The Vietnam War era is considered by the US Department of Veterans Affairs (VA) to have lasted from January 1962 to May 1975. During that time, over 3 million US military personnel were sent to Southeast Asia. During World War II, US forces that fought in tropical climates with jungle foliage throughout the Pacific theater suffered substantial loss of lives. In the Vietnam War, the US military had new weapons to help its personnel to penetrate the tropical forests: tactical herbicides. Those herbicides were used as defoliants to help in identifying enemy transportation and communication routes and camps, to reduce cover for enemy forces, and, for a time, to kill crops that might be used by the enemy. Of the several herbicides used in Vietnam, the best known and most widely used was Agent Orange. Agent Orange was contaminated with the highly toxic chemical 2,3,7,8-tetrachlorodibenzo-p-dioxin, also referred to as TCDD.
Since that time, veterans who served in Vietnam have reported numerous adverse health effects. Beginning in 1979, Congress enacted several laws to examine links between exposures to the herbicides used in Vietnam and possible long-term health effects. In 1984, Congress required the VA to establish guidelines and standards for evaluating the scientific studies related to the exposures and to issue regulations for adjudicating claims for VA benefits based on herbicide exposure. The Agent Orange Act of 1991 established a presumption of herbicide exposure for veterans who had served in Vietnam and who developed one or more of the diseases associated with Agent Orange; an amendment in 2001 maintained the presumption of herbicide exposure but removed the need for veterans to have developed a herbicide-associated disease. On the basis of the Institute of Medicine (IOM) Veterans and Agent Orange (VAO) reports and other information, the VA has recognized 14 health outcomes as associated with Agent Orange and other herbicide exposure and thus eligible for a presumption of
service connection (see Box 1-1). The 1991 legislation also asked the National Academy of Sciences, through the IOM, to conduct periodic reviews of the scientific and medical evidence connecting certain herbicide exposures to health effects. The IOM issued its first VAO report in 1994; the latest report, Veterans and Agent Orange, Update 2008, was published in 2009.
Before 1997, Vietnam veterans were eligible for a presumption of exposure to any of four herbicides used in Vietnam—2,4-dichlorophenoxyacetic acid (Agent Purple, Agent Orange, and Agent White), 2,4,5-trichlorophenoxyacetic acid (Agent Green, Agent Pink, Agent Purple, Agent Orange), cacodylic acid (Agent Blue), and picloram—if “during active military, naval, or air service, they had served in the Republic of Vietnam” unless there was evidence that they had not been exposed. A veteran’s receipt of the Vietnam Service Medal or service in the offshore waters of Vietnam was sufficient to establish a presumption of herbicide exposure. That broad policy was later narrowed so that service on the ground in Vietnam (ground troops) or on its inland waterways (Brown Water Navy) was required to receive a presumption of exposure. Service in the Republic of Vietnam under 38 CFR § 3.307(a)(6)(iii) was defined as actual service in the country, including inland waterways, from January 9, 1962, to May 7, 1975, and service offshore if the conditions of service involved duty or visitation onshore. The VA further stipulated that “mere service on a deep-water naval vessel in waters off shore of the Republic of Vietnam is not qualifying service in Vietnam” (VA, 1997).
Veterans’ Diseases Associated with Agent Orange Exposure
Acute and subacute peripheral neuropathy
Chronic B-cell leukemias
Diabetes mellitus (type 2)
Ischemic heart disease
Porphyria cutanea tarda
SOURCE: See http://www.publichealth.va.gov/exposures/agentorange/diseases.asp (accessed January 19, 2011).
