Seventeen locations across Syria are recorded as having been subjected to chemical-weapons bombardment, and hundreds of people have been killed since the first chemical attack in March 2013.
On the first anniversary of the chemical attack in Khan Sheikhoun, where sarin gas was used, Al Jazeera looks at the varous attacks in rebel-held areas.
The known chemical weapons that have been used in Syria are:
Sarin gas has no taste or smell, is essentially a cholinesterase inhibitor and within immediate exposure to the gas, it builds up acetylcholine. The nerve of the human body are manipulated to fire neurotransmittors to affect first the muscles, then secretions, which in rapid time makes a person drool, vomit, and the body evacuates themseves. If exposed at a large quantity, and close distance death can be within 10 minutes.
White phosphorus has been used in conflicts since World War I and II. The chemical creates a blanket of smoke which burns, produces significant smoke and allows the masking of movement in conflcits. On people it burns the skin, causes severe smoke inhalation, effects internal organs and, over the long term, exposure can impact the bones.
Napalm is a flamabble liquid agent that was widely used by the US forces in Vietnam, Korea and Japan. It can causes extreme burns, stop breathing, and lead to a quick death.
Its highly flammable composition makes it an effective war weapon as it immediate impact by flowing into locations which are not easiyl targetable. People can die due to heat, asphyxiation, dehydration, hypothermia and carbon monoxide poisoning. It creates an attachment to the human skin with no possiblity of removing it without damage.
Chlorine gas bomb
Pressurised chlorine, or hydrogen chloride in vessels can create an exploisve device when contacted with imapct.
This particular kind of chemical may be less hazardous than the others used in the Syrian civil war, but exposure to chlorine gases does and can affect the breathing, the inhalation damages the tract and has similar reactions like tear gas – which can cause blindness and eye injuries.
This particular chemical agent causes blisters and causes the skin to burn, along with damaging the eyes, internal organs and the respiratory tract which gets damaged by blisters and tissue tearing.
Unlike other chemical warfare, this particular vapour does not affect immediately and had a delayed reaction anytime within 24 hours.
It was used towards the end of World War I and during the Iraq-Iran war beween 1979-1988.
Source: Al Jazeera News