Erich W. Bretthauer, Chairman of the Exposure and Hazard Assessment Working Group U. s. Environmental Protection Agency Washington, D. C. The efforts of the Exposure and Hazard Assessment Working Group were focused on the exchange of information on a variety of topics including research projects, regulations/statutes, analytical laboratories, and methods of exposure/risk assessment involving CDDs and CDFs. It was evident to the leaders of the Working Group that several of the knowledge voids had to be addressed on a fundamental level before expanded efforts could be made. Several questions needed to be answered: • Who has done research on this topic, and what do the data indicate? • Who is performing research now, and what are their capabilities? • How are other nations addressing this problem, and do they have legislative mandates in place? • Is there a general consensus on the topic? The members of the Working Group believed that these questions could be answered by surveying the major participants in the field of interest. Three principal survey efforts were performed by the Working Group, which collected information on research, regulations/statutes, and analytical laboratories from each of the participating nations. In addition to answering these fundamental questions, these efforts also fulfilled the major objectives of the entire Pilot Study. The collection, analysis, and distribution of information on research projects, regulations/statutes, and analytical laboratories were very useful efforts in helping to fill some of the basic knowledge voids.

This book originated in a series of cross-disciplinary conversations in the years 1984-1990 between the editor, who is a physician-researcher involved in clinical and laboratory research, and a dioxin toxicologist. During the years in which the conversations took place, an extraordinary amount of new scientific literature was published related to dioxins, defined for purposes of this text as the chlorinated dibenzo-p-dioxins, dibenzofurans, polychlorinated biphe nyls (PCB's) and other compounds that are structurally and toxicologically similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7 ,8-TCDD), the most extensively studied and most toxic of this group of chemicals. Dioxins also began to interest not only chemists and toxicologists, but also specialists from diverse disciplines such as wildlife and environmental science, immunology, neuroscience,public health, epidemiology, med icine, government, law, sociology, and journalism. Specialists from such varied disciplines, while familiar with their own literature, frequently did not have time to follow the dioxin literature outside their specialty area. In addition, each specialty had unique knowledge, methods, and perspectives. Cross disciplinary conversation was necessary, but all too frequently, specialists from the various disciplines did not speak the same language, resulting in misunderstanding.

From 1972 to 1982, approximately 1,500-2,100 US Air Force Reserve personnel trained and worked on C-123 aircraft that had formerly been used to spray herbicides in Vietnam as part of Operation Ranch Hand. After becoming aware that some of the aircraft on which they had worked had previously served this purpose, some of these AF Reservists applied to the US Department of Veterans Affairs (VA) for compensatory coverage under the Agent Orange Act of 1991. The Act provides health care and disability coverage for health conditions that have been deemed presumptively service-related for herbicide exposure during the Vietnam War. The VA denied the applications on the basis that these veterans were ineligible because as non-Vietnam-era veterans or as Vietnam-era veterans without "boots on the ground" service in Vietnam, they were not covered. However, with the knowledge that some air and wipe samples taken between 1979 and 2009 from some of the C-123s used in Operation Ranch Hand showed the presence of agent orange residues, representatives of the C-123 Veterans Association began a concerted effort to reverse VA's position and obtain coverage. At the request of the VA, Post-Vietnam Dioxin Exposure in Agent Orange-Contaminated C-123 Aircraft evaluates whether or not service in these C-123s could have plausibly resulted in exposures detrimental to the health of these Air Force Reservists. The Institute of Medicine assembled an expert committee to address this question qualitatively, but in a scientific and evidence-based fashion. This report evaluates the reliability of the available information for establishing exposure and addresses and places in context whether any documented residues represent potentially harmful exposure by characterizing the amounts available and the degree to which absorption might be expected. Post-Vietnam Dioxin Exposure rejects the idea that the dioxin residues detected on interior surfaces of the C-123s were immobile and effectively inaccessible to the Reservists as a source of exposure. Accordingly, this report states with confidence that the Air Force Reservists were exposed when working in the Operation Ranch Hand C-123s and so experienced some increase in their risk of a variety of adverse responses.

For almost four decades, controversy has surrounded the tactical use of herbicides in Southeast Asia by the United States military. Few environmental or occupational health issues have received the sustained international attention that has been focused on Agent Orange, the major tactical herbicide deployed in Southern Vietnam. With the opening and establishment of normal relations between the United States and the Socialist Republic of Vietnam in 1995, the time has come for a thorough re-examination of the military use of Agent Orange and other "tactical herbicides" in Southern Vietnam, and the subsequent actions that have been taking place since their use in Vietnam. The United States Department of Defense has had the major role in all military operations involving the use of tactical herbicides, including that of Agent Orange. This included the Department's purchase, shipment and tactical use of herbicides in Vietnam, its role in the disposition of Agent Orange after Vietnam, its role in conducting long-term epidemiological investigations of the men of Operation RANCH HAND, and its sponsorship of ecological and environmental fate studies. This book was commissioned by The Office of the Deputy Under Secretary of Defense (Installations and Environment) with the intent of providing documentation of the knowledge on the history, use, disposition and environmental fate of Agent Orange and its associated dioxin.

