On the morning of February 13, 2017, travelers at Kuala Lumpur International Airport in Malaysia witnessed an incident that would soon make global headlines. Among the crowd was Kim Jong-Nam, the estranged half-brother of North Korean leader Kim Jong-un. Within an hour of a seemingly random encounter, he was killed by one of the most lethal nerve agents ever developed: VX.
Security footage later revealed two women approaching Kim Jong-Nam in quick succession. Each appeared to smear something across his face before hurrying away. Initially confused, Kim Jong-Nam sought help, reporting that someone had “wiped a liquid” on him. He collapsed minutes later, succumbing to respiratory failure before reaching the hospital. The cause: exposure to VX nerve agent, a highly toxic organophosphorus compound banned under international law.
According to the Centers for Disease Control and Prevention (CDC), VX is an odorless, tasteless, oily liquid that acts on the body’s nervous system.1 Developed in the 1950s during chemical warfare research in the United Kingdom, VX was designed as a “persistent agent,” meaning it could remain deadly on surfaces for days. Even a single drop on the skin can be fatal.
VX disrupts normal muscle function by blocking the enzyme acetylcholinesterase, which is responsible for breaking down the neurotransmitter acetylcholine. Without this regulation, muscles contract uncontrollably, leading to seizures, paralysis, and respiratory arrest.
The Organization for the Prohibition of Chemical Weapons (OPCW) classifies VX as a Schedule 1 chemical weapon, meaning it has no known legitimate use outside of military research. The Chemical Weapons Convention (CWC), which came into force in 1997, bans its production, stockpiling, and use.
Investigations revealed that the compound used on Kim Jong-nam was a binary form of VX, often referred to as VX2. In this form, two harmless precursor chemicals are stored separately and become lethal only when mixed.
Each woman in the assassination carried one half of the chemical formula. When the first woman smeared her compound on Kim’s face, nothing happened. When the second followed moments later with the second compound, the two substances combined on contact with the skin, instantly forming VX.
The women—Siti Aisyah from Indonesia and Đoàn Thị Hương from Vietnam—claimed they were told they were participating in a prank video for a television show. They were unaware that the chemicals they applied were deadly. Both were arrested and charged with murder but were later released after serving prison sentences for lesser offenses.
VX was first synthesized by British chemist Ranajit Ghosh in 1952 while developing pesticides. The compound was later weaponized for military purposes during the Cold War and stockpiled by both the United States and the Soviet Union.
Due to its extreme toxicity and lingering environmental effects, the U.S. Army classified VX as one of the most dangerous chemical warfare agents. Its use is now banned globally, and the United States completed the destruction of its VX stockpile in 2023 under OPCW supervision.
When VX enters the body—through skin contact, inhalation, or ingestion—it blocks communication between nerves and muscles. This causes muscles to contract continuously without relaxation. Death usually occurs due to asphyxiation, as the diaphragm, the muscle responsible for breathing, becomes paralyzed.
The antidote to VX poisoning is a combination of atropine and pralidoxime, which can restore enzyme function if administered immediately. Kim Jong-nam reportedly carried multiple vials of atropine, suggesting he may have been aware of previous threats to his life.
Is VX Still in Use Today?
Although officially banned, small-scale incidents involving VX and similar agents have surfaced. The 2017 assassination was the first confirmed case of VX use in a civilian setting. Experts suggest that rogue states or terrorist groups could still attempt to synthesize it in secret laboratories, though such efforts are closely monitored by international agencies.
VX may no longer be stockpiled officially, but its legacy continues to serve as a grim reminder of the thin line between science and destruction.
The Kim Jong-Nam assassination remains a chilling example of how weapons of mass destruction can be turned into tools of covert political violence.
References:
National Institute for Occupational Safety and Health (NIOSH). “Emergency Response – VX: Nerve Agent (ERSH DB Card 29750005).” Centers for Disease Control and Prevention, last revised ___. Accessed October 25, 2025. https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750005.html. CDC
Johnson, Quentin. “The Case of Kim Jong-nam and Questions of International Law.” Yale Journal of International Law Forum, August 17, 2017. Accessed October 25, 2025. https://yjil.yale.edu/posts/2017-08-17-the-case-of-kim-jong-nam-and-questions-of-international-law.
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