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Linking Science and Technology to Society's Environmental Goals Presentation Gilbert S. Omenn Dean, School of Public Health and Community Medicine, University of Washington RISK ASSESSMENT AND RISK MANAGEMENT: REPORT ON THE PRESIDENTIAL/CONGRESSIONAL RISK COMMISSION Thank you very much, Dr. Stever. It's a pleasure to be included in the program and to see many of you during your 10-day immersion in this important project. The notion of identifying and building an agenda for national science and technology goals for as crucial and large an area as the environment is ambitious. I gather your task is to envision what the goals should be 25 years from now, and to build the research and technology base to prepare for achieving that vision. Themes Certain themes are well developed in the papers that have been prepared for this meeting. First, sustainable development. I think there's still a task to explain this widely used phrase, but basically it's the convergence of economic and environmental objectives for the long-term. The second theme, not often highlighted in environmental circles, is the crucial role of population numbers and consumption patterns. Human activities account for most of the environmental problems we're trying to redress or anticipate, though we should not neglect natural disasters and the opportunities to anticipate and mitigate their effects. Third, we need a stewardship strategy that combines pollution prevention and aggressive cleanup. The most dramatic examples of lack of pollution prevention
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Linking Science and Technology to Society's Environmental Goals are the Department of Energy nuclear weapons production sites in this country and, even more so, the nasty situations in Eastern Europe and the former Soviet Union. Finally, we must somehow engage everyone, through the media and through our communities, to translate interest and support for protection of health and environment into core values and personal responsibility. At an international level, we need to draw the United States and all other countries together to share objectives, to achieve harmonization of test methods and risk assessment for chemicals and other hazards, to recognize ways in which environmental issues may be used or misused in trade negotiations under new trade agreements, and to bring the environment into the center of discussions about international relations and economic development. Risk is the coin of the realm in protecting health and the environment. Risk assessment, risk communication, and risk reduction strategies can help us determine priorities and help to persuade those who are paying, basically the taxpayers and consumers, that there is a decent return on our investment in risk management. We are stretching beyond the limits of science to discuss risk. So it is not surprising that scientists disagree on risk estimates or on what should be done, if anything, to reduce those risks. Nevertheless, the public finds such disagreement disconcerting, and the cartoonists mock us! In assessing health and ecological risks, we are stretching our knowledge of mechanisms and our capabilities below the range of exposures subject to the direct observations or experiments that are the domain of science. The extrapolation to low dose exposures reflects models, assumptions, speculation, and judgment. We need to explain better what is known and what is speculated. Objectives of Risk Assessment Risk assessment has been developed to address several different kinds of tasks. First, the laws covering pharmaceuticals and pesticides require that the responsible federal regulatory agencies (FDA and EPA) balance risks and benefits. Anticancer drugs, antimicrobial agents, and pesticides are designed to be toxic to living things. Balancing the benefits and risks depends on the margin of safety, patterns of use, and appropriate protections. Other laws, such as the Clean Air Act, do not explicitly authorize balancing benefits and risks. A second risk management strategy is to set target levels of risk, usually as federal guidance to the states. Devolution to the states will be an increasing theme over the next few years, probably for the 25-year period you are addressing. There will be more and more responsibility laid on states and localities, which will have to come together to deal with the fact that environmental pollution does not respect geographic or political boundaries. This strategy is used for food contaminants and water pollutants. Target levels
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Linking Science and Technology to Society's Environmental Goals are set, something that can be measured. If contaminant concentrations are above the target level, the food cannot be sold or the facilities discharging to water are out of compliance. If the contaminants are below the target level, the food or water is OK, "safe," presents negligible risk. Third, everybody has to set priorities in the face of limited resources. Regulatory agencies, environmental groups, consumer groups, and manufacturers must decide where to invest their efforts, people, and dollars, including their effort to explain to the public what they're up against in trying to prevent hazards or develop products. Finally, and most neglected, is the use of risk assessment to determine what we've accomplished. One source of skepticism about risk assessment and about our whole program of environmental stewardship and cleanup is that many people really don't understand how much has been accomplished in the last 25 years, despite well-documented gains in air quality, water quality, habitat protection, product safety, waste disposal, recycling, and pollution prevention. We should put ourselves to the test of predicting what can be done to reduce effects, or at least exposures, and then determine whether the steps that were taken, the investments that were made, really did accomplish those reductions. For regulatory decision-making, it is essential to have a guiding framework for risk management. We have such a framework for risk assessment, developed in the Carter Administration (Figure 1) and adapted in "The Red Book," the 1983 National Research Council report Risk Assessment in the Federal Government: Managing the Process (NRC 1983) (Figure 2). The first step is to determine whether a particular activity, chemical, microorganism, or radiation exposure could be hazardous to health or to the environment (Figure 1). FIGURE 1 Framework for regulatory decision-making.
