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Weapons of warfare: How nerve gas and other chemical weapons kill, in Syria or elsewhere

Anything specifically designed or intended for use in direct connection with the release of a chemical agent to cause death or harm is itself a chemical weapon.

Written by Abantika Ghosh | New Delhi |
Updated: April 12, 2018 9:02:55 am
syria gas attack, syria chemical attack, syria war, what is chemical weapon, russia, bashar al assad, world news, indian express A look at the history and mechanism of chemical weapons, of which nerve gases are the most dreaded. (Photo: Reuters)

Photographs streaming out of Syria, showing babies in oxygen masks or being hosed down to wash off the effects of an alleged nerve agent released in Douma, have turned the spotlight on chemical weapons, particularly nerve agents or nerve gases. Before these were reports of the daughter of an alleged Russian spy recovering from Novichok, a lethal nerve agent. A look at the history and mechanism of chemical weapons, of which nerve gases are the most dreaded:

What are chemical weapons?

It is a toxic chemical in a delivery system such as bomb or artillery. The definition was expanded for the Chemical Weapons Convention (CWC) — 192 countries as signatories — that seeks to limit availability of chemicals that can be used as tools of mass destruction while allowing member states to retain rights to use some of these chemicals for peaceful purposes such as riot control. According to CWC’s Organisation for the Prohibition of Chemical Weapons(OPCW), “… The Convention defines each component of a chemical weapon as a chemical weapon— whether assembled or not, stored together or separately. Anything specifically designed or intended for use in direct connection with the release of a chemical agent to cause death or harm is itself a chemical weapon.”

What is nerve gas?

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It is a compound that acts by incapacitating the mechanism within the body responsible for the conduction of nerve impulses. This is usually done by blocking the action of acetylcholineesterase — a compound that catalyses the breakdown of the neurotransmitter acetylcholine. When acetylcholinesterase is prevented from performing its normal function of breaking down acetylcholine, muscles go into a state of uncontrolled contraction — a sign of paralysis or a seizure-like state. Death usually happens because paralysis extends to the cardiac and respiratory muscles. Other symptoms could include dilation of pupils, sweating and gastrointestinal pain etc. Nerve agents can also be absorbed through the skin.

How do nerve gases compare with other chemical weapons?

They are among the most lethal. In the CWC list of chemicals under various degrees of manufacturing restriction, nerve gases are among the most restricted, given that they have no use other than in chemical warfare. When countries started to develop newer weapons to bypass these restrictions, they preferred nerve agents. That is how Novichok evolved: because restrictions are based on chemical formulae, newer molecules can bypass restrictions. Novichok is said to be 5-8 times more lethal than VX nerve agent and its effects are rapid, usually within 30 seconds to 2 minutes.

Which are the ones not restricted?

Teargas shells, for example, are frequently used for riot control. During the Telangana movement, a Congress MP smuggled in pepper spray — among the milder chemical weapons — inside Parliament and used it inside Lok Sabha.

How many countries possess or use chemical weapons?

Of the 192 CWC signatories, Albania, India, Iraq, Libya, Russia, Syria, and the US declared possession. Albania, India, Libya, Russia — and Syria — declared completion of destruction of chemical weapons. According to OPCW, 96.27% or 69,610 of 72,304 tonnes of the world’s stockpile of chemical weapons have been “verifiably destroyed”.

What was verified in Syria?

OPCW says: “The Syrian Arab Republic acceded to the Convention on 14 October 2013. The Executive Council, supported by a UN Security Council Resolution, decided on an accelerated plan… Destruction of Syria’s chemicals weapons equipment and munitions began in October 2013 and by January 2016 the destruction of all chemical weapons declared by Syria has been completed.”

What has Syria’s record been like?


In August 2013, an alleged nerve agent had killed 1,100 in in Ghouta. Since October 2013, when destruction was declared begun, there have been alleged chemical attacks in April 2014 (Kfar Zeita, poison gas, 2 dead, 100 ill); May 2015 (Sarmin, chlorine, 6 dead); August 2015 (Marea, mustard gas, 50 ill); September 2016 (Aleppo, chlorine, 2 dead), April 2017 (Khan Sheikhoun, sarin, 70 dead) and Douma.

Who else have used chemical weapons?

* In World War I, chlorine and phosgene gases were released on the battlefield.
* Iraq used chemical weapons in Iran during the 1980s war, and mustard gas and nerve agents against Kurdish residents in 1988.
* In Matsumoto in Japan in 1994, 8 people died and 500 were affected in a sarin attack.
* In a sarin attack in the Tokyo subway in 1995, 12 people died and 50 were injured.


Other chemical weapons

The Chemical Weapons Convention defines a chemical weapon, which includes nerve gas, as anything specifically designed or intended for use in direct connection with the release of a chemical agent to cause death or harm is itself a chemical weapon. All 192 states of the Chemical Weapons Convention have the right to use some of these for peaceful purposes – a common example would be a teargas shell.


Choking agents
Fluid builds up in lungs, choking victim. Examples include chlorine, phosgene, diphosgene and chloropicrin.

Blister agents
Burns skin, mucous membranes and eyes; causes large blisters on exposed skin; blisters windpipe and lungs; large casualties, low percentage of deaths. Examples: sulphur mustard, nitrogen mustard , phosgene oxime, Lewisite

Blood agents
Cyanide destroys ability of blood tissues to utilise oxygen, causing them to ‘starve’ and strangling the heart. Examples include hydrogen cyanide, cyanogen chloride, Arsine, VX

Riot control agents
Cause tears, coughing and irritation to eyes, nose, mouth and skin; constrict airway and shut eyes; teargas and pepper spray are examples of such agents

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First published on: 12-04-2018 at 02:18:48 am
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