gassed with chlorine, as evidenced in the line, "Gas! Gas! Quick, boys!". Chlorine gas was one of the fatal chemical weapons used during World War I. First used by the Germans in 1915, it was a strong irritant that caused damage to the eyes, nose, throat, and lungs of the soldiers. At high concentrations and long exposure, it could cause death by asphyxiation. Chlorine gas was not the only deadly weapon invented during the war. There are other weapons that are deadlier than chlorine gas. Mustard