several months to recover from his injuries. Whether this is true or not, the Germans seem to have had the belief that the agent was significantly more lethal than did the British - their estimate of the lethal concentration was one-tenth that of the Allies.

The Germans elected to proceed with sulfur mustard, which they designated Kampfstoff Lost (for Lommel and Steinkopf). Mass production was assisted by the fact that the production of dyes by I. G. Farben had given the German chemical industry experience with the production of the precursors used in synthesizing sulfur mustard. For instance, the mustard precursor thiodiglycol had been produced at the Ludwigshafen works for dye production in large lots even before the war. Thus, the initial demand was satisfied using the existing reactors for thiodiglycol production, and the plans for these reactors could be used to build new reactors to expand capacity (by the end of the war, sixty new reactors had been constructed to supplement the twelve which had existed at the beginning of the war). As a result, the Germans were able to rapidly build up stocks of sulfur mustard after beginning production at Leverkusen in Spring of 1917.

The Germans loaded their mustard into shells marked with a yellow cross or crosses and it is sometimes described as the yellow cross, or Gelbkreuz, agent. This is slightly inaccurate, as the Germans used variants of the yellow cross to represent a family of agents that caused damage to the skin (vesicants and caustics), but only slightly, since mustard was always the principal yellow cross agent.

The codes used for sulfur mustard are said to have originated from its description during the Great War. The British and Americans supposedly referred to mustard gas as "Hunstoffe" or "Hot Stuff" and at least the Americans fell to abbreviating it as H.S. in official documents. Eventually the periods were dropped and it became HS, and then the S was dropped and it became simply H. When distilled mustard came into use, it was referred to as sulfur mustard, distilled, and a D was added to the H to give HD. The British Army also used other codes. During World War I, they used BB (possibly derived from the beta locants in the chemical name) when they wanted to specify mustard gas in artillery shells. Later, they used Y3 for mustard and Y4 for thickened mustard - presumably Y for Yperite - before adopting the STANAG codes.

By July, the Germans had accumulated enough of the new agent to use it, and on the evening of July 12, 1917 they carried out a bombardment of British troops near Ypres, Belgium. Because of the latent period before the effects of mustard make themselves apparent, the men in many gases didn't realize they were being gassed, or thought that the agent was not very effective. This impression was corrected within a few hours, as the latent period ended. The effects of the attacks with sulfur mustard were overwhelming. In the first week in which the Germans employed the agent, the British would admit 2934 mustard gas casualties to their various medical units - units which had been treating around 350 gas casualties a week in the period leading up to the attack. In the first three weeks in which the Germans employed their new agent the British would suffer 14,296 gas casualties. While the German expectations for its lethality were not borne out (only a bit more than 2% of mustard casualties were fatalities, which should be compared to about 8% for casualties from rifle fire), its effects were certainly not disappointing in the military sense. Indeed, had it been more lethal, it might have been less damaging. The need to care for mustard gas casualties placed burdens on the supply and medical systems that would not have been produced by fatalities. At the same time, the nature of the injuries it inflicted - the potential for blindness, the disfiguring and slow-healing lesions of the skin, and the rather painful death of those who had inhaled significant amounts - produced a strongly negative effect on the soldiers who had to suffer attacks using it. Nor did it help that gas masks provided only a partial protection against this new agent - a man wearing a mask could still suffer incapacitating burns if his skin was exposed. The uniforms of the period could absorb the agent while someone was passing through a contaminated area, and carry contamination to others while the original victim was still unaware of exposure.

Mustard gas rapidly became the premier agent used by the Germans, as they were well aware of the psychological advantage it gave them. In one famous bombardment, of Armentières on April 9, 1918, the Germans would use so much mustard gas that the unfortunate witnesses claimed to have seen liquid mustard gas running in the gutters of the streets. The British troops occupying the village withdrew. However, it would be two weeks before the Germans could follow up the bombardment by occupying the town - they had no more means than the Allies of shielding their troops from the vesicant effects while permitting them to remain mobile. In the end, the primary use the Germans would make of mustard gas would be a defensive one - to secure flanks in advances and slow enemy advances. They would also develop special munitions, such as the delayed action demolition charge that included mustard agent (the so-called "Yperite mine") left behind by the Germans when evacuating bunkers, who counted on the fear of the device to slow occupation of bunkers and, after it exploded, on the persistence of the agent to hinder and harm any Allied troops who chose to shelter in the wreckage.

