Leonard Czarniecki served as procurement planning and control officer with 9812th Technical Services Unit (Special Engineer Detachment) at Oak Ridge, TN, with the Y-12 Plant. He coordinated and supervised procurement of materials and equipment, and was directly responsible for approving purchase requisitions submitted by civilian contractor for over $2000. He was also responsible for approving all government purchase requsitions submitted by civilian contractors. He assisted contractors in establishing control procedures and maintained detailed central records of important classes of materials. He also acted as Liaison Officer between civilian contractors and War Production Board expediting critical operational materials.
For his work, Czarniecki was awarded an American Theater Medal, a Victory Medal, an American Defense Service Medal, and a Meritorious Service Unit Plaque for the 9812 Technical Services Unit, US Corps of Engineers, Manhattan District.