An artile by John T. Correll who at one time was the editor in chief of Air Force Magazine

The UC-123K tactical transport known as “Patches” (above) got its name the hard way. The aircraft was held together nose to tail with repairs to the battle damage inflicted by almost 600 hits from enemy ground gunners in Vietnam.

When its flying days were over, Patches was retired to the US Air Force Museum in Dayton, Ohio, as a memorial to the airmen who flew the dangerous “Ranch Hand” missions from 1962 to 1970.

Ranch Hand used herbicides to defoliate the vegetation in Vietnam, where the jungle provided concealment and cover for Viet Cong insurgents. It began as a peripheral notion in 1961 on a White House list of “techniques and gadgets” that might be tried in lieu of all-out combat and expanded from there.

At its peak in 1969, Ranch Hand employed only 25 spray planes, but the results and consequences went far beyond anything the White House ever imagined. Local commanders and ground forces swore by Ranch Hand, which stripped bare the enemy ambushes and hiding places. It was part of a broader operation named “Trail Dust,” which included spraying from backpacks, trucks, and riverboats, but the main operation was Ranch Hand.

The propeller-driven C-123 had long since been declared obsolescent but it found new purpose in Vietnam. In 1968, auxiliary jet engines were mounted under the wings, making takeoffs less hazardous for the heavily loaded Ranch Hand aircraft. The enhanced model was designated UC-123K.

The spraying was done from treetop level and was especially risky with the original equipment, which dispensed no more than one-and-a-half gallons of herbicide per acre, half the amount necessary for defoliation. Before the Ranch Hand crews got better sprayers that pumped three gallons an acre, they had to fly a second mission against each target. The ground gunners knew this and were waiting for them. With the improved system it took four minutes to empty the 1,000-gallon tank and cover an area 16 kilometers (10 miles) long and 80 meters (260 feet) wide.

About 10 percent of the Ranch Hand sorties destroyed crops supporting the Viet Cong—a priority for the South Vietnamese government—but the vast majority of them were flown to expose the enemy’s strongholds and travel routes. Even critics of the program concede that this saved many thousands of American and allied lives.

The Ranch Hand achievements are seldom remembered today, eclipsed by the enormous controversy about Agent Orange, the principal defoliant used in Vietnam. It is widely agreed now that the herbicides—deemed safe to humans in the 1960s—might cause cancer and other ailments. By an act of Congress in 1991, a deadly health risk is presumed for those exposed to Agent Orange.

Among other revelations, the most famous of all Ranch Hand airplanes, Patches, was found to be “highly contaminated” with Agent Orange residues and had to undergo an extensive cleanup before it could be put on display at the Air Force Museum.

A Rainbow of Defoliants

The herbicides came in 55-gallon drums marked with colored bands four inches wide. The defoliants were named for the color of the bands: Agents Blue, Green, Pink, Purple, White, and the most famous of all, Agent Orange, referred to simply as “Orange” by the Ranch Handers.

agent_orange2The active ingredients were the same as weed killers used for years in the United States on farms, along highways and power lines, and in popular lawn care products sold to homeowners. The compound 2,4-D destroyed broad-leaf weeds and 2,4,5-T worked on brush and hardwoods. However, unlike the commercial products which cut the weed killers with inert thinners, the military herbicides were sprayed full strength.

In the early part of the war, the preferred herbicide was Agent Purple, a patented product of the Dow Chemical Co., consisting of half 2,4-D and half 2,4,5-T. Dow could not produce enough to meet the demand but was wary about permitting others to make up the difference on license. In 1964, Ranch Hand began replacing Purple with Agent Orange, the same mixture without patent complications.

There were some complaints about the defoliation program, but these came mostly from ecologists and opponents of the war in general. Industry and the Pentagon defended the chemicals as safe. A government-sponsored survey by the independent Midwest Research Institute in 1967 found no reason for alarm. Little attention was given to scattered instances of skin rashes among plant workers, farmers, loggers, and other handlers.

Warning signals went off with the release in October 1969 of a National Institutes of Health study reporting laboratory experiments in which high concentrations of 2,4,5-T led to birth defects in mice.

The basic problem was not the weed-killing ingredients themselves; it was the “dioxins,” a kind of impurity created in small amounts as byproducts in the manufacturing process. Dioxins are everywhere—in diesel exhaust, in Styrofoam cups and Formica tabletops, in smoke from trash fires—and toxic in extreme doses. Production of 2,4,5-T generated a poisonous dioxin abbreviated as TCDD.

In response to the NIH study, the Department of Defense prohibited the use of Agent Orange around population centers. In April 1970, the departments of the Interior, Agriculture, and Health, Education, and Welfare suspended the uncontrolled use of 2,4,5-T in the United States and the DOD—over the objections of the Joint Chiefs of Staff—temporarily halted the use of Agent Orange in Vietnam. The temporary halt was never lifted, and when supplies of other herbicides, chiefly Agent White, ran out, the Ranch Hand operation came to an end.