Chemical weapons in World War I volatile oily liquid. It was introduced as a vesicant by Germany in July 1917 prior to the Third Battle of Ypres. The Germans marked their shells yellow for mustard gas and green for chlorine and phosgene; hence they called the new gas "Yellow Cross". It was known to the British as "HS" ("Hun Stuff"), and the French called it "Yperite" (named after Ypres). Mustard gas is not an effective killing agent (though in high enough doses it is fatal) but can be used to harass and disable the enemy and pollute the battlefield. Delivered in artillery shells, mustard gas was
United States Army Gas School United States Army Gas School The United States Army Gas School was established during World War I at Camp A.A. Humphreys in Virginia. The first courses began in May 1918 and the school was designed to instruct commissioned and noncommissioned officers in chemical warfare. In late October 1917 the War College was badly underprepared for large-scale chemical warfare in World War I. With many U.S. soldiers operating in a chemical environment with no knowledge of chemical warfare the War College requested a British gas officers and NCOs, the requests were granted. The British experts arrived and were directed and coordinated