In mid-February 2017 Kim Jong-nam, once favored to be the leader of North Korea, was killed in assassination. The exiled half-brother of the current leader of the isolated country (Kim Jong-il) died after two women accosted him in a check-in hall
at a Kuala Lumpur airport. Reports from the Malaysian government indicate that Kim was attacked using VX nerve agent. This nerve agent is so deadly that it is classified as a weapon of mass destruction by the United Nations
(U.N. resolution 687, adopted on April 3, 1991). VX was banned by the 1993 Chemical Weapons Convention.
The general consensus is that North Korea was responsible for the attack, although the country strongly denies this
. The North Korean authorities have poured scorn over the post-mortem examination.
The geo-political ramifications of the murder continue to be discussed. The focus here is the VX agent. VX is one of the most potent chemical warfare agents (it is far more potent than sarin, another nerve agent toxin). Like many chemicals it looks innocuous, appearing as a clear, amber-colored, oily liquid. It doesn’t taste of anything and it has no odor.
The chemical name for VX is, as with most things chemical, very long: O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate). It is classed as an organophosphate, the general name for esters of phosphoric acid. It is classified as part of the V-series of nerve agents. V-series is a family of nerve agents and contains five members: VE, VG, VM, VR, and VX. Each of the V-agents are what are known as “persistent agents”. This means the agents do not degrade or wash away easily and can therefore remain on clothes and other surfaces for long periods.
VX was discovered by Ranajit Ghosh
, who was a chemist at the Plant Protection Laboratories of the British firm Imperial Chemical Industries (ICI). Ghosh’s discovery was, for a brief while, the basis of a pesticide marketed as Amiton in 1954. The product was shortly withdrawn, being regarded as far too toxic for safe use. The chemical was then examined by the British Army as a potential chemical weapon. This, along with other chemicals, led to the V group of nerve agents being established.
As a chemical warfare agent, VX acts by penetrating the skin. On seeping through the epidermal layers it disrupts the transmission of nerve impulses. Early symptoms of include local muscular twitching and sweating at the area of exposure. This is followed by nausea or vomiting. Other symptoms include having a runny nose and tightness in the chest. Death can occur within a few minutes. There is no standard treatment, although washing skin in the affected area and applying bleach can avoid the spread of the chemical and can lead to recovery, although this treatment needs to be administered quickly. The administration of nerve agent antidote drugs atropine and pralidoxime
can prevent the spread of the chemical and, while they can also be effective, they need to be given within a few minutes of exposure.
The chemical is so potent that a single drop on the skin can kill a person within minutes (ten milligrams or 0.00035 ounces is sufficient for it to be fatal through skin contact). In relation to the assassination, Bruce Bennett, who is a weapons expert at the research institute the Rand Corporation, told BBC News
it would have taken only a tiny amount of the substance to kill Mr Kim. It is not clear whether Kim was killed by spray or direct contact with a contaminated cloth, or a combination of the two methods.
Even at lower doses, sub-optimal to killing, the toxin can cause considerable damage. Depending on where the chemical is applied it can lead to eye pain, blurred vision, drowsiness and vomiting. Although application to the skin was the means by which Kim Jong-nam was killed, VX can be absorbed into the body by inhalation, ingestion, skin contact, or eye contact.
One reason for the VX appearing on the United Nations list of prohibited materials is because in the spray or vapor form the toxin poses a serious risk as a very dangerous chemical weapon. It could be used to eliminate small populations of people or be used to contaminate water, food, and agricultural products, leading to the elimination of a large number of people. The 1996 Michael Bay movie The Rock
centers on a fictional threatened VX attack on San Francisco
from the island of Alcatraz.
The chemical remains toxic for long periods after application. For instance, when sprayed onto clothing the chemical retains its ability to kill for at least thirty minutes.
VX is difficult to obtain and experts suggest that a state would probably need to have been involved. Here the spotlight is shone back at North Korea, considering it is one of just six countries not to have signed the Chemical Weapons Convention (CWC) arms control treaty banning the production, stockpiling and use of chemical weapons like VX. In addition, the Nuclear Threat Initiative project suggests
that North Korea has the world’s third largest stockpile of chemical weapons (following the U.S. and Russia). With North Korea, this could be between 2,500 and 5,000 tons of nerve agents. While North Korea is suspected of holding stock of VX specifically, both Russia and the U.S. have publicly admitted owning VX stockpiles
The Kim case has brought the world’s attention the serious risks associated with chemical weapons and the dangerous effectiveness of these chemicals in the wrong hands.
This article is part of Digital Journal's regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we looked at the novel use of virtual reality to help psychiatrists to assess people with schizophrenia
. The week before we considered neuroscience and how the Internet, by design or otherwise, has come to resemble the neural networks in the human brain