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Summary Virtually every aspect of life involves risk. How we deal with risk depends largely on how well we understand it. The process of risk assessment has been used to help us understand and address a wide variety of hazards and has been instrumental to the U.S. Environmental Protection Agency (EPA), other federal and state agencies, industry, the academic community, and others in evaluating public-health and environmental concerns. From protecting air and water to ensuring the safety of food, drugs, and consumer products such as toys, risk assess- ment is an important public-policy tool for informing regulatory and technologic decisions, setting priorities among research needs, and developing approaches for considering the costs and benefits of regulatory policies. Risk assessment, however, is at a crossroads, and its credibility is being challenged (Sil- bergeld 1993; Montague 2004; Michaels 2008). Because it provides a primary scientific rationale for informing regulations that will have national and global impact, risk assessment is subject to considerable scientific, political, and public scrutiny. The science of risk assess- ment is increasingly complex; improved analytic techniques have produced more data that lead to questions about how to address issues of, for example, multiple chemical exposures, multiple risks, and susceptibility in populations. In addition, risk assessment is now being extended to address broader environmental questions, such as life-cycle analysis and issues of costs, benefits, and risk-risk tradeoffs. The regulatory risk assessment process is bogged down; major risk assessments for some chemicals take more than 10 years. In the case of trichloroethylene, which has been linked to cancer, the assessment has been under development since the 1980s, has undergone multiple independent reviews, and is not expected to be final until 2010. Assessments of formalde- hyde and dioxin have had similar timelines. EPA is struggling to keep up with demands for â ilbergeld, E.K. 1993. Risk assessment: The perspective and experience of U.S. environmentalists. Environ. S Health Perspect. 101(2):100-104; Montague, P. 2004. Reducing the harms associated with risk assessment. Environ. Impact Assess. Rev. 24:733-748; Michaels, D. 2008. Doubt Is Their Product: How Industryâs Assault on Science Threatens Your Health. New York: Oxford University Press.
SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT hazard and dose-response information but is challenged by a lack of resources, including funding and trained staff. Decision-making based on risk assessment is also bogged down. Uncertainty, an inherent property of scientific data, continues to lead to multiple interpretations and contribute to decision-making gridlock. Stakeholdersâincluding community groups, environmental orga- nizations, industry, and consumersâare often disengaged from the risk-assessment process at a time when risk assessment is increasingly intertwined with societal concerns. Disconnects between the available scientific data and the information needs of decision-makers hinder the use of risk assessment as a decision-making tool. Emerging scientific advances hold great promise for improving risk assessment. For example, new toxicity-testing methods are being developed that will probably be quicker, less expensive, and more directly relevant to human exposures, as described in the National Research Councilâs Toxicity Testing in the 21st Century: A Vision and a Strategy (2007). However, the realization of the promise is at least a decade away. To address current challenges, EPA asked the National Research Council to perform an independent study on improving risk-analysis approaches, one of a number of studies by the National Research Council that have examined risk assessment in EPA. Specifically, the committee selected by the National Research Council was charged to identify practical im- provements that EPA could make in the near term (2-5 years) and in the longer term (10-20 years). The committee focused primarily on human health risk assessment but also considered the implications of its conclusions and recommendations for ecologic risk assessment. The committee conducted its data gathering for this study between fall 2006 and winter 2008, so materials published after this were not considered in the committeeâs evaluation. COMMITTEEâS EVALUATION The committee focused on two broad elements in its evaluation: (1) improving the tech- nical analysis that supports risk assessment (addressed in Chapters 4-7) and (2) improving the utility of risk assessment (addressed in Chapters 3 and 8). Improving technical analysis entails the development and use of scientific knowledge and information to promote more accurate characterizations of risk. Improving utility entails making risk assessment more relevant to and useful for risk-management decisions. Regarding improvement in technical analysis, the committee considered such issues as how to improve uncertainty and variability analysis and dose-response assessment to ensure the best use of scientific data, and it concluded that technical improvements are necessary. The committee concluded