Chapter VII: 
Dak To
(November-December 1967)
The overwhelming success of U.S. arms at Dak To maybe attributed in part to a number of innovations that had been developed by the forces supporting the infantry. Foremost among these were the new and vastly improved communication systems available at division level and below. Commanders were able to achieve greater control and provide better and more responsive support for maneuver units. Also the servicing of helicopters in forward areas contributed greatly to the effectiveness of airmobile operations. Engineer efforts to clear routes of communications and to deny the enemy cover and concealment were supplemented by the use of herbicides and a new "people sniffer."
The battle for Dak To during November and December 1967 was a disaster for the 1st North Vietnamese Army Division. Although the enemy had expected to gain an important psychological victory by swiftly striking western Kontum Province from border sanctuaries, his four fresh regiments were decisively defeated in what a ranking Communist officer termed a "useless and bloody battle." In a classic example of allied superiority in firepower and maneuver, fifteen U.S. and Vietnamese battalions beat the enemy to the punch and sent the survivors limping back to their sanctuaries.
The command and control and communications effort at Dak To was enormous. The 4th Infantry Division headquarters controlled its 1st and 2d Brigades, division artillery, division troops, division support command, the 173d Airborne Brigade, the 1st Brigade of the 1st Cavalry Division (Airmobile), and a myriad of attached and supporting units. The statistics in the three-week battle were impressive: Army aviation flew more than 13,000 hours; eighteen U.S. and Vietnamese artillery batteries fired more than 170,000 rounds; and the Air Force executed 2,100 tactical air and 300 B-52 sorties. Four enemy regiments lost 1,644 known dead.
The battle can be described best in the words of Major General William R. Peers, who was the Commanding General, 4th Infantry Division, during the operation:

The 'battle for DAK TO' was not a designated operation in itself, but occurred within the boundaries of the 4th Infantry Division's Operation MACARTHUR .  Nevertheless, the size of the two opposing forces, the length and violence of the engagement and the overall significance of the battle have made the events that occurred in the vicinity of DAK TO from 2 October to 1 December the most important that have occurred in the Central Highlands since the 1954 Geneva Convention ....
By late October intelligence sources began detecting unusual and large movements in the tri-border area-the junction of LAOTIAN-CAMBODIAN-SOUTH VIETNAMESE borders-west of the DAK TO Special Forces Camp in KONTUM Province. As the area was watched by the various means of aerial and ground intelligence gathering agencies it became apparent that the NVA was moving large forces into southwest KONTUM Province.
The 1st Brigade, which had been surveilling the border area in western PLEIKU Province, began deploying to new [sic] DAK TO airfield on 28 October. On 2 November an NVA reconnaissance sergeant became a CHIEU HOI and divulged what later proved to be the accurate positions and battle plans of the four NVA infantry regiments and one artillery regiment that were preparing to launch the largest enemy attack to date in the Central Highlands against the DAK TO-TAN CANH area. The NVA sergeant revealed that the enemy plan was to launch the primary attack with two regiments from the south and southwest of DAK TO supported by mortar and rocket fire. A second attack into the area, also supported by rockets and mortars, was to be launched from the northeast by one regiment. The fourth regiment was to be held in reserve. This information proved to be correct and was valuable in the initial deployment of our forces. The 1st Brigade sent one battalion on to the ridgeline that runs east to west south of DAK TO and an OPCON battalion from the 173d Airborne Brigade moved west and established a fire support base for medium artillery at BEN HET.
The initial contacts were made on the ridgeline south of DAK TO by the 3d Battalion, 12th Infantry; followed in succession by very heavy contacts to the southwest by the 3d Battalion, 8th Infantry, and by the 4th Battalion, 503d Airborne Infantry moving south from BEN HET. This initial phase took place from 1-6 November and can be viewed as the brigade's forces attacking into the face of enemy units as they were moving toward preselected and in some areas previously prepared positions. After these initial contacts the 173d Airborne Brigade with two battalions arrived at DAK TO and moved west to BEN HET. During this phase from 7 to 12 November, contact was continuous as battalions were combat assaulted behind the lead elements and into the base areas of the 32d and 66th NVA Regiments.
Meanwhile, the ARVN Forces placed their units in vicinity of TAN CAHN to the east of DAK TO. A battalion of the 42d ARVN Regiment, later joined by the 2d and 3d ARVN Airborne Battalions, oriented to the north and northeast to initially block and then attack the 24th NVA Regiment moving on to the DAK TO-TAN CANH area from the northeast down the TUMERONG Valley. The 2d Battalion, 8th Cavalry, moved into an AO southeast of TAN CANH to react against a possible attack from the southeast against the now large base complex along Route 512 from TAN CANH to DAK TO. The 1st Brigade, 1st Air Cavalry Division with the 1st Battalion, 12th Cavalry, arrived at KONTUM from the coast and was immediately deployed into the DAK HODRAI Valley south of the main battle area to intercept the withdrawing NVA.
The NVA forces were stopped and forced to withdraw. To the west of the BEN HET the NVA committed their reserves, the 174th NVA Regiment, to

