The 1399th Engineer Construction Battalion was established at Schofield Barracks in April 1944 as part of the Central Pacific Base Command. Soldiers of the previously activated 370th Engineer Battalion (Special Services) made up the nucleus of the new battalion. Americans of Japanese Ancestry (AJAs) soldiers from the Selective Service draft in the summer of 1944 were assigned to the 1399th. The 1536th Dump Truck and 1525th Base Equipment companies were added to work with the 1399th.
The 1399th battalion successfully completed more than 54 major projects throughout the island of Oahu. These projects included construction of:
- a million-gallon concrete water tank in upper Wahiawa that is still in use by the military
- jungle training villages in Kahuku, Kahana and Kaaawa with main streets, side roads, and primitive equipment for combat simulation, which were used by more then 300,000 American soldiers to train to fight in the Pacific
- rest and recreation camp facilities on Coconut Island in Kaneohe Bay
- ammunition storage facilities, bunkers for field artillery guns, bomb shelters and a fire hydrant system at Wheeler Field
- buildings and installation of landing mats at Kahuku Air Field
- warehouses in Kipapa Gulch.
Further projects included operating several rock quarries and continued maintenance of roads and bridges on Oahu. The “Chowhounds” of the 1399th established an outstanding record of completing major projects well and on time, if not ahead, of schedule and was awarded the Meritorious Service Award on October 29, 1945. The 1399th Engineer Construction Battalion was officially deactivated as of May 31, 1946, with the end of the war.