3
The U.S. Military and the Herbicide Program in Vietnam

From 1962 to 1971, the U.S. Air Force sprayed nearly 19 million gallons of herbicides in Vietnam, of which at least 11 million gallons was Agent Orange, in a military project called Operation Ranch Hand. An additional quantity (1.6 million gallons has been documented) of herbicides was applied to base perimeters, roadways, and communication lines by helicopter and surface sprayings from riverboats, trucks, or backpacks. Herbicide operations in Vietnam had two primary military objectives: (1) defoliation of trees and plants to improve observation, and (2) destruction of enemy crops.

Estimates of the number of U.S. military personnel who served in Vietnam during this period of herbicide use vary from 2.6 to 3.8 million. The total number of U.S. servicemen and women exposed to herbicides is also not known, although some individuals, such as those of the Air Force Operation Ranch Hand and the Army Chemical Corps, were more likely to have been exposed by the nature of their job assignments.

This chapter describes the characteristics of the Vietnam veteran population at potential risk of herbicide exposure during service in Vietnam, and reviews the U.S. military herbicide program of the 1960s and early 1970s. It summarizes what is known about the use of herbicides in Vietnam, their chemical formulations, and the quantities applied, and serves as background information for Chapter 6, which summarizes and evaluates the various methods for estimating exposure to herbicides in epidemiologic studies of veterans as well as other environmentally and occupationally exposed populations.



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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam 3 The U.S. Military and the Herbicide Program in Vietnam From 1962 to 1971, the U.S. Air Force sprayed nearly 19 million gallons of herbicides in Vietnam, of which at least 11 million gallons was Agent Orange, in a military project called Operation Ranch Hand. An additional quantity (1.6 million gallons has been documented) of herbicides was applied to base perimeters, roadways, and communication lines by helicopter and surface sprayings from riverboats, trucks, or backpacks. Herbicide operations in Vietnam had two primary military objectives: (1) defoliation of trees and plants to improve observation, and (2) destruction of enemy crops. Estimates of the number of U.S. military personnel who served in Vietnam during this period of herbicide use vary from 2.6 to 3.8 million. The total number of U.S. servicemen and women exposed to herbicides is also not known, although some individuals, such as those of the Air Force Operation Ranch Hand and the Army Chemical Corps, were more likely to have been exposed by the nature of their job assignments. This chapter describes the characteristics of the Vietnam veteran population at potential risk of herbicide exposure during service in Vietnam, and reviews the U.S. military herbicide program of the 1960s and early 1970s. It summarizes what is known about the use of herbicides in Vietnam, their chemical formulations, and the quantities applied, and serves as background information for Chapter 6, which summarizes and evaluates the various methods for estimating exposure to herbicides in epidemiologic studies of veterans as well as other environmentally and occupationally exposed populations.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam MILITARY AND DEMOGRAPHIC CHARACTERISTICS OF VIETNAM VETERANS As one historian notes in his account of the Vietnam conflict, "there was no 'typical' U.S. soldier in Vietnam … the three million Americans who served there went through many varied experiences—partly because the quality of the war varied in different areas of the country, and partly because the nature changed over time" (Karnow, 1991). Individual experiences also varied according to job assignment, military unit of service, rank, and branch of service. Artillery units, for example, tended to be less mobile than cavalry because of the heavy equipment involved. An individual assigned to base headquarters with an Army personnel position experienced a different tour of duty than an infantry commander, a field engineer, or an officer stationed aboard a Navy vessel off the coast of I Corps. Personnel assigned to units in the Mekong Delta might slog week after week across paddy fields, while others patrolling the perimeters of major U.S. installations at Danang, Bien Hoa, and Camranh were often targets for sniper attacks (Karnow, 1991). Individuals and units also varied in their consumption of locally grown foods and water from local supplies, as well as in their personal hygiene practices. Ground forces—the Army and Marines—were likely to experience more of the day-to-day fighting than Navy or Air Force personnel (Card, 1983). Sociological assessments of the American soldier in Vietnam suggest that no one factor is more important in understanding the experiences of the individual veteran than the degree of exposure to combat (Moskos, 1975; Fischer et al., 1980; Martin, 1986; Shafer, 1990). In order to properly evaluate existing epidemiologic studies of Vietnam veterans and to consider the possibility of new studies, the size and characteristics of the exposed population must be known. Remarkably, the number of U.S. military personnel who served in Vietnam during the Vietnam conflict is not known precisely. Estimates depend on definitions regarding time and place of service, and the source of the data on which the estimates are based. Although detailed records of demographic information were not compiled during the Vietnam era, some federal estimates are available. In addition, data from several national surveys of the Vietnam veteran population supplement the government estimates. Estimates of the Number of Military Personnel Serving in Vietnam According to official records, U.S. military advisory assistance to Vietnam began as early as 1950, during the First French-Indochina War; 128 personnel "spaces" were allotted for the U.S. advisory group (MACV, 1972). After the division of Vietnam along the seventeenth parallel in 1954, U.S.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam advisors were assigned the responsibility of training the South Vietnamese army. By the end of 1960, nearly 900 U.S. military advisors were stationed in the country—the vanguard of an estimated 2.6 to 3.8 million U.S. military personnel to serve in Vietnam over the next 13 to 15 years. Two advisors were killed in 1960 in a raid at Bien Hoa military base—the first American casualties of the Vietnam conflict (MACV, 1972). As American concerns about Communist control of South Vietnam heightened, U.S. involvement increased. Toward the end of 1962, 11,000 U.S. military advisors and personnel were serving in South Vietnam, and the U.S. Military Assistance Command, Vietnam (MACV) was organized. During the next two and a half years, the number of personnel would increase to nearly 60,000 and America began bombing North Vietnam—first as "retaliation for North Vietnamese aggression" and ultimately, in February 1965, as a sustained activity (Shafer, 1990). Shortly afterward, President Lyndon Johnson ordered the deployment of U.S. military troops to South Vietnam (see Table 3-1). The Vietnam era was characterized by heavy conscription that began to gain momentum in 1965 (Card, 1983). Between 1964 and 1968, as American involvement in Vietnam escalated, U.S. troop strengths doubled, then nearly tripled, peaking at 543,482 in April 1969. The number of military personnel declined in the following years, in keeping with President Nixon's policy of "Vietnamization," falling to 475,000 at the end of 1969 and to 334,600 at the end of 1970. By the end of 1972, fewer than 25,000 American troops remained in Vietnam. The final U.S. withdrawal of American combat troops in Vietnam was completed in March 1973. The remaining Americans, including the ambassador to Vietnam, were evacuated from the U.S. embassy in Saigon in April 1975 (Karnow, 1991). Although the military maintained accurate records of the number who died, reliable records-based information on the number and characteristics of men and women who served in the Vietnam conflict was more difficult to maintain during the wartime period. Because there is no master list of the millions of veterans who served during the Vietnam era, studies of Vietnam veterans must create their own sampling frames from which samples of veterans can be selected and from which national estimates can be generated. These estimates of the national Vietnam veteran population are necessary for epidemiologic studies of veterans that attempt to quantify the risk of various health effects for the entire veteran population-based on the results observed in representative samples. The extent to which the study sample is representative of the entire Vietnam veteran population in these epidemiologic studies is of utmost importance in designing programs to address the health needs of veterans (see Chapter 5 for further discussion of epidemiology and the evaluation of such studies). The identification of an appropriate veteran group for study often involves