cover the withdrawal to the southwest of their two hard hit regiments. This resulted in the violent, four day struggle for Hill 875 which ultimately involved two battalions of the 173d Airborne Brigade and the 1st Battalion, 12th Infantry, which was airlifted into the battle area from DARLAC Province. The hill was taken after receiving . . . TAC air and . . . artillery bombardment .... Meanwhile, northeast of TAN CANH an ARVN infantry battalion fixed a large NVA force on a hill mass while two ARVN airborne battalions swept up the flanks in a fierce two day battle, which inflicted heavy NVA casualties. Later, the same 2d and 3d ARVN Airborne Battalions sprang an attempted enemy ambush with one battalion while getting behind the positioned NVA forces with the other battalion and hitting the headquarters group, completely routing the battalion-size force.
One of the means by which .the division located and kept track of the enemy was the airborne personnel detector, commonly referred to as the "people sniffer." This air-transportable electrochemical instrument sensed microscopic particles suspended in the air. Mounted in the utility or light observation helicopters, the detector continuously sampled the atmosphere at the flight altitude of the aircraft for evidence of the enemy. It could also detect the ammonia excretions of men.
The improvement in communications available to the field commander in Vietnam stands as a hallmark of. accomplishment of Army communications personnel at all levels. Insight into the communications situation is given by Brigadier General William M. Van Harlingen, Jr., in his debriefing report after eighteen months as commanding general of the 1st Signal Brigade:
Communications has been a significant factor in the conflict in Vietnam. The enemy's limited tactical communications capability has forced him to adhere to preplanned offensive operations and denied to him the flexibility needed to react to the changing circumstances of battle. On the other hand our wealth of tactical communications has given us great flexibility and permitted us to use our tactical mobility to the fullest advantage. Communications organic to our divisions and field forces, along with substantial support by combat area signal units, have given U.S. field commanders a command and control capability which, along with their overwhelming firepower and tactical mobility has permitted them a freedom of action which they have exploited to the fullest in the conduct of operations.
The advances in communications since the Korean War have contributed immeasurably to the over-all effectiveness of the U.S. Army in combat. Through the extensive communication systems at each level, commanders were better able to control the personnel and weapons under their command. The communication improvement resulted from a number of factors, including the evolution in electronics technology that caused the vacuum tube to give way to transistor-solid state circuitry.
Because wire and cable were obviously not suitable for interconnecting widely separated units across unsecured areas, VHF radio relay became the backbone of division .communications. Responsive

PICTURE: Mock-Up of XM-2 (Modified E63) Airborne Personel Detector mounted on UH-1 Aircraft.
mounted on UH 1 aircraft.
telephone service was provided to all parties who genuinely needed it. Multichannel VHF connections extended from brigade to battalion level, using division resources. Howitzer batteries supporting infantry battalions were allocated patch-through circuits from these radio relays, and alternate routes and backup systems were used extensively during tactical operations.

Typically, the organic division's communications were augmented by the Field Force Signal Battalion and by the area system provided by the 1st Signal Brigade for use by all friendly forces. These supplements were required by the great size of the division's usual area of operations and by the terrain that posed many challenges to the communicator. The significant innovation in the area system was the provision of multichannel VHF radio relay to small units. According to published doctrine, corps (field forces) systems terminated at artillery group level, but in Vietnam, field forces sometimes provided multichannel service as far down as the artillery battery. This extension not only improved communications but also supported sole-user telephone service (hot lines) anywhere the commander desired. The actual use of the system varied greatly from division to division. The tactical operations center of the 1st Infantry Division was typical. It had thirty-five sole-user circuits that terminated in the operations center. In World War II four channels of communication ran from a corps to a division, while in the Korean War the use of eight channels from a corps to a division was standard practice. In Vietnam, however, thirty-two channels to a single combat brigade were common. This tremendous improvement in battlefield communications had a proportionate effect on the commander's ability to influence the battle.
Large-scale airmobile operations in Vietnam allowed, and virtually required, the commander to move his command post from the ground to the air. Effective command and control of widespread units in the jungle was not possible from the traditional command post of previous wars. An airborne command post was the solution. A critical component of this new command post was the communications equipment available to the commander and his staff. Several early configurations had been tried; in 1965 a basic console was approved that included two FM radios, one VHF radio, one UHF radio, and one high-frequency, single side band radio. Designated the AN/ASC6, this console was designed for quick installation and removal. In 1968 the AN/ASC-10 console was developed. This item was smaller and easier to install and provided an intercom system for the command group on board the aircraft. Another new console, the AN/ASC-11, consisted of two vehicular FM radios plus the organic, high-frequency, single side band in the aircraft. Two AN/ASC-11's could be installed in one aircraft. An alternative to the AN/ASC-10 was the AN/ASC-15. It had three UHF-FM radios with a secure voice device.
These radios allowed the commander and his staff to control combat operations. The command group could use several radio nets simultaneously. For example, a Vietnamese commander could use one FM net to control his ground units; the senior U.S. adviser could

