The Truth about Agent Orange and other Herbicides in Thailand during the Vietnam War

B. The military used the same herbicides in Thailand that were used in Vietnam.

The military used the same herbicides in Thailand that were used in Vietnam.

1. The Rules of Engagement for Vietnam and Thailand were similar.

Both Vietnam and Thailand were engagement zones for deployed military personnel, and both countries had similar Rules of Engagement (Rules). Although most of the Air Force bases in Thailand were seen as staging hubs for operations within Vietnam, military personnel located throughout Thailand were also subjected to hostile attacks from Communists. In the 1968 Contemporary Historical Examination of Current Operation (CHECO) Project Southeast Asia Report: Attack on Udorn, the Air Force recognized that Thailand was a “prime target of Communist expansion, and the interest of the Communists was intensified by the USAF presence.” The report also noted that there were an estimated 15,500 Communist insurgents and sympathizers in Thailand. From 1965 to 1968, 5,727 Communist insurgents in Thailand were either killed, arrested, or surrendered. From 1966 to mid-1968, insurgents conducted 331 assassinations and 1,087 armed encounters. The threats toward Air Force bases were legitimate and a serious concern for military units stationed in Thailand.

Bases in ThailandBases in Thailand, including Korat, Nakhon Phanom (NKP), Ubon, Udorn, and U-Tapao, were subjected to sniper fire, perimeter penetration, and sapper (combat engineer) attacks. These attacks resulted in both U.S. and enemy causalities. The Department of Defense had legitimate concerns about the threat to U.S. personnel and equipment, which led to the decision to use herbicides within base perimeters as a means of preventing ambushes in Thailand.6

The similarities between base defense in Vietnam and Thailand were highlighted in the 1969 CHECO Report titled “7AF Local Base Defense Operations: July 1965 – December 1968.”  This report provides a general analysis of Air Force base operations.  The report recognizes the heightened risk of attacks directed against air bases because they presented the enemy with a “concentration of lucrative targets.”  Additionally, the report states:  “Thailand is going through the same type of growing pains experienced in the Republic of Vietnam (RVN), but the knowledge and experience gained in the development of air base defense in RVN permit a more rapid evolution in Thailand.”  Thus, similar tactics and procedures in base defense were used in both Thailand and Vietnam because the bases were facing the same threat with similar resources.

The Rules provided authorization for, and limits on, the employment of herbicides throughout the Southeast Asian conflict.  Military Assistance Command, Vietnam (MACV) Directive 525-1 (1966) highlighted the procedure for requesting aerial spray, power spray, and hand spray in Vietnam.  The directive empowered the Commander U.S. Military Assistance Command, Vietnam (COMUSMAV), and the U.S. Ambassador to authorize herbicide operations.  The directive delegated authority to approve defoliation requests using hand spray and ground-based power spray methods. The directive highlights U.S. assistance to local government in requesting, supplying, and planning defoliation operations.

2. Tailand’s strong connection to Operation RANCH HAND demonstrates that its bases received a steady supply of herbicides.

Similarities between the Rules in Thailand and Vietnam were also necessary due to Operation RANCH HAND activities in Thailand.  Throughout the Vietnam War, RANCH HAND aircraft utilized bases in Thailand.  Aircraft used for RANCH HAND, UC-123Ks, launched from airbases in Thailand including Ubon, Udorn, NKP, and Takhli on numerous occasions to conduct missions against targets in Vietnam and Laos.  In August 1963, the government of Thailand requested aerial spraying services from RANCH HAND aircraft to assist with its locust problem.  From December 29, 1968, to January 2, 1969, RANCH HAND aircraft flew Agent Orange missions out of Udorn.  On January 17, 1969, seven RANCH HAND aircraft flew to Ubon to conduct an attack the next day against a special target in Laos.  From February 2 to 5, 1969, RANCH HAND flew Laos missions from Udorn. Udorn was again utilized August 31, 1969 to conduct an operation in which RANCH HAND aircraft flew 28 sorties from Thailand to target Laotian crops with Agent Blue using five UC-123s during a seven-day period.  Records from the Ranch Hand History Project show that Sergeant Richard E. Wolf, who worked on Operation RANCH HAND, received a letter of commendation for his actions in Thailand during these operation.  National Archive records also reveal that herbicide missions launched from Thailand on July 6, 1966, August 29, 1966, December 15, 1967, June 7, 1967, April 18, 1969, and March 25, 1970. Although these missions were classified, they demonstrate the robust relationship between U.S. military in Thailand and Operation RANCH HAND.

