Nerve agentsNerve agents: what are they and how do they work?

By Simon Cotton

Published 9 March 2018

The first nerve agents were invented by accident in the 1930s when researchers were trying to make cheaper and better alternatives to nicotine as insecticides. In their search, German scientists made two organic compounds containing phosphorus that were very effective at killing insect pests. However, they soon discovered that, even in minuscule amounts, the substances caused distressing symptoms in humans exposed to them. The two substances – too toxic to be used as commercial insecticides in agriculture – became known as tabun and sarin. Since then, other nerve agents have been developed, but much less is known about them, although they are thought to work in broadly the same way. Unlike street drugs, nerve agents cannot be made in your kitchen or garden shed, on account of their toxicity, even in tiny amounts. Synthesis of nerve agents requires a specialist laboratory, with fume cupboards. As more details emerge from the case of former Russian spy Sergei Skripal, we’ll know more about the precise substance used and how it should be tackled. Either way, nerve agents are horrendously lethal and chemical warfare is an obscene use of chemicals.

The former Russian spy Sergei Skripal and his daughter are in a critical condition in a hospital in Salisbury, U.K., following exposure to an unknown nerve agent. Several locations in the city have been cordoned off and decontaminated since the pair were found unconscious on a park bench on 5 March. But what are nerve agents exactly and how do they affect the body?

The first nerve agents were invented by accident in the 1930s when researchers were trying to make cheaper and better alternatives to nicotine as insecticides. In their search, German scientists made two organic compounds containing phosphorus that were very effective at killing insect pests. However, they soon discovered that, even in minuscule amounts, the substances caused distressing symptoms in humans exposed to them.

The two substances – too toxic to be used as commercial insecticides in agriculture – became known as tabun and sarin. The research was handed over to the Wehrmacht (the Nazi armed forces), which evaluated them as weapons and began constructing plants to manufacture them. The sarin plant was not operational by the time that the Russians overran Poland and Germany, but they would have acquired the knowledge they had so far.

Pesticide research continued after the war and the molecule known as VX was first made in an Imperial Chemical Industries (ICI) laboratory in the U.K. in 1952. It again proved too toxic to be used in agriculture and it was passed to the U.K.’s Porton Down Chemical Weapons Research Center, and subsequently to the U.S. government, when the U.K. renounced chemical weapons. Its destructive power became clear on 13 March 1968. Somehow, the substance escaped from the army’s chemical weapons proving ground and killed over 3,000 sheep grazing 27 miles away in the Skull Valley area of Utah.

Since then, other nerve agents have been developed, but much less is known about them, although they are thought to work in broadly the same way. Unlike street drugs, nerve agents cannot be made in your kitchen or garden shed, on account of their toxicity, even in tiny amounts. Synthesis of nerve agents requires a specialist laboratory, with fume cupboards.