In December 1943, the Chemical Warfare Service began design of a highly mobile laboratory unit for proposed laboratory teams accompanying task forces in the combat zone. This portable unit for gas intelligence missions weighed 3,293 pounds and was packed in seven plywood boxes and nine smaller cases that could be stowed in a single 2-l/2 ton truck. It was assembled and standardized in October 1944 as the M3 mobile laboratory.

As the battle lines shifted from North Africa across the Mediterranean, the National Defense Research Committee (NDRC) sent a mobile unit group from the University of California to Mount Shasta, where the climate and terrain were similar to those in sections of Italy. The investigation of this group was chiefly concerned with clouds of nonpersistent gas released from loo-pound M47A2 bombs. An NDRC report was prepared on the chemical warfare tests carried out on the slopes of Mount Shasta. The report indicates that the bombs were filled with butane and statically fired to observe dispersion patterns through the forest.