PICTURE: An/ASC-15 Communication Central
communicate with the American advisers on the other FM set; the air liaison officer could maintain UHF contact with the forward air controllers directing the air strikes; and the high-frequency, single side band would be available, if needed, to enter the corps' air support operations net. The commander of the aviation unit could use the helicopter radios to control his aircraft.
The composition of the command group varied depending on the desire of the commander and the nature of the mission. For Vietnamese units, the group often consisted of the Vietnamese commander, his senior U.S. adviser, an air liaison officer, and an artillery adviser. For U.S. units, the command group was made up of the airmobile force commander and his operations officer, air and artillery liaison officers, and sometimes the higher unit commander or a member of his staff. The commander of the U.S. Army aviation unit or his operations officer was normally the pilot or copilot of the helicopter command post.
The flexibility of the helicopter command post enabled the commander to control ground units, to co-ordinate the helicopter force with prestrike forces, to co-ordinate all fire support (attack helicop-

ters, ground support fire, and tactical air), and to perform special missions. In spite of these and other advantages, there were some limitations for the airborne commander. Bad weather caused the helicopter to fly at lower altitudes, thereby increasing its vulnerability to ground fire and causing congestion over the landing zone. The weight of the radio equipment limited the amount of fuel that could be carried. Furthermore, the commander had to decide between carrying more troops and less fuel, which decreased the flying time, and more fuel and fewer troops, which added to the flying time. The size of the helicopter also limited space and facilities. Especially important was the disadvantage of having all key personnel on one helicopter. While these limitations presented problems, the helicopter command post was still an effective command and control vehicle for the type of warfare and terrain found in Vietnam.
The airborne radio relay was an innovation conceived to provide communication links between separated elements beyond the range of normal communication equipment or deployed in terrain that lacked adequate sites for ground relay operations. Some of the configurations used were U1-A and CV-2 aircraft with four channels of communication, using FM radios and ARC-121 consoles; U-21 aircraft with six secure channels of FM communication, using an ARC149 console; O-1 aircraft with a ground or aircraft FM radio; OH-13 aircraft with aircraft FM radios; and UH-1D aircraft with a ground FM radio, During the first three months of 1966 an airmobile radio relay was used in eighteen of forty-two operations reported by brigades of the 1st Cavalry Division and 1st Infantry Division, by the 173d Airborne Brigade, and by the 1st Brigade, 101st Airborne Division. Specific note of this technique was made by Lieutenant Colonel Tom M. Nicholson, former commanding officer of the 13th Signal Battalion. Colonel Nicholson wrote:
On many occasions, airborne relay was provided by CV-2 aircraft, which had a capability of 6 relays at once. This multiple relay was used for simultaneous support of the battalion command, the brigade command, the artillery fire, the forward air control, and medical evacuation net, during many operations. The outstanding logistical support and medical evacuation, experienced by the battalions of the 1st Air Cav Division, would have been severely restricted without the airborne relay.
In some situations the bulk and weight of standard equipment configurations proved unsatisfactory, resulting in serious problems in mobility and flexibility. An example of such a situation is the AN/ MRC-69 VHF radio relay terminal that provided connection with division telephone and teletype networks. A minimum of two CH-47 helicopter sorties was needed to lift the AN/MRC-69 with its component generator set. After being landed in heavy jungle, the shelter was not mobile and in many cases was operating extremely close to

