Nerve Agent Detection

When we look back to the nerve-agent research and development in history, we can find two common unifying factors:

1. All nerve agents contain organophosphorus compounds.
2. All nerve agents were originally developed to be pesticides, but turned out to be too toxic (later in history, that was a good reason for 4^th generation nerve agents).

Pesticides are usually less toxic and have “safer” characteristics other than “military-use-updated-pesticides” aka nerve agents. Organophosphorus is a chemical compound that causes “nerve poisoning” and triggers the CWA alarms in chemical detectors.

When measuring also other chemicals, with current gas detectors, these are able to classify nerve agents, and some devices even make a wheel-of-fortune guessing type to identify the agent’s name.

Terrorist and other rogue actors are likely to use, or are willing to use, Sarin nerve gas. According to various sources, Sarin is easier and cheaper to manufacture than other nerve gases, such as Soman or Tabun. Sarin is also known for having “better” features:

• Sarin is a liquid at room temperature
• Sarin evaporates quickly forming a colourless, odourless, and deadly poison gas

Have we really detected a nerve agent?
There will always be delays in recognising the nature of usage of a poison gas during an attack.

First there is the incident recognition problem: this will allow for distinguishing it from a non-intentional chemical release — however, since nerve agents are CWA’s which development, production, stockpiling and use is banned by the CWC (Chemical Weapons Convention), an incident involving the dispersion of a nerve agent will always be considered intentional. Secondly, there needs to be capability for gathering information, constructing a pattern with the data, and making it reach to the chain of command. These correspond for both immediate, to short term response actions.

Something is wrong! There are sick people. People are complaining of eye pain and visual darkness!
First responders are responsible for gathering information when they arrive to the scene. These are not always fire fighters or police officers, first responders can also be, for instance, private security service guards. It is a must for responders to use adequate personal protection equipment before entering the scene, to prevent them from becoming victims themselves, and to avoid spreading the contamination.

Information collection on the incident scene is done visually and by using professional tools. The detection of a nerve agent should always be confirmed by using multiple types of detection technologies. An example of these supporting tools — to be used after a chemical detector alarms for nerve agent classification — are the 3-colour chemical papers, or simple straps. These normally work only for droplets, not for fumes in the air. Another possible tool consists on the usage of colorimetric tubes, but the process can take long if the user is not used to operate them.

A sophisticated chemical detector not only detects the chemical agent, but also classifies it as nerve agent, providing relevant information e.g. that the concentration is higher than the selected dangerous level. The operator can even visually see and hear, that the colourless gas nerve agent concentration on ambient air is rising when approaching the potential source, and vice versa, when walking away from it. Handy, isn’t it?

Putting together first victims’ symptoms, visual findings on the scene, and detection results provided by the detection tools and confirmed classification, the operators can quickly elaborate first conclusions that the chemical present on the scene is an organophosphorus based agent.
But can a normal house-hold bug-killer cause these same symptoms when people are overly exposed to it, or is it only nerve agents? Well… common sense is a stunning tool!

With the perfect chemical detector, an operator can confirm his result by finding out more “key info” about nerve agents on the chemical detector’s inbuilt agent database. This database automatically sorts the agents’ groups, and recommends the potential chemicals according to the detection information. This way, the operator can check basic characteristics of the chemicals, and compare them to those on the scene.

Sarin or even VX?
Both are odourless and colourless – Check!
In both cases exposed people’s symptoms are similar: pinpoint pupils, runny nose, and breathing difficulties – Check!
But, VX is a low volatile and persistent chemical, whereas Sarin is highly volatile and non-persistent! Further measurements may be required, if the operator haven’t found how the gas acts on low and high levels of the scene space. If it is possible to still find droplets or liquid, then the measuring distance from these also indicates the agent.

The biological symptoms of exposed victims are also a key factor to get the first level of identification, concerning to the present chemical agent. The agent’s name is not needed to start first aid actions, and to eventually save lives. The first classification of the agent’s group is enough to prescribe drugs that will mitigate the symptoms, like atropine, in the case of nerve agents.

Nobody wants to have un-wanted indications or false alarms on scene, that is true… But is it better than no indication at all? When first responders operate with early-warning detectors which are able to detect and classify tens of chemicals on real-time, it is always possible to have a detection indicator / alarm from some other similar type of agent. Many times, first responders comprised CWA-TIC detector to a single gas TIC detector which does not give false alarms… or do they (cross sensitivity chemicals)?

In order to support operators, and their common sense, the agent’s database also shares insights of where the detected chemicals or precursors in use can be found.

Chemical agents, in particular toxic chemical agents, are not familiar for all first responders (“first men on the scene”) and when their appearance is combined with a “coordinated” and a multi-site attack, not even trained fire fighters always handle it so well.

To ease the chemical agents’ detection and response actions, many operators need to have guidance at hand, on the scene, inside the hotzone. To speed up the response and incident management, real-time information at the incident site should become a “normal” feature. Everybody knows where others are moving and what are their statuses. This shared information can or have to be also possible over responsible sectorial levels, to save lives and resources.

Long story-short, the steps for detecting a nerve (or any other chemical) agent are:

Locate – Detect – Classify – Confirm – Monitor

Is all of this my own science fiction? Or is it based on real-life experiences, and lessons learned from historic events? Or can it be a depiction of the features of our new generation handheld chemical detector ChemProX, and how to get the best benefits from it?