|Description and Property Data||Detection||Symptoms and Effects|
|Medical Countermeasures||Physical Contermeasures||Decontamination|
|Selected Precursors||Comments and Historical Notes||ICD Codes|
FULL CHEMICAL PROTECTIVE ENSEMBLES ARE REQUIRED FOR PROTECTION!|
Masks, including self-contained breathing apparatus (SCBA) masks, alone do not
provide adequate protection against this agent.
Evacuate uphill and upwind without moving through the agent cloud.
|CA Index Name||Phosphonothioic acid, methyl-, S-[2-(diethylamino)ethyl] O-(2-methylpropyl) ester|
|CAS Registry Number||159939-87-4||RTECS Number||None|
VR is a liquid organophosphate nerve agent with an "oily" consistency which is colorless when pure.
O-isobutyl S-(2-diethylaminoethyl)methyl phosphothioate
O-isobutyl S-(2-diethylaminoethyl)methyl thiophosphonate
CHEMICAL AND PHYSICAL PROPERTIES
|323° at 760 torr (1 atm.)
(86° at 1 mtorr)
|0.00062 mm Hg at 25°||Volatility||8.9 mg/m3|
|Flammable; Flash Point 150°|
Few experimental values for the physical properties of VR are currently available in the open literature. Where experimental data is lacking and where reasonable calculation can be made, calculated values have been provided for selected critical properties. These calculated values are in blue.
Nerve agent sensitive chemical agent detectors (e.g., CAM, M18A2, M256, etc.) and papers (e.g., M8, M9) may be used for detection. However, detection limits have not been determined for this agent. Some reports suggest that this agent may be misidentified by automated detectors.
SYMPTOMS AND EFFECTS
Lowered acetylcholinesterase levels are indicators of nerve agent intoxication in victims.
Depending on the degree of intoxication, symptoms may include:
|Miosis (contraction of the pupil)|
|Rhinorrhea (runny nose), excessive salivation|
|Dyspnea (difficulty in breathing due to|
|Bradycardia (slow heartbeat)|
|Loss of consciousness|
|Loss of bladder and bowel control|
|Apnea (breathing stopped)|
Onset is usually rapid, occurring within minutes of exposure.
|11.3 micrograms/kg||subcutaneous||guinea pigs|
|Useful Drugs||Atropine sulfate||Pralidoxime salts||HI-6 oxime||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.
Studies in guinea pigs (Chang, F-C. T., B. E. Hoffman, and S. DeBus, Drug and Chem. Toxicol. 25(3) 321-337, 2002) suggest that patients exposed to VR may require higher doses of atropine than is needed for treatment of equivalent exposures to other organophosphate nerve agents.
The most effective oxime for use in post-treatment of VR exposure is HI-6, based on animal studies. However, it is not widely available.
Despite their lesser efficacy, pralidoxime salts are known to be of use in restoring acetylcholinesterase activity after VR exposure. Use of pralidoxime salts should be initiated in cases where VR intoxication is suspected, with a slow intravenous infusion of 500 mg to 1 g being given initially.
Diazepam should be administered to control convulsions. VR has been reported to be particulary capable of inducing seizures; however, the experiments in guinea pigs (op cit.) suggest that diazepam should be effective in controlling them. Diazepam 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.
Initial Isolation and Protective Action Distances
Based on values for VX, the nerve agent most similar to VR for which values have been published
(small package/leaking container)
in all directions
persons downwind during
|30 m (100 ft)||0.2 km (0.1 mi)||0.2 km (0.1 mi)|
(large package/multiple small packages)
in all directions
persons downwind during
|60 m (200 ft)||0.7 km (0.4 mi)||1.0 km (0.6 mi)|
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 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). 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.
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.
Large amounts of decontaminants should be used to ensure the elimination of the agent and any toxic degradation products.
VR-55 is a code designation seen in some documents which usually refers to thickened GD (Soman), not to VR. However, care must be taken in interpreting documents containing this designation, especially intelligence documents, as this designation is sometimes applied to poorly/incorrectly identified agents including VR.
VR was investigated and developed by the Soviet Union during the 1950's, in a manner which the open literature suggests roughly paralleled the development of VX in the west. It has been suggested that the Soviet investigations were partly guided by a knowledge of the molecular formula of VX but lacked information about the structural formula, and so settled on the on VR, which is a structural isomer of VX. However, it should be noted that there was explosion of interest in this class of compounds during this period, and so it is possible that initial studies had already been undertaken by the Soviets before the U.S. settled on VX. The greater difficulty of treatment and the possibility that detection might be more difficult could have served as incentives for the choice of VR even if the Soviets were aware of the structural formula for VX. This is supported by sources that suggest that a pilot production facility for VR was constructed at at a facility in Stalingrad (now Volgograd) by the Soviets as early as 1956, two years before VX was selected for production by the United States. Research on the agent continued for an extended period as well - in 1974, a Lenin Prize was awarded to researchers who were investigating issues associated with VR.
Despite the early experimentation, large scale production of VR may not have commenced until 1972 at a facility in Novocheboksarsk. Working conditions at this facility are said to have been rather unpleasant (protective gear that did not provide complete protection if one bent over, a lack of monitoring equipment, etc.).
On at least one occasion an accidental release apparently occurred at the Novocheboksarsk facility. A fire caused by a wiring fault on April 28, 1974 apparently damaged the seals on bombs filled with the agent, resulting in a "loss of control" of the agent they contained.
Despite their difficulties, the Soviets produced 15,557 tons of VR according to their declaration to the OPCW. There were two major variants weaponized, a polymethyl methacrylate-thickened VR and plain VR. There are reports that a binary version was also developed.
|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|
|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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