Have U.S. military personnel experienced health problems from being exposed to Agent Orange, its dioxin contaminants, and other herbicides used in Vietnam? This definitive volume summarizes the strength of the evidence associating exposure during Vietnam service with cancer and other health effects and presents conclusions from an expert panel. Veterans and Agent Orange provides a historical review of the issue, examines studies of populations, in addition to Vietnam veterans, environmentally and occupationally exposed to herbicides and dioxin, and discusses problems in study methodology. The core of the book presents What is known about the toxicology of the herbicides used in greatest quantities in Vietnam. What is known about assessing exposure to herbicides and dioxin. What can be determined from the wide range of epidemiological studies conducted by different authorities. What is known about the relationship between exposure to herbicides and dioxin, and cancer, reproductive effects, neurobehavioral disorders, and other health effects. The book describes research areas of continuing concern and offers recommendations for further research on the health effects of Agent Orange exposure among Vietnam veterans. This volume will be critically important to both policymakers and physicians in the federal government, Vietnam veterans and their families, veterans organizations, researchers, and health professionals.

By 1971 analytical scientists at Dow had good reason to believe that questions about "dioxin" (2,3,7,8-dibenzo-p-dioxin) had been appropriately addressed. This molecule had been identified as an unwanted trace contaminant in 2,4,5-trichlorophenol and its derivatives; synthesized and analytical standards prepared; characterized by all the known measurement techniques; and controlled in Dow products by newly developed analytical methods of confirmed integrity at levels 10 times lower than deemed necessary by Dow toxicologists. Thus we had not only fulfilled all the requirements of government agencies, we had gone the extra mile. No other product contaminant had been treated so rigorously. There was no doubt that Dow products were safe when used as directed. Once again we had proven that molecules could be successfully managed. Although there was already some noise decrying this conclusion, we were totally unprepared to weather the brouhaha which developed. "Dioxin" appeared to be a molecule that created fear and caused people to do strange (unscientific) things. Was it more than just a molecule? We now turned our attention to measuring the amount of "dioxin" in the environment. We were well prepared to develop methodology to do this. We had state-of-the-art equipment and some of the best chromatographers and mass spectroscopists in the world. We were confident we could find and measure "dioxin" (if present) in any matrix of interest at appropriate detection levels. Then we could determine how the dioxin got there and discover ways to completely control and manage the presence and movement of this molecule in the environment. This was our perception! This perception was reinforced by the merger of Dow analytical laboratories. For the first time powerful measurement tools would be under the same management as the separation systems. This created many opportunities for spectroscopists, chromatographers and instrument development folks to do extraordinary things together. The resulting laboratory, consisting of almost 200 technical people, was managed by a technical director and a technical manager. I was named technical manager, a position without a job description. We were not, however, positioned to communicate effectively with the world outside Dow. Those of us working in trace analysis had neither published much nor attended many scientific meetings outside the company. We had not honed either our writing or speaking skills. So our papers were rejected and we were seldom heard speaking. This took some years to correct as we didn't immediately recognize that we needed to have credibility with our peers in academia, government and other industry. In spite of this naivety on my part, I soon found myself serving on committees, task forces and study groups both within Dow and with government agencies in the United States and Canada. Immediately it became apparent to me that the integrity of analytical data at trace levels was a major problem. Different laboratories used different principles in the interpretation of signals. Consensus on data interpretation needed to be reached. But of even greater importance was the need to communicate with journalists. Each encounter with peers and others interested in "dioxin" became a great adventure filled with fun. Often these meetings were humorous, always challenging, sometimes testy scientists from industry always were portrayed as biased and even incompetent. So, "dioxin" appeared to cause people to do strange things. By means of anecdotal stories and essays this book attempts to convey the principal scientific and philosophical lessons learned, as well as reveal the astonishing behavior of those contributing to the frustration, agony and elation experienced by this industrial analytical chemist. Among the surprising lessons learned are: 1. Fear can create big business. 2. In a "crisis" situation, even

Incineration has been used widely for waste disposal, including household, hazardous, and medical wasteâ€"but there is increasing public concern over the benefits of combusting the waste versus the health risk from pollutants emitted during combustion. Waste Incineration and Public Health informs the emerging debate with the most up-to-date information available on incineration, pollution, and human healthâ€"along with expert conclusions and recommendations for further research and improvement of such areas as risk communication. The committee provides details on: Processes involved in incineration and how contaminants are released. Environmental dynamics of contaminants and routes of human exposure. Tools and approaches for assessing possible human health effects. Scientific concerns pertinent to future regulatory actions. The book also examines some of the social, psychological, and economic factors that affect the communities where incineration takes place and addresses the problem of uncertainty and variation in predicting the health effects of incineration processes.