Nevertheless, despite its lack of suitability for rapid attacks, the new weapon caused great consternation among the Allies and, while the Germans capitalized on the technological advantage that their new weapon had given them, the Allies struggled to catch-up. They did not do well.

In the area of defense against the new agent, the Allies found there was little they could do. Detection of chemical agents was in its infancy, relying for the most part on human senses - if someone detected an agent by smell, appearance of a cloud, or seeing a shell that burst in a manner suggesting that it was a gas shell, then that person would sound an alarm. Specialized gas units did possess means for chemical detection of of agents, but they were neither fast or easy to use. For instance, the use of Yablich's reagent to detect mustard gas (favored by the American Chemical Warfare Service) involved passing air through a solution of selenious acid in dilute sulfuric acid and then heating at 85° for 10 minutes. Not a task for the average soldier under artillery attack. While many detection methods were investigated, none was truly satisfactory. Protective equipment was likewise lacking - some specialized gas troops had oilcloth uniforms which could provide some protection against the new agent, but they were few and far between and not expected to actually close with the enemy. Most of the troops had to make do with such barrier preparations as the sag (apparently an acronym for "salve, anti-gas") paste, a mixture of zinc stearate and vegetable oil, with which soldiers had to cover their bodies. Provided it was applied early and thoroughly and also removed as soon as possible (it would absorb mustard gas and eventually allow it to reach the skin) it worked fairly well - some 900 tons were used by the American Expeditionary Force - but it was far from an optimum solution.

The methods investigated for detecting mustard gas included the use of snails, which were said to wave their tentacles wildly in the air and then withdraw into their shells when it was present. When the U.S. Army consulted the French about this, it is said that one French expert laughingly cautioned that French soldiers would eat the snails first. However, the need for any reliable detector was such that studies were conducted, but the snails were erratic in their responses and the research was ultimately abandoned.

Efforts at developing an ability to retaliate in kind were also painfully slow. A limited quantity of mustard was obtained from dud German shells and used in attempts to respond in kind, but significant Allied production would not be achieved until June of 1918 by the French. The use of the French mustard against the German Seventh Army produced significant psychological effects - the Germans had to produce propaganda addressing it directly - but had nowhere near the effect of the German use. The British would not receive significant stocks until September 1918, and both the French and the British paid heavily for their rush to production and lack of chemical expertise. In six months operation of the British Avonmouth plant almost 1400 mustard injuries were reported for the 1100 strong workforce, for instance.

The Americans also weighed in, and it must be said that the 711 tons of mustard gas produced by the Edgewood Arsenal during World War I is impressive, given that they started from scratch to build not only a mustard production facility but facilities to produce the necessary precursors. However, little of this was actually used, being mostly in transit to the battlefield when the war ended.

When the Great War ended, mustard gas had earned the sobriquet the "King of the Battle Gases." It was responsible for about 80% of Allied gas casualties, over 125,000 for the British alone. Its persistence had lead to the development of new doctrines for the use of gas (e.g, the use of gas, rather than troops, to secure flanks). Its effects would produce a horror of gas warfare. More than any other agent, mustard gas would shape post-war debates over how and whether chemicals should be used.

The Interwar Years

Mustard gas was used between the World Wars, but only against those who could not retaliate.

In 1925, Spanish forces allegedly used mustard gas bombs dropped from airplanes to help defeat the forces of Abd el-Krim in Morocco during the War of the Rif. There is some irony in that this first significant use of mustard gas from aircraft marked a year significant for the signing of the Geneva Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare. There is also a bit of irony in that the mustard gas was produced by the Fabrica Nacional de Productos Quimicos at La Maranosa near Madrid, which had been constructed with significant assistance from the German concern headed by Hugo Stoltzenberg, in what was at best a skirting of the intent of the Versailles Treaty, if not a violation of its letter. Of course, the facility for filling the bombs is said to have been equipped by French firms, which may explain in part why more of a fuss was not made.

1925 was a good year for German chemical warfare plant designers - a Chinese warlord, Zhang Zuolin, contracted for a plant in Shengyang which was to produce mustard gas, among other agents, for his use in the ongoing civil war. The plant was apparently completed at the end of 1927, but there is no reliable information on whether or how its products were used.