Those who served aboard deep-water naval vessels are the Blue Water Navy. Within the current VA interpretation, Blue Water Navy personnel are not eligible for a presumption of exposure. Although that interpretation was challenged by Blue Water Navy veterans, the VA position was upheld in the 2008 case of Haas v. Peake and stands today. Since 2008, the VA has, case by case, recognized numerous Blue Water Navy ships as having entered the inland waterways of Vietnam or having docked in Vietnam at specific times and locations. Navy personnel who served aboard those blue-water ships during the specific times when their ships were on inland waters or docked are now eligible for the presumption of service connection to Agent Orange–associated diseases. The VA continues to review the deck logs and other materials for Blue Water Navy ships to determine their crews’ eligibility for consideration of the presumption of exposure to herbicides, but this process has been slow and labor intensive. As of January 2011, over 140 individual ships and 51 classes of Navy vessels that served in the Seventh Fleet during the Vietnam era have been categorized as having served primarily or exclusively in inland waterways, temporarily in inland waterways, or in coastal waterways of Vietnam with evidence that crew members went ashore or that smaller ships regularly went ashore with supplies or personnel (James Sampsel, VA, personal communication, January 12, 2011). Navy personnel who served aboard Blue Water Navy ships that have not been categorized as brown-water ships or who served on such ships before or after the designated period of brown water activity are not eligible for the presumption of service connection.
Blue Water Navy Vietnam veterans have been active in notifying the VA of ships that entered Vietnamese inland waters by submitting deck logs and other documentation. They have also been active in working with members of Congress to enact legislation to expand the eligibility for presumption of herbicide exposure to Blue Water Navy veterans, although such legislation has not been enacted. Their concerns are related to potential exposure not only to the herbicides themselves but to the TCDD contaminant present in Agent Orange. Recent publications, such as that of an Australian study of potential TCDD enrichment of potable water onboard Royal Australian Navy ships as a result of the ships’ water-distillation process, have prompted additional concerns regarding exposure of Blue Water Navy veterans to herbicide-related TCDD (Muller et al., 2002).
The IOM committee that prepared the 2008 update in the VAO report series stated:
The evidence that this committee has reviewed makes limiting Vietnam service [emphasis in original] to those who set foot on Vietnamese soil seem inappropriate. The ongoing series of hearings and appeals in the US Court of Appeals for Veterans Claims (Haas v. Nicholson) reflect the controversy.... There is little reason to believe that exposure of US military personnel to the herbicides sprayed in Vietnam was limited to those who actually set foot in the Republic of Vietnam. Having reviewed the Australian report (Muller et al., 2002) on the fate of TCDD when seawater is distilled to produce potable water, the committee is convinced that this use of seawater would provide a feasible route of exposure of personnel in the Blue Water Navy, which might have been supplemented by drift from herbicide spraying.... The present  committee notes that all previous VAO committees have considered information on naval Vietnam veterans to pertain to possible Agent Orange exposure when evaluating the full spectrum of health outcomes. The present committee finds that exposure assignment to be appropriate. No new studies considered in this update contained Navy-specific information, but such information has been factored into the evolving conclusions of VAO committees. Given the available evidence, the committee recommends that members of the Blue Water Navy should not be excluded from the set of Vietnam-era veterans with presumed herbicide exposure. (IOM, 2009)
The growing concern of Blue Water Navy veterans that they were exposed to Agent Orange and TCDD during their service during the Vietnam War, possibly as a result of drinking contaminated water, prompted the VA to task the IOM with establishing a committee to
conduct a study and prepare a report on whether the Vietnam veterans in the Blue Water Navy experienced a comparable range of exposures to herbicides and their contaminants (focus on dioxin) as the Brown Water Navy Vietnam veterans and those on the ground in Vietnam (i.e., specifically with regard to
Agent Orange exposure). The IOM committee’s report is expected to include
Historical background on the Vietnam War, combat troops (ground troops), Brown Water Navy (includes inland waters), Blue Water Navy, and VAO legislation;
A discussion of exposures (Blue Water Navy in comparison with ground troops in Vietnam), specifically, a comparison of exposures on ground with those on ships (discuss all possible routes of exposure), and examining the range of exposure mechanisms for herbicide exposures (i.e., concentrating toxics in drinking water, air exposure possibly from drift from spraying, food, soil, skin);
A determination, if possible, of the comparative risks for long-term health outcomes comparing Vietnam veteran ground troops, Blue Water Navy veterans, and other “era” veterans serving during the Vietnam War at other locations (given the possible dioxin exposure); and
A review of studies of Blue Water Navy veterans for health outcomes (assuming there are studies specific to that cohort of veterans).
