Nerve Agent and VX Review

By David Millstein, April 2017
Your flight is delayed. As you sit with perhaps hundreds of other people in the terminal you become bored, even frustrated as times slowly passes. It’s late and you want to get home. Glancing up, you notice a small commotion at a gate desk and you assume it is another frustrated passenger with yet another delayed flight. But this is different, people start to run in every direction. Some scream. As you stand to get a closer look, you see a man clutching his face, covering his eyes. He appears sweaty, coughing – people rush to help as he collapses to the floor.
Although this might sound like a movie scene, it is a distilled version of the assassination of Kim Jong Nam on February 13, 2017. In the middle of a crowded airport two individuals wiped or otherwise contacted the face of Kim Jong Nam, introducing the nerve agent VX. He was dead by the end of the day.1 This is the first of a two-part article discussing some nerve agent and VX basics that are worth refreshing.
Terrorism and Weapons of Mass Destruction (WMD) events have received extensive coverage in the media during the past two decades. Internationally, governments have focused significant resources into the planning, training, educating, and information-sharing of WMD intelligence. Although the use of WMD agents is not new over the past twenty years, the use of VX in this manner is and that should raise concerns in the planning and response community. So with all of the media coverage, government spending, Fusion Centers, and training available, are we any more knowledgeable or prepared to response to a WMD event? Did this use of VX agent in the above manner raise any concerns?
There are dozens of examples of WMD attacks, from terrorist organizations, cults, to actual and theorized government uses.2 Clandestine synthesis of nerve agents is feasible as shown by the Aum Shinrikyo in 1994 when Tadahiro Hamaguchi was assassinated with VX.5 VX is now back on the RADAR and it should serve as a good catalyst to refresh on nerve agents.
HISTORY
Pesticide research was the precursor to nerve agent development. In fact, nerve agents were recognized as potential WMDs in the hunt for a better “bug killer” dating back to Germany in the 1930’s. It wasn’t long until governments realized the potential application of these chemicals in the military theater, and significant production and stockpiling occurred.7 Today, production of these chemicals is limited by international treaty, however this does not mean all countries participate (they don’t.)12 This also doesn’t mean that non-governmental organizations are unable to covertly develop or otherwise obtain these chemicals. Both are cause for concern since surveillance and intelligence can be a serious challenge.
NERVE AGENTS
There are two primary categories of nerve agents: G-agents and V-agents. G-agents were developed in Germany and include GA (tabun,) GB (sarin,) GD (soman,) and GF (cyclosarin.) 7 The “G” in these agent names stands for Germany, the country of development. V-agents were developed outside of Germany (the United Kingdom is one example) and include VE, VG, VM, VR, and VX. 7,13 Of the agents listed, the most common are GA, GB, GD, and VX.7
Nerve agents are organic compounds (containing hydrogen and carbon) combined with phosphorous and TWO oxygens, and are often referred to as organophosphates, organo-phosphorus compounds, or phosphorous esters.13 The key to recognizing organophosphates is to identify that they contain C, H, P, and 2 oxygens (O2) as shown in their molecular formulas in the following table. NOTE: Brackets added for emphasis.

MOLECULAR FORMULAS11
GA
[C5H11]N2[O2P] GB
[C4H10]F[O2P] GD
[C7H16]F[O2P] VX
[C11H26]N[O2P]S
​​​​
Specifically targeting the nervous system, these chemicals inhibit (or block) the enzyme acetylcholinesterase. This enzyme is used to “breakdown” acetylcholine which is used to tell the muscle or organ to “do something” such as contract. If this block (also called a neuromuscular blockade) occurs, the muscle or organ is unable to relax which leads to loss of muscle and organ control.5 Death occurs due to paralysis of the respiratory system, particularly the diaphragm, and can occur within minutes.8 The primary route of entry is inhalation although ingestion and absorption (skin, mucous membranes, ocular) are also common and can be significantly worse.8 A useful way to remember the signs and symptoms is the SLUDGEM mnemonic and it is a useful tool to identify nerve agent exposure.

It is important to note that organophosphates is a large class of chemicals, not all of which are considered to be WMD agents. Many insecticides used today are based on organophosphates, so it is possible to encounter exposed persons just about anywhere. “Location” will be touched on in the next section, but barns, storage facilities, pest control companies, “big box” stores, are a few locations that might contain significant quantities of these chemicals.
In general, G and V agents are colorless liquids, typically odorless, with varied volatility. V-agents differ from G-agents in terms of toxicity and persistence. In other words, when v-agents are present, they are there to stay until they are removed or degrade.13 Note the EXTREMELY low VP and Volatility of VX in the following table.

