Fragments of mortars fired by Islamic State militants at Kurdish fighters in northern Iraq earlier this month tested positive in a U.S. military field test for chemical weapons agent sulfur mustard, a U.S. general confirmed Friday.
Marine Corps Brig. Gen. Kevin Killea, chief of staff for operations against the militant group, also known as ISIS or ISIL, said the test results still did not qualify as conclusive proof of chemical weapons use, and said the fragments are undergoing more testing to confirm the finding, Reuters reported.
The shells were fired at Kurdish Peshmerga positions near the town of Makhmur in north-central Iraq on Aug 11, Gen. Killea said.
“We were able to take the fragments from some of those mortar rounds and do a field test … on those fragments, and they showed the presence of HD, or what is known as sulfur mustard,” he said, Reuters reported.
Mustard gas is a chemical warfare agent developed during World War I and banned by treaty in 1993, according to the Centers for Disease Control and Prevention.
Although the agent is not usually fatal, it can cause blistering of the skin, eye pain and blindness, as well as respiratory problems, the CDC said.
Senior U.S. officials said the attack earlier this month produced a small number of injuries with “wounds consistent with a blister producing-agent.”
U.S. officials are still investigating exactly what happened in the attack and, if mustard gas was used, how the terrorist group came to acquire the chemical weapon.
Gen. Killea told Reuters that sulfur mustard is a Class 1 chemical agent, which means it has few uses outside chemical warfare.
“It is very important to understand here that that is a presumptive field test and it is not conclusive, and what those results tell us is merely the presence of that chemical,” Gen. Killea said.
He added that it would take a couple of weeks to get more information on the fragments and that testing is under way.