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam TABLE 3-1 Summary of U.S. Military Strength in Vietnam and Quantities of Herbicides Sprayed: 1960-1973     Quantity of Herbicide Sprayed (million gallons)b Year No. of Troopsa Orange White Blue Total 1960 900         1961 3,200         1962 11,300 NA NA NA   1963 16,300 NA NA NA   1964 23,300 NA NA NA 1.27c 1965 184,300 0.37 0 0 0.37 1966 385,300 1.64 0.53 0.02 2.19 1967 485,600 3.17 1.33 0.38 4.88 1968 536,100 2.22 2.13 0.28 4.63 1969d 475,200 3.25 1.02 0.26 4.53 1970 334,600 0.57 0.22 0.18 0.97 1971 156,800 0 0.01 0 0.01 1972 24,200 0 0 0 0 1973 8 250 0 0 0 0 TOTAL   11.22 5.24 1.12 18.85 NOTE: NA = no data available. a Data represent year-end troop strengths. These counts include those who served more than one tour of duty in Vietnam. b As recorded on the HERBS tape. c Cumulative total from 1962 through 1964. d Peak U.S. troop strength of 543,482 occurred in April 1969. SOURCES: U.S. Department of Defense, 1978:Table P28.01S; National Academy of Sciences, 1974:Table 1 a time-consuming and labor-intensive search of military records for names or Social Security numbers. The General Services Administration, under an agreement with the Department of Defense, maintains the military personnel records of veterans, including those from the Vietnam era at the National Personnel Records Center (NPRC) in St. Louis, Missouri. These records include military service information, on microfiche, for all American veterans. Once an individual has been identified by name or Social Security number, he or she can be matched to their military personnel file at NPRC. A computerized index lists the physical location of the individual's personnel file; the file can then be retrieved to verify the service information. It is currently impossible to readily determine from these records the true number of U.S. military personnel who served in Vietnam during the Vietnam era because this information has not been entered systematically into a computerized database. Because of the difficulties in obtaining representative samples (and due

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam to the nature of the question being examined), many studies do not attempt to generalize their findings to the entire veteran population, but rather focus on a discrete subpopulation of veterans, for example, U.S. Army ground combat troops who served in III Corps during 1967-1968, Marines who served in I Corps, or Air Force Operation Ranch Hand personnel. The results of such studies are limited to the group under study and do not necessarily apply to the entire Vietnam veteran population. Comparison of the studies that do provide national estimates representative of the Vietnam veteran population is complicated, however, by differences in terminology and methodology. For example, the time and place of Vietnam service are not defined consistently across studies. Some studies define the Vietnam era as the period of service between August 1964 and June 1975. This period of service was defined as the "Vietnam era" by presidential proclamation on May 7, 1975 (Fischer, 1980). Others use January 1, 1965, to mark the beginning of the Vietnam era, and March 1973, the time of final withdrawal of combat troops, to designate its end. Yet other veteran population estimates refer to service in the "Vietnam theater" rather than Vietnam per se. The Vietnam theater includes Vietnam, Laos, Cambodia, and the adjacent waters of the South China Sea; service in Thailand may be also be included. Estimates of the number of military servicemen and women who served during the Vietnam era are provided by several federal agencies, including the Department of Defense (DOD), the Department of Veterans Affairs (DVA), and the Department of Labor. A number of postwar surveys have also attempted to determine retrospectively, from samples of the veteran population, the total number of U.S. military personnel who served in Vietnam during the Vietnam era. A comparison of the differences in definition and methodology for deriving these estimates is provided below. Federal Estimates According to DOD calculations (Defense Almanac, 1992), 8.7 million served in the military during the Vietnam era (defined here as the period August 4, 1964, through January 27, 1973). The DOD estimates that 2.6 million, or approximately one-third, of these Vietnam era veterans served in Vietnam. Nearly 40 percent of Vietnam era veterans, or 3.4 million, served in the Vietnam theater (U.S. DOD, 1976). These estimates are based on military records tabulated by MACV from summaries prepared by individual units that recorded end-of-the-month troop numbers. Although the completeness of these records varied by unit, they are the best official documents available for estimating the number of U.S. servicemen in South Vietnam. According to estimates of the Department of Veterans Affairs (DVA),