Use of chemical agents in conflicts between technically adept nations and those less advanced in places far from inquiring eyes would peak in the 1930s. The Soviet Air Force experimented with aerial spraying of mustard agent against the Basmachi in Central Asia. The Japanese used it in China. And the Italians used it in Africa.

The most disturbing use of mustard was in Abyssinia (now Ethiopia) by the Italians, who were attempting to reclaim the grandeur that was Rome under the guidance of Mussolini. The Italians had signed and ratified the Geneva Protocol, but seem not to have felt particularly restricted by it. After starting out relatively benignly with tear gas when their attempts at conquest didn't go as planned, they quickly moved to the use of mustard gas, both in the form of bombs and shells and also using a new means of delivery, aerial spraying, as described by the Emperor Haile Selassie when he was making an appeal to the League of Nations:

...special sprayers were installed on aircraft so that they could vaporize over vast areas of territory a fine death-dealing rain. Groups of 9, 15, and 18 aircraft followed one another so that the fog issuing from them formed a continuous fog.

World War II

The Germans used two methods to produce sulfur mustard during World War II - the "Oxol" process, using thiodiglycol as a precursor, and the "Direkt" process, which used sulfur dichloride. For a variety of reasons, they differentiated between the products at all stages down to the shell markings - a shell filled with "Direkt-Lost" would be marked with a D or DL, while one filled with "Oxol-Lost" would be marked O or OL. The distinctions were also often made with mixtures - OR was a "winter mustard" formd by mixing Oxol mustard with antrhracene oil; ZO was a thickened Oxol mustard, and so on.

The combatants in World War II expected chemical weapons to be used and stockpiled them accordingly. Mustard gas had the distinction of being the most heavily stockpiled agent of World War II. Between 1939 and 1945, the British produced 40,719 tons of mustard gas, the Soviets at least 77,400 tons, and the Americans over 87,000 tons. Even the Germans, the sole possessors of nerve agents, intended to use it in their chemical arsenal - during the Third Reich's span of existence they produced over 27,597 tons of sulfur mustard.

It was also during the Second World War that the process of distilling mustard gas to improve its storage properties was fully developed. The first pilot plant for producing the new distilled mustard (known by the code name HD) was brought on-line in 1944 at the Edgewood Arsenal. The results of the pilot project lead to the construction of a full scale plant at the Rocky Mountain Arsenal (near Denver in the U.S. state of Colorado) which alone would produce 4,600 tons of this "cleaner" mustard by the end of the war.

The stockpiling had its drawbacks, however. Resources which might have been directed to other uses were diverted to the production of chemical weapons and to protective gear for them. The need to stockpile the weapons close to where they might be needed also posed its own set of drawbacks, in terms of tying up transportation and storage of dangerous materials. Throughout the war, all sides suffered a steady trickle of chemical casualties due to leaky containers and the like.

The most significant unintended release involved a shipment of mustard gas. On the night of December 2-3, 1943, a German air raid on the port at Bari, Italy led to the destruction of a U.S. merchantman, the "John Harvey." In the cargo of the "John Harvey" were 2000 100 pound mustard gas bombs (containing 60-70 pounds of sulfur mustard each), intended for use in the event the Germans used chemical weapons. A significant fraction of this cargo was released. There were at least 628 casualties from exposure to the mustard, and at least 69 deaths.

Several factors contributed to the high death rate. The shipment of mustard was, of course, secret and the officer appointed to accompany it was killed in the air raid, and so it was not immediately recognized that mustard was present. As a result, decontamination was delayed for those rescued from the water (into which the mustard had been released). In fact, in order to help treat shock, victims were kept in their clothing and wrapped in blankets, which prolonged the exposure.

All exposures to mustard gas, however, were not unintentional. While the intentional use of chemical agents in combat in World War II was rare, at least in comparison to World War I, it was not totally absent.

What combat uses there were in the European theater seem to have been (for the most part) errors. In 1939, Polish troops used chemical training mines containing diluted mustard agent to mine a bridge near Jaslo, injuring 14 German soldiers. It is unclear whether this was a mistake or an attempt at retaliation for the reported use of chemical bombs by the Germans in Warsaw (on September 3, 1939, a number of sulfur mustard-containing bombs were dropped on a Warsaw suburb - the Germans aknowledged this in 1942, indicating it was accidental). The Germans may also have used mustard gas-containing munitions on a few occasions in the Crimea and elsewhere in Poland, but these appear to have either been genuine mistakes or instances of low-level commanders acting without authority.