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Linking Science and Technology to Society's Environmental Goals FIGURE 2
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Linking Science and Technology to Society's Environmental Goals Whether there's a risk depends on there being an exposure, on potency of the chemical, and on individual variation in susceptibility due to genetics, nutrition, coexisting exposures, and protective actions. The characterization of risk in qualitative and quantitative terms serves as input to decisions and strategies for risk reduction. This framework can be applied quite generally. In fact, people use such thinking intuitively in their daily lives and in making judgments about any public policy of interest to them. As I will tell you in a few moments, in the context of the Risk Commission, many people are uncomfortable with the term "risk." Probabilistic expressions and estimates of risk come out of science, engineering, and mathematical modeling; there is a perception that risk and risk analysis can be easily manipulated and is dominated by experts who see the world differently from ordinary people. We must take account of that discomfort and distrust if we hope to use these constructs broadly with all stakeholders. The Presidential-Congressional Commission on Risk Assessment and Risk Management I was asked to speak specifically about the Risk Commission. Table 1 lists the membership, all political appointees; six appointed by the Congress; three appointed by the Administration; the 10th member, Bernie Goldstein, appointed by the Academy. It's a group with considerable scientific expertise; some of these people are well known to many of you. This Commission is the second part of a two-part mandate from the 1990 Clean Air Act Amendments, which first instructed EPA to fund a study at the National Academy of Sciences, in which Debbie Stine was a key staff person, on Science and Judgment in Risk Assessment (NRC 1994a). Table 1 Presidential-Congressional Commission on Risk Assessment and Risk Management Membership PETER Y. CHIU, MD, Kaiser Permanente, San Francisco ALAN C. KESSLER, LLB, Buchanan Ingersoll, Philadelphia SHEILA MCGUIRE, Ph.D., Iowa Health Research Inc, Boone, Iowa NORMAN ANDERSON, American Lung Association, Augusta, Maine DAVID P. RALL, MD, Ph.D., former director, NIEHS; Washington D.C. JOHN DOULL, Ph.D., Toxicologist, Kansas University, Kansas City, Kansas JOSHUA LEDERBERG, Ph.D., former president, Rockefeller University, New York City GILBERT OMENN, MD, Ph.D., dean, University of Washington SPH, Seattle VIRGINIA V. WELDON, Ph.D., vice president, Monsanto Company, St. Louis, Missouri BERNARD GOLDSTEIN, MD, University of Medicine and Dentistry, Robert Wood Johnson Medical School, Piscataway, N.J. Staff: Gail Charnley, Ph.D.; Sharon Newsome; Joanna Foellmer
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Linking Science and Technology to Society's Environmental Goals Table 2 Mandate • Uses and limitations of risk assessment in decision-making • Appropriate exposure scenarios • Uncertainty and risk communication • Risk management policy issues • Consistency across agencies The title conveys the main theme, "science and judgment." That report is important input for our Commission. Our mandate has five components (Table 2). I want to talk about each of these briefly and see if it stimulates discussion. First, the uses and limitations of risk assessment. I broadly hinted at one of the basic problems, that there are people in our society and well-organized groups who are skeptical about the intentions of risk assessment, who do not see risk assessment as a neutral framing mechanism, but as a tool of people who are expert in its use and employed by those who want to have risk assessments done. We must address that distrust and discomfort, and persuade folks that this is an approach to problem-solving that can be utilized by all. The limitations are actually embedded in the science. Too much of what we've done in risk assessment, in my opinion and in the emerging opinion of the Commission as we prepare for recommendations to Congress next spring, has been focused on individual chemicals, one chemical at a time. Lay people do not associate exposures with one chemical at a time. They know that we have many, many exposures in our daily lives. There are hundreds of measured chemicals in contaminated water and contaminated air; there are thousands of chemicals, most of them already known to be carcinogenic, in cigarette smoke. So the fact that we talk about only one chemical at a time