Air Force documents confirm that herbicide deliveries not associated with RANCH HAND were transported to and from Thailand.  National Archives records reveal that herbicides were transported from Vietnam to Takhli on April 7, 1973. Moreover, the load class in the record, Y4, is the same load class that was noted in an Operation Steel Tiger mission in South Vietnam the primary goal of which was defoliation. This reporting directly corresponds to other Air Force archives documents from 1973 showing that the Civil Engineers had developed a standard operating procedure for the use of herbicide on Takhli to avoid misuse. By June 1973, the unit was waiting for more herbicides. Hence, the records suggest the movement of herbicides to and from Thailand was not exclusively associated with RANCH HAND missions and that herbicides were used throughout Thailand.

Despite this evidence, VA’s position is that RANCH HAND aircraft and herbicides were either temporarily staged, or never staged, on Thailand bases. Further documentation and sworn statements contradict that claim. William Easterly was stationed throughout Vietnam and Thailand from 1966-1967 and 1969-1970. He was a chief gunner on UH-1P helicopters that provided gun cover for RANCH HAND aircraft. He stated that when the weather was bad, the crew would stay in Thailand at Ubon, NKP, or Udorn. He stated, “back at our base, we would get buckets of Agent Orange and fill pump fire extinguishers with AO [Agent Orange] so we could spray around our local area.”

Because the spraying equipment on RANCH HAND aircraft and the barrels containing herbicides were known to leak, the risk of exposure throughout the flight lines as well as storage areas on Thailand bases was significant. John Scott, an Airman stationed at Ubon from 1969 to 1972, stated that he assisted in loading barrels of Agent Orange onto C-123s during the first part of his tour. He also noted in his sworn statement that the barrels “were leaking all the time” and the herbicide got all over his uniform and hands.

In Ubon veteran Ronald Switzer’s appeal to the Board of Veterans’ Appeals, he asserted that he was a material handler of Agent Orange during his time at Ubon from 1968-1969. He, too, stated that the barrels often leaked. Leakage from “empty” herbicide barrels was also noted because it was difficult to drain the last two or three gallons. The color distortion caused by leaking barrels containing herbicides is noted in pictures of herbicides stored on Johnston Atoll. The herbicides stored on Johnston Island were burned at sea in approximately 1977.

3. The historical record reveals substantial herbicide use on bases in Thailand.

Significant use of herbicides at numerous Thailand military basesAlthough VA recognizes “there was significant use of herbicides” at numerous Thailand military bases, it continues to deny Thailand veterans the presumption of exposure afforded to Vietnam veterans. Due to the density and high growth rate of tropical vegetation in Thailand, the military used herbicides because mowing was seen as labor intensive and ineffective. Furthermore, there are several reference reports admitting herbicide use throughout bases in Thailand. Herbicides were used to control vegetation in Thailand’s tropical environment. More specifically, herbicides were used to improve visual observation of the base perimeter.

Due to attacks on Thailand bases, military leaders ordered the use of herbicides. In a 56th Special Operations Wing memo with the subject “Lessons Learned from the Attack on Udorn, 26 Jul 68,” the Deputy Commander of the 7/13th Air Force ordered base commanders in Thailand to “review base defense plan with an eye to covering critical areas which are adjacent to the perimeter.” As a result, defense surveys and reassessments were conducted throughout Thailand, including one survey conducted from June 23 to 30 1969, at NKP, Udorn, Ubon, Korat, Takhli, and U-Tapao. Regarding base defense, the survey stated:

A continuing vegetation control program is required for cleared areas under and between perimeter security fences. The area between the fences is intended to be used as a no-man’s land with additional detection and deterrent devices such as trip flares, TSSE, tangle-foot, etc. being employed within. In view of the above, a mowing operation for vegetation control will be impossible. As a result, a conscientiously controlled program of vegetation control through the use of herbicides must be applied. Application of herbicides must be directed toward retarding growth to provide a cleared area ….