that EPAâs overall concept of risk assessment, which is generally based on the National Research Councilâs Risk Assessment in the Federal Government: Man- aging the Process (1983), also known as the Red Book, should be retained. The four steps of risk assessment (hazard identification, dose-response assessment, exposure assessment, and risk characterization) have been adopted by numerous expert committees, regulatory agencies, public-health institutions, and others. With respect to improving utility, the committee considered such issues as how risk- related problems are identified and formulated before the development of risk assessments and how a broad set of options might be considered to ensure that risk assessments are most relevant to the problems. CONCLUSIONS AND RECOMMENDATIONS A number of improvements are needed to streamline EPAâs risk-assessment process to ensure that risk assessments make better use of appropriate available science and are more
SUMMARY relevant to decision-making. Implementing improvements will require building on EPAâs current practices and developing a long-term strategy that includes greater coordination and communication within the agency, training and building a workforce with the requisite expertise, and a commitment by EPA, the executive branch, and Congress to implement the framework for risk-based decision-making recommended in this report and to fund the needed improvements. The committee recommends an important extension of the Red Book model to meet todayâs challenges betterâthat risk assessment should be viewed as a method for evaluating the relative merits of various options for managing risk rather than as an end in itself. Risk assessment should continue to capture and accurately describe what various research findings do and do not tell us about threats to human health and to the environment, but only after the risk-management questions that risk assessment should address have been clearly posed, through careful evaluation of the options available to manage the environmental problems at hand, similar to what is done in ecologic risk assessment. That alteration in the current approach to risk assessment has the potential to increase its influence on decisions because it requires greater up-front planning to ensure that it is relevant to the specific problems being addressed and that it will cast light on a wider range of decision options than has traditionally been the case. A second recommended shift in thinking is seen in the technical recommendations in this report that call for improvements in uncertainty and variability analysis and for a uni- fied approach to dose-response assessment that will result in risk estimates for both cancer and noncancer end points. Just as a risk assessment itself should be more closely tied to the questions to be answered, so should the technical analyses supporting it. For example, de- scriptions of the uncertainty and variability inherent in all risk assessments may be complex or relatively simple; the level of detail in the descriptions should align with what is needed to inform risk-management decisions. Similarly, the results of a dose-response assessment should be relevant to the problem being addressed, whether it is informing risk-risk tradeoffs or a cost-benefit analysis. Ensuring that the technical analyses supporting a risk assessment are supported by the science and are relevant to the problem being addressed will go a long way toward improving the value, timeliness, and credibility of the assessment. The committeeâs most important conclusions and recommendations are summarized below. The committee believes that implementation of its recommendations will do much to enhance the credibility and usefulness of risk assessment. Design of Risk Assessment The process of planning risk assessment and ensuring that its level and complexity are consistent with the needs to inform decision-making can be thought of as the âdesignâ of risk assessment. The committee encourages EPA to focus greater attention on design in the formative stages of risk assessment, specifically on planning and scoping and problem for- mulation, as articulated in EPA guidance for ecologic and cumulative risk assessment (EPA 1998, 2003). Good design involves bringing risk managers, risk assessors, and various stakeholders together early in the process to determine the major factors to be considered, âEPA (U.S. Environmental Protection Agency). 1998. Guidelines for Ecological Risk Assessment. EPA/630/R- 95/002F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environmen- tal Protection Agency). 