and present an elaborate risk assessment for one chemical stretches our credibility. We must find ways of thinking about mixtures and testing the effects of mixtures. In risk reduction we must indicate how much impact our actions could have in the broader contexts of all sources of air pollution or cancer rates or habitat protection. The second limitation is that there has been an obsession with risk associated with chemicals, particularly from industrial and agricultural activities. For the most part, people have come to neglect the risks associated with microorganisms. But people in Milwaukee were reminded when an outbreak of cryptosporidiosis affected 400,000 people in 1993. In Seattle, and in several other cities and states, there was an outbreak of toxigenic E. coli with deaths of children and dozens of children now on long-term kidney dialysis as a result. Medical and industrial uses and, more dramatically, the Department of Energy nuclear weapons production sites remind us that we must think about mixtures of radiation and chemical exposures and understand the similarities and differences in their effects, their mechanisms, and their dose-response curves and take some lessons from one into the
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Linking Science and Technology to Society's Environmental Goals other field. For example, it's always surprised me that, while it is routine to do dose fractionation studies in radiobiology and in medical radiotherapy, we tend to ignore the rate of exposure in chemical toxicology and just average over a year or an eight-hour working period. Sometimes we have short-term exposure limits, but for the most part, we just average exposures, as if that covered the situation. Those limitations in our science base limit the use of risk assessment as an analytical tool because the data are not there to address questions that state and local health officers and lay people logically expect us to address. The second mandate involves exposure scenarios. Exposure assessment is the element of risk assessment that has been ridiculed the most—and for good reason. It became standard practice at EPA and in other agencies to postulate that the exposure of an individual or of a population could be characterized in a precautionary way by a ''most-exposed individual," a hypothetical person with her or his nose in the fence line for 70 years breathing at a maximal breathing rate, with maximal assumptions compounded. To its credit, the EPA has moved away from this method in recent risk assessments toward a high-end, real-life individual or some subgroup of the upper end of the distribution. This is a promising development. Another aspect of exposure assessment is recognition of different population groups. There's been quite a lot of attention lately, including an NRC report on Pesticides in the Diets of Infants and Children (NRC 1993) and environmental group advocacy, around the special protections required for infants and children, who have much smaller body mass and may have special dietary intakes, as in the case of fruit drinks and baby foods with pesticide residues. We need to pay more attention to special exposures, differences in metabolism, and differences with age. We need to make them real and understandable to people who are the decision-makers and ultimately to the public trying to understand what the exposure scenarios are and which populations most need to be protected. Third, one of the best pieces of the NRC report Science and Judgment in Risk Assessment, in my opinion, was the distinction between variability and uncertainty. There is much variability in human populations, due to inherited differences in metabolism or in susceptibility at the site of action, nutrition, other exposures, effects of age early in life and late in life, coexisting diseases, and personal behaviors. All of that can be investigated and characterized. But some aspects are not observable and rest on assumptions and models. This problem plagues the standard extrapolation from observable ranges, for example, with tumors in 10 to 100 percent of animals exposed, to try to make a judgment that the risk is less than one in a million for lifetime excess human cancer risk in a upper-bound, worst-case scenario. That enormous extrapolation of at least a factor of 100,000 covers uncertainty that cannot be addressed by real data. Modelers are undeterred, of course. Monte Carlo simulations and other methods are de rigueur in federal and state regulatory agencies, even at the state level, and in environmental consulting firms.