Because of ongoing security concerns, Air Force leadership ordered the use of additional herbicides. Several documents demonstrate that Agents Orange and Blue were present in Thailand. For example, 28,000 gallons of herbicides were airlifted by two C-130s from Phu Cat Airbase in Vietnam to Udorn prior to some of the RANCH HAND missions later launched from Udorn to targets in Laos from February 2 to 7, 1969. However, per the 1971 CHECO Report, only 7,000 gallons of this herbicide, mostly Agent Orange, were dispensed in Laos. That leaves 21,000 gallons of herbicide unaccounted for with their last known location in Thailand. This directly coincides with Air Force documents stating that defoliation operations around the Udorn perimeter occurred during this period. It stands to reason that this remaining herbicide was used at other bases since 21,000 gallons was far more than necessary for a single base. Hence, herbicides including Agent Orange were used in Thailand despite VA’s denial.

The prevalence of herbicide use in Thailand is further demonstrated by the embassy’s approval of the use of herbicides on several occasions. In 1972, vegetation control on Korat was regarded as a serious issue because dense growth provided the enemy with the opportunity to access the KC-135 parking ramp. As a result, the embassy approved the use of herbicides. Additionally, the 1973 CHECO Report states that soil sterilization and herbicide use was approved by the embassy in 1969 in accordance with the Rules.

These admissions correlate with sworn statements provided by several Airmen. Mr. George Collins was assigned to the Aero Space Ground Equipment (AGE) unit in U-Tapao for seven months beginning in 1969 and ending in 1970. He wrote in a sworn statement that he was twice assigned the task of “diagnosing and repairing a Buffalo Turbine fogger/sprayer unit which sprayed the base consistently for insects and defoliated the base perimeter and other areas on the base.” He witnessed drums with orange, blue, or white bands being stored in a shed at the AGE facility surrounded by defoliated soil. His statements corroborate documentation demonstrating the use of herbicides on U-Tapao in 1971 and 1972. Historical reports establish that a squadron in 1971 “began spraying chemical herbicides on the troublesome plants.” In 1972, the leadership at U-Tapao sought to “expand use of herbicides” in clearing 100 feet from the perimeter fence and invoking an “aggressive program on vegetation control.” Together, the Airman’s statement and historical reports demonstrate consistent use of herbicides in which the Air Force utilized internal equipment to accomplish defoliation.

In Command Sergeant Major (Ret.) Kenneth Witkin’s statement, he attested to observing Agent Orange being sprayed around the barracks at Udorn in 1970-1971. This coincides with documentation demonstrating that Major George Norwood addressed the need for strong vegetation control and that the Base Civil Engineers had been requested specifically for vegetation control on Udorn in 1971. In his appeal to the Board of Veterans’ Appeals, Thailand veteran Ronald Switzer stated he was a material handler of Agent Orange and that after the 1969 attack on Ubon, the perimeter was pushed back and the “trees lost their foliage.” This correlates to documents showing the recommended use of herbicides in 1969 and their subsequent use in 1970, 1971 and 1973. Photographs of Ubon’s perimeter demonstrate it was pushed back and that there was a lack of foliage between the old and new perimeter.

Thailand Guard Post
The location of this guard post is no longer adjacent to the boundaries. This may support the documentation that the boundary was pushed back and that herbicides were used.

Thailand Guard Post Agent Orange

Thailand veteran Michael Williams, who was stationed at Ubon from May 1969 to May 1970, asserted that he was assigned to a detail that involved defoliating the perimeter of the base. During the detail, he used defoliants that were contained in 55-gallon drums with orange stripes. Although he worked on the detail for 10 days, he stated that the detail continued for the rest of his time there. This matches documentation indicating herbicide use at and after that time.

