Seabees were in Vietnam twice in the 1950s. First in June 1954, as elements of Operation Passage to Freedom and then two years later to map and survey the nation's roads. Seabee teams 501 and 502 arrived January 1963 and are recorded as the first Seabees of the Vietnam War. They went to Dam Pau and Tri Ton to build Special Forces camps. In 1964 ACB 1 was the first CB in the theatre. In 1965 Marines and Seabees made an amphibious landing at Chu Lai and entire Naval Construction Regiments followed. Seabees supported the Marines at Khe Sanh and Chu Lai combat bases in addition to building numerous aircraft-support facilities, roads, and bridges. Every mile of road improved equated to 100' of bridgedeck constructed. They also worked civic action projects throughout the country. In June 1965, Construction Mechanic 3rd Class Marvin G. Shields of Seabee Team 1104 was at the Battle of Dong Xoai. He was posthumously awarded the Medal of Honor and is the only Seabee to receive the award. Seabee Teams were deployed throughout the War. They typically built schools, clinics, or drilled wells. In 1966 Seabees repaired the airfield at Khe Sahn laying aluminum matting covering 3,900'x60' in four days. General Westmoreland "called it one of the most outstanding military engineering feats of the war." MCB 4 had a det at Con Thien whose actions were a near repeat of Dong Xoai.