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Linking Science and Technology to Society's Environmental Goals I think the Risk Commission is going to come out with a two-pronged recommendation here. We are quite keen to see probability distributions utilized for exposure parameters where you actually have data on adherence of chemicals to soils and release rates, on distribution of body weight in the population, on distribution of consumption of tap water or soil by children, and so forth. Exposure estimates can use real data, and the distributions can actually be validated for a particular site, if it's a site-specific problem. We are not comfortable with probabilistic uncertainty analysis for the overall risk assessment or for the health effects when we don't even know whether the chemical can be properly classified as an agent causing cancer or birth defects, or not. We have been told over and over by non-technical specialists that decision-makers don't want all that stuff. Qualitative judgments and full descriptions of the reasons for uncertainty are most welcome, however. What they really want from the technicians, the risk assessors, is guidance. Is it a problem or is it not a problem? I'm a busy person, I've got a full plate; is this something that requires my attention or not? That is not well captured with probability distributions and Monte Carlo simulations. There's a great risk that those folks just glaze over, walk away, and distrust all the risk assessment information. We are aware that there's quite a debate about what can be called "bright lines," the notion that if you're above a certain value it's a problem, if you're below a certain value it's not a problem. Of course, there are enormous assumptions that go into a bright line. You may set, say, 10-' upper bound for lifetime cancer excess risk as the cut point for what's acceptable or not. Maybe, it should be 10-', one in 100,000. That bright line was adopted by the State of California and accepted by industry and the environmentalists in California for labeling of chemicals under Proposition 65. That compromise between 10-' preferred by industry and 10-6 preferred by environmentalists was crucial to the smooth work on Proposition 65 after all the strife at the beginning (Roe and Omenn 1995). But let's be clear; there are numerous assumptions that go into that risk calculation, reflecting different future use scenarios, particularly. The Commission would like to encourage technical work to support choices of bright lines for exposures and emissions. As I have emphasized, risk cannot be measured, but exposure levels can be measured. We do this now for water pollutants and for food contaminants. We say you can sell peanuts and corn with aflatoxin B1 below a particular measured level, but not above. In this way, risk assessors and risk managers help bridge the gap between the people who want to have a practical basis for making a decision and taking action and explaining it and those who would like to deal with all the risk-related assumptions and details fresh every time. The fourth area of the Commission's mandate is a set of risk management issues for risk reduction. The biggest items here have to do with economic analyses and comparisons of risks. It's no secret that the regulatory reform agenda in the Congress is heavily tied to the notion of benefit-cost analysis. It is shocking to
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Linking Science and Technology to Society's Environmental Goals us that those bills go on at length about the assumptions and uncertainties that must be described in detail for risk assessment, but assume the estimates of costs and of monetized benefits would be highly reliable, not requiring attention to assumptions, uncertainties, and peer review! We're amazed that numbers like the gross domestic product or the census or the unemployment rate are published with no uncertainty comment. We know there's plenty of uncertainty in those numbers. They are estimates. They are commonly revised, as you know . Maybe others would like to address this matter. We have strongly urged the Congress to encourage cost-effectiveness analysis. We believe that costs should be considered and should be evaluated in making decisions about health and environmental protection. The last five Presidents, including the present President, have demanded that of their agency heads through executive order. Once the objective is determined to reduce exposures to certain levels to protect against cancers, birth defects, neurotoxicity, or immunological effects, or to protect habitat or achieve otehr environmental objects, it should be clear that we want to do so in the least costly manner. It should not be a burden to an agency head to stand before the public and explain that the benefits expected to be achieved through these regulatory actions justify the costs, by whatever metric that person feels capable of marshaling to build public support for the decision. Finally, we were mandated to address consistency across federal agencies. It is a bone of contention with numerous parties that agencies, including programs within EPA, seem to take different approaches with similar data. Sometimes that's required by current statutes, or by the current interpretations of those statutes, at least. Other times, it's lack of coordination, lack of a common strategy, a failure to share data, or failure to compromise on assumptions like body weight extrapolation from rodents to humans. We believe there are many ways to improve consistency. This matter was of great interest to the Carnegie Commission Task