Q&A: Sarin

The Tokyo sarin attack in 1995 killed 12 and made about 5,000 ill

Sarin is one of a group of nerve gas agents invented by German scientists in the 1930s as part of Hitler's preparations for World War II.

Huge secret stockpiles of sarin weapons were built up by the superpowers during the Cold War years of the 1950s and 1960s.

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How deadly is it?

Sarin is 20 times as deadly as cyanide. It has been described as the poor man's atomic bomb because of the large numbers of people that can be killed by a small amount. A drop the size of a pin-head is sufficient to kill a person.

Its effect is similar to that of certain kinds of pesticides called organophosphates - but much stronger.

Sarin kills by effectively crippling the nervous system. It does this by blocking the action of an enzyme which removes acetylcholine, the chemical that transmits signals down the nervous system.

What are the symptoms?

Even a small drop of sarin on the skin can cause sweating and muscle twitching.

Exposure to a low or moderate dose can cause the following:

• Runny nose
• Watery eyes
• Blurred vision
• Drooling and excessive sweating
• Cough
• Chest tightness
• Rapid breathing
• Diarrhoea
• Confusion
• Drowsiness
• Headache
• Nausea
• Vomiting
• Abdominal pain
• Slow or fast heart rate
• Low or high blood pressure

Exposure to large doses of sarin can lead to:

• Loss of consciousness
• Convulsions
• Paralysis
• Respiratory failure possibly leading to death

Mild or moderately exposed people usually recover completely. Severely exposed people are not likely to survive.

Is there any treatment?

Antidotes are available for sarin. They are most useful if given as soon as possible after exposure.

If exposed to sarin, it is important to strip off contaminated clothing as quickly as possible, and to wash exposed areas of the body with large amounts of soap and water.

The eyes should be rinsed with plain water for 10 to 15 minutes if they are burning or if vision is blurred

How is it made?

There are four main ingredients needed for the production of sarin, including phosphorus trichloride.

It is a type of weapon that can only be manufactured in a laboratory, though it does not require very sophisticated equipment. It is very dangerous to manufacture.

Where has it been used?

Although the Germans never released sarin in battle, it was used to lethal effect by Iraq during the 1980s both in the war against Iran and against the Kurds.

After the Gulf War, United Nations inspectors found large quantities of sarin in production at an Iraqi chemical weapons plant.

The Japanese doomsday cult, Aum Shinrikyo, also used the nerve agent in a Tokyo subway in 1995.