DPG was established in 1942 during WWII as a proving ground for chemical weapons. Shortly after its establishment, biological warfare testing and evaluation were also being carried out at the facility. Both chemical and biological weapons testing have continued since the establishment of DPG, although open-air tests were banned in 1969. During WWII, the work at DPG played an important role in the development of weapons used in battle (incendiary and smoke) and weapons that were to be used as important elements of military stratagems. After WWI, it was clear that enemy forces had access to and were developing new chemical weapons. Although chemical weapons did not play a large role in WWII, the Allies and Axis powers felt the need to continue developing weapons and defensive measures in order to be prepared in the event of a chemical weapon attack.
At DPG, researchers carried out airplane spray tests of unthickened and thickened mustard at various altitudes to develop the technique of air-spraying; to determine the effect of the height and speed of the plane as well as meteorological conditions of the atmosphere, upon the spray; and to evaluate agents and apparatus. Planes dropped incendiaries on facsimile German and Japanese buildings to enable investigators to learn what happened when bombs of certain types struck enemy structures.