Larry Slawson received his Masters Degree at UNC Charlotte. He specializes in Russian and Ukrainian History.
Throughout the world, there exists a large array of weapons designed to inflict maximum casualties (and fatalities) on enemy forces. Although nuclear weapons continue to be one of the greatest threats of the modern age, chemical weapons are a close second in regard to their power, potency, and overall destructive capabilities. This article provides a direct analysis of the 10 most powerful chemical weapons known to exist. From their introduction in the 1900s to the present day, this work examines their history, effectiveness on the battlefield, and overall threat to both civilians and military personnel. It is the author's hope that a better understanding (and appreciation) of chemical weapons will accompany readers following their completion of this work.
The 10 Most Powerful Chemical Weapons in History
- Mustard Gas
- 3-Quinuclidinyl Benzilate (BZ)
- Chlorine Gas
- Phosgene (CG)
- Sarin (GB)
- Soman (GD)
- Novichok Agents
10. Mustard Gas
Sulfur Mustard, also known as “Mustard Gas,” is a highly potent chemical weapon first used by the German Army during World War One against entrenched troops. Although rarely fatal (with less than 1-percent of individuals exposed to the gas dying), mustard gas is capable of incapacitating large numbers of people within two to twenty-four hours after exposure, leaving victims with severe skin, eye, and respiratory burns (usually first and second-degree burns). In more severe cases, the gas is known to cause permanent scarring, DNA damage, as well as complete blindness. Due to the relatively simple procedures involved in storing the chemical agent, mustard gas can be delivered by a wide array of munitions, including aerial bombs, mines, mortars, rockets, and artillery shells. After delivery, the gas is often referred to as a “persistent weapon” due to the fact that the chemical remains on the ground for several days (or weeks) depending on weather conditions. Initial symptoms of exposure are usually categorized as mild to moderate in severity, and include runny nose, coughing, skin and eye irritation, sensitivity to light, temporary blindness, sneezing, abdominal pain, diarrhea, nausea, and vomiting (cdc.gov).
Although outlawed by the Geneva Protocol of 1925 and the Chemical Weapons Convention of 1993, mustard gas has been used by a variety of nation states and terrorist groups during the last 100 years, including the Soviet Union, Iran, Iraq, Sudan, Egypt, Syria, and most recently, ISIS.
9. 3-Quinuclidinyl Benzilate (BZ)
3-Quinuclidinyl Benzilate, also referred to as BZ, is a highly potent chemical weapon first developed by the United States during the 1960s. First developed as a gastrointestinal medication, BZ was later rejected by pharmaceutical companies due to its suppression of the central nervous system and unintended side effects. In response, the United States military adopted BZ for its own use during the mid-1960s, creating weaponized forms of the chemical compound that were far more potent than its original formula. As an odorless chemical weapon, BZ acts relatively quickly (within three hours of exposure), suppressing the central nervous system and causing dizziness, confusion, hallucinations, erratic behavior, and loss of basic motor skills. Due to its ability to inhibit glandular secretions, BZ is also known to cause dry mouth as well as skin flushing. In cases involving extreme exposure, coma, seizures, tremors, acute renal failure, and death are common.
The military first deployed BZ against Viet Cong guerrillas during the Vietnam War; however, due to the compound’s unpredictability, control issues, and its relatively long half-life, the United States quickly abandoned the project. Today, it is estimated that BZ is still used by a variety of nation states, worldwide, including the Russian Federation and Syria. The most recent use of BZ involved the chemical attack on Ghouta, Syria by the Syrian regime. Upwards of 1,729 people were killed in the attack, leaving 3,600 individuals severely crippled with neurotoxic symptoms.
Ricin is a highly potent chemical weapon derived from the seeds of castor bean plants. It is highly lethal to humans, and was first developed by the United States military for use during the First World War in either bullets or toxic dust form. Despite being outlawed by the Hague Convention of 1899, the United States and Canada began further study of ricin during WWII, weaponizing the compound in cluster-bomb trials, with the Soviet Union following suit with their own weaponized forms of ricin in the years that followed. Ricin is extremely potent, with a single milligram capable of killing an individual between 4 to 24 hours after exposure. Despite being easy to produce, however, ricin is deeply affected by temperature and weather conditions, making delivery of the substance (particularly through bombs or various weapons) a difficult process to achieve. As a result, ricin is often considered an effective tool for assassinations, rather than largescale attacks on troops or populations. The most famous incident involving ricin can be seen with the 1978 assassination of Bulgarian writer, Georgi Markov, who was killed by an assassin using a ricin-coated pellet. Several international terrorist groups, such as al-Qaeda, have also attempted to use ricin with limited results.
