If you served at a qualifying Royal Thai Air Force Base between January 9, 1962 and June 30, 1976 and were denied an Agent Orange claim before 2022, the PACT Act may have changed your eligibility. Supplemental Claims based on PACT Act changes to Thailand presumptive policy are available. You do not need a nexus letter for the perimeter security pathway — you need proof of qualifying service.
During the Vietnam War, the United States operated from numerous Royal Thai Air Force Bases (RTAFBs) in Thailand, using them as staging bases for bombing campaigns over Vietnam, Laos, and Cambodia. The bases were considered semi-permanent installations, housing thousands of U.S. personnel — from pilots and aircrew to maintenance technicians, security police, intelligence personnel, and logistics specialists.
To maintain security at these installations, the U.S. military adopted vegetation management practices similar to those used along the Vietnamese perimeters: herbicides were applied along base fence lines, perimeter access roads, and cleared security zones to eliminate the concealment that vegetation provided to potential infiltrators. U.S. Air Force Security Police (Air Police in the earlier era) and Army security elements who patrolled these perimeters worked in close proximity to areas where herbicides — including tactical-grade formulations containing dioxin TCDD — had been applied.
Department of Defense and USAF records confirm herbicide application at multiple RTAFBs. Former Air Force Security Police veterans who served at these bases have documented their exposure through testimony, unit records, and photographs. The herbicide program at Thai bases was smaller in scale than the massive Operation Ranch Hand aerial spraying campaign in Vietnam, but the exposure for perimeter security personnel was direct and sustained — these soldiers and airmen walked the same fence lines day after day where herbicides had been applied.
VA initially took a restrictive position on Thailand claims, often requiring veterans to prove personal, individual contact with herbicides — a nearly impossible standard for events 50+ years ago. The PACT Act of 2022 changed this framework, establishing the "perimeter security rule" as a pathway to presumptive benefits without requiring case-by-case proof of exposure for qualifying security personnel.
VA recognizes specific Royal Thai Air Force Bases and U.S. installations in Thailand as qualifying locations for the Agent Orange presumptive pathway. The primary qualifying bases are:
| Base | Location | Key U.S. Functions |
|---|---|---|
| Ubon Royal Thai Air Force Base | Eastern Thailand (near Laos border) | 8th TFW operations, F-105 and F-4 combat sorties over Vietnam and Laos |
| Nakhon Phanom (NKP) | Northeast Thailand (Mekong River border) | Top-secret surveillance, Air Commando units, MACV-SOG support |
| Udorn RTAFB (Udorn) | Northern Thailand | 432nd TRW, reconnaissance, CIA Air America operations |
| Takhli RTAFB | Central Thailand | 355th TFW, F-105 Thunderchief strike missions over North Vietnam |
| U-Tapao Royal Thai Navy Airfield | Eastern Gulf coast | B-52 Stratofortress arc light bombing missions, tanker operations |
| Don Muang RTAFB (Bangkok) | Bangkok metropolitan area | Logistics hub, VIP operations, Air Force advisory functions |
| Korat RTAFB | Northeast Thailand | 388th TFW, F-105 and F-4 combat operations |
VA may also consider other U.S. military installations in Thailand where herbicide use along perimeters can be established through documentary evidence. If you served at a base not listed above, you can still file a claim — the question becomes whether you can provide evidence that herbicides were used at the specific base perimeter where you served.
VA's qualifying period for Thailand herbicide exposure is January 9, 1962 through June 30, 1976. This date range encompasses:
Service outside this window — either before January 9, 1962 or after June 30, 1976 — does not qualify for the presumptive pathway, though veterans in those periods can still attempt to establish direct service connection with specific evidence of herbicide exposure.
Any amount of service at a qualifying base during the qualifying period is sufficient — the regulations do not impose a minimum duration at the Thai base, unlike the Camp Lejeune 30-day requirement. Even temporary duty (TDY) assignments to a qualifying RTAFB can satisfy the location requirement.
The most important concept for Thailand Agent Orange claims is the perimeter security rule. Here is how it works:
Veterans who performed perimeter security duty at qualifying RTAFBs during the qualifying period are presumed to have been exposed to herbicides used along base perimeters. This presumption is based on the documented herbicide application practices along RTAFB perimeters and the operational reality that security personnel regularly patrolled these areas.
Veterans whose roles included perimeter security duty at qualifying Thai bases include:
USAF Security Police (AFSC 811XX and related codes) and Air Police (the earlier designation) who served at qualifying Thai RTAFBs are the primary beneficiaries of the perimeter security rule. If your Air Force specialty code (AFSC) was Security Police or Air Police, and your records show service at a qualifying Thai base during the qualifying period, the perimeter security rule presumption applies to you. Document your AFSC from your DD-214 or military records and include it prominently in your VA claim.
Veterans who served at qualifying Thai bases in roles other than perimeter security are not automatically covered by the perimeter security rule. However, they can still pursue a Thailand Agent Orange claim if they can provide evidence that:
This evidence-based pathway is harder than the perimeter security rule but not impossible. Many Thailand veterans in aviation, maintenance, and support roles have successfully established service connection through direct evidence of exposure.
