Russian spy: What are nerve agents and what do they do?

From BBC - March 8, 2018

Police say a nerve agent was used in an attempt to murder the Russian former spy Sergei Skripal and his daughter, Yulia, in Salisbury, Wiltshire. The pair are critically ill, along with a police officer who was among the first to attend the scene. But what are nerve agents and what do they do?

What are nerve agents?

They are highly toxic chemicals that prevent the nervous system from working properly, and can be fatal.

They take different forms - including powder and gas - but they tend to be a liquid, which can seep through the skin.

"Nerve agents are possibly some of the most dangerous things that humans have ever made, after the atom bomb," says Dr David Caldicott, clinical senior lecturer at the faculty of medicine at Australian National University.

What are the different types?

Some of the better-known nerve agents include:

The first three agents are clear, colourless, tasteless liquids.

VX, an oily, amber-coloured liquid, is the most deadly - a drop on the skin can kill a person within minutes.

What was used in this case?

Police have not confirmed what agent was used, but a source has told the BBC it was likely to be rarer than sarin or VX nerve agents - two of the best known.

When have they been used in the past?

The half-brother of North Korean President Kim Jong-un was killed by a nerve agent in an attack in Malaysia last year.

Kim Jong-nam died in less than 20 minutes after two women smeared his face with VX nerve agent ingredients at Kuala Lumpur airport in 2017.

The UN says the nerve agent sarin has been used by the Syrian government - in an attack on Ghouta, near Damascus, in 2013 and again in Khan Sheikhoun in the north-west of the country in April 2017, killing hundreds.

In an attack on Tokyo's subway system in 1995, which killed 13 people, liquid sarin was placed in plastic bags that were pierced by umbrellas with sharpened tips.

When Russian dissident Alexander Litvinenko was poisoned in London in 2006, a radioactive substance - not a nerve agent - called polonium 210 was used in a cup of tea.

What do they do to the body?

Nerve agents block the messages from the nerves to the muscles. This causes a collapse of many bodily functions.

They will act within seconds or minutes if inhaled and slightly more slowly if exposure is the result of skin contamination.

Symptoms include white eyes, as the pupils become constricted, convulsions, drooling and in the worse cases - coma, respiratory failure and death.

If you have ever sprayed insect repellent at a fly, you might have seen it drop to the ground and lie on its back, legs twitching. This is the result of nerve agents taking hold.

How are they delivered?

The nerve agent needs to be ingested, inhaled or to penetrate through the skin, so it usually requires the person delivering it to get very close to the people they are targeting.

Only tiny amounts are required for it to take effect. It is so toxic that it would usually be transported in something tightly sealed and those who apply it will need protective clothing.

Dr Andrea Sella, professor of inorganic chemistry at University College London, said because of the extreme toxicity of the nerve agents it would be "very dangerous" to the person who delivered the poisoning.

Is there a risk to the public?

Despite their extreme toxicity, Dr Sella said the agent posed "very little risk" to the public.

You would need to be very close to these chemicals to be affected by them.

What is the treatment?

Where are they made?

How do you find where it came from?


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