The 10 Most Dangerous Chemical Weapons

The last of three nitrogen mustard agents developed, HN-3 is a colorless or pale yellow liquid or vapor that acts as a vesicant (blistering agent) and alkylating agent, which alters cells, affecting the DNA and suppressing the immune system. It can enter the body through aerosol inhalation, ingestion, or direct contact with skin or eyes. Although its cellular action is immediate, its painful effects may take days to fully develop. Nitrogen mustards have not yet been used in warfare.

Similar to HN-3 and colloquially known as mustard gas, this liquid or vapor vesicant was first utilized in battle during World War I, and has been used extensively in many armed conflicts since. It can be deployed by bombs, artillery shells, or direct spraying. About 1,800 tons of HD were deployed by Iraqi troops against the Iranian military, civilians, and Kurds during the Iraq-Iran war (1980-1988), leading to thousands of deaths.

Tabun, which can be absorbed through skin contact, ingestion, or inhalation, can cause death within minutes of exposure. It was first mass manufactured by Germany during World War II, although the factory and its contents were subsequently seized by the Soviets and shipped to Russia. Tabun was among many chemical agents that the Iraqi Army used against Kurdish civilians in the 1988 Halabja Massacre.

Sarin, which can kill victims in minutes, was first discovered by German scientists while attempting to synthesize pesticides. Although Nazi Germany may have produced up to 10 tons of the nerve agent, it was never deployed against Allied troops. It has subsequently been used in numerous battles, chemical attacks, and possibly even an assassination. The Aum Shinrikyo cult used sarin in the 1995 Tokyo subway terrorist attack.

Another of the G-series of highly toxic nerve agents discovered by German scientists, cyclosarin works similarly to sarin, although its liquid form evaporates much more slowly, making it a more persistent chemical agent. It has rarely been mass-produced because its ingredients are more expensive than those for sarin. Iraq is the only country known to have produced significant amounts of GF, used during the Iraq-Iran War.

Soman was discovered by German biochemists in 1944 but was never used during World War II. It may smell like camphor, mothballs, or rotting fruit, and can be deployed through air, water, food, or surface contact. Symptoms can appear within seconds after inhalation, and within minutes after liquid contact. As soman is quite volatile, it evaporates quickly and doesn’t pose a lasting threat after its initial deployment.

First synthesized in 1904, this vesicant and lung agent, which contains arsenic, has the ability to penetrate regular clothing and latex gloves. It was produced in Ohio during World War I, but was never deployed in battle. Stockpiles in the U.S. were eventually neutralized and dumped into the Gulf of Mexico, but World War II stockpiles abandoned in China by the Japanese are known to have caused multiple accidental deaths.

Also used as a pesticide, this lung-damaging agent was used by the Germans during World War I as a tear gas that induced vomiting, causing Allied troops to remove their gas masks and become exposed to other chemical agents. Although it is no longer authorized for use in war, the suspected poisoning of Russian billionaire Roman Abramovich and other delegates at peace talks on the Ukrainian border in early March of this year may have been caused by chloropicrin.

Classified as an urticant (a chemical agent that corrodes skin tissue on contact), phosgene oxime causes instant, unbearable pain. In liquid form, it can quickly penetrate rubber and protective gear, causing rapid skin damage that can make a victim more susceptible to secondary chemical agents used in tandem with it. Not to be confused with phosgene, which was used extensively during World War I as a choking agent, CX has never been utilized in battle.

Discovered in the U.K. in 1952, VX was subsequently produced by the U.S. Army in 1962. As little as one drop of VX (short for venomous agent X) on the skin can lead to death within minutes. Trace evidence suggests that VX was deployed by Cuban troops during the Angolan Civil War in the ’80s, and Iraqi troops during the Iraq-Iran war. It was also utilized in the assassination in exile of Kim Jong-nam, the eldest son of former North Korean leader Kim Jong-il.