In the Pacific theater, the Japanese used a variety of chemical agents, including mustard, against the Chinese, albeit on a rather haphazard basis. The use in this case appears to have been facilitated by the lack of chemical protection available to the Chinese forces and their inability to retaliate. Reports of attacks seem to have dropped off significantly after President Roosevelt's warning in June 1942 that the United States would retaliate in kind for any use by the Axis of chemical weapons.

Perhaps the most significant intentional use of mustard gas in the war was in experiments designed to obtain more information on the effects of and treatment for the effects of mustard gas. The Germans carried out a series of "experiments" at the Sachsenhausen and Natzweiler concentration camps to investigate the effects and treatment of mustard gas injuries. The Japanese also used Chinese prisoners and civilians as subjects for experiments with mustard-containing munitions. Not surprisingly, given the nature of Axis science when applied to human subjects, none of these experiments seems to have produced any useful data.

The Allies also carried out experiments with mustard gas, but on volunteers. Unlike the Axis experiments, the experiments were not intentionally taken to the point of death of the experimental subjects. The Allied experiments were also somewhat better designed, and led to some improvements in protective gear and treatment methods.

The better experimental design notwithstanding, these experiments have become controversial. In part, they were massive in scope. At least 4000 Americans were involved as subjects in various mustard agent trials. Records from other Allied nations are scanty, but it is likely that at least an equivalent number were exposed in experiments conducted by the British Commonwealth. Many of these subjects have suffered from long-term consequences of their exposure to mustard gas. Because of the high levels of security surrounding the various test programs, those exposed have also had trouble getting treatment for the conditions (or, in some cases, even an acknowledgement that the exposure occurred).

Post-World War II

- United Arab Republic

Between 1963 and 1967, the United Arab Republic (Egypt) intervened in the Yemeni Civil War, aiding those fighting against the royalist forces. On a number of occasions, allegations were made that aircraft bearing UAR markings had dropped chemical bombs. A variety of chemicals were said to have been used, including phosgene and mustard gas. The politics of the situation made a conclusive investigation impossible, but there was excellent evidence for at least the use of mustard gas.

The case of possible mustard gas use best documented by external observers was an attack on Gahr (or Gahar) which occurred on May 10 or 11, 1967. An International Committee of the Red Cross team was able to reach the village within four days, interviewing four surviving victims and noting the symptoms of mustard exposure (bronchitis, conjunctivitis, and facial edema). They also exhumed a body (one of 75 killed) and found no evidence that death had been caused by blast effects; a garlic-like odor detected during exhumation also suggested mustard.

There has been considerable speculation about the origin of the mustard gas used in Yemen by the UAR. It has often been assumed that it was received from the Soviets, who were allied with the Egyptians; this story is bolstered by reports that some bomb fragments had Cyrillic characters painted on them and by (never verified) claims that a Russian pilot may have been shot done in Yemen during an attack. However, it has also been plausibly suggested that the agent may have originated from British stocks that had been abandoned after World War II, and, of course, it may have been produced locally.

- Iraq

Although it had carried research aimed at developing a chemical weapons capability beginning in the 1970s, it was not until the 1980's that Iraq became seriously interested in mustard gas. The Iraqis were driven by a desire to use it as a force equalizer during its war with Iran, presumably attracted by its effectiveness in World War I under operational conditions similar to those they faced. Experiments began early in the war with Iran. A small amount of a blistering agent believed to be mustard gas, possibly supplied by Egypt, was used in a mortar attack in October of 1981. While not decisive, the results were encouraging, and the Iraqis began a project to produce mustard gas using imported precursors. (For more information on the process used by Iraq to import precursors, go HERE.)

The first confirmed employment of mustard gas by the Iraqis was in August of 1983 near Haj Umran, when they attempted to use it to support an assault on Iranians occupying positions near the crest of a mountain - perhaps not the best of tactics, given the vapor density of mustard gas.