The use of herbicides on NKP was noted in the 1973 CHECO report and in a soldier’s sworn statement. Thailand veteran Wayne Hogstad was stationed at NKP from April 1967 to April 1968 and was assigned to the police squadron. In Mr. Hogstad’s statement, he said that he observed a C-123 aircraft mounted with spray equipment next to barrels with orange stripes. He reported that he took time “to ride with a mobile unit Security Alert Team around NKP bases perimeters, [and] while going along the east perimeter a crew from civil engineering with a truck with a tank” sprayed what Mr. Hogstad believed to be Agent Orange. His statement aligns with the CHECO report, which notes that “heavy use of herbicides kept the growth under control in the fenced areas.” Moreover, Mr. Hogstad’s statement correlates with a historical record showing a request dated October 11, 1967, sought “six C-123 herbicide aircraft and 60 personnel to operate from [NKP] for a 15 day period.”

There are several additional pieces of evidence indicating that herbicides were used throughout Southeast Asia. The article “Viet Cong – Right or Wrong,” published in the National Guardsman in 1966, notes the Defense Department’s Advance Research Project Agency was moving forward with defoliant improvement projects in Thailand. This suggests that the defoliant improvement projects occurred after the herbicide testing (1964-1965). In turn, this supports veterans’ statements regarding the use of herbicide to clear bases in Thailand during this period. Mr. Dennis Oliver, who was stationed in Thailand from 1966-1967, stated that during his assignment to the base’s munition storage area, he witnessed 55-gallon drums being stored near the revetments and observed barren land throughout the perimeter and base.

The author of a 1982 article published in the Journal of Legal Medicine, titled “Agent Orange: Government Responsibility for Military Use of Phenoxy Herbicides,” states that “[e]very American who served in Southeast Asia was potentially exposed to Agent Orange, as the herbicide was used to clear areas before construction and to defoliate compound perimeters, landing zones, and fires bases.” For support, the author cites to an appendix to the 1979 hearing on Senate Bills 741 and 196. During the Committee hearing on S.B. 741 and S.B. 196, Congress considered perimeter spraying. Similar to the Air Force unit histories in Thailand, the 1979 hearing noted that herbicides were used around bases in order to maintain base security.

RANCH HAND was also not prohibited from herbicide spray missions in Thailand. In November 1969, the NKP Commander requested RANCH HAND assistance to defoliate the ordnance drop area. In his request, the Commander stated: “Application must be by air because area is overgrown and ground application would be extremely dangerous due to live munitions in the area.”

4. The Air Force developed a standard for herbicide use on Thailand bases

In order to create a uniform standard for the use of herbicides, military leadership established annual training and standard operating procedures. Annual training was conducted on Takhli from March 17 to 21, 1969, and July 13 to 16, 1970, with representatives from all Thailand bases. The 355th Civil Engineer Squadron and Pacific Air Force ( PACAF) Command Agronomist sponsored the training. The training is an indicator that Air Force leadership took a cohesive approach regarding the application of herbicides on Thailand bases. On the herbicide school application, the listed purpose of the training was to “train and certify Thailand based personnel who will be handling herbicides for chemical vegetation control” and “train personnel on the use, application, dangers and safe handling of herbicides.” The class consisted of twelve non-commissioned officers. Moreover, the application stated that select personnel would receive “their own copy of the herbicide manual.” Although the current whereabouts of the herbicide manual are unknown, the publication of such a manual demonstrates the regular use of herbicides throughout Thailand. As Mr. Raymond Gross, a PACAF agronomist, conducted the training, the herbicide manual was most likely employed throughout Southeast Asia.

This notion is further strengthened by the fact that the civil engineers developed a standard operating procedure (SOP) specifically for the disposal of herbicides due to fear that indiscriminate use of herbicide could be a source of pollution. The Air Force leadership argued that adherence to the SOP “should eliminate any misuse of herbicide application” on Takhli. This statement indicates that misuse of herbicides by service members led to the necessity of establishing an SOP. It is also another indicator that herbicide use was prevalent and supports statements from Airmen regarding the use of herbicides throughout Thailand. Command Sergeant Major Kenneth Witkin stated that grounds personnel informed him they were using Agent Orange when he observed them spraying around barracks. Technical Sergeant William L. Easterly stated that RANCH HAND crew would use Agent Orange around their personnel area because they were not aware of the herbicide’s harmful effects. Although the SOP is not available or remains classified, the development and enforcement of the SOP highlights the prevalence of herbicide use and the concern of misuse on Thailand bases.


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