Under the PACT Act and subsequent VA guidance, claims adjudicators are directed to apply the perimeter security rule when: (1) the veteran's records confirm service at a qualifying Thai RTAFB during the qualifying period, and (2) the veteran's MOS/AFSC or duty description indicates perimeter security functions. Veterans who meet both criteria should have their claims adjudicated as presumptive — no nexus letter should be required.
If you are a qualifying perimeter security veteran at a Thai RTAFB and VA requests a nexus letter to establish herbicide exposure, this may indicate the claim has been misrouted or the adjudicator is not applying the perimeter security presumption correctly. You should: (1) explicitly reference the perimeter security rule in your claim or response, (2) cite VA's Thailand herbicide exposure policy, and (3) consider requesting a review by a VSO or VA-accredited attorney. The perimeter security rule exists specifically to avoid requiring individual exposure proof for these veterans.
Thailand veterans who establish eligibility under the perimeter security rule or other evidence receive the full Agent Orange presumptive conditions list — identical to Vietnam veterans and Korean DMZ veterans. Post-PACT Act, this list includes:
For a comprehensive breakdown of all Agent Orange-related conditions and how they are rated, see our Agent Orange presumptive conditions guide. For Blue Water Navy veterans who may also have Thailand connections through carrier operations, see our Blue Water Navy Agent Orange guide.
The PACT Act of August 2022 represented the most significant expansion of Agent Orange presumptive benefits since the original presumptive list was established. For Thailand veterans specifically:
Prior to PACT Act, the perimeter security rule existed as a policy applied inconsistently. PACT Act codified and strengthened this pathway, making it a more reliable basis for claims adjudication and reducing the chance that individual adjudicators would incorrectly demand case-by-case exposure evidence from qualifying security personnel.
The addition of hypertension alone affects a large proportion of aging veterans. Hypertension is one of the most common chronic conditions in the veteran population, and its addition to the presumptive list means Thailand veterans with elevated blood pressure — in addition to any other qualifying condition — now have a recognized presumptive pathway. If you were previously denied for hypertension-based claims, a Supplemental Claim based on PACT Act changes is appropriate.
The PACT Act created an "Any cancer due to toxic exposure" framework that extends beyond the specific Agent Orange cancer list. Thailand veterans who develop cancers not specifically listed in the Agent Orange regulations may qualify under this broader PACT Act cancer provision if they can connect their service-related toxic exposure to the cancer diagnosis.
Surviving spouses of Thailand veterans who died from Agent Orange-related conditions may be eligible for improved Dependency and Indemnity Compensation (DIC) under PACT Act provisions. If a survivor's DIC claim was previously denied, the PACT Act changes are grounds for a Supplemental Claim.
Establishing your Thailand service at a qualifying base during the qualifying period is the foundation of your claim. Here is what VA needs:
You do not need to have been permanently stationed (PCS) at a Thai RTAFB to qualify. Temporary duty assignments (TDY) to qualifying bases during the qualifying period are sufficient to establish Thailand service for Agent Orange purposes. If you flew missions to or from a qualifying Thai base, if you were sent TDY for weeks or months, or if you had repeated TDY rotations — this service qualifies. Document TDY orders and any records showing your presence at the base.
In your claim and personal statement, clearly identify:
See our PACT Act presumptive conditions guide for the current full list of presumptive conditions relevant to your claim, including conditions added since the original Agent Orange list was established.
Request your complete Official Military Personnel File (OMPF) from NPRC via eVetRecs before filing your claim. Having your full records in hand allows you to verify what documentation VA will receive and supplement with additional evidence where records are incomplete. This is especially important for Thailand veterans, whose records may show only the primary duty station (in the U.S.) without clearly reflecting TDY periods at Thai bases.
VA Form 21-4138 (Statement in Support of Claim) or a personal letter included with your claim allows you to describe your Thailand service in your own words. Include: dates at the Thai base, specific base name, your security police duties and patrol assignments, the perimeter areas you routinely covered, any herbicide or defoliant application you witnessed, and any health symptoms or diagnoses you have developed since your service.
The Agent Orange presumptive list includes numerous conditions. If you have type 2 diabetes, ischemic heart disease, prostate cancer, hypertension, and/or any of the listed cancers — file for all of them in your initial claim. You can claim multiple conditions simultaneously, and each service-connected condition increases your combined disability rating.
Veterans who served at Ubon, NKP, Udorn, Takhli, U-Tapao, and other Thai bases have formed online communities and veterans' organizations that share information about Agent Orange claims, available evidence, and successful claim strategies. Fellow veterans from your specific base may be able to provide buddy statements documenting your service and the perimeter herbicide practices they witnessed.
Medical Evaluations for Thailand Agent Orange Veterans
While presumptive claims don't require a nexus letter for service connection, the severity rating for your condition is determined by medical evidence. REE Medical provides medical evaluations and documentation that help ensure your Agent Orange conditions are rated at the correct level — not underrated by an inadequate C&P exam.
Learn About Medical Evaluations for Agent Orange Claims →claim.vet may receive a referral fee if you use this link. Veterans never pay more.
Editorial Standards: Written by Marcus J. Webb, veterans benefits researcher. Verified against VA Thailand Agent Orange policy, 38 CFR § 3.307, and PACT Act of 2022 provisions. Last reviewed: July 2026. Not legal advice — for representation, consult a VA-accredited attorney.
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