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam approximately 8.3 million veterans of the Vietnam era (August 4, 1964, to May 7, 1975) were represented among the adult civilian U.S. population (U.S. VA, 1985). Approximately one-third, or some 2.7 million, of the Vietnam era veterans served in the Vietnam theater (defined as service in Laos, Cambodia, Vietnam, or the surrounding waters). The DVA adjusts its veteran population estimates based on the U.S. decennial census; estimates of Vietnam era service are based upon receipt of the Vietnam Service Medal, as identified on individual military discharge forms. Qualification for a service medal is limited to military units that supported operations within Vietnam and to those individuals that served in the Vietnam theater between July 1965 and April 1974 (Fischer et al., 1980). Therefore, the DVA estimate of the number who served in the Vietnam theater is restricted, based on use of the Vietnam Service Medal as an indicator of service. Various demographic data on veteran populations, in addition to employment and disability statistics, are reported by the Bureau of Labor Statistics (BLS). These data, tabulated from the Current Population Survey (U.S. Department of Labor, 1992a,b), suggest that of the 7.9 million male veterans of the Vietnam era (August 1964 to May 1975), nearly one-half, or 3.7 million, reported having served in the Vietnam theater of operations (Vietnam, Laos, or Cambodia, or in the waters or air surrounding these countries). Estimates of the number of veterans who served in Vietnam per se are not available from these data. Other Survey Estimates Various other postwar surveys of Vietnam era veterans also provide estimates of the number who served. A 1979 Louis Harris survey of the U.S. adult, noninstitutionalized population who served on active duty in the military during the Vietnam era (defined as the period between August 1964 and June 1975) reported that approximately 3.8 million (42.5 percent of Vietnam era veterans) served in Vietnam (Fischer et al., 1980). An estimated 4.3 million, or 47.8 percent, of Vietnam era veterans reported service in the Vietnam theater during the Vietnam era. The National Survey of the Vietnam Generation was conducted as part of the National Vietnam Veterans Readjustment Study (Kulka et al., 1988). The reference population for this survey was 8.3 million veterans who served during the Vietnam era (August 1964 to May 1975). According to these data, an estimated 3.1 million men and 7,000 women, or 37 percent of Vietnam era veterans, served in the Vietnam theater (defined as Vietnam, Laos, Cambodia, or the surrounding waters); nearly 2.6 million were stationed directly in Vietnam. These various estimates of the Vietnam veteran population are summarized in Table 3-2. From these data, it is estimated that one-third to one-half

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam TABLE 3-2 Estimates (in millions) of the Vietnam Veteran Population Reference Definition of Service N U.S. DOD, 1976 Vietnam, 1/1/65-3/31/73 2.6 Fischer et al., 1980 Vietnam, 8/64-6/75 3.8 U.S. VA, 1985 Vietnam theater, 8/4/64-5/7/75 2.7 Kulka et al., 1988 Vietnam theater, 8/64-5/75 3.1 U.S. DOD, 1976 Vietnam theater, 1/1/65-3/31/73 3.4 U.S. Dept. of Labor, 1990 Vietnam theater, 8/64-5/75 (males) 3.7 Fischer et al., 1980 Vietnam theater, 8/64-6/75 4.3 U.S. Dept. of Labor, 1990 Vietnam era, 8/64-5/75 (males) 7.9 U.S. VA, 1985 Vietnam era, 8/4/64-5/7/75 8.3 U.S. DOD, 1976 Vietnam era, 8/4/64-1/27/73 8.7   SOURCES: U.S. Department of Defense, 1976; Fischer et al., 1980; U.S. Veterans Administration, 1985; Kulka et al., 1988; U.S. Department of Labor, Bureau of Labor Statistics, 1990. of Vietnam era veterans, or 2.7 million to 4.3 million persons, served in the Vietnam theater of operations, depending on the definition of the period and/or location of military service. Comparable estimates of those who served in Vietnam range from 2.6 million to 3.8 million. Military and Demographic Characteristics Selected military and demographic statistics on U.S. personnel who served in Vietnam are available from these official records and postwar surveys. According to BLS estimates of the veteran population in 1989-1990, veterans who were between 40 and 44 years of age comprise the single largest age cohort of male Vietnam era veterans; 38 percent of male Vietnam era veterans and 43 percent of male Vietnam theater veterans were born between 1946 and 1950 (see Table 3-3). These statistics on the current age distribution of Vietnam veterans corroborate findings from several recent veteran surveys (Fischer et al., 1980; Kulka et al., 1988; CDC, 1989; U.S. DVA, 1990). Some veteran surveys obtain information retrospectively on the veteran's background characteristics upon entering military service, whereas others describe the veteran's characteristics at the time of the survey (which could be 10 to 25 years after military discharge). Differences in sampling procedures limit comparisons of the surveyed populations. As discussed previously, some studies provide data only on Vietnam theater veterans, including those who served in Laos and Cambodia or other areas of Southeast Asia, depending on how theater is defined. Some studies do not include a comparison group of nonveterans or do not provide contrasts among various

