For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty as commanding officer of the 3d Assault Battalion Landing Team, 25th Marines, 4th Marine Division, in action against enemy Japanese forces on Iwo Jima, Volcano Islands, from 19 to 22 February 1945. Under a furious barrage of enemy machinegun and small-arms fire from the commanding cliffs on the right, Col. Chambers (then Lt. Col.) landed immediately after the initial assault waves of his battalion on D-day to find the momentum of the assault threatened by heavy casualties from withering Japanese artillery, mortar rocket, machinegun, and rifle fire.
For outstanding bravery and exceptional courage in a dangerous situation as the commanding officer of the 3d Assault Battalion Landing Team, 25th Marines, 4th Marine Division, during combat against Japanese forces on Iwo Jima, Volcano Islands, from February 19 to 22, 1945.