One of my Great-Grandfathers was in the 3rd Arkansas Infantry Regiment's Machine-gun Battalion which then became part of the 39th Infantry Division. The 39th was redesignated as the 5th Depot Division and my Great-Grandfather served in some unknown division as a replacement in the Meuse-Argonne as a Machine-gunner. He was gassed, but survived the war.
Another Great-Grandfather was an artilleryman, but I don't know his unit. He was also gassed and survived. He actually died as an old man to lung cancer from both smoking all his life and the damage to his lungs from the mustard gas.