If inhaled during a chemical attack, ricin is known to produce severe respiratory issues, including coughing, labored breathing, tightness in the chest, and eventually respiratory failure within twenty-four hours. Other symptoms of inhalation include fever, nausea, and low blood pressure. If ingested, ricin’s symptoms vary significantly, and include vomiting, inability to eat or drink (causing severe dehydration), seizures, acute renal failure, organ failure, and shutdown of the body’s central nervous system. In both cases, fatalities are common, while survivors of ricin exposure often suffer from long-term complications for the remainder of their life. Although ricin is rarely used as a chemical weapon by modern nation-states and organizations, it remains one of the deadliest chemical agents devised by humans during the Twentieth-Century.
7. Chlorine Gas
Although first discovered in the 1600s, chlorine gas was first used as a weapon during the First World War by Germany on 22 April 1915. During the Second Battle of Ypres, German forces deployed several thousand chlorine gas cylinders on the battlefield with devastating consequences. Nearly two French and Algerian divisions were wiped out by the yellowish-green gas, as the compound immediately began to burn, blind, and choke its victims. Wilfred Owen, a famous British poet from WWI, once equated chlorine gas to drowning, as he described the compound’s victims as “flound’ring like a man in fire or lime.” Possessing a distinctive smell of peppers and pineapples, chlorine enters the respiratory system of its victims, causing severe damage to lung tissue within seconds. Burning nose and throat, coughing, wheezing, nausea, vomiting, watery eyes, chest tightness, blurred vision, pulmonary edema (fluid in the lungs) and death are extremely common.
Fortunately, the development of gas masks with charcoal filters drastically reduced the effectiveness of chlorine gas during the First World War, making it relatively obsolete during warfare. Nevertheless, chlorine is still used as a chemical weapon by various nation states and terrorist groups, worldwide, including Iran, ISIS, and most recently Syria, who has repeatedly deployed the lethal gas against its own populations. Due to the widespread availability of chlorine for sanitation purposes, the compound is easily obtainable and continues to pose a tremendous threat to individuals, worldwide.
Quote on Chemical Weapons
"I believe the proliferation of weapons of mass destruction presents the greatest threat that the world has ever known."
— William Cohen
6. Phosgene (CG)
Phosgene gas is an extremely potent chemical weapon first used during the First World War. Used extensively by both sides of the conflict, researchers estimate that nearly 80-percent of the Great War’s gas-attack victims died from the weapon. Known as the “creeping death,” phosgene is completely colorless and provides only a trace smell of corn or moldy hay after delivery; often taking its victims by surprise. Delivered via gas canisters, phosgene requires carbon monoxide and chlorine (both in the presence of charcoal) to activate. Once used, symptoms usually begin 24 hours later, and include severe coughing, difficulty breathing, vomiting, nausea, blurry vision, burning eyes and throat, skin lesions, pulmonary edema (fluid in the lungs), extremely low blood pressure, organ failure (in particular, the heart), and eventually death.
Following the First World War, countries such as Japan actively incorporated phosgene gas into their military arsenal, using the weapon against the Chinese during the Second Sino-Japanese War. Use of the gas in more modern times, however, has been limited by militaries worldwide. Currently, phosgene exposure is more likely to occur in industrial plants where the chemical is used to make various pesticides and plastics than during an attack (cdc.gov).
5. Sarin (GB)
Sarin gas is an extremely deadly chemical weapon, and is classified as a nerve agent due to its toxicity and impact on the central nervous system of humans. Although originally created as a pesticide by Germany in 1938, the Nazis soon realized the deadly capabilities of the nerve agent and developed weaponized versions for warfare. Although sarin was thankfully never used during the war, the United States and Soviet Union began to develop stockpiles of weaponize sarin gas in the years that followed. Sarin is colorless and contains no odor, making it an ideal weapon for surprise attacks. When activated, the liquid-based agent rapidly evaporates, turning into a vapor (gas) that spreads throughout the nearby environment. The weapon is highly lethal, and is capable of killing individuals within seconds. Sarin works by inhibiting an enzyme in humans known as acetylcholinesterase which, in turn, causes an overstimulation of the body’s muscles and glands (causing its victims to spasm uncontrollably). Depending on the amount of exposure, individuals often die within seconds (or upwards of a few hours in cases involving minor contact).