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam TABLE 3-3 Age Distribution of Vietnam Era and Vietnam Theater Veterans 1989-1990 (numbers in thousands) Age Group (years) Vietnam Era, N (%) Vietnam Theater, N (%) All ages 8,071a 3,886a ≤ 34 133 (1.6)    32 (0.1) 35-39 1,109 (13.8) 369 (9.4) 40-44 3,031 (37.6) 1,676 (43.1) 45-49 2,301 (28.5) 1,090 (28.0) 50-54 675 (8.4) 280 (7.2) 55-64 511 (6.3) 322 (8.3) > 65 178 (2.2)    83 (2.1) a Totals reflect the addition of an estimated 33,000 women who served in the Vietnam theater and 137,000 who served during the Vietnam era; these data are not included in the age distributions since they were not available by 5 year age groups. SOURCE: U.S. Department of Labor, Bureau of Labor Statistics, 1990. subgroups (i.e., race, branch or region of service), whereas others select only discrete groups for study (e.g., veterans of a particular age cohort or unit of service during a specific period of time). Furthermore, most surveys sample only males; less information on the characteristics of women who served in Vietnam is available (Schwartz, 1987). With these deficiencies in mind, estimates from several surveys involving large samples of veterans are presented below. Approximately 50 percent of Vietnam era veterans served in the Army, 20 percent in the Navy, 20 percent in the Air Force, and the remaining 10 percent in the Marines or Coast Guard (Kulka et al., 1988). These data are in close agreement with DOD (Defense Almanac, 1992) estimates of the proportion serving by branch of service. Other than IV Corps, where 7 percent served, military personnel in Vietnam were relatively evenly distributed throughout the four military regions of the country. Approximately 80 to 85 percent of male Vietnam veterans were white, 10 to 12 percent black, and the remaining Hispanic or other (Fischer et al., 1980; Kulka et al., 1988; U.S. Department of Labor, 1990). Of those surveys that provided comparison groups, there were no differences in the racial composition of Vietnam era veterans compared to those who did not serve in Vietnam during the Vietnam era (Fischer et al., 1980; Card, 1983). Although race was not associated with military service, whites who did serve, and especially those who enlisted willingly, came from poorer families than whites who did not serve. For blacks, there were no significant socioeconomic differences between those who did and did not serve. However, blacks who

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam served, and especially those who served more than two years, had completed more years of education than those who did not serve (Card, 1983). Twenty percent of soldiers sent to Vietnam were assigned to combat units (Shafer, 1990), although surveys of veterans indicate much higher percentages who reported having experienced combat. A survey published by the Veterans Administration indicated that 70 percent of those sampled reported exposure to combat, which meant that they had come under some kind of attack (U.S. Department of Labor, 1990; Karnow, 1991). The CDC Vietnam Experience Study found that 57 percent of Army veterans had served in combat type units (i.e., infantry, artillery, armor, cavalry, and engineer; CDC, 1989). The average age of those who experienced combat in Vietnam was 19 years, compared to 27 years in World War II (Shafer, 1990). Draftees were more likely to see heavy combat in Vietnam, compared to those who enlisted and served in other parts of the theater (Fischer et al., 1980; Kulka et al., 1988). No differences among racial or ethnic groups were found for either service in the Vietnam theater or exposure to combat. However, those who served in Vietnam with less than a high school education at the time of entry into military service were three times as likely to see heavy combat as those with college educations, and those who were less than 20 years of age at the time they went to Vietnam were twice as likely to be exposed to heavy combat as those aged 35 years or older (Fischer et al., 1980). A 1981 survey of a 1960 male high school cohort of military age during the Vietnam era found that veterans with lower academic aptitude, as measured by a series of cognitive tests scores received in the ninth grade, reported more combat experiences, such as seeing Americans wounded, firing a weapon at the enemy, or receiving fire from the enemy, than those with higher test scores (Card, 1983). Just as there was no ''typical" American soldier or typical military experience in Vietnam, there was no one combat experience (Shafer, 1990; Karnow, 1991). The combat experiences of individual soldiers varied according to assignment, geographical region of duty, and the period during which they served. In addition, most soldiers who were sent to Vietnam after the first American troops arrived in 1965 were sent as individual replacements, rather than as units (Karnow, 1991). The military found it more efficient administratively to replace losses piecemeal than to replace units and rebuild them. Unfortunately, this operational strategy minimized prospects for unit cohesion and contributed to low troop morale (Shafer, 1990). It should be noted that these estimates describe the surviving veteran population: more than 58,000 U.S. men and women were killed and over 300,000 were wounded, of which more than one-half were wounded seriously enough to require hospitalization (U.S. VA, 1985). The Combat Area