VX SPECIFICS (9, 10)
• VX is a manmade military-use organophosphate nerve agent.
• Molecular formula: C11H26NO2PS
• Class: organophosphate à contains phosphorous (P)
o Also considered an “organothiophosphate” à contains phosphorous (P) AND sulfur (S)
o thio- Means “sulfur”
• VX gas is heavier than air, has no odor, no taste, and can be clear to amber in color.
• VX is the most viscous (often compared to motor oil) and least volatile of the nerve agents.
• Routes of exposure: inhalation, absorption (skin, ocular, mucous membranes,) and ingestion.
o Repeated exposure can cause a “cumulative effect”
o The length and strength of exposure can determine severity and speed of symptom onset.
o Absorption is the primary concern
• Effects can be seen within seconds or delayed for hours.
• VX is PERSISTANT. It can remain at a hazardous level in the environment for days.
QRESPONDER ENCOUNTERS13
As was indicated earlier in this article, VX is a nerve agent designed by and for use in military theaters yet it has also shown up in non-military attacks, which is certainly cause for alarm. Whether manufactured in a clandestine manner or obtained from a military source, VX is chemical that CAN be found in the civilian population. The methods to disperse the agent are varied and can come from something as simple as a point-of-contact exposure or contamination of food or water sources (PERSISTENT). It can also be dispersed or weaponized through explosive ordinance or IED-style devices, introducing a wider-spread vapor exposure concern, potentially to a much larger population. The point here is simple: be alert for nerve agent events.
WRAPPING-UP
Up to this point, we have discussed the history and characteristics of nerve agents, with a bit of added detail for VX. This is not intended to be an all-inclusive article about these topics, but to provide a refresher for material that you’ve likely seen before. These events are infrequently encountered by responders, especially in North America, but their severity warrants this discussion. Response to nerve agent incidents are low frequency-high risk events that require practice and a solid knowledgebase to properly recognition and respond so they can be safely mitigated. Nerve agents are designed to kill and improper recognition can cause injury or death to response personnel if not identified rapidly. The second part of this article will look at size-up considerations and some discussion about instrumentation and who to call for assistance.

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David (Dave) Millstein has been involved in the emergency services since 2000 as a volunteer in Pennsylvania. Early in 2004 he began working for the USFA supporting the NFIRS system at the local, state, and federal levels. Later that year he began his career with Frederick County (MD) Fire/Rescue, where he currently serves as a Lieutenant on the HazMat Team. Originally from Massachusetts, he decided to stay in Pennsylvania after obtaining a business degree from Gettysburg College. Dave’s passion is focused on leadership and management in the areas of HazMat/WMD and homeland security. This includes training development and management to prepare personnel for current and future threats/hazards, creating policy and procedure to address real problems, and data-driven decision making. When he is not working, he enjoys hiking, Tae Kwon Do with his family, and reading.[/author]

NOTES/REFERENCE
1. https://www.opcw.org/fileadmin/OPCW/EC/84/en/Malaysia_ec84_statement.pdf. Accessed 28 March 2017.
2. https://www.stimson.org/content/ataxia-chemical-and-biological-terrorism-threat-and-us-response. Accessed 28 March 2017.
3. https://www.fbi.gov/history/famous-cases/amerithrax-or-anthrax-investigation. Accessed 28 March 2017.
4. https://www.opcw.org/news/article/the-sarin-gas-attack-in-japan-and-the-related-forensic-investigation/. Accessed 28 March 2017.
5. http://www.cs.amedd.army.mil/Portlet.aspx?ID=bddf382f-3ca0-44ba-bd67-fdc48bfa03de. Accessed 28 March 2017.
6. https://www.opcw.org/about-chemical-weapons/types-of-chemical-agent/nerve-agents/. Accessed 29 March 2017.
7. https://fas.org/programs/bio/chemweapons/cwagents.html. Accessed 29 March 2017.
8. https://emergency.cdc.gov/agent/vx/basics/facts.asp. Accessed 29 March 2017.
9. https://www.osha.gov/SLTC/emergencypreparedness/guides/nerve.html. Accessed 29 March 2017.
10. https://pubchem.ncbi.nlm.nih.gov. Accessed 29 March 2017.
11. https://www.opcw.org/chemical-weapons-convention/. Accessed 29 March 2017.
12. http://www.toxipedia.org/display/toxipedia/Nerve+Agents. Accessed 29 March 2017.
13. https://emergency.cdc.gov/agent/vx/basics/facts.asp. Accessed 29 March 2017.

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