Nine days later, when researchers examined fragments of munitions at Tel Brak, they were covered in a chemical residue which still had an acrid odor and caused powerful throat and eye irritation. At a hospital in Qamishli, several of the affected fighters tested positive for PH3, a phosphine-based chemical used as an insecticide or fumigating compound.
On the same day as the Tel Brak attack, a home in Hasakah was struck by a rocket that contained a chemical liquid whose residue was dark olive green. The projectile had been fired from a village about four kilometers away which was then under the control of ISIS, Bevan said. Again, investigating teams found residues that “emitted an acrid odor and induced powerful throat and eye irritation.”