In cases involving small does of sarin, symptoms begin within seconds to hours of exposure and include watery eyes, runny noses, eye pain, uncontrollable drooling, excessive sweating, severe coughing, confusion, drowsiness, weakness, headaches, accelerated (or occasionally slow) heartbeats, as well as chest tightness, diarrhea, and low/high blood pressure. Large doses, however, involve far more serious symptoms, including convulsions, paralysis, loss of consciousness, muscle spasms, complete respiratory failure, and death (in almost all cases). Although officially outlawed by the 1993 Chemical Weapons Convention, Iraq, Syria, and various terrorist groups have been involved in sarin gas attacks over the last few decades. In 1995, for example, terrorists in Tokyo, Japan released impure forms of sarin into the Tokyo Metro, killing twelve and seriously injuring 6,200 people. More recently, sarin gas has also been used by the Syrian Air Force against rebels and civilians near its Idlib Province. To this day, the gas continues to be one of the deadliest chemical weapons ever designed.
4. Soman (GD)
Soman is a man-made “G-series” nerve agent originally developed as an insecticide by Germany during 1944. As with sarin, however, soman was never used against Allied forces, despite the fact that weaponized canisters of the gas were stockpiled for later use. Soman is naturally clear and colorless (like sarin), but possesses a mild odor comparable to that of mothballs or rotting fruit (cdc.gov). The liquid-based nerve agent is activated with heat, causing it to form into a vapor (gas) that penetrates the surrounding environment. Soman works much like sarin; albeit, at a far more lethal and persistent level, as it directly attacks the human enzyme known as acetylcholinesterase. In doing so, direct exposure (by skin/eye contact or inhalation) quickly causes the body’s muscles and glands to convulse (uncontrollably). Symptoms generally appear within seconds to minutes of exposure. In cases involving low levels of soman gas (indirect exposure), victims usually experience a rapid onset of confusion, uncontrollable drooling, fatigue, nausea, vomiting, abdominal pain, accelerated heart rate, chest tightness, watery eyes, weakness, excessive sweating, and uncontrollable bowel movements/urination, followed occasionally by death. Other symptoms include diarrhea, runny nose, severe coughing, and small pupils. During direct (severe) exposure, however, victims immediately experience convulsions, followed by complete paralysis, loss of consciousness, complete respiratory failure, and death within minutes. Soman is considered highly volatile, and usually disperses within minutes of activation. For this reason, the Center for Disease Control classifies soman as an “immediate but short-lived threat” as it “does not last a long time in the environment” (cdc.gov).
Despite the fact that soman gas was stockpiled by many countries during the Cold War, production of the nerve agent was officially banned by the 1993 Chemical Weapons Convention. As of December 2015, nearly 84-percent of all soman stockpiles have been destroyed, worldwide.
Cyclosarin is a G-Series nerve agent developed shortly after the discovery of soman (1944). Considered five times deadlier than sarin gas, cyclosarin is incredibly lethal to humans and has been classified as a “weapon of mass destruction” by the United Nations. Although the agent shares numerous characteristics with its predecessors sarin and soman (notably its colorless feature), cyclosarin is far easier to detect due to its sweet odor (similar to peaches). In addition to being highly toxic, cyclosarin is also highly persistent, meaning that the liquid-based agent evaporates very slow when heated/activated (approximately 69 times slower than sarin). This is crucial for the weapon’s toxicity, as a slower evaporation rate results in a great chance for environmental exposure, making cyclosarin a highly efficient and deadly weapon on the battlefield. As with sarin and soman, the nerve agent is known to actively attack the human enzyme known as acetylcholinesterase, causing muscles and glands in the body to convulse uncontrollably within seconds of exposure. In addition to convulsions, victims also experience a rapid onset of paralysis across their body, complete respiratory failure, loss of consciousness, and finally, death. Fatalities are quick, usually occurring within less than a minute (upwards of ten minutes).
Fortunately, the high cost associated with cyclosarin production prompted many countries during the Cold War era to avoid mass-production of the weapon. Currently, the only nation to have used cyclosarin in combat was Iraq during the Iraq-Iran War of the 1980s. The chemical weapon is currently outlawed, worldwide.
VX chemical weapons are one of the most dangerous and powerful nerve agents developed in human history. First discovered by the United Kingdom during the 1950s, VX contains an odorless and tasteless mixture that is amber in color (cdc.gov). Unlike other nerve agents of the past, however, VX is comprised of an oily liquid similar in consistency to motor oil. This oily concoction is crucial for its effectiveness as a weapon, as VX has one of the slowest evaporation rates of any chemical weapon in existence, and can contaminate a large area for several days (and for several months if conditions are relatively cold). As with sarin and soman, VX is most effective when heated to high temperatures, causing the agent to form into a vapor (gas). Due to its “heavy” nature, however, VX gas is much heavier than air, causing the gas to be most-effective in low-lying areas as it sinks to the ground. Like most nerve agents, VX directly inhibits the human enzyme known as acetylcholinesterase, causing muscles and glands to kick into overdrive, resulting in severe convulsions. Experts believe that VX is approximately ten times more deadly than sarin, killing its victims within a matter of minutes through paralysis and finally respiratory failure. Even when exposed to lower levels of VX, the Center for Disease Control (CDC) states that individuals are “not likely to survive” a VX attack (cdc.gov).
