1. Nerve Agent GB: Sarin Chelsea Smith
EMHS 389- Awareness and Response to WMDs, Ball State University
Introduction
How Sarin is Used and Dispersed
How to Properly Respond to a Sarin Attack
There are many types of harmful biological and chemical agents in the world that can be used as a weapon, but nerve agents are among the most deadly types. Nerve agents can affect the human body quickly, and they are effective at extremely low quantities. Sarin is perhaps the most common nerve agent because most people are aware of its negative impact on civilian populations. Sarin has many names associated with it, but the most common is the military abbreviation GB. This substance is completely man-made and does not occur naturally in the environment. Sarin has many unique properties that separate it from all other nerve agents, and these factors influence how well it could be used as a weapon. There are many symptoms associated with a sarin attack, and people should take extra precautions when responding to an attack.
Due to the potency of this nerve agent, sarin is only used as a chemical warfare agent. It is most likely used as a weapon by terrorists. The most common methods to weaponize sarin include using bombs, missiles, or spray tanks , but it can also be ingested through contaminated food or water. According to the CDC, it can disperse easily as a gas or vapor, which means that inhalation exposure is the greatest threat for human health.
Since the effects of sarin occur quickly, decontamination must be done rapidly. According to the CDC, an antidote such as Atropine is available, but it must be given as soon as possible (when symptoms are detected) to be effective (see Figure 4). When entering an area known to be contaminated with sarin, responders should don Level A personal protective equipment (PPE) to prevent further exposure to the toxin.
The Level A suit includes a fully encapsulating chemical-resistant suit that covers a self-contained breathing apparatus, as shown in Figure 5. Victims exposed to sarin need to remove their clothing and seal them in plastic bags. The victims then need to wash their skin with large amounts of soap and water to remove the substance. This is done to protect those who were exposed as well as prevent further contamination.
Figure 1 shows the volatility values of four different nerve agents. Volatility is used as a measurement for the persistence of a substance. The graph demonstrates that sarin will volatilize much faster than the rest of these substances. Since sarin is so volatile, and therefore non-persistent, a larger quantity is usually needed to be effective in an attack.
Figure 5. Level A PPE. (
Figure 1. A Comparison of the Volatility of
Gaseous Nerve Agents
Chemical and Physical Properties
The compound sarin has many chemical and physical properties that are similar for all nerve agents. They are clear liquids that behave like organophosphate pesticides, but nerve agents are much more powerful and dangerous. Sarin is unique in many ways, mainly that it is odorless and has a high volatility rate. Table 1 below shows a few of these properties. Since its specific gravity is above 1.0, sarin will tend to sink in water. It also will sink in air due to its vapor density exceeding Because sarin gas is odorless, colorless, and tasteless, it becomes highly difficult to detect its presence.
Sarin is soluble in water, which means any water used for decontamination of a sarin attack should be handled as hazardous as well. According to the Agency for Toxic Substances and Disease Registry, sarin can decompose many metals including tin, aluminum, and magnesium. It can also hydrolyze into hydrogen fluoride when in acidic conditions. The greatest worry for humans is that sarin inhibits the acetylcholinesterase enzymes, which is involved in the neurotransmissions of the nervous system.
Figure 4. Example of an Atropine Pen. (
Health Effects of Sarin Exposure
Even though there are many ways sarin can enter the human body, inhalation and absorption through the skin and eyes are the most dangerous. All nerve agents produce similar symptoms by causing the nervous system to be in “overdrive.” Initial symptoms including nausea, contracting pupils, and headache will occur within seconds of exposure. As the dose increases, the symptoms worsen and can include convulsions and possibly death (OSHA). The mnemonic device SLUDGEM can be used to remember the common nerve agent symptoms (see Figure 2).
The LC50 (lethal concentration of 50 percent of test organisms) is given for four common nerve agents and the poison hydrogen cyanide (Figure 2). Even though sarin is highly toxic, it is not the most dangerous toxin. Cyanide, a well-known poison, requires at least six times the dosage to be as effective as sarin.
Conclusion
Sarin is a toxic chemical warfare agent that can debilitate or kill large amounts of people in the event of a terrorist attack. Sarin inhibits the acetylcholinesterase enzymes from working properly, which in turn causes the nervous system to constantly send signals through the body uncontrollably. Thus exposure can cause “SLUDGEM” symptoms, which can lead to death if not treated promptly. Since sarin will volatilize quickly, it is an immediate and short-term hazard (CDC). Responders should take extreme precautions when entering an area contaminated with sarin, especially if the concentration is unknown. Victims of sarin exposure need to have their clothing and skin decontaminated immediately. Even though sarin is not the most potent toxin, it should still be viewed as a dangerous weapon of mass destruction.
Table 1. Physical and Chemical Properties of Sarin
Common Symptoms
Salivation
Lacrimation
Urination
Defecation
Gastrointestinal upset
Emesis
Miosis
Figure 2. Symptoms of a Nerve Agent Exposure
Figure 3. Lethal Concentrations (LC50) of Toxic Agents Through Inhalation
References