Chemical Weapons of Mass Destruction – How they Kill, Explained.

The United States Government announced today that it has evidence that strongly suggests that the Syrian army has used chemical weapons, namely sarin gas, against the rebels that are revolting against the Syrian dictator, Bashar Al-Assad — Chemical weapons have been used since antiquity, mostly in the form of noxious smokes that were used to encourage defenders to evacuate castles and the like. The Byzantine Empire successfully employed  an ancient form of napalm called “Greek Fire” that they used to dominate the Mediterranean Sea during the age of galley warfare, a concoction which I suppose might technically fit into the category of chemical warfare agents. However, chemical warfare as we generally think of it today – deadly gases that are released into crowds of people – didn’t take off until World War I. The German army was the first to use chemical weapons in the form of chlorine gas in 1915, but the Allies soon followed suit and before long both sides were blasting each other with gases that had the nasty habit of blowing back onto their own troops whenever the prevailing winds shifted, which was a common occurrence. Adolf Hitler was one of the unlucky grunts who was gassed in the trenches of “The War to End all Wars” (a poor choice of monikers in retrospect, huh!) and this experience kept his trembling hand off of the chemical weapons trigger during World War II, this despite the fact that Nazi Germany possessed ungodly quantities of chemical bombs and artillery shells. The Soviets and the Allies responded in kind and chemical warfare has been a global taboo ever since. Saddam Hussein was one of the few leaders of a modern state to defy the world’s antipathy towards chemical weapons when he used them against revolutionary Iran during the 1980s. The Iranians responded in kind – later Mr. Hussein would stoop to a new low when he used chemical weapons to gas Kurdish citizens of his own country.

There are four main types of chemical weapons. I have listed the categories and a stereotypical agent of that category below. Also explained are the effects of exposure to these horrible weapons and the antidotes/treatments for people who have been exposed. Remember that the gases that are used in chemical weapons are generally heavier than air and that they settle as a result – in other words, moving to a higher place during a chemical weapons attack is usually a better idea than crouching to the ground or moving to an area of lower elevation like a basement. Also, the first step of treating exposure to just about any chemical agent is to remove the victims clothing (tell them to do it so that you don’t expose yourself), to wash them down with soap and water and lots of it (a hose works well so that you don’t touch the exposed person and contaminate yourself), and to seek immediate medical assistance. All of these treatments, even the basic stuff, should be performed by trained personnel if those personnel are available because it is very easy to fatally contaminate yourself while trying to help someone who has been exposed to chemical agents, particularly nerve agents, and that doesn’t do anyone any good. By the way, I’ve never had to deal with a chemical weapons attack in “real life” (thank god), but I know a lot about the subject because I trained in medical decontamination drills when I was in the military on multiple occasions.

1. Pulmonary Irritants — Chlorine gas. Chlorine gas is widely available because it is used in all sorts of industrial processes. Other agents in this class are similarly easy to get, ammonia for instance, which is used as an industrial cleaning agent and in some refrigeration processes. Irritant agents are directly toxic to the tissues that they come in contact with, especially moist tissues like the eyes and the lungs, both of which suffer searing injuries when chlorine is aerosolized and dispersed by the bad guys. Chlorine causes blindness and acute lung injury – the acute lung injury is what kills the victim and it can sometimes be treated with a combination of bronchodilators (e.g. medications like the albuterol that is used in your kid’s asthma inhaler), corticosteroids (e.g. prednisone), and mechanical ventilation (“life support”).

2. Blood Toxic Agents – Cyanide. Your body consists of an interconnected lump of cells that work in concert to make the being known as “you” and every cell in your body is a tiny little chemical power plant. Your body cells stay alive and functioning by taking up glucose and free fatty acids from the food you eat and then “burning” it via a reaction with the oxygen that you breathe to form energy to power the cells activities. Cyanide works by poisoning one of the essential enzymes in the biological chemical reaction that turns food + oxygen into energy. Thus cyanide causes your body to essentially suffocate and to starve to death simultaneously. Yes, a victim of cyanide poisoning still has plenty of glucose, fat, and oxygen, just like they did before they were exposed to the cyanide. But they can’t use any of it because of the cyanide so the net effect is basically the same as being starved for a few months and then tying a plastic bag over your head and around your neck. The treatment for cyanide poisoning is with 100% oxygen (the stuff you’re breathing right now is 21%, unless you’re on top of a mountain in which case it is less) and with specialized drugs called sodium nitrite and sodium thiosulfate (hydroxycobalamin, a form of vitamin B12, also works) that help your body get rid of the cyanide. You may remember that some nasty people in Chile during the 1980s poisoned apples bound for America with cyanide – what you may not know is that cyanide is readily available in every city and town in America because it is used by jewelers and other professionals as a cleaning agent. Cyanide smells like almonds because, big surprise, almonds contain cyanide. By the way, never eat wild almonds because they contain enough cyanide to make you very ill–the grocery store kind were selected by humans over the centuries and have thus evolved into the nontoxic kind that I’m eating while I write this blog post!