COMMITTEE’S APPROACH TO ITS CHARGE
The committee was tasked with describing possible routes of exposure of Blue Water Navy personnel during the Vietnam War to herbicides, particularly Agent Orange, and their contaminants, specifically TCDD, and compare those exposures with ground troops in Vietnam. The committee was not tasked with nor did it attempt to determine what health effects have been associated with exposure to TCDD. Rather the committee relied on health effects assessments of TCDD made by organizations such as the US Environmental Protection Agency (EPA), and other IOM committees.
The committee describes below its conceptual approach to those tasks and the sources that it used for information on which to base its conclusions.
At the heart of this report is the question of whether Blue Water Navy veterans had the potential for exposure to the tactical herbicides used in Vietnam, specifically Agent Orange, and particularly the TCDD contaminant of that herbicide, and whether that exposure, if any, could lead to increased risk of long-term adverse health outcomes. The committee’s approach was to ask
Whether it is possible to demonstrate that Blue Water Navy personnel were or were not exposed to Agent Orange–associated TCDD, and
Whether it is possible to state with certainty that exposure of Blue Water Navy personnel, taken as a group, was qualitatively different from that of their Brown Water Navy and ground counterparts.
The committee considered that the most appropriate approach for assessing the risks would be the risk-assessment framework used by the EPA, albeit with modifications specific to these populations and in consideration of the available data. The framework begins with identifying the sources of the environmental agent (in this case, the herbicides used in Vietnam, particularly Agent Orange and its TCDD contaminant) and potential receptors (in this case, ground troops and Brown Water Navy and Blue Water Navy populations). The next step is to evaluate how the chemicals move in the environment to reach the populations of interest (for example, via transport in soil, water, and air) and plausible routes of exposure (inhalation, dermal contact, and ingestion). That information is used in conjunction with toxicologic information to assess the health outcomes, such as cancer, diabetes, and neurologic effects, that the chemicals may have on the populations of interest.
Given the conclusions reached by previous VAO committees, the present committee decided that the focus of its report would be on exposure to Agent Orange and not to the other tactical herbicides used in Vietnam, such as Agent Purple, Agent White, and Agent Blue. Agent Orange was used in far greater quantities and over a larger area of Vietnam than were the other herbicides. The earlier VAO committees had determined that TCDD was the most toxic substance to which
Vietnam veterans may have been exposed during their tours of duty; therefore, the present committee focused on Agent Orange and TCDD.
In the sections below, the committee describes its approach to assessing veterans’ exposure to and health outcomes associated with Agent Orange and TCDD during the Vietnam War.
Sources of Agent Orange in the Environment
The committee began by gathering information on how Agent Orange and the other tactical herbicides had been used in Vietnam and the quantity and geographic range of herbicide application. The committee also considered data on the magnitude of TCDD contamination of Agent Orange. Much of that information had been collected and evaluated by earlier IOM committees and other researchers. Primary among the data available to earlier IOM committees were Department of Defense (DoD) Herbicide Reporting System records on Operation Ranch Hand, a file containing information on each Ranch Hand mission. Operation Ranch Hand was the code name for the US military’s use of tactical herbicides in the Republic of Vietnam (and Laos) during the Vietnam War.
Fate and Transport of Agent Orange and TCDD in Vietnam
After reviewing information on releases of Agent Orange in the environment, the committee explored the fate and transport of TCDD in air, water, and soil to assess the plausibility of Agent Orange and TCDD exposure of military personnel that did not handle the herbicide themselves. The committee attempted to identify any monitoring data on TCDD that had been gathered during or shortly after the Vietnam War. Such monitoring data would include samples from environmental media (soil, air, water, sediment, and food) and any biologic samples collected from military personnel (such as blood samples). The committee also considered fate and transport models that could be used to examine the plausibility of exposure of ground troops, Brown Water Navy veterans, and Blue Water Navy veterans to the chemicals.
