The Chemical Warfare Service was created to help the United States fight World War I, where chemical weapons were used in combat by all the participants. After the war, US military spending shrank dramatically and the War Department sought to reduce personnel and programs within its organization wherever possible. Simultaneously, many different groups of Americans opposed continued chemical warfare research and the future use of chemical weapons. These factors made the elimination of the Chemical Warfare Service likely after World War I. The Chemical Warfare Service spent the 1920s trying to continue its work in spite of these obstacles.

Introduction -- Origins, 1917-1918 -- Crisis, 1919-1920 -- Improvement, 1921-1925 -- Legacy, 1926-1929.