What are nerve agents and why are they so deadly?

Chemical weapons launched by rockets can indiscriminately kill soldiers and civilians by the thousands.

But assassins can also target individuals with insidious nerve agents such as sarin, VX or novichok, a military-grade nerve agent made in Russia and used in early March against Sergei Skripal, a British citizen, and his daughter Yulia in England.

Infographic showing parts of human body affected by nerve agents (State Dept./J. Maruszewski)
(State Dept./J. Maruszewski)

What is a nerve agent?

Nerve agents are highly toxic chemicals that poison the body’s central nervous system and prevent it from working properly. They are fast-acting. At high doses, they can cause a victim to go into immediate convulsions and suffocate or die from cardiac arrest.

They can be delivered as a gas, aerosol or liquid. They can be released using bombs, explosives, spray tanks and rockets — or even by hand. Kim Jong-nam, half-brother of North Korean leader Kim Jong-un, was murdered at a Malaysian airport last year by attackers who rubbed VX on his face.

Iraq’s former ruler Saddam Hussein used sarin to kill 5,000 Kurds in 1988. The Bashar al-Assad regime in Syria has been accused of using it in attacks on rebel-held territory.

Who invented them?

A German civilian scientist in the 1930s trying to make a more potent crop pesticide accidentally discovered the first nerve agent. It killed pests but also was lethal to animals and humans.

The German military built a factory to make sarin in World War II and stockpiled nerve agents, but didn’t use them in battle.

Are nerve agents easy to recognize?

No. Usually they are clear, colorless liquids that may be odorless or have only a faint, sweetish smell.

How do people come into contact with a nerve agent?

They may inhale the toxic vapor or absorb the chemical through the eyes or skin. It can linger on surfaces, but also can be washed off.

What do they do?

Nerve agents block an enzyme that regulates a chemical vital to normal bodily functions including breathing.

At low amounts of exposure, a person’s nose starts running, the pupils contract, they get nauseous and may hallucinate, get blurred vision, become incontinent and suffer chest pains.

Higher doses can cause convulsions leading to coma or death. Victims may suffocate as the nervous and respiratory systems shut down.

The Centers for Disease Control and Prevention says liquid sarin can kill someone in one to 10 minutes.

Are there antidotes?

Yes, the muscle relaxant atropine and pralidoxime chloride. Soldiers’ first-aid kits often include autoinjectors they can administer themselves. But they must be used quickly, within minutes or a few hours depending on the agent.