Blue Water Navy Operations and Locations
An understanding of where and how the Blue Water Navy operated was considered to be important in assessing whether veterans had any potential for exposure to Agent Orange and TCDD. Unlike the previous VAO committees, which did not distinguish among Vietnam veteran
populations in terms of potential Agent Orange and TCDD exposure, the present committee was required to make such distinctions so it could discuss exposure and risks of long-term health effects specifically in Blue Water Navy veterans. Therefore, the committee attempted to identify where Blue Water Navy ships were during the war, their missions, how close they came to the Vietnamese coast, whether they docked in Vietnam, and the activities conducted aboard the ships and possibly ashore by the sailors in performance of their duties and during their leisure time. Such information would assist the committee in comparing Agent Orange and TCDD exposures potentially experienced by ground troops, Brown Water Navy veterans, and Blue Water Navy veterans. The committee also sought information that would help it to coordinate ship locations with Ranch Hand spray missions and fate and transport data on TCDD to establish what, if any, Blue Water Navy ships may have had a potential for TCDD exposure.
Routes of Exposure
One of the committee’s tasks was to determine whether Blue Water Navy veterans had exposures to TCDD comparable with those of ground troops and Brown Water Navy veterans. To accomplish that task, the committee sought to determine whether there were plausible exposure pathways between the release of Agent Orange (the spraying of Agent Orange, primarily by fixed-wing aircraft, and riverbank spraying) and Blue Water Navy personnel. Therefore, the committee assessed the fate and transport of TCDD in each environmental medium as described above. On the basis of that assessment, various exposure mechanisms and routes of exposure were assessed to determine the plausibility of exposure.
Long-Term Adverse Health Outcomes
The long-term adverse health outcomes associated with exposure to TCDD have been examined by other IOM committees, particularly the VAO committees, and by other organizations, such as the EPA and the International Agency for Research on Cancer. The VAO committees identified and reviewed studies of Vietnam veterans that assessed possible health effects associated with TCDD exposure. Those studies generally used control groups of veterans who served in the armed forces during the Vietnam War but who were not deployed to Vietnam—the “Vietnam-era veterans.” Given the breadth of the studies considered by
those groups and the fact that the studies have previously been subjected to peer review, the present committee elected not to review the primary literature related to long-term adverse health effects that might result from TCDD exposure, such as studies of occupational cohorts and animals. Rather, it focused its literature searches and other efforts on identifying epidemiologic studies of health effects seen in Vietnam veterans that included Navy personnel as a specific study group and studies that divided Navy personnel into those who may have served in the Blue Water Navy, in the Brown Water Navy, or onshore.
To accomplish the tasks laid out in the conceptual approach, the committee used a multitude of data sources and methods to determine what work had been done on the exposure of Vietnam veterans to TCDD and what studies had been undertaken to assess the health effects associated with TCDD exposure. What sets the present effort apart from other efforts to assess the health of Vietnam veterans is the need to determine whether Blue Water Navy Vietnam veterans experienced different exposures and thus different health risks compared to other Vietnam veterans. That required an understanding of Blue Water Navy activities in Vietnam—from ship locations to daily activities aboard the ships or ashore during port visits. The committee also needed to be able to compare the experiences of these veterans with those of ground troops (Army soldiers and marines) and of Brown Water Navy veterans, where possible.
Many data sources and methods were identified and pursued, including published peer-reviewed literature, models for assessing the environmental concentrations of TCDD, modeling the likely transfer of TCDD from sea water to the potable water used aboard Blue Water Navy ships, and information from veterans and other interested parties on veteran experiences during the war and afterwards, and such other information sources as written and published accounts of the war (including memoirs), government documents, and ships’ deck logs. Although much of the information reviewed by the committee was not new, some fresh sources and documents were identified, including new VA policies, Blue Water Navy veterans’ reports, materials specific to the operations of the Blue Water Navy, and further documentation of the use of Agent Orange in Vietnam. The information sources used by the committee are discussed below.
