Sarin decontamination

Spill/Leak Disposal If leaks or spills of Sarin occur, only personnel in full protective clothing will remain in the area. Spills must be contained by covering with vermiculite, diatomaceous earth, clay, fine sand, sponges, and paper or cloth towels. Decontaminate with copious amounts of aqueous sodium hydroxide solution (a minimum of 10 wt.%). Scoop up all material and place it in a DOT approved container. Cover the contents with decontamination solution as above. After sealing, the exterior will be decontaminated and labeled according to EPA and DOT regulations. All leaking containers will be over packed with sorbent (e.g., vermiculite) placed between the interior and exterior containers. 

Immediate decontamination is required for the smallest drop. VX can be very rapid, and death can occur within fifteen minutes after absorption of a fatal dosage. Heavily splashed liquid persists for long periods under average weather conditions, and VX can persist for months in cold weather. For instance, VX is calculated to be approximately 1,500 times slower in evaporation than sarin (GB). As for LD-50 dose on the skin, sarin (GB) requires a dose of 1700 mg while VX requires only ten mg (tabun requires 1000 mg, soman requires 50 mg, and GF requires 30 mg). 

Dialkyl alkylphosphonates are of interest as analytes for a number of reasons. They may be present as impurities in nerve agents, and as such may be useful indicators of use or production as they are much more stable in the environment an example is diisopropyl methylphosphonate found in sarin. Dialkyl methylphosphonates may be formed in decontamination reactions of nerve agents in basic formulations containing alcohols or cellusolves. They are also important precursors to nerve agents, for example, dialkyl methylphosphonates are converted to the key... 

Parchment et al. (67) used a diamond ATR probe to monitor decontamination of mustard gas, sarin, soman, and VX. They conclude that because of relatively low sensitivity of the method, it can only be used for analysis of CWA in realistic concentrations in real time and in situ. 

It is also important to consider the issue of patient decontamination. Many hospitals rely on local fire or HAZMAT resources to decontaminate patients prior to arrival at the emergency department. This model is almost always effective as the typical HAZMAT or chemical exposure is an isolated event in which a limited access/egress quarantine can be established, and in which patients can be controlled and decontaminated. However, as was demonstrated during the sarin gas attack in Tokyo, in a disaster, there is no control over the scene or scenes. Patients will self-refer to emergency departments without being decontaminated (Auf der Heide, 2006 Okumura, Suzuki, Fukuda, 1998 Okumura, Takasu, Ishimatsu, 1996). 

In an attempt to think outside the box, the U.S. Army Soldier and Biological Chemical Command (SBCCOM) attempted to discover possible alternative ambulatory decontamination facilities, which would be able to supplement standard shower decontamination in the event of a large scale mass casualty event. One such alternative would be to use an Olympic-sized, heated swimming pool. The SBCCOM calculated that such a swimming pool as a communal bath with soap (and the water already present) could decontaminate large numbers (well in excess of 100,000 people) of ambulatory casualties exposed to nonconvulsive doses of the nerve agent sarin (SBCCOM, January 2002). The dilution factor of the large quantity of water would keep it nontoxic for many tens, if not hundreds of thousands, of people. 

The toxicity of liquid nerve agents on the skin was studied extensively. In the first study reported (Freeman et al, 1953), 5-mg droplets of sarin (6-129 droplets total doses of 25-550 mg) were placed on the volar aspects of the forearms of 11 subjects. The agent evaporated in 1.5-6 min from the skin when the area was relatively free of hair, and in 6.5-15 min from the skin when placed in areas of heavy hair. The agent was mixed with a dye for visualization, and after evaporation was complete the site was tested for the agent and then decontaminated. Maximal inhibition of erythrocyte cholinesterase activity was 18% (82% of normal). Two subjects (cholinesterase of 82%) had transient diarrhea. Sweating at the site of application continued for as long as 34 days. 

Later, under the same experimental conditions VX was allowed to remain on the serge in two subjects for 24 h. Erythrocyte cholinesterase activity began to fall within 14 h, and at 24 h, when the material was removed and the arms decontaminated (5.25% hypochlorite), it was 73% in one subject and 81% in the other. Maximal inhibition of the enzyme (34% and 64% of baseline) occurred at 48 h and 24 h after decontamination. The activity of the lower cholinesterase returned at a rate of about 10% per day for the next 3 days, but then slowed to about 1% per day. Both subjects were symptom- and sign-free. (This study should be compared to that in which sarin was placed on serge and flannel and left in place for 30 min.)... 

There were inadequate facilities in the Emergency Department at St Luke s to permit a large number of casualties to remove contaminated clothing and to shower formal decontamination was, therefore, impossible. In addition, the ventilation in the patient reception area was poor. Consequently, some of the medical staff complained of eye or throat pain, nausea, or miosis (Okumura et al, 1996). This was relieved by improving ventilation and by rotation of affected staff to other locations within the hospital. Secondary exposure of medical staff from patients affected by sarin vapour was limited. No medical staff required pharmacological treatment for their signs and symptoms. 

In the Tokyo subway sarin attack, primary decontamination was not undertaken at the attack sites, and the first responders and healthcare workers did not wear appropriate personal protective equipment (PPE). Because of this, 135 of 1364 firefighters (9.9%) suffered from symptoms associated with secondary exposure. While the number of policemen who experienced secondary exposure has not been released, the proportion who suffered from secondary exposure is expected to be similar. Fortunately, no deaths were officially attributed to secondary exposure. If higher-purity sarin had been used in the Tokyo subway sarin attack, it is possible that some people might have died from secondary exposure. However, a pregnant nurse who was exposed to sarin at the hospital became concerned whether or not her child would be bom healthy, and after consulting with her doctor, she had an abortion. Therefore, while this was not officially recorded, one life may be said to have been lost due to secondary exposure. 

In instances where a chemical gas is used in a terrorist attack, it is necessary to perform dry decontamination (i.e. change clothes) in order to minimize secondary exposure. Because the Tokyo subway sarin attack occurred in winter, many victims were wearing many layers of clothes. The extent of secondary exposure could have been... 

In 1948, the army partially standardized sarin and the year after, tabun. In 1948, the army also issued a new circular116 on G-series nerve agents and a technical bulletin117 on the treatment of nerve agent poisoning.3 The circular provided current information on detection, protection, and decontamination of nerve agents. For detection, the M9 and the improved M9A1 detection kits, standardized in 1947, could detect vapor after a complicated procedure ... 

Three types of chemical mechanisms have been used for decontamination water/soap wash oxidation and acid/base hydrolysis.9 Mustard (HD) and the persistent nerve agent VX contain sulfur molecules that are readily subject to oxidation reactions. VX and the other nerve agents (tabun [GA], sarin [GB], soman [GD], and GF) contain phosphorus groups that can be hydrolyzed. Therefore, most chemical decontaminants are designed to oxidize mustard and VX and to hydrolyze nerve agents (VX and the G series).1 Water and Water/Soap Wash... 

Concerns about the possible use of chemical agents in acts of terrorism have increased in the decade since the nerve agent Sarin caused a mass casualty incident in the Tokyo subway system. Chemical warfare poisons include nerve agents, vesicants, cyanides, riot control agents, and pulmonary irritants. Presenting symptoms as well as the clinical circumstances may help identify the agent and lead to effeotive treatment as well as proper decontamination. 

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