VA clearly assumes that all congressional presumptions governing veterans’ benefits are type 1 presumptions (see Chapter 2 for an explanation of the difference between type 1 and type 2 presumptions) (Zeglin, 2006). Consequently, the veteran is relieved both of producing sufficient evidence of an exposure that is service connected and of persuading VA that his or her adverse health effect was incurred through a service-connected exposure (Basic Entitlement. 2006. 38 U.S.C. § 1110 provides for disability payments for illnesses that were “aggravated” or “incurred” during service). Once a medical condition is service connected through presumptions, and the veteran can document military service consistent with the given exposure or risk, the veteran only has to show the basic fact that he or she suffers from the condition in order to receive the specified disability payment.
The discussion below will focus on the link between disease and service—the question to which scientific reviews are directed. Equally important to the compensation decision, however, is the creation of a presumption that relieves the veteran of having to provide evidence of a military exposure of sufficient magnitude to account for his or her illness or injury (Brown, 2005). See, for instance, 38 U.S.C.A. § 1116(f) (a veteran who served in Vietnam during a specified period is presumed to have been exposed to herbicide containing dioxin); 38 U.S.C. § 1116(f) (Presumptions of Service Connection for Diseases Associated with Exposure to Certain Herbicide Agents; Presumptions of Exposure for Veterans Who Served in the Republic of Vietnam. 2006. 38 U.S.C. § 1116(f); and Haas v. Nicholson (2006). United States Court of Appeals for Veterans Claims, Case Number 04-0491 § 1116[f]) is ambiguous as to whether it required veterans to have set foot in Vietnam, and the court extended the presumption to veterans serving in the waters near the shore of Vietnam. Often, as is evident in the case studies, exposure data are lacking, making it impossible to conduct epidemiologic studies of the veterans. In such cases, the medical evidence for the presumption that links the disease to the exposure will relate to a surrogate group, such as workers exposed to the substances at issue. For a discussion of this problem in connection with the Vietnam War presumptions, see Stellman and Stellman (2005).
In theory, all presumptions, including those that govern a veteran’s ability to show exposure, prove health outcomes, establish that a disability did not predate service (Wagner v. Principi. 2004. United States Court of Appeals for the Federal Circuit, Case Number 02-7347), or establish some other element of a claim, are rebuttable as provided in 38 U.S.C.S. § 1113 (Presumptions Rebuttable. 2005. 38 U.S.C. § 1113). VA assumes that an individual was medically sound when entering military service. However, that presumption of soundness is sometimes challenged if evidence shows