Weapons inspectors find Syrian insurgents used mustard gas

BEIRUT — Inspectors have conclusively identified mustard gas as the toxic agent used in an attack by insurgents in northern Syria this past summer, according to a statement released Friday by an international chemical weapons watchdog.

The findings by the Organization for the Prohibition of Chemical Weapons are the first confirmation that non-state actors have used mustard gas in Syria’s four-year-old conflict. They also are the first confirmation of the use of the toxin since the Syrian government agreed two years ago to destroy its stockpile of chemical weapons. Since then, Syrian President Bashar alAssad’s forces have been accused of carrying out many attacks using chlorine gas, a choking agent.

The OPCW did not specify which group used mustard gas in the attack, which the organization said killed at least one person on Aug. 21 in the village of Marea. Doctors and an aid organization in the village north of Aleppo blamed the attack on the Islamic State militants who have been battling rebel groups in the area for months.

The use of mustard gas by either the Islamic State or rebels, or both, represents a significant escalation in a conflict that has killed 250,000 people and displaced millions.

“In this case, the team was able to confirm with utmost confidence that at least two people were exposed to sulfur mustard, and that it is very likely that the effects of this chemical weapon resulted in the death of an infant,” the OPCW statement said.

A spokesman for the National Security Council said U.S. officials are “very concerned” about the OPCW findings.

Mustard gas, formally known as sulfur mustard, is a banned chemical weapon that can cause severe blistering, wheezing and itching.

After the Marea attack, doctors in the area reported dozens of affected residents exhibiting such symptoms.

It is unclear how nongovernment forces in Syria could obtain and weaponize chemical toxins such as mustard gas.

The Assad government says it has destroyed its 1,300-ton chemical weapon stockpile as part of an agreement between the United States and Russia. Weapons inspectors and U.S. intelligence officials question that assertion, suspecting that the Syrian leader has concealed some of the cache.