hydrolysis reaction of sulfur mustard(HD, bis 2-chloroethylsulfide), one type of the blister agents wasstudied in water to find the operation conditions which can convert HD into less toxic compounds. The reaction was pro-ceed into two steps. First, 10~20 wt% of HD was hydrolyzed in water at 90oC for 2 hr and aqueous sodium hydrox-ide solution(2.1 eq) was subsequently added to the reaction mixture at rom temperature. The efficiency of HDhydrolysis at this experimental conditions was greater than 99.99% and the final degradation products of HD were 68 wt% of