Sarin gas: A look at the deadly chemical weapon

Damascus areas of influence and areas reportedly affected by the chemical attack. (White House)

U.S. Secretary of State John Kerry announced Sunday that new laboratory results indicate that sarin nerve gas was unleashed last month in an attack in Syria that killed more than 1,400 people – marking the first time a U.S. official has identified what kind of chemical weapon may have been used.

What is sarin gas?

Originally developed as a pesticide in Germany in 1938, sarin is a man-made toxin that is similar to a class of insecticides called organophosphates.

The chemical warfare agent, also known as GB, is a clear, colourless and tasteless liquid that has no odour in its pure form. It is considered the most volatile of nerve agents, meaning it easily evaporates from a liquid to a vapour and spreads into the environment.

According to Daryl Kimball, executive director of the Washington-based Arms Control Association, sarin gas leads to a particularly horrible form of death.

"Sarin gas attacks the nervous system, it leads to convulsions, uncontrollable twitching, it shuts down the brain and most die from asphyxiation from just a small exposure," Kimball told CTV News Channel on Sunday.

How can people be exposed to sarin?

The extent of poisoning caused by sarin depends how much a person was exposed to, the length of time of the exposure, and how the individual was exposed.

Following the release of sarin into the air, people become vulnerable to exposure through skin contact, eye contact or by breathing air that has been contaminated with sarin.

A person’s clothing can also release sarin after it has come in contact with the vapourized gas, which can lead to the exposure of others.

Signs and symptoms of sarin exposure

Symptoms will likely appear within a few seconds after exposure to the vapour form of sarin, however people may not be aware that they were exposed because sarin has no odour.

A low or moderate dose of sarin exposure may result in some or all of the following symptoms: runny nose, water eyes, eye pain, diarrhea, vomiting, drooling and excessive sweating, rapid breathing, confusion and weakness.

According to the Centers for Disease Control and Prevention, even a small drop of sarin on the skin can cause muscle twitching where the agent came in contact with a person.

Exposure to a large dose of sarin can result in a loss of consciousness, convulsions, paralysis and respiratory failure.

"It is very clear that from the types of injuries and deaths we saw in the videos that this was an attack consistent with a sarin gas exposure," Kimball said.

When has sarin been used?

Sarin and other types of nerve agents was used during the Iraq-Iran war in the 1980s. The deadly nerve gas was also used in two terrorist attacks in Japan in 1994 and 1995.

Chemical weapons have been banned in warfare for 90 years.

"The revulsion goes back to the terrible experience in World War I with the trench warfare with both sides using chemical weapons on a mass scale," Kimball said.

The 1925 Geneva Protocol outlawed the use of chemical weapons, but not their possession. In 1997 the protocol was replaced by the Chemical Weapons Convention (CWC) , which requires the destruction of chemical weapons within a specified period of time.

Currently 188 states-parties have signed the treaty. Key non-signatories include North Korea and Syria.

The last time chemical weapons were used on a large scale came during the 1980s when Iraqi leader Saddam Hussein used them against Iran.

Kimball says inaction by the global community at the time "probably led countries like Syria to acquire chemical weapons and believe today that they can use them with impunity."