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Since Doll and Peto's 1981 monograph on causes of cancer, periodic efforts have been made to re-estimate the numbers and percentages of cancer cases "attributable" to various types of environmental and occupational exposures. We argue that much of this effort, especially in the occupational realm, is wasted, not because the information is not worth knowing, but because governmental initiatives to carry out needed studies, translate them into recommendations, and generate and enforce standards have been badly eroded and the system created by passage of occupational health and safety laws in the latter part of the twentieth century has become largely dysfunctional. For example, whereas NIOSH released over eighty criteria documents between 1975 and 1990, it published only one between 2000 and 2006. Furthermore, the increasing complexity of chemical products and potential exposures have made many classical risk assessment paradigms obsolete, while the fragmented nature of the work force and the rapidly increasing globalization of chemically-dependent industries has made epidemiological studies of workplace hazards increasingly difficult. We advocate replacement of chemical-by-chemical exposure standards with standards focused on process safety management, increasingly based on structure-activity relationships for chemicals for which human toxicity is not yet known.

Between 1961 and 1970, the U.S. military engaged in massive chemical defoliation and crop destruction operations in Southeast Asia. In 1985, nearly two decades after the spraying had ceased, a landmark tort settlement was reached between a class of Vietnam veterans and the chemical manufacturers that had supplied the Agent Orange and other military herbicides to the U.S. Department of Defense. It is notable that, at the time of the settlement, there was little convincing epidemiological evidence available, either positive or negative, on the health consequences to veterans of the herbicide operations. Today, more than three decades after this massive environmental exposure, there is still a dearth of epidemiological data on the extent to which adverse health consequences resulted from the use, storage, and disposal of the herbicides in Vietnam. This paucity of epidemiological data stands in stark contrast to the extensive amount of experimental data available on dioxin, an important contaminant in about 60% of the herbicide sprayed. Much laboratory data convincingly demonstrate dioxin's extreme toxicity. The scientific literature also is growing with respect to the carcinogenicity of the organic arsenical that was a primary component of the Agent Blue used to destroy enemy food crops. Many epidemiological studies have been carried out on other, much smaller populations exposed to the same chemicals. Indeed, when the Institute of Medicine (IOM) conducts its biennial review of the scientific literature and provides the Department of Veterans Affairs (VA) with a summary, including its appraisal of the relationship between herbicide exposure and a list of health outcomes, it relies to a large extent on the studies carried out of non-veteran populations to support its conclusions. The degree to which these other studies correctly estimate the health effects in Vietnam veterans is not known. Thus there continue to be practical ramifications to the paucity of definitive epidemiological studies on a sufficiently large exposed population of either veterans or Vietnamese citizens.

Nearly 19.5 million gallons of herbicides were sprayed on the Republic of Vietnam between 1961 and 1971 for military purposes. Amounts of spray and patterns of applications are available in an electronic file called HERBS that contains records of 9141 defoliation missions, including detailed coordinates of US Air Force Ranch Hand aircraft flight paths, along with chemical agent and gallonage sprayed. Two classes of models for use in epidemiological and environmental studies that utilize the HERBS data for estimating relative exposure opportunity indices are presented: a discrete "hits" model that counts instances of proximity in time and space to known herbicide applications, and a continuous exposure opportunity index, E4, that takes into account type and amount of herbicide sprayed, distance from spray application, and time interval when exposure may have occurred. Both direct spraying and indirect exposure to herbicide (or dioxin) that may have remained in the local environment are considered, using a conservative first-order model for environmental disappearance. A correction factor for dermal versus respiratory routes of entry has been incorporated. E4 has a log-normal distribution that spans six orders of magnitude, thus providing a substantial amount of discrimination between sprayed and unsprayed areas. The models improve on earlier ones by making full use of the geometry of the HERBS spray flight paths of Ranch Hand aircraft. To the extent possible so many decades after the War, the models have been qualitatively validated by comparison with recent dioxin soil and biota samples from heavily contaminated areas of Vietnam, and quantitatively validated against adipose dioxin obtained in epidemiological studies of Vietnamese. These models are incorporated within a geographic information system (GIS) that may be used, as one would expect, to identify locations such as hamlets, villages, and military installations sprayed by herbicide. In a novel application, the GIS also facilitates quantitative risk assessment in epidemiological and ecological studies by applying the models within a framework of historical reconstruction of exposure history of individuals based upon their location histories.

Two pivotal problems in determining whether exposure to herbicides has caused disease in Vietnam veterans or their offspring are definition of which troops were exposed and extent of exposure. The DoD HERBS tape is the most complete publicly available record of herbicide spraying in Vietnam. It contains about 17,000 records consisting of coordinates of spray missions, dates, chemical agent, quantity and area sprayed, and mission purpose. We have developed a set of discrete and continuous indexes of probability of exposure to herbicides for individual veterans. These probability indexes are based on HERBS tape spray data and on locations and dates of service derived from a place-and-date matrix completed by the veteran. They can take into account a conservative estimate of environmental persistence of herbicide by using first-order exponential decay kinetics with an estimated half-life of dioxin. Mean values for the continuous exposure probability indexes were significantly greater among veterans judged to be exposed according to self-reported job titles and specific military experiences than among men judged unlikely to have been exposed. Probabilistic exposure indexes based on HERBS tape for classification of likely exposure to herbicides in South Vietnam during 1965-1971 appear to be well suited for comparative classification of veterans and hence for use in epidemiologic studies.

