GD is a colorless liquid organophosphate nerve agent with an intermediate persistence (evaporation rate about 1/4th that of water; volatility similar to that of engine oil). When pure, it has a faint fruity odor which may not be detected; impurities which are commonly present may produce a smell of camphor, nutmeg, or orange peel.

CHEMICAL AND PHYSICAL PROPERTIES

DETECTION

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

SYMPTOMS AND EFFECTS

Lowered acetylcholinesterase levels are indicators of nerve agent intoxication in victims.

Depending on the degree of intoxication, symptoms may include:

Onset is usually rapid, occurring within minutes of exposure.

MEDICAL COUNTERMEASURES

Useful Drugs	Atropine sulfate	Oximes	Diazepam

The immediate treatment for nerve agent intoxication is intravenous injection of 2 mg atropine sulfate (intramuscular injection should be considered if the patient is hypoxic and ventilation can not be initiated, as there is a risk of ventricular fibrillation). This should be followed by additional injections of atropine at 10-15 minute intervals, continuing until bradycardia has been reversed (e.g., until the heart rate is at 90 beats/minute). If breathing has stopped, a mechanical respirator should be used to ventilate the patient. While exhaled air is not ordinarily a hazard, DO NOT ATTEMPT MOUTH-TO-MOUTH RESUCITATION without proper shields owing to the possible presence of residual agent on the face. If possible, oxygen or oxygen-enriched air should be used for ventilation. If possible, monitor cardiac activity.

Both pralidoxime salts and obidoxime are somewhat ineffective in restoring acetylcholinesterase activity after exposure to Soman (presumably due to the aging process for the Soman-inhibited cholinesterase); however, they do not interfere with treatment, and so there is no reason to refrain from their use if the agent is unidentified, and some benefit may accrue from very early administration. HLö-7 (a bispyridinium dioxime) may be useful if available.

Diazepam should be administered to control convulsions. It also has value in controlling fear on the part of the patient. Diazepam may also help to protect against Soman-induced neuropathies. An initial dose of 5 mg may be followed by additional doses at 15 minute intervals up to a total of 15 mg.

PHYSICAL COUNTERMEASURES

Protective equipment (self-contained breathing equipment or gas mask, barrier suit) must be used. 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. Casualties should be decontaminated as rapidly as possible (see the section on decontamination). Remove casualties from exposure as rapidly as possible. Casualties must not be moved into clean treatment areas where unmasked/ungloved personnel are working until decontamination is complete.

Also refer to 2004 Emergency Response Guidebook (ERG2000) Guide 153.

DECONTAMINATION

The preferred decontaminant for Soman for surfaces is a solution of sodium hydroxide 10 wt.% (or greater) in water (note that hydrogen fluoride may be produced in sufficient quantities to pose a hazard). Surface decontamination may also be accomplished using hypochlorite bleach slurries, dilute alkalis, or DS2 decontaminating solution. Steam and ammonia may be used for the decontamination of confined spaces. Hot, soapy water can also be effective.

Decontamination of victims is accomplished by removing the victim from the contaminated area, removal of clothing, and removal or neutralization of agent present on the skin. Any visible droplets should be blotted (not wiped) away using an absorbant material (e.g., paper towels, facial tissues, etc.); if available, towelettes moistened with a neutralizing solution should be used. Adsorbant powders may also be used for removal of droplets (in the absence of standard adsorbants, field expedients such as flour may be useful). Hair should be thoroughly cleaned using soap and water, with care being taken to prevent wash water from contacting skin.

GD solubility in water is 2.1% at 20° and 20% at 25°. It hydrolyzes with a half-life of 80 hours at pH 7 and 20 °; 45 hours at pH 6.65 and 25°, hydrolysis goes to completion in 5 minutes in 5% sodium hydroxide (NaOH) solutions. However, hydrogen fluoride (HF) is a major hydrolysis product and may present a hazard. GD can persist for quite long times in water if the pH and temperature are right.

SELECTED PRECURSORS

• Ammonium bifluoride
• Dimethyl methylphosphonate
• Diethylphosphite
• Dimethylphosphite
• Hydrogen fluoride
• Methylphosphonous difluoride
• Methylphosphonyl dichloride
• Methylphosphonyl difluoride
• Pinacolone
• Pinacolyl alcohol
• Potassium bifluoride
• Potassium fluoride
• Phosphorus trichloride
• Sodium bifluoride
• Sodium fluoride
• Thionyl chloride
• Trimethyl phosphite

COMMENTS

Binary Weapons

Binary weapons in which GD is formed at the time of use have been developed. One component in the binary is methylphosphonyldifluoride (Code DF; CAS Registry Number 676-99-3) and the other is pinacolyl alcohol (CAS Registry Number 464-07-3) and an amine. These weapons may be identified by the code GD-2 in some documents.