3. Blistering Agents – Mustard Gases. These miserable creations—and yes, there are several different types of mustard gases—cause severe blistering and, like the irritant agents, are especially fond of causing respiratory failure by blistering your lungs and blindness by destroying your eyes. Mustard gases have nothing in common with the mustard that you eat on your yummy, greasy, mystery meat hotdog. Rather, “mustard” in this case refers to a specific type of organic chemistry reaction that I’m not going to explain because I forgot that crap a decade ago! It is interesting that several chemotherapy drugs are related to the mustard gases. One of these drugs is cyclophosphamide, a miserable chemo drug that is used to treat a plethora of cancers including leukemias and lymphomas. Cyclophosphamide can cause you to urinate frank blood and it can also knock out your bone marrow and set you up for a catastrophic infection (recall that white blood cells fight off the bacteria, fungi, and parasites that are constantly trying to eat your body—including right now!). Mustard gases also destroy your bone marrow, so if they don’t kill you right away by destroying your lungs they may get you a few weeks later by knocking out your bone marrow. If you are unfortunate enough to be exposed to a large dose of aerosolized mustard gases you will also likely be blind; good times! Dimercaprol is a chelating agent–a drug that is used to bind heavy poisons and it can be used to treat mustard gas exposure. Dimercaprol is also used to treat arsenic, mercury, and (sometimes) lead poisoning. The good news is that mustard gases are highly unstable and that it is difficult to transport them, qualities that make mustard gases a less than ideal weapon for terrorists.

4. Nerve Agents – Sarin. Sarin, tabun, and VX gases are probably the worst-of-the-worst when it comes to chemical warfare, and they are what Mr. Al-Assad is accused of recently using against his people. All of these agents are colorless, odorless, and deadly in microscopic doses. They also kill in a horrific fashion, thus making the nerve agents excellent weapons from the terrorists’ point of view. Nerve gases work by inhibiting an enzyme in your body called acetylcholinesterase. Acetylcholinesterase breaks down acetylcholine, a neurotransmitter that controls the contractions of the muscles of your body, that controls “housekeeping” functions like defecation and urination, and that regulates the secretion of body fluids. So how do nerve agents work??? Blocking acetylcholinesterase results in increased levels of acetylcholine because it prevents the body from recycling the acetylcholine that it has already released. Normally, acetylcholine is released by a nerve cell, passes on its message to a muscle or gland cell, and then it is rapidly recycled–nerve agents block the recycling of this potent neurotransmitter causes acetylcholine to build up to dangerous levels in the body. Increased acetylcholine makes your eyes tear like after a teenage breakup, makes you salivate so profusely that you choke on your own saliva, and causes you to urinate, vomit, and defecate uncontrollably just for good measure. But it gets worse. Acetylcholine also controls the contractions of skeletal muscles and, paradoxically, when too much acetylcholine is present for too long the skeletal muscles first spasm uncontrollably and then become paralyzed. Since the muscles that control breathing– namely the diaphragm and the intercostal muscles between your ribs–are skeletal muscles you stop breathing and die. Luckily many of the effects of nerve agents can be blocked and sometimes even reversed by the prompt administration of atropine and 2-PAM. These drugs are administered intramuscularly just like a tetanus shot—the “inject it into your heart” technique that is seen in the movies is Hollywood drama and a really terrible idea! Mechanical ventilation may also be necessary in victims of nerve agents, the downside being that in a major nerve agent attack on a large population center there probably wouldn’t be nearly enough ventilators to save everyone. Poisoning with nerve agents (aka: organophosphates) can also occur accidentally because farmers use relatives of these deadly weapons as pesticides. An isolated incidental exposure is usually easy to spot because terrorists are unlikely to target a couple of farmers in North Dakota and because organophosphate pesticides are unlikely to normally be present in the subway system in a major metropolitan area.

Dr. Leonardo Noto

Physician and Author of Medical School 101, Intrusive Memory, The Life of a Colonial Fugitive, and The Cannabinoid Hypothesis.

Author Bio: Dr. Leonardo Noto is the nom de plume of a former airborne battalion surgeon who is now in civilian practice. Dr. Noto is the author of four books and he also writes for a medical education corporation that assists medical students, interns, and residents as they prepare for the medical board examinations. Dr. Noto is the proud father of an extremely spoiled 12-month-old American Bulldog who enjoys slobbering everywhere and tearing up things that he is not supposed to! Dr. Noto is an amateur practitioner of muay Thai and Brazilian jiu jitsu and he recently began learning to play the guitar (but he is currently a quite terrible musician, as his neighbors will readily attest).

Remember to discuss all health concerns with your personal physician (I don’t count!) before making any medical decisions. is intended to present general medical information for entertainment purposes and not as specific guide to any medical treatment. The author has made every effort to present accurate information; however, due to the ever-changing nature of medicine and the intrinsic caveats that are inherent in any particular case, no medical decisions should ever be made based on information gleaned from the internet (duh!). The internet and self-education are great, but they don’t replace your Doc!

The Life of a Colonial FugitiveIntrusive MemoryMedical School 101The Cannabinoid Hypothesis


Beary JF and Arkadi Chines. Chemical terrorism: Diagnosis and treatment of exposure to chemical weapons. In: Accessed 25 APR 2013. In: Accessed 25 APR 2013.