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam Casualties Current File, maintained by the Department of Defense, contains records on U.S. personnel who died as a result of hostilities (killed in action, died from wounds, died while missing, or died while captured) or other causes (died from illness or nonhostile injury or other nonhostile causes) while serving in Cambodia, China, Laos, Vietnam, or Thailand during the conflict in Southeast Asia. As of November 1992, the file contained information on 58,166 deaths. Information potentially available in each casualty record includes branch of service, military grade and occupation code, birth date, cause and date of death, and length of service. Forty-four percent of the 58,166 U.S. military deaths occurred in those under age 21; three-fourths were aged 23 and younger. Among the recorded deaths, enlisted personnel suffered six times as many casualties as officers (86 percent and 14 percent, respectively), and pay grades E-3 and E-4 suffered the heaviest losses. The majority of deaths occurred among U.S. Army forces (66 percent), 25 percent occurred among the Marine Corps, 4.5 percent among the Navy, and 4.5 percent among the Air Force (U.S. DOD, 1986). As a group, Marines sustained the heaviest proportion of losses. Although blacks made up 11 percent of the American population and 12.6 percent of American forces in Vietnam, they accounted for 20 percent of Army combat deaths from 1961 to 1966 (Shafer, 1990). Black casualties ultimately accounted for 15.1 percent of total Army casualties and 13.7 percent of total U.S. casualties. Studies of Women Veterans There are no centrally maintained records or files of all women who were stationed in Vietnam during the Vietnam era (Thomas et al., 1991). The Veterans Administration (1985) reported that 263,000 women served in the military between 1964 and 1975 (the Bureau of Labor Statistics estimates that about 210,000 women served during the Vietnam era (U.S. Department of Labor, 1990); an estimated 5,000 to 7,000 women served in Vietnam (Thomas et al., 1991). Eight women were killed in Vietnam; all were nurses. Very little information on the demographic characteristics of women veterans exists (Schwartz, 1987). The National Vietnam Veterans Readjustment Study (Kulka et al., 1988) sampled 736 Vietnam era female veterans, 432 of whom were Vietnam theater veterans. Over 70 percent of women who served in the Vietnam theater were born during the period 1940-1949. An estimated 97 percent were white. Nearly 80 percent served in the Army, 90 percent were officers, and 87 percent were military nurses (Kulka et al., 1988). Thomas and colleagues (1991) conducted a study of 4,582 female Vietnam veterans who served between July 1965 and March 1973. The women

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam were identified from the review of morning reports of Army hospital and administrative support units stationed in Vietnam, and from Air Force personnel files, Navy muster roles, and Marine Corps listings of all women assigned to Vietnam. More than 90 percent (93.9 percent) of the women in the study were white. They also tended, on average, to be older than male veterans; about one-third were younger than age 25 at the time they entered Vietnam service. Most female veterans (75 percent) served in the Army, followed by the Air Force (16 percent), Navy (8 percent), and Marines (less than 1 percent). Eighty percent of the female veterans included in this study were nurses. These estimates are similar to those determined by Kulka and colleagues (1988) in their review of women serving in the military during the Vietnam era. THE MILITARY USE OF HERBICIDES IN VIETNAM In 1960, U.S. assistance to the Diem government in South Vietnam was limited to military advisors, economic aid, and some logistic support (Karnow, 1991). American military advisory forces in South Vietnam numbered fewer than 900 (MACV, 1972). Some leaders within the U.S. government and military warned that the time to act against a Communist takeover of South Vietnam had come and that further U.S. intervention was inevitable. Defoliation operations were among several supplemental actions proposed that could be conducted while decisions regarding the commitment of combat troops were pending (Buckingham, 1982). The use of herbicides in South Vietnam was recommended for several reasons: to remove foliage along thoroughfares used as cover for enemy ambushes, to defoliate vegetative areas surrounding enemy bases and communication routes, to improve visibility in heavily canopied jungle, and to destroy enemy subsistence crops (Collins, 1967; Huddle, 1969; U.S. Army, 1972). Although the first combat troops did not arrive in Vietnam until April 1965, preparations for the testing and conduct of a major aerial defoliation program proceeded in cooperation with the South Vietnamese government. In December 1961, President Kennedy authorized the use of herbicides, and on January 12, 1962, the first U.S. Air Force herbicide missions of Operation Ranch Hand were flown over South Vietnam (Warren, 1968; MACV, 1972). Much of the currently available information on the military use of herbicides in South Vietnam during the period 1962 to 1971—the chemical formulations used, the quantities applied, the operational procedures for aerial spray missions, and the aircraft used—was compiled in the 1970s and early 1980s from military records kept during the conflict, DOD technical reports, and procurement records. In 1974, the National Academy of Sciences' Committee to Review the Ecological Consequences of Herbicides in Vietnam evaluated the available DOD records of herbicide spray missions

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam crop production, and to weaken enemy strength in these areas (Warren, 1968). According to a 1972 Department of the Army report, Herbicides and Military Operations, the dense forest along many of the key marine and land transportation routes served as effective cover for enemy ambush (U.S. Army, 1972). In particular, the Rung Sat Special Zone, an area of dense mangrove forests, afforded enemy concealment along the main shipping route to Saigon. Defoliation of the area began in the mid-1960s, and by the late 1960s, most of the mangrove forests adjacent to the shipping routes were defoliated. The defoliation operation was so complete that it eliminated enemy attacks on shipping in the Rung Sat area (U.S. Army, 1972). Infiltration of the enemy and their supplies into Vietnam was also a major problem for military operations. The predominant points of entry were in densely forested areas, where U.S. patrols were subject to enemy ambush, and the forest cover concealed the enemy and its supplies. The Ca Mau peninsula was a temporary staging area for infiltration into the Mekong Delta and for attacks on local shipping and Navy patrol craft along the peninsula's streams and canals. Defoliation operations in 1967 and early 1968 aided military operations by improving observation of formerly heavily forested jungle areas (U.S. Army, 1972). The enemy infiltration terminated in base camps within South Vietnam; several were located near the Cambodian border and others were located near Saigon. These enemy camps were the source of raids on and harassment of friendly forces, terrorist attacks on local inhabitants, and attempted infiltration into cities. War Zone C (an area in III Corps on the Cambodian border), and War Zone D and Bear Cat (both near Saigon), were three such enemy base camp areas noted by the Army that were sprayed repeatedly to reach all levels of the canopy forest and restrict regrowth. Perimeter spraying by hand or helicopter at base camps and other installations was required to control the growth of tall grasses and brush. In areas where bamboo or tall grass surrounded a base, it was necessary to respray every two or three months to keep the vegetation low; however, the Army notes that in most locations, the topography, hazardous conditions, mine fields, and limited work force and equipment precluded the use of hand sprays for clearing base perimeters (U.S. Army, 1972). Crop destruction targets were primarily located in I Corps and the western region of II Corps. Rice was the main target for destruction, and Agent Blue was found to be most effective. Although the immediate effect of the herbicides was to destroy the rice crop, the Army reported that new crops could be planted during the next growing season due to the lack of residuals in the soil that restricted subsequent plant growth. Assuming a flight swath width of 80 m, the NAS estimated that from 1965 to 1971, 3.6 million acres, or nearly 10 percent of the land area of

