More than 80 people, including at least 30 children and 20 women, were killed in the chemical attack on the Syrian town of Khan Sheikhoun and the death toll could still rise.

Who is behind the attack?
The U.S. and other Western countries accused President Bashar Assad of being behind the attack, while Syria and its main backer, Russia, denied it.

Despite world condemnation, bringing justice is difficult in the absence of independent investigation of Syria’s chemical arsenal, which the government insists it has destroyed.

What is a chemical weapon?
Even though modern munitions, through precision of application and specialised use, can cause catastrophic damage, chemical weapons trigger unmatched horror and leave deep psychological scars.

Chemical weapons are specialised munitions that deliver chemicals which inflict death or injury on humans through chemical actions.

Because they are relatively cheap and easy to produce, chemical weapons are referred to as the “poor man’s bomb”.

Among the most commonly used chemical weapons are mustard gas, phosgene, chlorine, and the nerve agents Sarin and VX.

Sarin: Doctors and first-responders at Tuesday’s attack site said symptoms shown by victims suggested use of Sarin. This odourless, colourless agent is extremely potent — even trace amounts can kill humans — but its threat after being released in the atmosphere is short-lived. The UN had confirmed the use of Sarin in the deaths of hundreds in a rebel-held Damascus suburb in 2013.

Mustard gas: Possibly the world’s most commonly used chemical weapon, it was widely used in World War I, and gets its name from its distinctive odour of rotten mustard. It is slow acting, and only about 5% to 10% of people exposed to it usually die.

VX: This is the nerve agent that was reportedly used in the assassination of Kim Jong-nam, half-brother of North Korean leader Kim Jong-un. In its original form, it is odourless, and appears as a brownish oily substance. It is very persistent — once in the atmosphere, it is slow to evaporate, and thus tends to cause prolonged exposure.

What are the international conventions against the use of chemical weapons?

  1. Geneva Protocol in 1925 banned use of both Chemical and Biological weapons.
  2. Chemical Weapons Convention (CWC) of 1993. The CWC outlawed the production as well as stockpiling of chemical weapons.

192 countries have so far agreed to be bound by the CWC — 4 UN states are not party: Israel, Egypt, North Korea and South Sudan.

The CWC is administered by the Organisation for the Prohibition of Chemical Weapons (OPCW), which won the Nobel Peace Prize in 2013 for its efforts to curb use of chemical weapons internationally.