the landing zone. To solve these problems, some units built special re configurations, commonly called MRC-341A (half of 69). Typically, they consisted of a 3/4 -ton trailer with enough equipment from the AN/MRC-69 to terminate twelve channels of voice communication links (half of the AN/MRC-69 capacity). As one report on command communications states:
The trailer configuration was chosen because of its several advantages. Though a vehicular mounted set was self transporting, it was deemed too heavy for the intended purpose. Also, the rig could not be employed if the vehicle was deadlined. Finally, a trailer mounted radio terminal was lighter and easier to handle. It could be backed into a Chinook and followed by the skid mounted 3kw generator with little or no trouble.
Before the battle of Dak To, the 4th Infantry Division's communication unit, the 124th Signal Battalion, had had some experience with the MRC-341/2. The first MRC-341/2 constructed by the 124th Signal Battalion was based on pictures of radio relay units built by another division. Numerous improvements were made on the final version. What resulted was an exceptional, air-transportable communications system, which proved itself in the Dak To operation, according to the after action report of the battle.
Due to inaccessibility of some areas by road movement and also the requirement for immediate communications it was necessary to airlift the AN/MRC-341A on four different occasions. The first was when the 1st Brigade, 1st Air Cav located a TAC CP at Polei Kleng. From there it was airlifted to the 1st Brigade, 1st Air Cav Div, CP when they displaced to the Dak To area. When they were released from Div OPCON and the 1/12th Air Cav Squadron relocated in the vicinity of Plei Mrong it was again airlifted by chopper and the last time was back to Dak To Airfield when the 173d Abn Brigade assumed OPCON of the 1/12th Cav. This extreme flexibility of movement for 12 channel VHF communications equipment proved once again to be an invaluable assist to this Division.
In 1968 the Nestor program, which included a group of speech security apparatus-KY-8 and KY-38 ground equipment and KY28 airborne equipment-for FM radios, was introduced. The use of this new equipment was limited at first; however, more command emphasis coupled with attempts to procure missing and desired items increased its use to approximately 85 percent as of June 1970. The HYL-3 Regenerative Repeater was introduced to meet the need for secure retransmission. Over-all, secure voice equipment was an innovation of major importance.
In 1969 a durable, easy-to-use, low-level, numeral, authentication code, the Circe wheel code, patterned after an Air Force wheel code, was designed to replace the existing low-level codes (KAC-Q). The KAC-Q codes had been bulky, easily torn, and time-consuming and, consequently, had promoted the use of unauthorized codes. Field tests of the Circe wheel code by the 23d Infantry Division (Americal) and 1st Brigade, 5th Infantry Division, revealed that the new code

was easier to operate and more durable and that it discouraged the use of unauthorized codes.
The battle for Dak To was a logistician's nightmare. The helicopters supporting the operation consumed 863,190 gallons of JP4 fuel and 32,550 gallons of aviation gasoline and used an enormous quantity of ammunition. To sustain this effort, rearm and refuel points were established at Dak To, Kontum, Camp Enari, and Camp Holloway. In the early days of the war, civilian trucks traveled through enemy territory to the forward area of operations where the helicopters were refueled. As the war intensified, this method proved unreliable and inadequate. Experience indicated the need for forward support bases for the rearming and refueling of helicopters. Operations in areas remote from the base camp stood a much better chance of success if the round-trip time of the helicopters could be reduced.
Beginning in January 1966, aviation battalions made good use of Vietnam airfields as logistic bases of operations. This practice placed almost any area of operations within a 25- to 30-nautical-mile radius of an airfield. Each refuel and rearm station was already stocked with the proper munitions, petroleum products, and equipment. Using these stockpiles, the units were able to respond quickly to previously planned and quick-reaction-type operations.
Refueling was accomplished using either 500-gallon bladders or 55-gallon drums and portable pumping equipment. By placing the 500-gallon bladders in line, an entire flight element could refuel in minutes without shutting down. From 1966 through 1968 several equipment changes were prompted by the need to increase the ability of aviation units supporting tactical operations to refuel rapidly. By spring of 1967, aviation units could refuel at a rate of 350 gallons per minute. This system simultaneously refueled twelve UH-1 aircraft within four to six minutes and reduced the average refueling time for the CH-47 by at least ten minutes. One aviation unit reported success with this system using two 10,000-gallon bladders, one 350gallons-per-minute pump, and a 4-inch manifold with twelve UH-1 and four CH-47 refueling points.
At Dak To there were six 10,000-gallon bladders (two for the CH47 and four for the UH-1) set up in two JP4 refueling areas. All aviation gas was dispensed from 5,000-gallon trailers. The neoprene bladders with 350-gallons-per-minute pumps and filter-separators were vital elements in the support of combat aircraft.
The refueling and rearming time for gunships could be considerably reduced by keeping small quantities of ammunition at refueling points. Therefore, ammunition was assembled and prepared at one location and transported to the rearming area by 3/ -ton trucks. Waste and packing materials were not brought near the aircraft because of the danger to rotor blades. The size of the 3/ -ton truck al-

