After many years and the uncovering of documents, VA has finally acknowledged that there was significant use of herbicides on the fenced in perimeters of military bases in Thailand. The use of AO in these locations was intended to eliminate vegetation and ground cover for base security purposes. Evidence of this use be found in a declassified Vietnam era Department of Defense (DoD) document titled Project CHECO Southeast Asia Report: Base Defense in Thailand.
It has also been confirmed that commercial herbicides, rather than tactical herbicides, were also used within the confines of Thailand bases to control weeds. These commercial herbicides do not fall under the VA regulations governing exposure to tactical herbicides such as AO. However, there is evidence that the herbicides used on the Thailand base perimeters may have been either tactical, procured from Vietnam, or a commercial variant of much greater strength and with characteristics of tactical herbicides.
The majority of troops in Thailand during the Vietnam era were stationed at the Royal Thai Air Force Bases of U-Tapao, Ubon, Nakhon Phanom, Udorn, Takhli, Korat, and Don Muang. If a US Air Force Veteran served on one of these air bases as a security policeman, security patrol dog handler, member of a security police squadron, or otherwise served near the air base perimeter, as shown by MOS (military occupational specialty), performance evaluations, or other credible evidence, then herbicide exposure should be acknowledged on a facts found or direct basis. This allows veterans to obtain presumptive service connection of the diseases associated with herbicide exposure, just the same as a "boots on the ground" Vietnam veteran. As a result, when VA receives a herbicide-related claim from a veteran with service in Thailand the key issue is whether the veteran's service involved duty on or near the perimeter of a military base during the Vietnam era, from February 28, 1961 to May 7, 1975.
Along with air bases, there were some small Army installations established in Thailand during this period, which may also have used perimeter herbicides in the same manner as the air bases. Therefore, if a US Army veteran claims a disability based on herbicide exposure and the veteran was a member of a military police (MP) unit or was assigned an MP MOS and states that his duty placed him at or near the base perimeter, then herbicide exposure on a facts found or direct basis should be acknowledged for this Veteran. The difference in approach for US Army veterans is based on the fact that some MPs had criminal investigation duties rather than base security duties. Therefore, the Veteran's lay statement is required to establish security duty on the base perimeter.
This process also applies to US Army personnel who served on air bases in Thailand because during the early years of the Vietnam war, before Air Force security units were fully established on air bases in Thailand, US Army personnel may have provided perimeter security. In such cases, if the veteran provides a lay statement that he was involved with perimeter security duty and there is additional credible evidence supporting this statement, then herbicide exposure on a facts found or direct basis can be acknowledged.