Background and History Diphenylchloroarsine (DA), 10-chloro-5,10-dihydrophenarsazine (DM, Adamsite), and diphenylcyanoarsine (DC) are closely related chemical compound developed near the conclusion of World War I. All three compounds are solids when pure, and must be used as aerosols. These agents are used in either thermal grenades or smoke generators. The effects of all three are similar: severe irritation of the eyes, nose, and throat. If the agent is inhaled for 1-2 minutes, tightness of the chest and headache are experienced. The headache develops into general nausea, which can result in vomiting in approximately three minutes. Under concentrations expected to occur under combat conditions, fatalities are not expected; however, these compounds can be fatal at higher concentrations.