The Iraqis continued to use mustard, however, and learned from their mistakes. While their delivery methods were in some cases crude (some reports suggest that they simply tipped drums of the agent out of helicopters), they were adequate to cause severe problems for their Iranian adversaries. The effects on the Iranians were substantial. At one point they would claim to have suffered at least 16,000 fatalities due to mustard gas. While outside experts view this number as high (and the Iranians have backed away from it, reducing their claims of total chemical agent fatalities by more than two-thirds), the claim speaks to the substantial psychological effects that the Iraqis produced by their use of this weapon.

Throughout the war, Iraq would attempt to deny its use of chemical weapons, initially with some success. However, when the Iranians began to send gas casualties displaying the clear symptoms of exposure to mustard gas to European hospitals for treatment, the Iraqi denials quickly became transparent. A UN commission sent to investigate the allegations made by Iran (both Iran and Iraq had signed the 1925 Geneva Protocol on the use of chemical weapons) quickly returned a report confirming their use, and in March 1986, the UN secretary general, Javier Perez de Cuellar, formally accused Iraq of using chemical weapons against Iran.

The net effect of the UN accusation was a slight interruption in precursor supplies. Iraq would continue to be charged with using chemical weapons, most notably in connection with the 1988 Halabja incident, but saw no reason to stop. After all, gas was effective and the Iranians had no ability to retaliate in kind, and the sanctions imposed were hardly rigourous.

That mustard gas was so effective was due in large measure to the fact that the Iranians were poorly equipped for gas warfare - in many ways their situation was similar to that of the Allies in 1917. They were also poorly trained, and this may have hurt them even more than the lack of equipment. The Iranians could have suffered a lower rate of fatalities had they had better training in decontamination - many fatalities resulted from extended inhalation exposure to vapors coming from liquid mustard-contaminated clothing.

Iranian attempts to develop a retaliatory capability were initially blocked by the Ayatollah Khomeini and other members of the ruling group on religious grounds. By the time the Ayatollahs relaxed their prohibition in 1987, the war was nearly over.

There was some use of chemical agents by Iranian forces, but this appears to have been mainly the use of captured Iraqi munitions. Indeed, Iranian use of chemical munitions may, in at least some cases, have been unknowing. The Iraqis marked some of their gas munitions with distinctive symbols (e.g., a yellow ring and a skull-and-crossbones), but others were unmarked.

The case of Iraq also points up the difficulties in preventing a state from acquiring chemical weapons. Initially, the sulfur mustard used by Iraq was probably produced on a small scale - samples obtained showed a relatively high purity (the impurities also turned aside suggestions the the Soviet Union was supplying the agents, since they were not those which would have been present had the Soviet method of manufacture been used). The utility of the agent quickly brought it into high demand, however, and industrial scale production was quickly undertaken.

In order to do this, they purchased substantial quantities of equipment abroad. Despite the growing protests and awareness of their use of chemical weapons, they had little difficulty in obtaining export permission for essentially everything needed to build a mustard gas production plant. And so, by 1985, the al-Muthanna State Establishment (Sammara) had sufficient capacity to supply the needs of the Iraqi army for mustard gas. Initially, the Iraqis had imported all of the precursors, including the key precursor thiodiglycol, purchasing about 1000 tons from various U.S. and European sources. However, as the war went on and international pressure against the use of chemical weapons mounted, Iraq elected to develop a local capacity for thiodiglycol production using ethylene oxide and hydrogen sulfide obtained from its petroleum industry. By the end of the Iran-Iraq war, they had the capability to produce mustard gas without the need to use outside suppliers for precursors (although they still bought hydrochloric acid abroad because they could do so relatively cheaply and - by claiming a different use - easily). They were thus effectively immune to the opinions - and the sanctions produced by those opinions - of the international community.

- And Others

Iraq may not have been the only country to use mustard gas in the 1980's. Uncorroborated reports indicate that Libya may have attempted to use it during its involvement in Chad. It does not appear to have used it effectively, however - the best of the reports described a drop from a transport plane that affected the Libyan troops, since the wind on the ground was blowing in the wrong direction.

The Libyan Pharma 150 chemical production plant at Al-Rabitah was reportedly to be capable of producing 42 tons of mustard a day. However, the Libyans had bad luck with this plant - a leak at the pilot plant in mid-1988 forced a shutdown of production, and international pressure and surveillance have curtailed operations.