2003. Framework for Cumulative Risk Assessment. EPA/600/P-02/001F. National Center for Environmental Assessment, Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT the decision-making context, and the timeline and depth needed to ensure that the right questions are being asked in the context of the assessment. Increased emphasis on planning and scoping and on problem formulation has been shown to lead to risk assessments that are more useful and better accepted by decision-mak- ers (EPA 2002, 2003, 2004); however, incorporation of these stages in risk assessment has been inconsistent, as noted by their absence from various EPA guidance documents (EPA 2005a,b). An important element of planning and scoping is definition of a clear set of op- tions for consideration in decision-making where appropriate. This should be reinforced by the up-front involvement of decision-makers, stakeholders, and risk assessors, who together can evaluate whether the design of the assessment will address the identified problems. Recommendation: Increased attention to the design of risk assessment in its formative stages is needed. The committee recommends that planning and scoping and problem formulation, as articulated in EPA guidance documents (EPA 1998, 2003),2 should be formalized and implemented in EPA risk assessments. Uncertainty and Variability Addressing uncertainty and variability is critical for the risk-assessment process. Un- certainty stems from lack of knowledge, so it can be characterized and managed but not eliminated. Uncertainty can be reduced by the use of more or better data. Variability is an inherent characteristic of a population, inasmuch as people vary substantially in their ex- posures and their susceptibility to potentially harmful effects of the exposures. Variability cannot be reduced, but it can be better characterized with improved information. There have been substantial differences among EPAâs approaches to and guidance for addressing uncertainty in exposure and dose-response assessment. EPA does not have a con- sistent approach to determine the level of sophistication or the extent of uncertainty analysis needed to address a particular problem. The level of detail for characterizing uncertainty is appropriate only to the extent that it is needed to inform specific risk-management deci- sions appropriately. It is important to address the required extent and nature of uncertainty analysis in the planning and scoping phases of a risk assessment. Inconsistency in the treat- ment of uncertainty among components of a risk assessment can make the communication of overall uncertainty difficult and sometimes misleading. Variability in human susceptibility has not received sufficient or consistent attention in many EPA health risk assessments although there are encouraging exceptions, such as those for lead, ozone, and sulfur oxides. For example, although EPAâs 2005 Guidelines for Car- cinogen Risk Assessment acknowledges that susceptibility can depend on oneâs stage in life, â PA (U.S. Environmental Protection Agency). 2002. A Review of the Reference Dose and Reference Concentra- E tion Processes. EPA/630/P-02/002F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environmental Protection Agency). 2003. Framework for Cumulative Risk Assessment. EPA/600/P- 02/001F. National Center for Environmental Assessment, Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environmental Protection Agency). 2004. Risk Assessment Principles and Practices. Staff Paper. EPA/100/B-04/001. Office of the Science Advisor, U.S. Environmental Protection Agency, Washington, DC. â PA (U.S. Environmental Protection Agency). 2005a. Guidelines for Carcinogen Risk Assessment. EPA/630/P- E 03/001F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environ- mental Protection Agency). 2005b. Supplemental Guidance for Assessing Susceptibility for Early-Life Exposures to Carcinogens. EPA/630/R-03/003F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
SUMMARY greater attention to susceptibility in practice is needed, particularly for specific population groups that may have greater susceptibility because of their age, ethnicity, or socioeconomic status. The committee encourages EPA to move toward the long-term goal of quantifying population variability more explicitly in exposure assessment and dose-response relation- ships. An example of progress that moves toward this goal is EPAâs draft risk assessment of trichloroethylene (EPA 2001; NRC 2006), which considers how differences in metabolism, disease, and other factors contribute to human variability in response to exposures. Recommendation: EPA should encourage risk assessments to characterize and commu- nicate uncertainty and variability in all key computational steps of risk assessmentâfor example, exposure assessment and dose-response assessment. Uncertainty and variability analysis should be planned and managed to reflect the needs for comparative evaluation of the risk management options. In the short term, EPA should adopt a âtieredâ approach for selecting the level of detail to be used in the uncertainty and variability assessments, and this should be made explicit in the planning stage. To facilitate the characterization and interpretation of uncertainty and variability in risk assessments, EPA should develop guidance to determine the appropriate level of detail needed in uncertainty and variability analyses to support decision-making and should provide clear definitions and methods for identifying and addressing different sources of uncertainty and variability. Selection and Use of Defaults Uncertainty is inherent in all stages of risk assessment, and EPA typically relies on as- sumptions when chemical-specific data are not available. The 1983 Red Book recommended the development of guidelines to justify and select from among the