Force on Regulatory and judicial decision-making. There's quite a lot of work internationally on harmonization, testing protocols, risk assessment strategies, and standards. We expect harmonization to be increasingly important with globalization of trade and impacts of the World Trade Organization, NAFTA, and GATT. In fact, there's a cartoon character called GATTzilla, depicting the role of trade agreements on the environmental discussions. Observations About Public Health and Environment I was asked to make some comments about the relevant fields of public health sciences, especially epidemiology, biostatistics, and environmental health. Epidemiology is the core field of public health, investigating factors that cause or prevent diseases, deaths, injuries, or poor health. Epidemiology is undergoing a dramatic transformation with much more interest about underlying biological
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Linking Science and Technology to Society's Environmental Goals TABLE 3 Characteristics of ATSDR Health Assessments and EPA Risk Assessments ATSDR Public Health Assessment • Qualitative, site specific; uses environmental contamination, health outcomes, and community health concerns data • Medical and public health perspective are weighted to assess health hazards • Used to evaluate human health impacts and to identify public health interventions • Is advisory • May lead to pilot health effects studies, surveillance, epidemiologic studies, or exposure registry EPA Risk Assessment • Quantitative, compound oriented, not site specific • Statistical and/or biologic models of dose-response and of exposure are used to calculate numerical of health risk • Used to facilitate remediations or other risk management actions • Bears regulatory weight • May lead to selection of particular remediation measures at a site mechanisms and many more tools to relate animal studies to human studies. Biomarkers and mechanisms should be exciting scientific connections between ecology and human health. Biostatistics is crucial to the design of studies and evaluation of data. Environmental health covers biological, chemical, and physical hazards; investigations of mechanisms; and assessments of to risks, exposures, and ways to reduce exposures. Engineering plays a big role her, as do behavioral interventions. I started off by saying that one of the problems with risk assessment it is tends to be chemical specific. Table 3 shows a contrast between EPA risk assessment and health assessment as normally practiced by local health departments, state health departments, and the Agency for Toxic Substances and Disease Registry, part of the U.S. Public Health Service, around Superfund sites or other places of possible contamination and exposure for local populations. From a health point of view, people want to know more about what should be done. Qualitatively, is it a problem? Do I have to drink water from special bottled sources? Do we have to evacuate people? Do we have to take other kinds of precautions, or not? It relates to the site as a whole and not to particular individual chemicals. Medical and public health perspectives are weighted and put in context. The response tends to be advisory. It doesn't bear the weight of regulation, although state and local health officers may have plenty of regulatory authority, as for quarantine. The health assessment may lead to further studies, whereas the risk assessment is intended to lead to remediation proposals at the sites. One of the more interesting papers in recent years is one by Michael
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Linking Science and Technology to Society's Environmental Goals McGinnis, just stepping down as long-time head of the Office for Disease Prevention and Health Promotion in the Department of Health and Human Services, and Bill Foege, former head of the Centers for Disease Control (McGinnis and Foege 1993). This paper included Table 4, which shows the official 10 leading medical causes of death in the United States in 1990 and the lifestyles leading to half of these, 2.1 million deaths per year. As shown here, heart disease and cancers still account for a majority of all the deaths. But when you ask what are the "real causes" of death (i.e., the lifestyles leading to these deaths), we get some guidance for public health attention. There's no question that the leading cause, by far, is tobacco. It's interesting that there's a whole new struggle developing between the President and FDA and the Congress over what, if anything, will be done to try to deal with the scourge of cigarette smoking in our country and increasingly around the world. The second is a big number, but a lot less certain: diet and especially sedentary life-style contribute mightily to mortality rates in this country. Then comes alcohol. In fact, it's easy to say, in Johnny Carson's style, that the four "biggies" are cigarettes, alcohol and drugs, vehicles, and guns. Ask yourself if any of those TABLE 4 The 10 Leading Medical Causes of Death… Heart disease 720,000 Cancer 505,000 Cerebrovascular disease 144,000 Accidents 92,000 Chronic pulmonary disease 87,000 Pneumonia and influenza 80,000 Diabetes 48,000 Suicide 31,000 Liver disease, cirrhosis 26,000 AIDS 25,000 …and Lifestyle Factors Leading to Half of Them Tobacco 400,000 Diet, sedentary life-style 300,000 Alcohol 100,000 Infections 90,000 Toxic agents 60,000 Firearms 35,000 Sexual behavior 30,000 Motor vehicles 25,000 Illicit drug use 20,000 Total 1,060,000 The nation's investment in prevention is estimated less than 5 percent of the total annual health care cost.