lowed it to move close enough so that the ammunition could be loaded directly onto the helicopter, thus eliminating one handling step. When properly loaded, a 3/ -ton truck could carry enough ammunition to rearm several helicopters.
Route 14, the main ground supply route that ran from Pleiku through Kontum to Dak To, passed through many miles of dense growth that grew to within ten feet of the road. This growth provided cover and concealment from which the enemy could ambush a supply column. Early in Operation MACARTHUR the engineers were called on to clear the area on either side of the road. A unique aspect of land clearing in support of tactical operations lay in the amount-in some cases, thousands of acres. The problem was to find equipment that would be both speedy and efficient.
During 1966 and 1967 several methods of land clearing were used. The King Ranch concept-developed on King Ranch property in Australia-consisted of dragging a heavy length of chain (at least fifty pounds per foot) strung between two tractors. For large trees or rocky soil, a steel ball fourteen feet in diameter was placed at the middle of the chain. The technique was found to be especially effective over nonrocky terrain with small-to-medium-diameter trees having shallow roots, but not over land with grasses and light shrubs. The 1st Infantry Division used the King Ranch concept to clear 1,500 trees in four hours. Tests eventually revealed, however, that the division's D7 tractors were too small to pull the anchor chain efficiently. Since very few larger tractors were used in Vietnam, the technique had only limited use.
Another land clearing device, the transphibian tactical crusher, was tested during mid-1967. This massive 97-ton machine used a pusher bar against large trees and cleated drums to chop up felled trees and small vegetation. During testing, trees forty to forty-eight inches in diameter proved to be no obstacle to the crusher. Two crushers were initially used to clear 2,083 acres in the vicinity of Long Binh and then assigned to the 93d Engineer Battalion (Construction) for use in a tactical environment near the Binh Son Rubber Plantation, thirty-five miles southeast of Saigon. Approximately 1, 300 acres were cleared in support of the 9th Infantry Division, but the crushers suffered an inordinate amount of time under repair. Therefore, after the testing was completed, no additional crushers were procured.
The equipment that finally filled the need for a rapid, efficient land clearing device was the Rome K/G Clearing Blade-better known as the Rome plow. It consisted of a tractor attachment with a blade that "stung" and "sliced" large trees. A sharp projection on the left side of the blade split the trees, while the cutting edge sheared them off at ground level. The attachment came in two sizes: a 4,600pound blade that fit the Allis Chalmers HD-16M and Caterpillar

PICTURE: Bulldozers With Rime Plows Clear Jungle Growth While Mechanized Infantry Stands Guard.
while mechanized infantry stands guard.

D7E, and smaller 4, 000-pound blade used on the airmobile D6B tractor. In late 1966 four Rome plow blades were tested in the 20th Engineer Brigade. They efficiently cleared all vegetation where the soil could support the tractor.
Seventy Rome plow blades were procured for combat engineer units. Although the original purpose of the plow was to clear jungle base areas, it was only a short time before many other uses were found. For example, this land clearing equipment provided a quick way to clear fields of fire around base camps and fire support bases and to construct helicopter landing zones and night defensive positions. The clearing of all vegetation from within 100 to 200 meters of roads significantly reduced the very serious problem of enemy ambush.
Before August 1967, Route 13 north of Lai Khe was completely controlled by the Viet Cong. Field positions and outposts in the northern section of the area depended on aerial resupply, and only rarely did a convoy chance running the road. Occasionally, when this section of Route 13 was opened to support an operation or to resupply Quan Loi or Loc Ninh, extensive engineer efforts and large security

forces were required. Radio Hanoi boasted that this road would never again be used for South Vietnamese and American traffic. To meet this challenge and to deny cover and concealment to the enemy, a combat engineer battalion used six bulldozers equipped with land clearing blades and heavy steel cabs for the operators' protection. Working with armored security forces, the bulldozers peeled back the jungle 200 meters on both sides of Route 13. Concurrently engineer work parties repaired culverts, craters, and bridges in an extensive effort to improve this route for division traffic. On 1 November 1967, during Operation SHENANDOAH II, Route QL 13 was opened for resupply convoys.
Initially, an enormous amount of manpower was required to secure the road. This need tied down many units of an infantry division and limited the number of battalions available for conducting other offensive operations. Again the bulldozers with land clearing blades solved the problem by cutting night defensive positions having wide fields of fire at 4- to 5-kilometer intervals along the road. These positions were then fortified with enough troops and equipment to sweep and secure the road each day. Early in 1968 the bulldozers pushed back the jungle an additional 200 meters on each side of Route QL 13, thus reducing night defensive positions by 50 percent.
The first major combat support clearing operation was conducted in the Iron Triangle area during Operations NIAGARA FALLS and CEDAR FALLS, when 3,000 acres were cleared. During Operation PAUL BUNYAN, the 168th Engineer Battalion cleared over 14,000 acres in support of the 1st Infantry Division.
The land clearing organization grew from a few isolated tractors to a battalion-size operation. In mid-1967 three land clearing teams, composed of thirty Rome plow blades, mounted on ME tractors, and sixty-four men, were activated and attached to the 27th, 86th, and 35th Engineer Battalions. Their success led to the formation of six land clearing companies. Finally, the 62d Engineer Battalion (Construction) was reorganized and equipped as a land clearing battalion. By October 1969 the engineers had cleared 388,852 acres.
Since the beginning of land clearing operations, enemy sanctuaries, base camps, and infiltration routes have been exposed, and the enemy has been separated from local supply sources and tax-collection points. Land cleared by Rome plows has been immediately available for farming and resettling, particularly along the major lines of communication. Wood for cooking and heating has been easily obtainable, and a potential exists for the development of lumber production.
Defoliation operations also deprived the enemy of his hiding places. Although they later became the center of much controversy, herbicides were important tactical weapons. Defoliation and crop de-

