Operation Ranch Hand - Operations

Operations

For most of the war Operation Ranch Hand was based out of Bien Hoa Air Base (1966–1970), for operations in the Mekong Delta region where U.S. Navy patrol boats were vulnerable to attack from areas of undergrowth along the water's edge. Storage, mixing, loading, and washing areas and a parking ramp were located just off the base's inside taxiway between the Hot Cargo Ramp and the control tower. For operations along the central coast and the Ho Chi Minh trail regions, Ranch Hand operated out of Da Nang Air Base (1964–71). Other bases of operation included Phu Cat Air Base (1968–1970), Tan Son Nhut Air Base (1962–66), Nha Trang Air Base (1968–69), Phan Rang Air Base (1970–72), and Tuy Hoa Air Base (1971–72). Other bases were also used as temporary staging areas for Ranch Hand. The Da Nang, Bien Hoa and Phu Cat Air bases are still heavily contaminated with dioxin from the herbicides and have been placed on a priority list for containment and clean-up by the Vietnamese government.

The first aerial spraying of herbicides was a test run conducted on 10 August 1961 in a village north of Đắk Tô against foliage. Testing continued over the next year and even though there was doubt in the State Department, The Pentagon and the White House as to the efficacy of the herbicides, Operation Ranch Hand began in early 1962. Individual spray runs had to be approved by President John F. Kennedy until November 1962, when Kennedy gave the authority to approve most spray runs to the Military Assistance Command, Vietnam and the U.S. Ambassador to South Vietnam. Ranch Hand was given final approval to spray targets in eastern Laos in December 1965.

The issue of whether or not to allow crop destruction was under great debate due to its potential of violating the Geneva Conventions. The president of South Vietnam, Ngo Dinh Diem began to push the U.S. Military Advisory Group in Vietnam and the White House to begin crop destruction in September 1961, but it was not until October 1962 when the White House gave approval for limited testing of Agent Blue against crops in an area believed to be controlled by the Viet Cong. Soon after, crop destruction became an integral part of the Ranch Hand program.

Targets for the spray runs were carefully selected to satisfy the strategic and psychological operations goals of the U.S. and South Vietnamese military. Spray runs were surveyed to pinpoint the target area and then placed on a priority list. Due to the low altitude (ideally 150 feet (46 m)) required for spraying, the C-123s were escorted by fighter planes that would strafe or bomb the target area in order to draw out any ground fire if the area was believed to be 'hot'. Spray runs were planned to enable as straight a run as possible to limit the amount of time the planes flew at low altitude. Data on the spray runs, their targets, the herbicide used and amount used, weather conditions and other details were recorded and later put into a database called the Herbicide Reporting System (HERBS) tapes.

The effectiveness of the spraying was influenced by many factors including weather and terrain. Spray runs occurred during the early morning hours before temperatures rose above 85 degrees and the winds picked up. Mangroves in the Delta region required only one spraying and did not survive once defoliated, whereas dense forests in the uplands required two or more spray runs. Within two to three weeks of spraying the leaves would drop from the trees which would remain bare until the next rainy season. In order to defoliate the lower stories of forest cover, one or more follow-up spray runs were needed. About 10 percent of the trees sprayed died from a single spray run. Multiple spraying resulted in increased mortality for the trees, as did following up the herbicide missions with napalm or bombing strikes.