available inference op- tions, the assumptionsânow called defaultsâto be used in agency risk assessments to ensure consistency and avoid manipulations in the risk-assessment process. The committee acknowl- edges EPAâs efforts to examine scientific data related to defaults (EPA 1992, 2004, 2005a), but recognizes that changes are needed to improve the agencyâs use of them. Much of the scientific controversy and delay in completion of some risk assessments has stemmed from the long debates regarding the adequacy of the data to support a default or an alternative approach. The committee concludes that established defaults need to be maintained for the steps in risk assessment that require inferences and that clear criteria should be available for judging whether, in specific cases, data are adequate for direct use or to support an inference in place of a default. EPA, for the most part, has not yet published clear, general guidance on what level of evidence is needed to justify use of agent-specific data and not resort to a default. There are also a number of defaults (missing or implicit defaults) that are engrained in EPA risk-assessment practice but are absent from its risk-assessment guidelines. For ex- â PA E (U.S. Environmental Protection Agency). 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. External Review Draft. EPA/600/P-01/002A. Office of Research and Development, Washington, DC. August 2001 [online]. Available: http://rais.ornl.gov/tox/TCEAUG2001.PDF [accessed Aug. 2, 2008]; NRC (National Research Council). 2006. Assessing the Human Risks of Trichloroethylene. Washington, DC: The Na- tional Academies Press. â EPA (U.S. Environmental Protection Agency). 1992. Guidelines for Exposure Assessment. EPA/600/Z-92/001. Risk Assessment Forum, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environmental Protection Agency). 2004. Risk Assessment Principles and Practices. Staff Paper. EPA/100/B-04/001. Office of the Science Advisor, U.S. Environmental Protection Agency, Washington, DC; EPA (U.S. Environmental Protection Agency). 2005a. Guidelines for Carcinogen Risk Assessment. EPA/630/P-03/001F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT ample, chemicals that have not been examined sufficiently in epidemiologic or toxicologic studies are often insufficiently considered in or are even excluded from risk assessments; because no description of their risks is included in the risk characterization, they carry no weight in decision-making. That occurs in Superfund-site and other risk assessments, in which a relatively short list of chemicals on which there are epidemiologic and toxicologic data tends to drive the exposure and risk assessments. Recommendation: EPA should continue and expand use of the best, most current science to support and revise default assumptions. EPA should work toward the development of explicitly stated defaults to take the place of implicit defaults. EPA should develop clear, general standards for the level of evidence needed to justify the use of alternative assumptions in place of defaults. In addition, EPA should describe specific criteria that need to be addressed for the use of alternatives to each particular default assumption. When EPA elects to depart from a default assumption, it should quantify the implications of using an alternative assumption, including how use of the default and the selected alternative influences the risk estimate for risk management options under consideration. EPA needs to more clearly elucidate a policy on defaults and provide guidance on its implementation and on evaluation of its impact on risk decisions and on efforts to protect the environment and public health. A Unified Approach to Dose-Response Assessment A challenge to risk assessment is to evaluate risks in ways that are consistent among chemicals, that account adequately for variability and uncertainty, and that provide informa- tion that is timely, efficient, and maximally useful for risk characterization and risk manage- ment. Historically, dose-response assessments at EPA have been conducted differently for cancer and noncancer effects, and the methods have been criticized for not providing the most useful results. Consequently, noncancer effects have been underemphasized, especially in benefit-cost analyses. A consistent approach to risk assessment for cancer and noncancer effects is scientifically feasible and needs to be implemented. For cancer, it has generally been assumed that there is no dose threshold of effect, and dose-response assessments have focused on quantifying risk at low doses and estimating a population risk for a given magnitude of exposure. For noncancer effects, a dose threshold (low-dose nonlinearity) has been assumed, below which effects are not expected to occur or are extremely unlikely in an exposed population; that dose is a reference dose (RfD) or a reference concentration (RfC)âit is thought âlikely to be without an appreciable risk of deleterious effectsâ (EPA 2002). EPAâs treatment of noncancer and low-dose nonlinear cancer end points is a major step by the agency in an overall strategy to harmonize cancer and noncancer approaches to dose- response assessment; however, the committee finds scientific and operational limitations in the current approaches. Noncancer effects do not necessarily have a threshold, or low-dose nonlinearity, and the mode of action of carcinogens varies. Background exposures and under- lying disease processes contribute to population background risk and can lead to linearity at the population doses of concern. Because the RfD and RfC do not quantify risk for different magnitudes of exposure but rather provide a bright line between possible harm and safety, â EPA (U.S. Environmental Protection Agency). 2002. A Review of the Reference Dose and Reference Concentra- tion Processes. EPA/630/P-02/002F. Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