Several methods were used by the committee to search for published studies of Vietnam Navy veterans and Agent Orange and TCDD exposure. The search included studies of non-American Navy veterans of the Vietnam War, such as veterans who served in the Royal Australian Navy. The first method used was a review of the biennial VAO IOM reports (1994–2008). The second method was an exhaustive database search. IOM library staff searched MEDLINE, EMBASE, National Technical Information Service, PsychINFO, SCOPUS, Web of Science, WorldCat, JSTOR, DTIC (Defense Technical Info Center), and Lexis Nexis databases, using search terms intended to identify any epidemiologic studies of Vietnam-era Navy personnel.
Other studies in the published literature that were retrieved included studies of the fate and transport of Agent Orange and TCDD in the environment and studies that assessed the potential exposure of Vietnam veterans to these chemicals. Although not always peer-reviewed, books that discussed those subjects were also retrieved, such as a 2009 book by Alvin Young on the use, disposition, and fate of the tactical herbicides used in the Vietnam War; veterans’ memoirs and accounts of the war to help the committee to understand the day-to-day activities of the men and women who served during the war; and scholarly histories of Navy operations during the war, including books that described Navy ships and their classes and specifications.
In addition to published studies in peer-reviewed journals, the committee looked for published documents in the “gray literature.” They were found through additional database searches by the IOM information specialist and Internet searches by IOM staff. Documents that were obtained in that manner included such reports as those by Hatfield Consultants on dioxin concentrations in present-day Vietnam.
From the beginning of the committee’s deliberations, open sessions were held to hear directly from veterans themselves about their experiences with Agent Orange while they served in the Vietnam War. In addition, it was agreed that much of the information that the committee would need to complete its task was not available in the published literature and that veterans would be able to provide certain types of critical information. The committee held three open sessions to collect public input. At the first and third sessions, held in Washington, DC, the
committee heard from the VA, several veterans service organizations (for example, the Blue Water Navy Vietnam Veterans Association), numerous individual veterans, and other interested parties. The second open session was held aboard the USS Midway, an aircraft carrier that is now a museum in San Diego, so that the committee could view firsthand the distillation plants used aboard a Vietnam-era ship. Docents on the USS Midway explained and answered questions about the working of the plants. The committee found these information sources useful in framing its approach to its task and appreciating life aboard Blue Water Navy ships during the war. Committee members talked with veterans of many ranks and experiences, from vice admirals to enlisted men.
Several veterans provided the committee with numerous reports, articles from the peer-reviewed literature and popular press, and other documentation, all of which the committee considered during its deliberations. Veterans also talked with IOM staff about specific activities aboard Blue Water Navy ships. Finally, many veterans and their family members and friends sent e-mails to the committee; most of these e-mail messages pertained specifically to Blue Water Navy veterans’ experiences during the war and their later health issues.
Other Information Sources
Numerous other information sources also proved useful to the committee. These included government documents from the VA and the Navy; other Navy documents, such as deck logs and maps; and reports from the Australian government about Australian Vietnam veterans. Several Web sites also provided useful compendiums of information, such as the site maintained by the Blue Water Navy Vietnam Veterans Association (http://www.bluewaternavy.org/) and the Virtual Vietnam Archive at Texas Tech University.
Navy documents, such as Machinist’s Mate 2 & 3: “Steam Operated Distilling Plants,” (Department of the Navy, 2003) assisted the committee in understanding the operations of the water-distillation systems that provided potable water to the crew aboard Blue Water Navy ships—a critical issue, as noted in the discussion of the committee’s charge. Other Navy regulations indicated where and when such water could be prepared.
Given the committee’s interest in identifying where ships were with respect to the spraying of Agent Orange, documentation to this effect was also sought. Ship logs were one source of information, but the committee was provided neither the time nor the resources to review
individual deck logs to ascertain where a certain ship was at any given time; additionally, this was considered to be outside the scope of the committee’s charge. However, the logs were useful in providing evidence of how far off the coast of Vietnam some ships were stationed. The difficulty in using deck logs is the need to coordinate the dates of Ranch Hand missions near the coast with the identification of ships that were near the flight paths and how far off the coast the ships were on the dates of the spraying missions. Several Web sites, such as http://www.history.navy.mil/branches/org10-8.htm and http://www.cc.gatech.edu/~tpilsch/AirOps/ranch.html, provided useful summaries of ship locations, and these were also considered by the committee.