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam FIGURE 3-2a Herbicide defoliation missions in Vietnam as recorded on HERBS tape. SOURCE: NAS, 1974. NOTE: Lines indicate mission tracks.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam FIGURE 3-2b Herbicide defoliation missions in Vietnam during 1966. SOURCE: NAS, 1974. NOTE: Lines indicate mission tracks. FIGURE 3-2c Herbicide defoliation missions in Vietnam during 1967. SOURCE: NAS, 1974. NOTE: Lines indicate mission tracks. Shading indicates populated area.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam FIGURE 3-2d Herbicide defoliation missions in Vietnam during 1968. SOURCE: NAS, 1974. NOTE: Lines indicate mission tracks. FIGURE 3-2e Herbicide defoliation missions in Vietnam during 1969. SOURCE: NAS, 1974. NOTE: Lines indicate mission tracks.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam TABLE 3-6 Herbicide Use by Military Region, 1965-1971 (million gallons) Military Region Agent Orange Agent White Agent Blue TOTAL (%) I 2.25 0.36 0.30   2.91 (16.5) II 2.52 0.73 0.47   3.72 (21.0) III 5.31 3.72 0.29   9.32 (52.7) IV 1.23 0.44 0.06   1.73 (9.8) TOTAL 11.31 5.25 1.13 17.68 (%) 63.9 29.7 6.4 100.0   SOURCE: Tschirley, 1992. South Vietnam, had been sprayed at least once with herbicides (NAS, 1974). About 1.2 million acres, or roughly 34 percent of the sprayed area, was sprayed more than one time. These calculations are based on figures for the spraying missions by the C-123s and do not take into account unrecorded helicopter or ground sprays, or the effects of wind drift, aircraft speed, and rates of delivery. III Corps was the most heavily sprayed area of Vietnam, receiving about 53 percent of all herbicide sprays from 1965 to 1971 (Table 3-6). Thirty percent of III Corps was sprayed at least once (Westing, 1984). War Zones C and D, and the Iron Triangle in III Corps, can also be identified as heavily sprayed areas in maps of herbicide defoliation missions. The Rung Sat Special Zone in III Corps near Saigon, where the Saigon and Dong Nai Rivers linked together, was the most heavily sprayed region in Vietnam, as well as a site of frequent U.S. Navy operations. In 42 missions, the C-123s sprayed thousands of gallons of herbicides on the mangrove swamps to flush out Vietcong from hidden strongholds, from which they attacked supply ships and instituted offensives in the Delta region and surrounding provinces (Dux and Young, 1980). The area was sprayed consistently until 1970; the NAS (1974) estimated that 57 percent of the Rung Sat Special zone had been sprayed. Another heavily sprayed area, the Ca Mau Peninsula at the southern tip of South Vietnam, was almost entirely covered with dense mangrove forests up to 1968. However after extensive spraying of the peninsula in 1967 and 1968, the NAS (1974) concluded that nearly half of the mangrove trees had been destroyed. Mangrove forests were more heavily affected by herbicide spraying than any other vegetation type in South Vietnam. One spray usually killed all mangrove trees (NAS, 1974). Another limitation of the HERBS tapes, and the maps generated from it, is that the plotted lines represent the center of each mission. The assumed swath width for a sortie was 80 m. Typical missions consisted of

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam three aircraft, and some as many as 12 to 16; these differences in effective spray area are not reflected by the maps. A detailed study of the frequency of sprays in the Rung Sat Special Zone conducted by the NAS (1974) is shown in Figure 3-3. For each herbicide mission, the date, number of gallons sprayed, and type of herbicide are indicated. These maps show how many times any FIGURE 3-3 Herbicide spray missions (1966-1967) in the Rung Sat Special Zone. Data from HERBS tape include date of mission, number of gallons, and type of herbicide agent. SOURCE: NAS, 1974.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam hectare had been sprayed due to repetition or overlapping of herbicide applications and, more accurately, depict the extent of spraying conducted in the Rung Sat Special Zone during 1966 and 1967. Areas designated as defoliation targets were much more likely to be sprayed repeatedly than targets of crop destruction missions. Less than 10 percent of the targets for crop destruction missions were sprayed more than once, and the intervals were usually 6 to 12 months; one-third of the areas classified as defoliation were resprayed, and approximately 70 percent received the second spray within 6 months of the initial spray (NAS, 1974). Military documents report the use of herbicides over areas of Laos, particularly near the Vietnam border and along the Ho Chi Minh Trail. The purpose of the operation in Laos was to expose foot trails, roads, and other lines of communication that led into Vietnam. Herbicide operations began in December 1965; within a six month period, more than 200,000 gallons of herbicide had been sprayed over approximately 1,500 km of roads and trails in Laos (Collins, 1967). SUMMARY Some 3 million U.S. military personnel served in or near Vietnam, but the precise number cannot be readily determined from existing military records since individual service records have not been computerized. Surveys of veterans vary in their estimates because of differences in terminology and sample selection procedures. Existing military records do document assignments of military personnel to units and the location of most units at most times. Individual military experiences of Americans who served in Vietnam varied as the nature of the war in different areas of the country changed over time. Individual experiences also varied by branch of service, military occupation, rank, and type of military unit. Between 1962 and 1971, U.S. military forces sprayed nearly 19 million gallons of herbicides over approximately 3.6 million acres in South Vietnam. The preparation known as Agent Orange accounted for approximately 11.2 million gallons of the total amount sprayed. Seven different herbicide formulations were used in varying quantities for a variety of purposes in different parts of the country. Approximately 65 percent of all herbicides sprayed were contaminated by TCDD, in varying concentrations. Herbicides were used to strip the thick jungle canopy that helped conceal opposition forces, to destroy crops that enemy forces might depend upon, and to clear tall grass and bushes from around the perimeters of U.S. base camps and outlying fire support bases. Aerial spraying of herbicides by Operation Ranch Hand accounted for approximately 86 percent of all spraying, and existing computerized records indicate which herbicides were used and where. These records indicate that