SUMMARY their use in risk-risk and risk-benefit comparisons and in risk-management decision-making is limited. Cancer risk assessments usually do not account for differences among humans in cancer susceptibility other than possible differences in early-life susceptibility. Scientific and risk-management considerations both support unification of cancer and noncancer dose-response assessment approaches. The committee therefore recommends a consistent, unified approach for dose-response modeling that includes formal, systematic assessment of background disease processes and exposures, possible vulnerable populations, and modes of action that may affect a chemicalâs dose-response relationship in humans. That approach redefines the RfD or RfC as a risk-specific dose that provides information on the percentage of the population that can be expected to be above or below a defined accept- able risk with a specific degree of confidence. The risk-specific dose will allow risk managers to weigh alternative risk options with respect to that percentage of the population. It will also permit a quantitative estimate of benefits for different risk-management options. For example, a risk manager could consider various population risks associated with exposures resulting from different control strategies for a pollution source and the benefits associated with each strategy. The committee acknowledges the widespread applications and public- health utility of the RfD; the redefined RfD can still be used as the RfD has been to aid risk-management decisions. Characteristics of the committeeâs recommended unified dose-response approach include use of a spectrum of data from human, animal, mechanistic, and other relevant studies; a probabilistic characterization of risk; explicit consideration of human heterogeneity (includ- ing age, sex, and health status) for both cancer and noncancer end points; characterization (through distributions to the extent possible) of the most important uncertainties for cancer and noncancer end points; evaluation of background exposure and susceptibility; use of probabilistic distributions instead of uncertainty factors when possible; and characterization of sensitive populations. The new unified approach will require implementation and development as new chemi- cals are assessed or old chemicals are reassessed, including the development of test cases to demonstrate proof of concept. Recommendation: The committee recommends that EPA implement a phased-in ap- proach to consider chemicals under a unified dose-response assessment framework that includes a systematic evaluation of background exposures and disease processes, possible vulnerable populations, and modes of action that may affect human dose-response rela- tionships. The RfD and RfC should be redefined to take into account the probability of harm. In developing test cases, the committee recommends a flexible approach in which different conceptual models can be applied in the unified approach. Cumulative Risk Assessment EPA is increasingly asked to address broader public-health and environmental-health questions involving multiple exposures, complex mixtures, and vulnerability of exposed populationsâissues that stakeholder groups (such as communities affected by environmental exposures) often consider to be inadequately captured by current risk assessments. There is a need for cumulative risk assessments as defined by EPA (EPA 2003)âassessments that â PA E (U.S. Environmental Protection Agency). 2003. Framework for Cumulative Risk Assessment. EPA/600/P- 02/001F. National Center for Environmental Assessment, Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
10 SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT include combined risks posed by aggregate exposure to multiple agents or stressors; aggre- gate exposure includes all routes, pathways, and sources of exposure to a given agent or stressor. Chemical, biologic, radiologic, physical, and psychologic stressors are considered in this definition (Callahan and Sexton 2007). The committee applauds the agencyâs move toward the broader definition in making risk assessment more informative and relevant to decisions and stakeholders. However, in practice, EPA risk assessments often fall short of what is possible and is supported by agency guidelines in this regard. Although cumulative risk assessment has been used in various con- texts, there has been little consideration of nonchemical stressors, vulnerability, and back- ground risk factors. Because of the complexity