**2. Historical background**

Mustard gas was possibly developed as early as 1822 by César-Mansuete Desperetez (1798– 1863) (10). SM was used as the late 1880 for treating minor tumors (11). Mustard gas is the most widely – used vesicant chemical war agent in the past century (2).Unfortunately SM was first employed effectively as a weapon in World War by the Germans on the British at Ypres (3, 11). It was then used during the Iran-Iraq war (1983-1988) and more than 100 000 military and civilian people were injured by SM gas (12).Now, over 45000 patients are suffering from the late complications of SM exposure (11, 12) and now SM is included as a threat to both military and civilians (13).