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam the spraying was not uniform, but concentrated in certain geographical and tactical areas. Units and individuals other than the members of the Air Force Ranch Hand, such as the Army Chemical Corps, were also likely to have handled or sprayed herbicides around bases or lines of communication. Considerable quantities of herbicides were also sprayed from boats and ground vehicles, as well as by soldiers wearing back-mounted equipment. Although the recording of such sprays was not as systematic as those of Ranch Hand, some records do exist on the ''Services HERBS" computer tape. REFERENCES Australian Senate Standing Committee on Science and the Environment. 1982. Pesticides and the Health of Australian Vietnam Veterans. First report. 240 pp. Badillo G, Curry D. 1976. The social incidence of Vietnam casualties: social class or race? Armed Forces and Society 2:3. Barnett A, Stanley T, Shore M. 1992. America's Vietnam casualties: victims of a class war? Operations Research 40:856-866. Boyle CA, Decoufle P, O'Brien TR. 1989. Long-term health consequences of military service in Vietnam. Epidemiologic Reviews 11:1-27. Breslin P, Kang H, Lee Y, Burt V, Shepard BM. 1988. Proportionate mortality study of U.S. Army and U.S. Marine Corps veterans of the Vietnam War. Journal of Occupational Medicine 30:412-419. Brown JW. 1962. Vegetational Spray Test in South Vietnam. Fort Detrick, MD: U.S. Army Chemical Corps Biological Laboratories. DDC Number AD 476961. 119 pp. Buckingham WA. 1982. Operation Ranch Hand: The Air Force and Herbicides in Southeast Asia 1961-1971 . Washington, DC: U.S. Air Force Office of Air Force History. Card JJ. 1983. Lives After Vietnam: The Personal Impact of Military Service. Toronto: Lexington Books. Centers for Disease Control (CDC). 1989. Health Status of Vietnam Veterans. Vietnam Experience Study. Atlanta: U.S. Department of Health and Human Services. Vols. I-V, Supplements A-C. Clarke JJ. 1988. U.S. Army in Vietnam. Advice and Support: The Final Years, 1965-1973. Washington, DC: U.S. Army, Center of Military History. Collins CV. 1967. Herbicide Operations in Southeast Asia, July 1961-June 1967. San Francisco: Headquarters, Pacific Air Forces. NTIS AD-779 796. Craig DA. 1975. Use of Herbicides in Southeast Asia. Historical Report. Kelly AFB, TX: San Antonio Logistics Center, Directorate of Energy Management. 58 pp. Darrow RA, Irish KR, Minarik CD. 1969. Herbicides Used in Southeast Asia. Kelly AFB, TX. Technical Report SAOQ-TR-69-11078. 60 pp. Dashiell TR. Office of the Director of Defense Research and Engineering. 1973. Comments to Dr. Peter Kunstadter's Comparison of HERBS and 202 Records. Memorandum to Dr. Philip Ross, National Academy of Sciences. July 11, 1973. Defense Almanac. 1992. Service and casualties in major wars and conflicts (as of Dec. 31, 1991). Defense '92 Almanac:47. Dux J, Young PJ. 1980. Agent Orange: The Bitter Harvest. Sydney: Hodder and Stoughton. Fischer V, Boyle JM, Bucuvalas M. 1980. Myths and Realities: A Study of Attitudes Toward Vietnam Era Veterans. Submitted by the Veterans Administration to the Committee on Veterans' Affairs, U.S. House of Representatives. House Committee Print No. 89.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam Gonzales J. 1992. List of Chemicals Used in Vietnam. Presented to the Institute of Medicine Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides. Illinois Agent Orange Committee, Vietnam Veterans of America. Harrigan ET. 1970. Calibration Test of the UC-123K/A/A45Y-1 Spray System. Eglin AFB, FL: Armament Development and Test Center. Technical Report ADTC-TR-70-36. NTIS AD 867 004. Heizer JR. 1971. Data Quality Analysis of the HERB 01 Data File. MITRE Technical Report, MTR-5105. Prepared for the Defense Communications Agency. McLean, VA: MITRE. Heltman LR. 1986. Veteran Population in the United States and Puerto Rico by Age, Sex, and Period of Service: 1970 to 1985. IM&S M70-86-6. Washington, DC: Veterans Administration, Office of Information Management and Statistics. Huddle FP. 1969. A Technology Assessment of the Vietnam Defoliant Matter. Report to the Subcommittee on Science, Research, and Development of the Committee on Science and Astronautics, U.S. House of Representatives. 91st Cong., 1st sess. August 8, 1969 . Irish KR, Darrow RA, Minarik CE. 1969. Information Manual for Vegetation Control in Southeast Asia. Misc. Publication 33. Fort Detrick, MD: Dept. of the Army, Plant Sciences Laboratories, Plant Physiology Division. NTIS AD 864 443. Karnow S. 1991. Vietnam: A History. New York: Penguin. Kulka RA, Schlenger WE, Fairbank JA, Hough RL, Jordan BK, Marmar CR, Weiss DS. 1988. Contractual Report of Findings from the National Vietnam Veterans Readjustment Study. Research Triangle Park, NC: Research Triangle Institute. Conducted for the Veterans Administration under contract number V101(93)P-1040. Lewis WW. 1992. Herbicide Exposure Assessment. New Jersey Agent Orange Commission, Pointman II Project. Military Assistance Command, Vietnam (MACV). 1966. Evaluation of Herbicide Operations in the Republic of Vietnam as of 30 April 1966. MACV, Office of the Assistant Chief of Staff Intelligence. NTIS AD 779 792. Military Assistance Command, Vietnam. 1968. The Herbicide Policy Review. Report for March-May 1968. APO San Francisco: MACV. NTIS AD 779 794/7. 140 pp. Military Assistance Command, Vietnam. 1969a. Accidental Herbicide Damage . Vietnam Lessons Learned No. 74. APO San Francisco: MACV. September 15, 1969. NTIS AD 858-315-5XAB. 14 pp. Military Assistance Command, Vietnam. 1969b. Military Operations: Herbicide Operations. APO San Francisco: MACV. August 12, 1969. NTIS AD 779 793. 20 pp. Military Assistance Command, Vietnam. 1970. Command Manual for Herbicide Reporting System (HERBS). Document Number DARU07. NTIS AD 875 942. Military Assistance Command, Vietnam. Military History Branch. 1972. Chronology of Events Pertaining to U.S. Involvement in the War in Vietnam and Southeast Asia. Martin R. 1986. Who went to war. In: Boulanger G, Kadushin C, eds. The Vietnam Veteran Redefined: Fact and Fiction. Hillsdale, NJ: Lawrence Erlbaum. Midwest Research Institute (MRI). 1967. Assessment of Ecological Effects of Extensive or Repeated Use of Herbicides. MRI Project No. 3103-B. Kansas City, MO: MRI. NTIS AD 824 314. Moskos CC Jr. 1975. The American combat soldier in Vietnam. Journal of Social Issues 31:25-37. National Academy of Sciences (NAS). National Research Council, Assembly of Life Sciences. 1974. The Effects of Herbicides in South Vietnam. Washington, DC: National Academy of Sciences. National Research Council (NRC). 1985. Ascertainment of Mortality in the U.S. Vietnam Veteran Population. Washington, DC: Commission on Life Sciences, Medical Follow-Up Agency.