of considering so many factors simultaneously, there is a need for simplified risk-assessment tools (such as databases, software packages, and other modeling resources) that would allow screening-level risk assessments and could allow communities and stakeholders to conduct assessments and thus increase stakeholder participation. Cumulative human health risk assessment should draw greater insights from ecologic risk assessment and social epidemiology, which have had to grapple with similar issues. A recent National Research Council report on phthalates addresses issues related to the framework within which dose-response assessment can be conducted in the context of simultaneous exposures to multiple stressors. Recommendation: EPA should draw on other approaches, including those from ecologic risk assessment and social epidemiology, to incorporate interactions between chemical and nonchemical stressors in assessments; increase the role of biomonitoring, epide- miologic, and surveillance data in cumulative risk assessments; and develop guidelines and methods for simpler analytical tools to support cumulative risk assessment and to provide for greater involvement of stakeholders. In the short-term, EPA should develop databases and default approaches to allow for incorporation of key nonchemical stress- ors in cumulative risk assessments in the absence of population-specific data, considering exposure patterns, contributions to relevant background processes, and interactions with chemical stressors. In the long-term, EPA should invest in research programs related to interactions between chemical and nonchemical stressors, including epidemiologic investigations and physiologically based pharmacokinetic modeling. Improving the Utility of Risk Assessment Given the complexities of the current problems and potential decisions faced by EPA, the committee grappled with designing a more coherent, consistent, and transparent pro- cess that would provide risk assessments that are relevant to the problems and decisions at hand and that would be sufficiently comprehensive to ensure that the best available options for managing risks were considered. To that end, the committee proposes a framework for risk-based decision-making (see Figure S-1). The framework consists of three phases: I, enhanced problem formulation and scoping, in which the available risk-management op- tions are identified; II, planning and assessment, in which risk-assessment tools are used to determine risks under existing conditions and under potential risk-management options; and III, risk management, in which risk and nonrisk information is integrated to inform choices among options. The framework has at its core the risk-assessment paradigm (stage 2 of phase II) estab- â allahan, M.A., and K. Sexton. 2007. If âcumulative risk assessmentâ is the answer, what is the question? En- C viron. Health Perspect. 115(5):799-806.
PHASE I: PHASE II: PHASE III: PROBLEM FORMULATION PLANNING AND CONDUCT RISK MANAGEMENT AND SCOPING OF RISK ASSESSMENT Stage 1: Planning â¢ For the given decision context, what are the attributes of assessments necessary to characterize risks of existing conditions and the effects on risk of proposed options? What level of uncertainty and variability analysis is appropriate? â¢ What problems are â¢ What are the relative health or associated with existing environmental benefits of the environmental conditions? proposed options? Stage 2: Risk Assessment â¢ If existing conditions appear â¢ How are other decision- to pose a threat to human or â¢ Hazard Identification making factors (technologies, environmental health, what costs) affected by the proposed options exist for altering those What adverse health or environmental effects options? conditions? are associated with the agents of concern? â¢ What is the decision, and its â¢ Under the given decision â¢ Dose-Response Assessment â¢ Risk Characterization justification, in light of benefits, context, what risk and other costs, and uncertainties in each For each determining adverse effect, what is the What is the nature and technical assessments are option? relationship between dose and the probability of magnitude of risk associated necessary to evaluate the with existing conditions? the occurrence of the adverse effect in the range â¢ How should the decision be possible risk-management of doses identified in the exposure assessment? communicated? options? What risk decreases (benefits) are associated with each of the â¢ Is it necessary to evaluate the options? effectiveness of the decision? â¢ Exposure Assessment Are any risks increased? What â¢ If so, how should this be done? are the significant uncertainties? What exposures/doses are incurred by each population of interest under existing conditions? How does each option affect existing conditions and resulting exposures/doses? Stage 3: Confirmation of Utility NO â¢ Does the assessment have the attributes called for in planning? YES â¢ Does the assessment provide sufficient information to discriminate among risk- management options? â¢ Has the assessment been satisfactorily peer reviewed? FORMAL PROVISIONS FOR INTERNAL AND EXTERNAL STAKEHOLDER INVOLVEMENT AT ALL STAGES â¢ The involvement of decision-makers, technical specialists, and other stakeholders in all phases of the processes leading to decisions should in no way compromise the technical assessment of risk, which is carried out under its own standards and guidelines. FIGURE S-1 A framework for risk-based decision-making that maximizes the utility of risk assessment. 11 Figure S-1.eps landscape