Following its creation in the 1950s, Great Britain eventually traded the agent’s ingredients for thermonuclear secrets from the United States; prompting a massive buildup (and stockpiling) of V-Series nerve agents in the years that followed. The Soviet Union soon followed suit in the decades that followed. Although most VX stockpiles were dismantled at the end of the Cold War, it is believed that Cuba and Iraq have used variations of VX gas during the 1980s against enemy troops and insurgents, with lethal consequences. More recently, Kim Jong-nam (the half-brother of North Korean leader, Kim Jong-un) is believed to have been murdered with VX gas as well. Examples such as this indicate that the presence of VX gas continues to be a serious threat to the world at large.
1. Novichok Agents
Novichok (meaning “newcomer” in Russian), are a relatively new form of chemical weapons first developed at the end of the Cold War by Soviet scientists. Currently, Novichok Agents are considered the most potent and deadly chemical weapons ever designed in history. Designed under the Soviet program known as “FOLIANT,” former Russian scientists claim that five separate variants of the Novichok were developed between 1971 and 1993, and are estimated to be approximately eight times more powerful than VX (and more than ten times more deadly than soman). Although little is known about these weapons, they are believed to be nerve agents that affect the muscles and glands by suppressing human enzymes (similar to VX, sarin, soman, and cyclosarin). Convulsions and disruptions to the neuromuscular system are believed to be common symptoms with Novichok exposure, with respiratory failure and cardiac arrest following soon after (due to the heart no longer being able to function properly). Exposure is almost always fatal. Even in cases where only small traces of the Novichok agent have come into contact with humans (such as the 1987 Novichok accident in a Moscow laboratory), Andrei Zhelezyakov - the Russian scientist who was exposed only to trace amounts of the agent’s residue - was permanently disabled from the accident, suffering from severe cirrhosis of the liver, epilepsy, depression, and an inability to read, write, or concentrate in the years that followed. He later died in July of 1992, only five years after his brief exposure to the agent.
In contrast to prior chemical weapons, the Novichoks are reportedly capable of being delivered via aerosol, gas, liquids, or powdered form onboard artillery shells, missiles, and bombs with lethal consequences. Despite Soviet claims that all Novichoks (and their production facilities) were dismantled at the end of the Cold War, the recent murders of Russian citizens abroad by Novichok agents (including the 2018 attack on Sergei and Yulia Skripal) has led the United States (and other western countries) to believe that the weapons are still in use by the Russian Federation’s security services. Such claims, however, are difficult to prove as Novichok agents are incredibly difficult to trace. Whatever the case may be, one thing is certain: Novichok nerve agents are the most potent (and deadly) chemical weapons ever developed in human history, and will continue to pose a tremendous threat to civilians and military personnel, worldwide, for the foreseeable future.
“CDC Ricin | Emergency Preparedness & Response.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Accessed August 23, 2019.
“CDC Sulfur Mustard (Mustard Gas) | Emergency Preparedness & Response.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Accessed August 23, 2019.
“CDC VX | Emergency Preparedness & Response.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Accessed August 23, 2019.
“CDC | Case Definition: BZ Poisoning.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Accessed August 23, 2019.
“CDC | Facts About Chlorine.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Accessed August 23, 2019.
Esfandiary, Dina. “The Five Most Deadly Chemical Weapons of War.” The National Interest. The Center for the National Interest, July 16, 2014.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2019 Larry Slawson
Jozef from Slovenia on August 27, 2019:
Thanks for helping keep the memory of the dark side of our history.
Larry Slawson (author) from North Carolina on August 27, 2019:
I agree, Pamela! Its terrifying to think that one of these could be used. It would be a horrible death, for sure!
Pamela Oglesby from Sunny Florida on August 25, 2019:
I am glad to hear sorin and sarin gas were not used in WWII. my husband worked at a plant where chlorine gas was used, and just a fairly small amount was released one night and it called all the trees close by, which is scary. All of these gases sound horrid, with number 10 being the worst, of course.
Larry Slawson (author) from North Carolina on August 25, 2019:
Thank you Hacicu! So glad you enjoyed :)
Hacicu Bogdan from Cluj-Napoca, Romania on August 25, 2019:
Thank you for taking the time to study such an interesting topic and share with us some knowledge that very few people know.