The use of chlorine gas against civilians in the Syrian city of Aleppo should be investigated as a “war crime,” a top United Nations diplomat said Thursday. It was a deadly reminder of the persistence of makeshift chemical weapons in Syria despite an international effort to destroy the country’s chemical weapons caches.
Four people were killed when at least four barrels containing the gas were dropped Wednesday over Zubdiya, a rebel-held neighborhood in eastern Aleppo, witnesses said. The bombing was the latest in a series of chlorine gas attacks that have killed or wounded scores during Syria’s five-year civil war.
What Is Chlorine?
Chlorine is one of the most common naturally occurring elements on earth and has a variety of beneficial uses. It is used to make pesticides and the bleach that disinfects hospitals, and it is injected into municipal drinking water to make it clean and potable.
It is a legal and necessary chemical, freely traded across international borders. But chlorine was among the first chemical gases to be turned into a weapon during World War I. Given its accessibility and the ease with which it can be weaponized, it has been commonly used in homemade bombs.
Chlorine gas was reintroduced to warfare in the Middle East during the American occupation of Iraq when insurgents made improvised explosive devices out of chlorine.
What Are the Effects of Chlorine Gas?
Chlorine gas is classified as a choking agent. When inhaled in its concentrated form, it causes a person’s lungs to fill with liquid, leading to asphyxiation. The yellow-green gas is extremely corrosive to the mucuous membranes of the eyes, skin and upper respiratory tract.
Children and older people are particularly susceptible to its effects.
Why Was Chlorine Not Destroyed?
In 2013, President Bashar al-Assad of Syria, facing the threat of an American attack, agreed to join the Chemical Weapons Convention and subsequently turned over for destruction thousands of tons of deadly agents.
That deal, brokered by Russia and the United States, led to the destruction of most of Syria’s most dangerous chemical weapons, including the nerve agents Sarin and VX, and sulfur mustard, a blister agent.
Using chlorine as a weapon is banned under the Chemical Weapons Convention, but because of its widespread use for legal purposes, the substance was not included in the wholesale eradication of Syria’s chemical weapons.
Who Is Responsible for the Recent Attacks?
The rebels and the government in Syria have each accused the other, and the Islamic State, of using chlorine as a chemical weapon.
The combatants in the country have not had difficulty producing improvised bombs. Canisters of chlorine can be packed into a barrel along with conventional explosives. In some recent attacks, including one on Aug. 2, in Saraqeb in Idlib Province, witnesses reported seeing barrel bombs being thrown from helicopters. In that attack, in which 30 people were sickened, according to the BBC, it was unclear who was responsible, but the rebels and the Islamic State do not have helicopters.
In August 2015, the United Nations Security Council unanimously adopted a resolution to identify “to the greatest extent feasible individuals, entities, groups or governments perpetrating, organizing, sponsoring or otherwise involved in the use of chemicals as weapons in Syria.” The one-year mandate for that investigation ends this month.
On Thursday, the United Nations’ special envoy for Syria, Staffan de Mistura, told reporters that “there is a lot of evidence” that chlorine gas was used in the attack on Aleppo.
“If it did take place, it is a war crime,” he said.