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Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam U.S. Department of Labor, Bureau of Labor Statistics. 1992a. BLS Reports on Labor Market Situation of Vietnam-Era Veterans. Washington, DC: BLS. USDL 92-255. U.S. Department of Labor, Bureau of Labor Statistics. 1992b. Employment Status of Veterans: Data from the Current Population Survey. Washington, DC: BLS. U.S. Department of Veterans Affairs (DVA). 1991. Annual Report of the Secretary of Veterans Affairs. Fiscal Year 1990. Washington, DC: DVA. U.S. Department of Veterans Affairs. 1992. Trend Data: Fiscal Years 1967-1991. Washington, DC: DVA, Assistant Secretary for Policy and Planning. U.S. General Accounting Office (GAO). 1978. Use of Agent Orange in Vietnam. Washington, DC: GAO. CED-78-158. U.S. General Accounting Office. 1979a. Health Effects of Exposure to Herbicide Orange in South Vietnam Should be Resolved. CED-79 22. Washington, DC: GAO. U.S. General Accounting Office. 1979b. U.S. Ground Troops in South Vietnam Were in Areas Sprayed with Herbicide Orange. Report by the Comptroller General of the United States FPCD 80-23. Washington, DC: GAO. U.S. Veterans Administration (VA). 1985. Data on Vietnam Era Veterans. Washington, DC: VA Office of Information Management and Statistics. Warren WF. 1968. A Review of the Herbicide Program in South Vietnam. San Francisco: Scientific Advisory Group. Working Paper No. 10-68. NTIS AD 779-797. Westing AD, ed. 1984. Herbicides in War: The Long-Term Ecological and Human Consequences. London: Taylor and Francis. Young AL. 1980. Use of Herbicides in South Vietnam 1961-71. Presentation at the Educational Conference on Herbicide Orange, May 1980. Silver Spring, MD: U.S. Veterans Administration. Young AL. 1992. The Military Use of Herbicides in Vietnam. Presentation to the Institute of Medicine Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides. December 8, 1992. Washington, DC. Young AL, Reggiani GM, eds. 1988. Agent Orange and Its Associated Dioxin: Assessment of a Controversy. Amsterdam: Elsevier. Young AL, Thalken CE, Arnold EL, Cupello JM, Cockerham LG. 1976. Fate of 2,3,7,8,-Tetrachlorodibenzo-p-dioxin (TCDD) in the Environment: Summary and Decontamination Recommendations. Colorado Springs: U.S. Air Force Academy. USAFA-TR-76-18. 47 pp. Young AL, Calcagni JA, Thalken CE, Tremblay JW. 1978. The Toxicology, Environmental Fate, and Human Risk of Herbicide Orange and Its Associated Dioxin. Brooks AFB, TX: Air Force Occupational and Environmental Health Lab. USAF OEHL-TR-78-92. 262 pp.