More than that, Mustard Gas was fairly important in the development of chemotherapy after US Army Doctors noticed it's effect on white blood cells following an air raid in WW2 when a ship carrying Mustard Gas was bombed. From there, in part, was sparked the idea of using similar drugs to attack cancers.

http://www.the-hospitalist.org/details/article/243771/From_W... http://en.wikipedia.org/wiki/Sulfur_mustard#Development_of_t...