Eyes watering, struggling to breathe, Abd al-Mouin, 22, dragged his nephews from a house reeking of noxious fumes, then briefly blacked out. Even fresh air, he recalled, was “burning my lungs.”
The chaos unfolded in the Syrian town of Sarmeen one night this spring as walkie-talkies warned of helicopters flying from a nearby army base, a signal for residents to take cover. Soon, residents said, there were sounds of aircraft, a smell of bleach and gasping victims streaming to a clinic.
Two years after President Bashar al-Assad agreed to dismantle Syria’s chemical weapons stockpile, there is mounting evidence that his government is flouting international law to drop jerry-built chlorine bombs on insurgent-held areas. Lately, the pace of the bombardments in contested areas like Idlib Province has picked up, rescue workers say, as government forces have faced new threats from insurgents. The Assad government has so far evaded more formal scrutiny because of political, legal and technical obstacles to assigning blame for the attacks — a situation that feels surreal to many Syrians under the bombs, who say it is patently clear the government drops them.
“People are so used to it, they know from the sound,” said Hatem Abu Marwan, 29, a rescue worker with the White Helmets civil defense organization, a note of exasperation creeping into his voice when asked to explain. “We know the sound of a helicopter that goes to a low height and drops a barrel. Nobody has aircraft except the regime.”
Prodded by the United States, the United Nations Security Council is discussing a draft resolution that would create a panel, reporting to the secretary general, to determine which of the warring parties is responsible for using chlorine as a weapon, according to Council diplomats.
“The Security Council must address the need to determine who is responsible for using chlorine as weapons in Syria,” said an American official, who declined to offer specifics and requested anonymity to discuss continuing negotiations. “Doing so is critical to getting justice for the Syrian people and accountability for those who have repeatedly used chemical weapons in Syria.”
Syrian state media dismiss the allegations as propaganda, and the Council remains divided and hamstrung. That leaves people like Mr. Abu Marwan, who has responded to nine suspected chlorine attacks, feeling abandoned. “There is no law to defend us as human beings, this is what we understand from the Security Council,” said Mr. Abu Marwan, a law school graduate, weeping as he recalled holding a dying child in Sarmeen. “I didn’t see in humanitarian law anything that says ‘except for Syrians.’ ”
In contrast to stronger toxins like nerve agents and mustard gas, chlorine is lethal only in highly concentrated doses and where medical treatment is not immediately available, making it more an instrument of terror than of mass slaughter. It is typically dropped in barrel bombs containing canisters that explode on impact, distributing clouds of gas over civilian populations, and is distinguishable by its characteristic odor.
So it falls under a kind of loophole. With many civilian uses, like purifying water or disinfecting hospitals, it is not banned under international law and thus was not on the list of chemicals that Mr. Assad promised to destroy — though using chlorine as a weapon is forbidden.
The Security Council did condemn the use of chlorine as a weapon in Syria in February. But with Russia, the Syrian government’s most powerful ally, wielding a veto, there was no Council agreement to assign blame.
The Organization for the Prohibition of Chemical Weapons, which monitors agreements on toxic arms, found that chlorine had been used “systematically and repeatedly” in three Syrian villages in 2014, and mentioned witness accounts of helicopter-borne chlorine bombs in its report. But it, too, lacked authorization to say who used them.
Chlorine Bombs in Syria
During March and April at least 20 barrel bombs containing chlorine were dropped in six towns in northwestern Syria, rescue workers say.
On March 16, four bombs reportedly left seven dead and approximately 180 wounded in attacks on Sarmeen and Qminas.
Alistair Hay, a toxicologist at the University of Leeds who has trained Syrians to collect environmental samples, called the attacks a “slap in the face” to the international chemical weapons convention that Syria had joined less than a year earlier. Syria signed under a Russian-American deal to avoid American military strikes after sarin, a nerve agent, killed more than 1,000 people in insurgent-held areas near Damascus.
Frustrated with the Security Council’s impasse over the issue, rescue workers and doctors are now working to bring evidence of chlorine gas attacks directly to the French, British and American governments for testing. The aim is to give states a solid basis for action against the attacks, in the Security Council or through quieter diplomatic pressure, said James Le Mesurier, the British director of a nonprofit group, Mayday Rescue, that trains and equips the White Helmets, Syrian volunteers supported by the British, Danish and Dutch governments.
Going directly to governments that have pushed for Mr. Assad’s ouster creates its own challenges. His allies may dismiss their evidence as politically tainted and can point to recent chlorine attacks in Iraq for which the government there blamed insurgents, not to mention the discredited American claims of an Iraqi chemical weapons program that were used to justify invading Iraq.
To deter allegations of tampering or falsification, Mr. Le Mesurier and three Syrian doctors involved said they systematically documented the chain of custody from collection to handover.
They have plenty of cases to work with. Since March 16, in Idlib alone, the White Helmets have documented 14 attacks with 26 suspected chlorine barrels that sickened scores of people.
For emergency workers and residents in northern Syria, such attacks have become just another of the war’s bizarre routines. Civilians and rescuers alike carry walkie-talkies to warn of approaching aircraft. Water supplies are readied to spray victims.
Chlorine gas is far less deadly than the conventional bombardments that have rained down on populated areas, schools and hospitals, killing thousands. But it can still kill and terrorize. On March 16 in Sarmeen, a basement bomb shelter filled with gas, suffocating a family of six, including a grandmother and three children.
A video of the incident, which recently drew tears when played for the Security Council, showed rescue workers rinsing the young siblings. Two, their waxy faces glistening, lay atop their dead grandmother as gloved hands pumped the third’s tiny chest.
Civilians fled the town the next day, said Dr. Mohammad Tennari, a friend of the family and the head of Sarmeen’s hospital.
The attack left a tantalizing clue: A crude barrel bomb like those seen falling from helicopters landed unexploded in a nearby field. Inside were a household gas canister and a plastic bottle of viscous purplish liquid, according to rescue workers and images from the site.
Dr. Tennari, who works with the Syrian American Medical Society, showed images of corroded, mangled oblong canisters, punctured on one side, and the remnants of a metal barrel strewn across a field in Sarmeen.
A video taken Sunday in the town of Khansafra shows a barrel dropping from a helicopter and rescue workers holding up a portion of a canister labeled in English. The camera shakes, blurring all but a few words: “hazard,” “may cause irritation,” “caution,” “breathing.”
But investigators face difficulties. Chlorine dissipates quickly in the atmosphere and does not last in blood or urine, and residue stays in soil for just 48 hours, leaving little time to transport samples across borders. Also, Mr. Le Mesurier said, the Organization for the Prohibition of Chemical Weapons differentiates evidence it collects itself from evidence collected by rescue workers, categorizing the latter as circumstantial.
Emergency workers said they met recently with investigators from the organization, but Dr. Tennari called the body’s response “poor and slow.” Mr. Le Mesurier remarked, “No one showed up on a white steed.”
Three other Syrian doctors said the organization’s rules resulted in valuable evidence they collected going unexamined.
One, who protects his identity with the nickname “Chemical Hazem” for his safety, said he reached one of the April 2014 attack sites, Tal Minnes, within hours, smelling bleach in the air. He smuggled samples from two victims to Turkey without waiting for border clearances. But he said the O.P.C.W. refused to accept an unexploded canister, which remains in Syria.
“The ultimate evidence of the regime’s use of chemical weapons is gone,” he said, adding that no one seemed interested in getting samples out of Syria. “We can’t blame anyone who wants to follow the legal channels — but do any exist?”