struction were first tested as counterinsurgency measures in 1961 as a part of Project AGILE, a joint U.S. -South Vietnamese development program. Chemical spray tests were made by the Vietnamese Air Force with experimental dissemination devices and off-the-shelf commercial herbicides. Despite the serious limitations of the components, the results demonstrated clearly that available growth-regulator and desiccant chemicals were capable of defoliating tropical forests and destroying enemy food crops. The first U.S. Air Force C-123/MC-1 (Hourglass) spray system, along with herbicide agents Purple and Blue, reached Vietnam in 1962, and Operation RANCH HAND was initiated to conduct defoliation and anticrop operations.
By the time of the U.S. buildup in 1965-1966, the two agents most commonly used in RANCH HAND were Blue and Orange, so named for the color markings on the containers in which the herbicides were shipped. Orange is a mixture of two relatively common herbicides (2, 4-D and 2, 4, 5-T) and is classified as a systemic herbicide. As such it is absorbed into the plant from the point of application. Once inside the plant's system, Orange interferes with the growth processes, such as photosynthesis, and eventually kills the plant if the dose is adequate. Blue is a desiccant, contact herbicide that damages plant tissue at the point where it is applied. Desiccants are drying agents that will cause leaves to drop off but will not necessarily kill the plant itself. In Vietnam new foliage may grow back within thirty to ninety days after applying Blue.
The rather complicated procedures and safeguards governing approval for operational use of herbicides in South Vietnam were set forth in MACV Directive 525-1. The use of herbicides for defoliation and crop destruction was primarily an operation of the government of South Vietnam, supported by U.S. assets and expertise. Under policy guidance established by the U.S. Departments of State and Defense, the Commander, U.S. Military Assistance Command, Vietnam, and the U.S. Ambassador were empowered jointly to authorize U.S. support of the South Vietnamese government's requests for herbicide operations. General co-ordination of the program and guidance was the responsibility of the Chemical Operations Division of MACV's J-3 (Operations Directorate).
All requests for fixed-wing aircraft defoliation and for fixed-wing, helicopter, and ground spray crop destruction originated at the district or province level. These requests were processed through ARVN division and corps tactical zones to the joint General Staff of the Republic of Vietnam armed forces. Simultaneously, U.S. commanders and advisers involved in the project were submitting their views through channels to MACV's J-3. Requests approved by the Vietnamese Joint General Staff in their 203 Committee were then passed to the chemical operation division of MACV's J-3, where the approved

project was consolidated with the position of the U.S. commanders and advisers before being submitted to the U.S. 203 Committee. This committee consisted of representatives from MACV's J-3, J-2, and Psychological Operations section and from Operation RANCH HAND, Civil Operations and Revolutionary Development Support (CORDS), U.S. Agency for International Development (USAID), Joint U.S. Public Affairs Office (JUSPAO), and the American Embassy. After reviewing each project, as well as necessary U.S. support, the U.S. 203 Committee forwarded its recommendation to the MACV commander and the U.S. Ambassador for consideration. If they approved the project for support, the joint General Staff was notified, and a coordination meeting was held in the capital of the province concerned, The province chief who sponsored the meeting was joined by the U.S. province and corps advisers, MACV's Chemical Operations Division action officer, joint General Staff representatives, and RANCH HAND personnel. Final details and changes in previous requests were made, and special conditions required during spray operations were established. The Joint General Staff then published an operation order for the project and established target priorities. They requested that U.S. support be provided on order. Details of the co-ordination of U.S. support were provided by the Chemical Operations Division to the commander of the Seventh Air Force and to the 12th Special Operations Squadron. A final opportunity was given to the province chief to cancel the mission twenty-four to forty-eight hours before the individual mission was executed.
U.S. and Vietnamese corps commanders jointly were authorized to carry out helicopter defoliation operations approved by the province chief and the U.S. senior adviser. These operations were conducted to support local base defense, to maintain Rome-plowed areas, and to clear known ambush sites along lines of communication. Vietnamese corps commanders and their U.S. senior advisers could approve requests for defoliation with ground-based equipment.
During the battle for Dak To, the 2d Battalion, 503d Infantry, of the 173d Airborne Brigade, established a fire support base in an area of dense vegetation. The brigade's chemical section conducted three defoliation missions close to the fire support base in an attempt to deprive the enemy of cover for ground or standoff attacks. The defoliation of allied base perimeters was usually carried out by ground or helicopter spray. The spraying had to be increased during the growing season. Because of the 400-gallon metal tank in the CH- I 47 and the use of pressurized bottles to refill the tanks in flight, 700 to 800 gallons of defoliant could be delivered in a single sortie.
Defoliation along the lines of communication, with emphasis on ambush sites and tax-collecting points, was quite effective in opening these areas and improving aerial observation. On two occasions de-

