Most veterans are aware that if they served in Vietnam they were exposed to Agent Orange. The VA presumes certain medical conditions were the result of exposure to Agent Orange. Some medical conditions must have started within a certain time frame within exposure to Agent Orange, while other conditions are presumed to be service connected no matter when they arose. Please see http://www.publichealth.va.gov/exposures/agentorange/diseases.asp#veterans for more information.
The VA also recognizes that veterans who served on certain military bases in Thailand could have been exposed to Agent Orange, also.
The bases are:
Air Force bases: U-Tapao, Ubon, Nakhon Phanom, Udorn, Takhli, Korat, and Don Muang, between February 28, 1961 and May 7, 1975. Also included are Army Veterans who provided perimeter security on said bases in Thailand between February 28, 1961 and May 7, 1975.
Please see http://www.publichealth.va.gov/exposures/agentorange/thailand.asp for more information.
If you tried to get service connection for Agent Orange exposure but were denied because you never served in Vietnam, but you served in Thailand, please consider whether you served on any of the bases listed above.