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Linking Science and Technology to Society's Environmental Goals are on the list of priority risks for this meeting or if any of those are regulated significantly by the EPA or other regulatory agencies or your state agencies. There are political reasons why they have been excluded, but we should have some perspective on what the major causes of death and disability really are in this country. Toxic agents come in right in the middle of the list. Sixty thousand deaths, roughly estimated, is not an insignificant number. This estimate is fairly well justified in the original article and by many background articles, and it is certainly worthy of extensive reduction. Before closing, let me mention one other item, the cleanup at DOE facilities, the legacy of 50 years of accumulation, decomposition, and migration of radioactive and chemical contamination. The polling paper in your meeting book describes how technology has been at the core of many human activities that have led to pollutants and contamination, as well as population growth and its attendant problems. At the same time, people have a great faith that technology can provide a fix to any problem. After crucial technical advances that helped our Nation prevail in World War II and now in the Cold War, we are left with a task that will take at least 50 years for the cleanup. The estimated price tag of $250 billion, in 1990 dollars, represents promissory notes against the precious discretionary funds of the U.S. government, surely a source of tremendous future state and federal confrontation. The Department of Energy has responded to the need for effective and continuing stakeholder involvement. There is considerable uncertainty about the technical assessments and priorities upon which those cleanup plans and associated promissory notes were built, and there has been a congressional demand for risk-based, integrated assessment of the present risks and the risks and cost-effectiveness of remediation options. The recommendations of the National Research Council report called Building Consensus (NRC 1994b), turned out in 60 days from the time DOE Assistant Secretary Tom Grumbly made the request to the Academy at a meeting in November 1993, are very compatible with how our Risk Commission feels about stakeholder involvement in comprehensive, iterative risk assessments. The word "iterative" has a lot of baggage. Science and Judgment in Risk Assessment suggested a very conservative first analysis, a screening analysis to be followed by a more substantial analysis. Our Commission is anxious about that recommendation, because we believe all this work should be done in the open, disclosed to the public, involving the public. Once a very high risk estimate is generated under extremely conservative assumptions, we believe it is impossible to retain the public's confidence when a more careful assessment with more data is reported to justify a much lower risk estimate. It is very hard, we feel, to overcome the sense that somebody influential had a vested interest in reducing that risk estimate. At the complex DOE sites, an iterative process as things are done and more is
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Linking Science and Technology to Society's Environmental Goals learned is very appropriate. Risk assessment(s) should compare potential outcomes and cost-effectiveness. Building Consensus recommended that risk assessments should involve the public, evaluate the risks of remediation, and involve an external organization. My colleagues and I have organized that new external entity, the Consortium for Risk Evaluation with Stakeholder Participation (CRESP). We are paying attention to potential grief to workers, ecosystems, and public health from the cleanup efforts themselves. Finally, as we look 25 years ahead, we don't want to be in the position that we have picked up the problems, but not found the solutions. As a cartoonist put it, a driver of a tank truck is telling his hitchhiker, "Didn't you know, we just drive around. This is a mobile toxic waste dump!" I look forward to comments from the panel and from all participants. My best wishes with your work. References Calkins D.R., R.L Dixon, C.R. Gerber, et al. "Identification, characterization, and control of potential human carcinogens: A framework for federal decision-making." JNCI 61:169–175 (1980). McGinnis J.M., W.H. Foege. "Actual causes of death in the United States," Journal of the American Medical Association 270:2207–2212 (1993). NRC (National Research Council), Risk Assessment in the Federal Government: Managing the Process (Washington, D.C.: National Academy Press, 1983). NRC (National Research Council), Pesticides in the Diets of Infants and Children (Washington D.C.: National Academy Press, 1993). NRC (National Research Council), Science and Judgment in Risk Assessment (Washington D.C.: National Academy Press, 1994a) NRC (National Research Council), Building Consensus Through Risk Assessment and Management of the Department of Energy's Environmental Remediation Program (Washington, D.C.: National Academy Press, 1994b). Omenn G.S., "Can Systematic, Integrated Risk Assessment with Full Stakeholder Participation Enhance Cleanup at DOE's Sites?" in (G.W. Gee and R. Wing, editors) The 1994 Herbert H. Parker Lecture presented at the Thirty-Third Hanford Symposium on Health and the Environment In-situ Remediation: Scientific Basis for Current and Future Technologies (Battelle Press, 1994, Part I). p. xv-xxx Roe D., and G.S. Omenn, "California Has Successful Model of Regulatory Risk Assessment," (Oped), Seattle Post-Intelligencer p. A9 (July 25, 1995).
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