12 SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT lished in the Red Book (NRC 1983).10 However, the framework differs from the Red Book paradigm, primarily in its initial and final steps. The framework begins with a âsignalâ of potential harm (for example, a positive bioassay or epidemiologic study, a suspicious disease cluster, or findings of industrial contamination). Under the traditional paradigm, the ques- tion has been, What are the probability and consequence of an adverse health (or ecologic) effect posed by the signal? In contrast, the recommended framework asks, implicitly, What options are there to reduce the hazards or exposures that have been identified, and how can risk assessment be used to evaluate the merits of the various options? The latter question focuses on the risk-management options (or interventions) designed to provide adequate public-health and environmental protection and to ensure well-supported decision-mak- ing. Under this framework, the questions posed arise from early and careful planning of the types of assessments (including risks, costs, and technical feasibility) and the required level of scientific depth that are needed to evaluate the relative merits of the options being considered.11 Risk management involves choosing among the options after the appropriate assessments have been undertaken and evaluated. The framework begins with enhanced problem formulation and scoping (phase I), in which risk-management options and the types of technical analyses, including risk assess- ments, needed to evaluate and discriminate among the options are identified. Phase II consists of three stages: planning, risk assessment, and confirmation of utility. Planning (stage 1) is done to ensure that the level and complexity of risk assessment (including uncertainty and variability analysis) are consistent with the goals of decision-making. After risk assessment (stage 2), stage 3 evaluates whether the assessment was appropriate and whether it allows discrimination among the risk-management options. If the assessment is determined not to be adequate, the framework calls for a return to planning (phase II, stage 1). Otherwise, phase III (risk management) is undertaken: the relative health or environmental benefits of the proposed risk-management options are evaluated for the purpose of reaching a decision. The framework systematically identifies problems and options that risk assessors should evaluate at the earliest stages of decision-making. It expands the array of impacts assessed beyond individual effects (for example, cancer, respiratory problems, and individual species) to include broader questions of health status and ecosystem protection. It provides a formal process for stakeholder involvement throughout all stages but has time constraints to en- sure that decisions are made. It increases understanding of the strengths and limitations of risk assessment by decision-makers at all levels, for example, by making uncertainties and choices more transparent. The committee is mindful of concerns about political interference in the process, and the framework maintains the conceptual distinction between risk assessment and risk man- agement articulated in the Red Book. It is imperative that risk assessments used to evalu- ate risk-management options not be inappropriately influenced by the preferences of risk managers. With a focus on early and careful planning and problem formulation and on the options for managing the problem, implementation of the framework can improve the utility of risk assessment for decision-making. Although some aspects of the framework are achievable in the short term, its full implementation will require a substantial transition period. EPA should phase in the framework with a series of demonstration projects that apply it and 10â RC (National Research Council). 1983. Risk Assessment in the Federal Government: Managing the Process. N Washington, DC: National Academy Press. 11â he committee notes that not all decisions require or are amenable to risk assessment and that in most cases T one of the options explicitly considered is âno intervention.â