Thickened GD

Thickened forms of Soman, sometimes identified by the code TGD, have also been produced. In the United States, the thickener selected was an essentially nontoxic butyl acrylate-ethyl acrylate-methyl methacrylate copolymer with the trade name Acryloid K-125 which was added to GD to form a 5 % thickener/95 % GD mixture.

Thickened forms of Soman were also produced in the Soviet Union. In fact, only thickened Soman was identified as a "standard agent" in the information released by the Soviets in 1987 about their chemical arsenal.

Thickened Soman and VR-55

Soviet thickened Soman is sometimes identified by the code VR-55 in western documents. This code may have been derived from the viscosity of the thickened Soman - Viscous Russian - with the 55 arising from the designation of GD by the Soviets by a code name usually translated as Substance 55. However, caution should be used in interpreting documents that contain this designation, because it may also have been applied to Soviet second generation (V) nerve agents.

Historical Notes

Soman was first synthesized in 1944 as a result of the investigations into organophosphate nerve agents triggered by the discovery of GA (Tabun), and it was the most toxic agent of its time. Known initially by its code number, T-300, it was the last of the Grün 3 (Green 3) nerve agents that the Germans attempted to move to production during World War II. Its synthesis is generally credited to Richard Kuhn (who headed a group investigating the nerve agents), occasionally with mention of his collaborator Konrad Henke, of the Kaiser Wilhelm Institute for Medical Research.

The production process settled on by the Germans for Soman was a four-step process in which highly corrosive intermediates were used. The corrosive compounds required the use of special silver apparatus, and production in 1944 was only about one ton, with perhaps two more tons being produced in 1945 before the end of the war.

The Soviets acquired the production facility and also recovered the documents related to Soman's synthesis from an underground storage facility near Berlin. Richard Kuhn, however, fell into the hands of the Americans.

In the 1950s, several methods of producing the agent were developed by researchers in the Soviet Union and in Great Britain and the United States which avoided many of the production problems the Germans had encountered. This lead to considerable interest in the mass production of GD for military use.

The United States seriously considered making Soman its primary nerve agent, but economics finally swung the decision against it (there was no industrial use, and thus no industrial source, for pinacolyl alcohol, and the large scale production of Soman would have required the creation of such a production capability from scratch).

The Soviet Union saw sufficient advantages to the material that they commenced industrial-scale production of Soman in 1967. Interest in Soman appears to have persisted into at least the early seventies, with at least one Lenin Prize for work on Soman being awarded as late as 1972. Significant amounts were produced - the Russian Federation declared some 4800 metric tons of GD to the OPCW.

In 1973, the Israelis discovered that Egyptian prisoners of war captured during the so-called Yom Kippur War were carrying personal chemical protective equipment that included decontamination kits containing an antidote that comprised an unusual combination of ingredients: atropine, benactyzine, and the oxime TMB4. The Israelis were worried by the personal protective gear, since it implied the Egyptians were planning for operations in a chemical environment. It was the components of the antidote that drew the most attention in other countries, since they seemed to be intended for use against Soman as well as the better-known nerve agents. As a result, several Western countries embarked on crash programs to develop countermeasures specific for this agent.

No other country is known to have seen enough utility in Soman (relative to the other nerve agents) to enter into mass production of it, although most countries with an interest in chemical weapons have produced it on a laboratory scale. It has been suggested that North Korea (the Democratic People's Republic of Korea) may have produced significant quantities of this agent. However, the evidence for this is somewhat equivocal.

Project 112 Testing

Beginning in 1962, a variety of tests of chemical and biological agents were carried out as a result of the Project 112 review of U.S. chemical and biological warfare capabilities. These tests were supervised by the Deseret Test Center, which had been established to conduct them. Some of these tests involved GD. The table below provides a brief synopsis of the tests which are known to have included GD and their objectives.

Related International Classification of Diseases Codes

Heading	ICD-9-CM
Toxic effect of organophosphate & carbamate	989.3
Accidental poisoning by other specified gases and vapors	E869.8
Suicide and self-inflicted poisoning using other specified gases and vapors	E952.8
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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