Stocks of Iraqi chemical agents, including mustard gas, were reportedly transferred to Sudan for safekeeping beginning in 1991. Some transfers in 1993 were made via Iran, leading to confusion over their origin. Subsequently, the Iraqis are reported to have cooperated in the construction and operation of chemical agent production plants in the Sudan. Reportedly, a plant located in the town of Wau, the capital city of the Bahr El-Ghazal region in the south of Sudan, is used to produce mustard gas.

Opposition forces in the Civil War in the Sudan claimed that Sudanese government forces have used mustard gas on at least two occasions in 1995 and on several subsequent occasions. At least the first alleged use occurred before the Wau plant was on-stream, and presumably involved the use of agent drawn from the transferred Iraqi stockpile. The has been independent (of the rebels) corroboration of the use of mustard gas canisters in 1997 in raids in eastern Sudan as well.

Terrorists and Mustard Gas

There seems to have been little actual interest by terrorists in mustard gas, perhaps because it is significantly less toxic than the stars of modern war gases, the nerve agents. It has played a central role in some anti-terrorism exercises. There is, however, one exciting story about mustard gas and a famous terrorist group.

In the 1970's, the British Army of the Rhine (BAOR) decided that some of their stocks of chemical agents were redundant and should be disposed of. In particular, they decided to reduce their holdings of mustard gas, most of which had originally been produced for use in World War I, and which was showing its age. They enlisted the services of the Germans to do this, and transferred the stocks to facilities for the destruction fo chemical weapons belonging to the Federal Republic of Germany.

On April 27, 1975, guards at a facility for destruction of chemical weapons (Test Center 53) near Munster, (West) Germany found evidence of an unauthorized entry. An inventory of materials was conducted and it was determined that two 1 liter containers of the BAOR mustard gas had been damaged and that two others could not be accounted for (although the accounting left a bit to be desired).

In May, 1975, reports appeared in the Bild Zeitung and the Times stating the members of the Baader-Meinhof Gang (or the Rote Armee Fraktion, or Red Army Faction, as they preferred to be called) had stolen 53 (possibly a transcription error from the Test Center number) containers of mustard gas which they planned to use to free several members of the gang who were being held in Stuttgart for trial on a variety of counts. Some versions of the story also transferred the mustard's origin from the BAOR to the U.S. Army.

It subsequently turned out that the missing canisters were only missing on paper due to an inventory error. It is unclear who, if anyone actually threatened the use of the mustard. It may be that the threat was only a reporters assumption (threats of bombings were being made) or that the gang (or some other terrorist group) found out about the supposed theft and tried to capitalize on it.

The only terrorist group to use chemical agents on a large scale to date, the Aum Shinrikyo cult, also flirted with mustard gas, producing about half a kilogram in their laboratory. However, there is no evidence that they ever actually used mustard or undertook mass production.

Related International Classification of Diseases Codes

Heading	ICD-9-CM
Toxic effect of other specified gases, fumes, or vapors	987.8
Toxic effect of unspecified gases, fumes, or vapors	987.9
Accidental poisoning by other specified solid and liquid substances	E866.8
Accidental poisoning by unspecified solid and liquid substances	E866.9
Accidental poisoning by other specified gases and vapors	E869.8
Accidental poisoning by unspecified gases and vapors	E869.9
Suicide and self-inflicted poisoning using other and unspecified solid and liquid substances	E950.9
Suicide and self-inflicted poisoning using other specified gases and vapors	E952.8
Suicide and self-inflicted poisoning using unspecified gases and vapors	E952.8
Assault by poisoning using other solid and liquid substances	E962.1
Assault by poisoning using other gases and vapors	E962.2
Injury due to terrorism involving chemical weapons	E979.7
Injury due to war operations by gases, fumes, and chemicals	E997.2
Death due to terrorism involving chemical weapons	U01.7
Heading	ICD-10
Accidental poisoning by and exposure to other and unspecified chemicals and noxious substances	X49
Intentional self-poisoning (suicide) by and exposure to other gases and vapors	X67
Assault (homicide) by gases and vapors	X88
Assault (homicide) by other specified chemicals and noxious substances	X89
Assault (homicide) by unspecified chemical or noxious substance	X90
War operations involving chemical weapons and other forms of unconventional warfare	Y36.7

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