foliation operations reportedly disrupted Viet Cong ambushes by forcing the enemy to move out of the area as soon as it had been sprayed. The defoliation of infiltration routes greatly inhibited the enemy's movement during the daylight hours, because he feared detection from the air. On several occasions defoliation forced unplanned moves because it affected the protective tree foliage within six hours. The spraying of herbicides on enemy base areas kept the Viet Cong and North Vietnamese Army on the move and forced them to avoid defoliated areas for fear of detection.
The destruction of crops intended for the enemy was another significant accomplishment of the herbicide operations. This type of operation had, in some instances, forced the enemy to divert tactical units from combat missions to food procurement tasks. The resulting food shortages among enemy ranks prompted some defections. Defoliation accounted for approximately 90 percent of the herbicide effort in Vietnam. The remaining 10 percent was devoted to crop destruction.
In January 1968, a Herbicide Review Committee was established at the direction of U.S. Ambassador Ellsworth Bunker to conduct a comprehensive review of each aspect of the U.S.-South Vietnamese herbicide program. Subcommittees were organized to study defoliation and crop destruction.
In its findings, the defoliation subcommittee "recognized the military worth of defoliation beyond any doubt." The program was important in denying the enemy cover in heavily forested areas such as War Zones C and D and in Boi Loi Woods. It also increased the security of all allied forces by eliminating foliage around base camps and at likely ambush sites along water and land routes of communication. Captured Viet Cong and Chieu Hois who were questioned about the effects of defoliation admitted that their units often avoided crossing defoliated areas and would not camp in them. One soldier indicated that his unit had been prevented from occupying ambush sites along a canal because of defoliation operations.
The subcommittee made note of the economic and psychological costs of the program by calling attention to the possible loss of valuable stands of timber in War Zones C and D which would be unavoidable unless salvage operations were begun within two years. It also expressed concern over the success of the Viet Cong in promoting propaganda about the program which reflected adversely on U.S. motives and actions. The committee called for improved operational and program controls to minimize the effect of herbicide drift on crops near target areas.
The subcommittee on crop destruction found that such operations had been successful in weakening enemy strength and in denying food to the Viet Cong and North Vietnamese Army military units.

PICTURE: Result od Defoliation Operations Along Canal and Secondary Road.
RESULT OF DEFOLIATION OPERATIONS along canal and secondary road.
In some cases when food crops were destroyed, civilians who were sup porting the communists were compelled to seek refuge in areas controlled by the government of South Vietnam, thereby depriving the enemy of labor as well as food. Communist military forces were then compelled to raise their own crops which detracted from their operational mission. Food-growing detachments were forced to work harder, and the results were poor. Frequently, subsistence had to be obtained elsewhere to sustain an additional burden to the already strained communist transportation system.
However, evidence also indicated that since the civilian population in Viet Cong-controlled areas inevitably bore the brunt of crop destruction operations, considerable adverse political and psychological costs were incurred. The subcommittee called attention to the fact that the use of herbicides was only part of the total food denial program. Consequently, if crops were destroyed while other sources of food remained available, then the program was less effective. The committee found that past food control and denial activities had not been sufficiently co-ordinated at mission level and, therefore, had not realized their full potential.
As a result of the committee's findings and conclusions, the defoliation and crop destruction programs were continued, but tighter control measures were imposed.
By the end of 1968, the most intensive defoliation efforts had been made in the infamous Rung Sat Special Zone, which surrounded the 