SUMMARY 13 that determine the degree to which it meets the needs of the agency risk managers, how risk-management conclusions differ as a result of its application, and the effectiveness of measures to ensure that risk managers and policy-makers do not inappropriately influence the scientific conduct of risk assessments. Recommendation: To make risk assessments most useful for risk-management decisions, the committee recommends that EPA adopt a framework for risk-based decision-mak- ing (see Figure S-1) that embeds the Red Book risk-assessment paradigm into a process with initial problem formulation and scoping, upfront identification of risk-management options, and use of risk assessment to discriminate among these options. Stakeholder Involvement Many stakeholders believe that the current process for developing and applying risk assessments lacks credibility and transparency. That may be partly because of failure to involve stakeholders adequately as active participants at appropriate points in the risk- assessment and decision-making process rather than as passive recipients of the results. Previous National Research Council and other risk-assessment reports (for example, NRC 1996; PCCRARM 1997)12 and comments received by the committee (Callahan 2007; Kyle 2007)13 echo such concerns. The committee agrees that greater stakeholder involvement is necessary to ensure that the process is transparent and that risk-based decision-making proceeds effectively, efficiently, and credibly. Stakeholder involvement needs to be an integral part of the risk-based deci- sion-making framework, beginning with problem formulation and scoping. Although EPA has numerous programs and guidance documents related to stakeholder involvement, it is important that it adhere to its own guidance, particularly in the con- text of cumulative risk assessment, in which communities often have not been adequately involved. Recommendation: EPA should establish a formal process for stakeholder involvement in the framework for risk-based decision-making with time limits to ensure that deci- sion-making schedules are met and with incentives to allow for balanced participation of stakeholders, including impacted communities and less advantaged stakeholders. Capacity-Building Improving risk-assessment practice and implementing the framework for risk-based deci- sion-making will require a long-term plan and commitment to build the requisite capacity of information, skills, training, and other resources necessary to improve public-health and environmental decision-making. The committeeâs recommendations call for considerable modification of EPA risk-assessment efforts (for example, implementation of the risk-based decision-making framework, emphasis on problem formulation and scoping as a discrete 12â RC N (National Research Council). 1996. Understanding Risk: Informing Decisions in a Democratic Society. Washington, DC: National Academy Press; PCCRARM (Presidential/Congressional Commission on Risk Assessment and Risk Management). 1997. Framework for Environmental Health Risk Management - Final Report, Vol. 1. 13â allahan, M.A. 2007. Improving Risk Assessment: A Regional Perspective. Presentation at the Third Meeting C of Improving Risk Analysis Approaches Used by EPA, February 26, 2007, Washington, DC; Kyle, A. 2007. Com- munity Needs for Assessment of Environmental Problems. Presentation at the Fourth Meeting of Improving Risk Analysis Approaches Used by EPA, April 17, 2007, Washington, DC.
14 SCIENCE AND DECISIONS: ADVANCING RISK ASSESSMENT stage in risk assessment, and greater stakeholder participation) and of technical aspects of risk assessment (for example, unification of cancer and noncancer dose-response assessments, attention to quantitative uncertainty analysis, and development of methods for cumulative risk assessment). The recommendations are tantamount to âchange-the-cultureâ transforma- tions in risk assessment and decision-making in the agency. EPAâs current institutional structure and resources may pose a challenge to implementa- tion of the recommendations, and moving forward with them will require a commitment to leadership, cross-program coordination and communication, and training to ensure the requisite expertise. That will be possible only if leaders are determined to reverse the downward trend in budgeting, staffing, and training and to making high-quality, risk-based decision-making an agencywide goal. Recommendation: EPA should initiate a senior-level strategic re-examination of its risk- related structures and processes to ensure that it has the institutional capacity to imple- ment the committeeâs recommendations for improving the conduct and utility of risk assessment for meeting the 21st century environmental challenges. EPA should develop a capacity building plan that includes budget estimates required for implementing the committeeâs recommendations, including transitioning to and effectively implementing the framework for risk-based decision-making. CONCLUDING REMARKS Global impacts are combining with the high financial and political stakes of risk manage- ment to place unprecedented pressure on risk assessors in EPA. But risk assessment remains essential to the agencyâs mission to ensure protection of public health and the environment. Much work is needed to improve the scientific status, utility, and public credibility of risk assessment. The committeeâs recommendations focus on designing risk assessments to en- sure that they make the best possible use of available science, are technically accurate, and address the appropriate risk-management options effectively to inform risk-based decision- making. The committee hopes that the recommendations and the proposed framework for risk-based decision-making will provide a template for the future of risk assessment in EPA and strengthen the scientific basis, credibility, and effectiveness of future risk-management decisions.