This Leavenworth Paper chronicles the introduction of chemical agents in World War I, the U.S. Army's tentative preparations for gas warfare prior to and after American entry into the war, and the AEF experience with gas on the Western Front. Chemical warfare affected tactics and almost changed the outcome of World War I. The overwhelming success of the first use of gas caught both sides by surprise. Fortunately, the pace of hostilities permitted the Allies to develop a suitable defense to German gas attacks and eventually to field a considerable offensive chemical capability. Nonetheless, from the introduction of chemical warfare in early 1915 until Armistice Day in November, 1918, the Allies were usually one step behind their German counterparts in the development of gas doctrine and the employment of gas tactics and procedures.

"September 1984."

The Introduction of Gas Warfare in World War I -- The Europeans Face Chemicals on the Battlefield, 1915-1918 -- The U.S. Army's Response to Chemical Warfare, 1915-1917 -- The AEF Organizes for Chemical Warfare -- "The Quick and the Dead" : The AEF on the Chemical Battlefield -- "We Can Never Afford to Neglect the Question.".