GF is a liquid organophosphate nerve agent with an intermediate persistence (evaporation rate about 1/20th of water). It has a nondescript odor (20 test subjects; 35% smelled an odor at 10.4 mg/m³; 65% at 14.8 mg/m³; odor was variously described as sweet, musty, like peaches, and like shellac).

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	Pralidoxime salts	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. DO NOT ATTEMPT MOUTH-TO-MOUTH RESUCITATION. If possible, oxygen or oxygen-enriched air should be used for ventilation. If possible, monitor cardiac activity.

Oximes (pralidoxime salts, obidoxime) may be of use in restoring acetylcholinesterase activity. Obidoxime may be used to treat GF intoxication; however, it may cause liver damage. Animal studies indicate that the oxime Hi-6 may be significantly superior to other oximes in the treatment of GF intoxication, but it is not widely available. Therefore pralidoxime salts should be used, with a slow intravenous infusion of 500 mg to 1 g being given initially.

Diazepam should be administered to control convulsions. It also has value in controlling fear on the part of the patient. 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 (ERG2004) Guide 153.

DECONTAMINATION

Victims

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 (skin decontamination may be unnecessary if the exposure was only to GF vapor). 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). A solution of 0.5% hypochlorite bleach may be used for skin decontamination. Hair should be thoroughly cleaned using soap and water, with care being taken to prevent wash water from contacting skin.

Property

Surface decontamination may be accomplished using hypochlorite bleach slurries, dilute alkalis, or DS2 decontaminating solution. Steam and ammonia may be used for the decontamination of confined spaces.

GF is only slightly soluble in water and the liquid, if present in relatively large amounts, can layer out at the bottoms of pools.

Bioremediation using Alteromonas prolidases (organophosphorus acid anhydrolases) has been proposed (Chem.-Biol. Interact. (1999), 119-120, 455-462).

SELECTED PRECURSORS

• Ammonium bifluoride
• Cyclohexylamine
• Cyclohexanol
• Diethyl phosphite
• Dimethyl methylphosphonate
• Dimethylphosphite
• Hydrogen fluoride
• Methylphosphonous difluoride
• Methylphosphonyl dichloride
• Methylphosphonyl difluoride (DF)
• Phosphorus trichloride
• Potassium bifluoride
• Potassium fluoride
• Sodium bifluoride
• Sodium fluoride
• Thionyl chloride
• Trimethyl phosphite

COMMENTS

Binary weapons

Iraq reportedly developed a binary system in which GF was formed at the time of use. The open literature does not offer detail, but this most likely involves the use of methyphosphonyldifluoride (Code DF; CAS Registry Number 676-99-3) as one component with the other being cyclohexanol (CAS Registry Number 108-93-0) or a mixture of cyclohexylamine (CAS Registry Number 108-91-8) and cyclohexanol.

GB-GF Mixtures

Iraq fielded munitions filled with mixtures of GB (sarin) and GF. Tests on mice indicated that GB-GF mixtures have a toxicity intermediate between the toxicities of GB and GF; thus, there appear to be no synergistic effects producing enhanced or unexpected toxic effects that would require any change in treatment protocols for those exposed to a mixture.

Historical Notes

Cyclosarin was probably first synthesized during World War II as part of the systematic study of organophosphates undertaken by the Germans after their potential military utility was identified. It was again looked at in the early 1950's by both the United States and great Britain as they undertook a systematic study of potential nerve agents (some U.S. sources suggest that interest in GF was stimulated by work undertaken in "another country"). However, the higher cost of the precursors for GF relative to those for GB along with its lower toxicity prevented it from being chosen for manufacture.

Iraq is the only country in which large amounts of cyclosarin have ever been produced for use as a chemical warfare agent. As with most issues surrounding the Iraqi chemical weopons programs, the basis for their decision to produce GF is somewhat unclear. However, it seems likely that the choice was driven by a combination of a desire for a more persistent agent combined with problems with obtaining alcohol precursors for sarin (due to an embargo).

As noted above, Iraq also fielded weapons filled with mixtures of sarin and cyclosarin. These mixtures appear to have been produced in part for purposes of increasing persistence and in part because of raw material issues.

Related International Classification of Diseases Codes

Heading	ICD-9-CM
Toxic effect of organophosphate & carbamate	989.3
Toxic effect of unspecified gases, fumes, or vapors	987.9
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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