Very soon after the first use of gas by the Germans at Ypres the chemical substance involved was identified by Grignard's group as dichloroethyl sulphide (
yperite or mustard gas) and its method of preparation was deduced.
An examination by the Self-Defense Forces had earlier indicated that the shells were flammable and contained
yperite, better known as mustard gas, and Lewisite.
An examination by the Self-Defense Forces had earlier indicated that the shells are flammable poison-gas bombs containing a
yperite mixture, better known as mustard gas.
Of these, three were of
yperite lethal poison gas and seven were of a nauseating poison gas, they said.
In 2005, it finished disposing of more than 1,143 tons of
yperite, lewisite and their mixtures.