Information packet on video display terminals and international trends in legislation and collective bargaining produced by the Women's Occupational Health Resource Center (WOHRC). The WOHRC (1979-1987) was a research and training program devoted to identifying and better understanding hazards faced by women workers. WOHRC was housed in Columbia's School of Public Health and directed by Professor Jeanne Mager Stellman. WOHRC was a designated OSHA New Directions Training program, and also received support from other federal and private agencies. As a New Directions project, WOHRC trained thousands of workers and professionals in hazard recognition and accident and illness prevention for women workers. In order to carry out its public health programs, WOHRC developed and disseminated original educational materials. The materials were designed to be authoritative while at the same time accessible to non-professional users (e.g. the workers). WOHRC published a monthly newsletter that contained a "fact sheet" focusing on a particular job or a particular hazard. The fact sheets were also made available individually or collected into "fact packs" of related materials.

A random sample of American Legion members in six states who had served in the Armed Forces during the Vietnam Era was conducted through a mailed questionnaire, in order to determine patterns of usage of Veterans Administration health facilities, as well as attitudes toward the VA and experiences at these facilities. Of the 6810 male respondents, 42.0% had served in Southeast Asia. These subjects were categorized according to their level of combat in South Vietnam. Thirty-six percent of those who had served in Southeast Asia had used VA health facilities, compared to only 18% of men who served elsewhere. Among Southeast Asia veterans, combat level was an important predictor of extent of usage of VA facilities for problems of both physical and mental health. Combat level was also associated with lack of basic and major medical insurance. While men with lower incomes tended to make greater use of VA mental health facilities, nearly one-fourth of mental health users had family incomes above $30,000. Despite their greater usage of the VA, men with higher combat levels expressed lower feelings of security about this agency, and rated its staff less helpful and of lower quality than did men who experienced lower levels of combat. On the other hand, higher combat veterans thought themselves better informed about VA services. Men who had gone to the VA for mental health assistance reported a disturbingly low frequency of having been asked basic questions that relate to possible diagnosis of post-traumatic stress disorder (PTSD), questions related to combat, which may be one of its etiologic factors, or other questions relating to their military history'. Because combat level in Vietnam veterans is a major determinant of both attitudes toward and utilization of VA health facilities, the VA as well as other health agencies which deal with Vietnam veterans should be especially sensitive to this factor, and should take it into consideration when evaluating veterans' physical and mental health.

History of diagnosed illnesses, medical symptoms, and reproductive outcomes and their relation to combat intensity and herbicide exposure were studied, via a mailed questionnaire, among 6810 American Legionnaires who served during the Vietnam War (42% in Southeast Asia, 58% elsewhere). Heart disease, venereal disease, and benign fatty tumors were reported significantly more often by Vietnam veterans than by controls. Combat intensity was significantly dosage-related to history of high blood pressure, ulcers, arthritis and rheumatism, genito-urinary problems, nervous system disease, major injury, hepatitis, and benign fatty tumors. Agent Orange exposure was significantly dosage-related to history of benign fatty tumors, adult ache, skin rash with blisters, and increased sensitivity of eyes to light. Rates of the latter two conditions and of change in skin color were especially elevated in men whose military occupations involved direct handling of herbicides. Five "symptom complex" scales were constructed via factor analysis to measure degrees of feeling faint, fatigue or physical depression, body aches, colds, and skin irritation. Means of all five scales were significantly higher in Vietnam veterans compared to controls, and in herbicide handlers compared to non-handlers. Both combat and Agent Orange exposure were significant, independent predictors of each of the five scales. Neither combat nor Agent Orange exposure was associated with difficulty in conception, time to conception of first child, or to birthweight or sex ratio of offspring, but maternal smoking was strongly related to reduced birthweight. The percentage of spouses' pregnancies which resulted in miscarriages was significantly higher for Vietnam veterans than controls (7.6% vs 5.5%, P & 0.001). Logistic regression analysis showed that Agent Orange exposure and maternal smoking were both independently and significantly associated with miscarriage rates in a dose-related manner.

Herbicides including Agent Orange were sprayed by United States forces for military purposes during the Vietnam War (1961–1971) at a rate more than an order of magnitude greater than for similar domestic weed control. In 1974, the US National Academy of Sciences published estimates of the extent and distribution of herbicides sprayed. Here we present revised estimates, developed using more-complete data. The spray inventory is expanded by more than seven million litres, in particular with heavily dioxin-contaminated herbicides. Estimates for the amount of dioxin sprayed are almost doubled. Hamlet census data reveal that millions of Vietnamese were likely to have been sprayed upon directly. Our identification of specific military herbicide targets has led to a more coherent understanding of spraying. Common errors in earlier interpretations of the spray data are also discussed.