shipping channel into Saigon and in War Zones C and D. A survey of these areas was conducted in March and April 1968 by Fred H. Tchirley, an expert in the Agricultural Research Division of the U.S. Department of Agriculture. He concluded at the time that the defoliation program, especially in the areas of intense treatment, had caused ecological changes. He did not feel that such changes were irreversible but, as he said, ". . . recovery may take a long time . . . ." For example, regeneration of the mangrove forests in the Rung Sat was estimated to require about twenty years. Mr. Tchirley made no prediction on the semideciduous forests, such as those found in War Zones C and D. He said:
A single treatment on semideciduous forest would cause inconsequential change. Repeated treatments will result in invasion of many sites by bamboo . . . . The time scale of regeneration of semideciduous forest is unknown. Available information is so scanty that a prediction would have no validity and certainly no real meaning. Most of the defoliation treatments in semideciduous forests have been made along lines of communication. The ecological effect of defoliation in those areas would not be as severe as in areas where large blocks have been treated.
In April 1970, the Department of  Defense ordered a temporary ban on the use of agent Orange. This restriction resulted in a corresponding decrease in the number of defoliation missions flown, and by July 1970 all defoliation missions by fixed-wing aircraft were halted. Crop destruction missions, although never flown in the rice-producing delta, were also severely curtailed and then stopped completely a short time later.
There were a number of articles in scientific magazines in 1969 and 1970 that criticized the U.S. government's herbicide program in Vietnam. The Herbicide Assessment Commission of the American Association for the Advancement of Science (AAAS) made a fiveweek inspection tour of Vietnam in the summer of 1970. The commission, headed by Harvard biologist Matthew S. Meselson, asserted that the spraying program had caused "extremely serious harm" to the land and to "some of the peoples of the war-torn country." In addition to condemning the destruction of the mangrove and hardwood forests, Meselson's group charged that the crop destruction effort was a failure and that spraying may have been responsible for a high number of stillbirths and birth defects among the Vietnamese in 1967 and 1968. The commission did stress that "neither effect could safely be attributed to the impact of herbicides." It felt that further studies were necessary to determine the cause of medical phenomenon in children born of women who lived in heavily sprayed areas. Meselson indicated that the focus for future action "should be shifted away from assessing harm and toward finding ways to repair the damage done."
A number of other articles had been written which seemed to

imply that Indochina had been totally destroyed by herbicides and that all spraying was done without plan or purpose. The AAAS commission found that there was a "spectrum of opinion" on the military usefulness of the program but did not discuss the improved security for civilians and allied forces along lines of communications after spraying operations.
In October 1970, Congress passed a bill which became Public Law 91-441. One provision of this law directed the Secretary of Defense to ". . . enter into appropriate arrangements with the National Academy of Sciences to conduct a comprehensive study and investigation to determine (a) the ecological and physiological dangers inherent in the use of herbicides, and (b) the ecological and physiological effects of the defoliation program carried out by the Department of Defense in South Vietnam . . . ." The National Academy of Sciences (NAS) report was to be completed by 31 January 1972 and forwarded to the President and the Congress "with such comments and recommendations as . . . appropriate" by 1 March 1972. Until the findings of the academy are made public, and perhaps even afterward, speculation about the detrimental effects of herbicides in Vietnam will probably continue to be debated. Vietnam has certainly not been destroyed, as some critics claim, and many U.S. soldiers are alive today because of the defoliation of ambush sites and the uncovering of enemy base areas.
In addition to taking away the enemy's hiding places, U.S. forces developed methods to conceal their own operations. In early 1966 a method was developed to dispense smoke from a low-flying helicopter so that all or part of a landing zone could be obscured from the enemy's view to protect landing helicopters. The first system used a UH1C "Hog" gunship with its M3 rocket system mounted backwards. Smoke grenade canisters were inserted into the rocket launcher tubes and ejected to the rear as the aircraft flew at a slow speed and close to the ground. This method proved to be satisfactory if the landing zone was not inundated.
The integral smoke generator, XM-52, was designed to produce a dense cloud of smoke by injecting atomized fog oil into the hot exhaust gases of the turbine engine of the UH-1. The oil was immediately vaporized, and smoke billowed to the rear. One 60-gallon tank or two 55-gallon bladders were used; the bladders provided eight minutes of smoke. The smoke generator proved to be so successful that a contract was awarded for the manufacture of 121 systems. In addition to its use in landing zones during combat assaults, smoke could be dispensed along a flight route to screen helicopter movement, in landing zones during medical evacuations, and in unused landing zones as a diversionary tactic.
The battle for Dak To has been characterized as one of the longest

continuous battles fought by the U.S. Army in Vietnam. Contributing to the defeat of expert North Vietnamese Army units were U.S. superiority in the command and control of units, close and timely logistic support, the removal of enemy hiding places, and the imaginative use of new techniques and weapons.

page created 15 December 2001


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