The VA provided background information on the Blue Water Navy Vietnam veterans’ issues, including a presentation to the committee on compensation and the history of the court case (Haas v. Peake) that resulted in Blue Water Navy Vietnam veterans no longer being presumed to have had herbicide exposure during the war. The VA is reviewing deck logs case by case to classify ships that entered inland waters as Brown Water Navy ships and would thus be eligible for the presumption of herbicide exposure. As each ship is recategorized, it is listed in the VA Compensation and Pension Service Bulletin. The committee received copies of the bulletin, documentation from the Haas v. Peake case, and a document from the Board of Veterans’ Appeals lecture series on herbicide exposure (Janec and Smith, 2009).
As noted in the committee’s charge and the 2008 VAO report, the decision by the Royal Australian Navy to compensate Australian Navy Vietnam veterans for TCDD exposure was an impetus for the current study by the IOM. The Australian decision was based on several reports that showed that Australian Navy veterans had higher incidences of some cancers than Navy veterans who had not served in Vietnam. A further Australian report suggested that TCDD may have been concentrated in the potable water of the Navy ships as a result of the water-distillation processes used on the ships. The committee thoroughly reviewed those documents and contacted the Royal Australian Navy to seek further information on the issue.
ORGANIZATION OF THE REPORT
Chapter 2 of this report provides a short historical background on the Vietnam War and the military personnel who constituted the ground combat troops, the Brown Water Navy, and the Blue Water Navy. It also presents a synopsis of the legislation regarding veterans and Agent Orange since the Vietnam War and of the recent legal issues that have arisen over Blue Water Navy veterans’ compensation. In Chapter 3, the committee describes the use of tactical herbicides during the Vietnam War, particularly Agent Orange, and some of the chemicals to which naval personnel may have been exposed while on active duty. The environment of Vietnam and the fate and transport of Agent Orange–associated TCDD are explored in Chapter 4 with a discussion of the role of modeling in estimating environmental concentrations of TCDD. Chapter 5 addresses the committee’s task of comparing exposure of ground troops with Navy personnel on ships and explores the mechanisms by which these military personnel may have been exposed to Agent Orange. The comparative risks of long-term health effects in ground troops, Blue Water Navy veterans, and other veterans who served during the war but were not deployed to Vietnam are presented in Chapter 6. Finally, in Chapter 7, the committee summarizes what it has learned about the potential exposure of and health effects in Blue Water Navy Vietnam veterans. An appendix reviews the Australian report Examination of the Potential Exposure of Royal Australian Navy Personnel to Polychlorinated Dibenzodioxins and Polychlorinated Dibenzofurans via Drinking Water (Muller et al., 2002).
Department of the Navy. 2003. Machinist’s mate 3 & 2 (Surface). NAVEDTRA 14151. Pensacola, FL: Naval Education and Training, Professional Development and Technology Center.
IOM (Institute of Medicine). 2009. Veterans and Agent Orange: Update 2008. Washington, DC: The National Academies Press.
Janec, S., and T. Smith. 2009. Herbicide exposure. In Board of Veterans’ Appeals Lecture Series. Washington, DC: Department of Veterans Affairs.
Muller, J. F., C. Gaus, K. Bundred, V. Alberts, M. R. Moore, and K. Horsley. 2002. Examination of the potential exposure of Royal Australian Navy (RAN) personnel to polychlorinated dibenzodioxins and polychlorinated dibenzofurans via drinking water. A report to: The Department of Veteran Affairs, Australia. Brisbane, Australia: National Research Centre for Environmental Toxicology.
VA (Department of Veterans Affairs). 1997. Service in the Republic of Vietnam for purposes of definition of Vietnam Era—1-38 U.S.C. § 101(29)(A). Memorandum from VA General Counsel to Director of Compensation and Pension Service. VAOPGCPREC 27-97. July 23, 1997.