The relationship between combat stress, DSM-III-defined post-traumatic stress disorder (PTSD), and a variety of behavioral factors was examined in a large nonclinical population. A total of 2858 randomly selected American Legion members who had served in Southeast Asia completed a questionnaire which elicited information on military service, personal health, and a variety of mental health outcomes. The data confirm the utility of the PTSD diagnosis as a distinct clinical entity. The frequency of PTSD and the extent of symptoms developed varied with the severity of criteria used for determining the extent of traumatic exposure. The PTSD rate ranged from 1.8 to 15.0% of the total sample, depending on whether "exposure" to combat was defined relatively narrowly or broadly. A distinct linear dose-response relationship between combat stress and a quantitative measure of PTSD intensity was observed. The frequency of PTSD diagnosis was not affected by the presence of either physical or mental health problems which predated military service. A strong, stable relationship was found between combat stress and PTSD intensity for cohorts with differing intervals since the experience of combat trauma, which persisted up to 20 years after discharge from the military. The data thus support a broader approach to defining traumatic events which recognizes individual differences in response to combat, as well as the existence of other behavioral outcomes as residual effects of combat. Implications of these findings and the importance of treating veterans with varying presentations of PTSD are discussed.

Many Vietnam War veterans who experienced military trauma still exhibit PTSD symptomatology. Little is known about how new stressful situations, like the COVID-19 pandemic, affect previously traumatized people or whether they will react differently to them. We explore whether military combat experiences in Vietnam affect veterans' perceived abilities to cope with COVID-19 and whether current PTSD symptoms and later-adulthood reengagement with trauma memories are related to coping. We examine the extent that current PTSD symptoms and trauma reengagement relate to preventive practices. Participants were part of a randomly sampled cohort of American Legionnaires who responded to two previous surveys (1984, 1998), were born 1945-1953 and deployed to Vietnam 1963-1973, thus representing an aging veteran population. A survey supplement assessed coping with the pandemic and adherence to public health guidelines. The response rate was 74% (N = 507); 422 (61.6%) completed the COVID-19 supplement. Military experiences were found to affect coping with 41.4% reporting they affected ability to cope with COVID-19. Medium- and high-combat veterans were more likely to report that military experience affected coping than low-combat (OR 2.4, 95% CI 1.51–3.96; 2.6, 95% CI 1.41–4.61, respectively). Those with high PTSD scores had 7.7-fold (95% CI 4.3–13.17) increased likelihood of reporting that their coping was affected, compared to low-PTSD scorers. Few adopted social distancing (4%), staying at home (17%), or ceasing usual activities (32%); high-combat veterans were least likely to stay home. Veterans who practiced handwashing, sanitizer use, mask-wearing, and surface disinfection had significantly higher PTSD scores than those who did not. Veterans with higher scores on the LOSS-SF scale associated more reengagement with trauma memories and were more likely to engage in personal preventive strategies. Analysis of open-ended responses supported these findings. We conclude that fifty years after returning from Vietnam, PTSD ...

Experiences of women who served during the Vietnam War have been described in interviews/anecdotal reports but rarely in empirical literature. Potential positive (versus negative) aspects of service or its impact on well-being are seldom considered. We describe stressful and positive experiences reported by approximately 1,300 female military personnel, Red Cross workers, and others deployed to Vietnam. Prominent stressful (e.g., negative living/working conditions) and positive (e.g., interpersonal relationships) themes and differences based on trauma history, Vietnam experiences, and group membership are explored. We evaluate associations between themes and psychological well-being. Findings provide insight into experiences of this understudied group of women.

Between 1961 and 1971, U.S. military forces dispersed more than 19 million gallons of phenoxy and other herbicidal agents in the Republic of Vietnam, including more than 12 million gallons of dioxin-contaminated Agent Orange, yet only comparatively limited epidemiologic and environmental research has been carried out on the distribution and health effects of this contamination. As part of a response to a National Academy of Sciences' request for development of exposure methodologies for carrying out epidemiologic research, a conceptual framework for estimating exposure opportunity to herbicides and a geographic information system (GIS) have been developed. The GIS is based on a relational database system that integrates extensive data resources on dispersal of herbicides (e.g., HERBS records of Ranch Hand aircraft flight paths, gallonage, and chemical agent), locations of military units and bases, dynamic movement of combat troops in Vietnam, and locations of civilian population centers. The GIS can provide a variety of proximity counts for exposure to 9,141 herbicide application missions. In addition, the GIS can be used to generate a quantitative exposure opportunity index that accounts for quantity of herbicide sprayed, distance, and environmental decay of a toxic factor such as dioxin, and is flexible enough to permit substitution of other mathematical exposure models by the user. The GIS thus provides a basis for estimation of herbicide exposure for use in large-scale epidemiologic studies. To facilitate widespread use of the GIS, a user-friendly software package was developed to permit researchers to assign exposure opportunity indexes to troops, locations, or individuals.