The Perceived Health Risks of Indoor Radon Gas and Overhead Powerlines: A Comparative Multilevel Approach

Radon and overhead powerlines are two radiation risk cases that have raised varying levels of concern among the general public and experts. Despite both involving radiation—a typically feared and unseen health hazard—individuals' perceptions of the two risk cases may invoke rather different factors. We examined individual and geographic-contextual factors influencing public perceptions of the health risks of indoor radon gas and overhead powerlines in a comparative research design, utilizing a postal questionnaire with 1,528 members of the general public (response rate 28%) and multilevel modeling techniques. This study found that beliefs about the two risk cases mainly differed according to the level of "exposure"—defined here in terms of spatial proximity. We argue that there are two alternative explanations for this pattern of findings: that risk perception itself varies directly with proximity, or that risk is more salient to concerned people in the exposed areas. We also found that while people living in high radon areas are more concerned about the risks of indoor radon gas, they find these risks more acceptable and have more trust in authorities. These results might reflect the positive effects of successive radon campaigns in high radon areas, which may have raised awareness and concern, and at the same time may have helped to increase trust by showing that the government takes the health risks of indoor radon gas seriously, suggesting that genuine risk communication initiatives may have positive impacts on trust in risk management institutions.     

Social Equity and Environmental Risk1

Social equity has become an important concern of the environmental movement over the past decade. The equity issue is analyzed here for practically all of the inactive hazardous waste disposal sites on the National Priorities List (NPL) regulated under the Comprehensive Response Compensation and Liability Act and its 1986 Superfund Amendments and Reauthorization Act (CERCLA/ SARA). Two dimensions of equity are emphasized, namely, site location relative to the location of minority populations and the distribution of cleanup plans or Records of Decision (ROD) across communities with NPL sites that have different socioeconomic characteristics. With respect to site location, the percentage of Blacks and Hispanics aggregated at the Census Place or MCD level in communities with NPL sites was greater than is typical nationwide (largely attributable to the concentration of minority populations in a few large urban areas with NPL sites). In contrast, the percentage of the population below the poverty line in communities with NPL sites largely matched that of the nation as a whole. With respect to site cleanup, communities with relatively higher percentages of racial minority populations have fewer cleanup plans (Records of Decision signed) than other communities with NPL sites. Whether a ROD exists is influenced by when the site was designated for the NPL: sites designated earlier (prior to the SARA amendments of 1986) are more likely to have RODs, and also less likely to have high proportions of racial minority populations than sites designated later. This implies that initially the designation process may have resulted in NPL sites being located disproportionately in minority areas, but this pattern seems to be reversing itself in more recently designated sites. As with any statistical analysis, these findings are findings of association and not causality. Thus, racial and ethnic disproportionalities with respect to inactive hazardous waste site location seem to be concentrated in a relatively few areas. Disproportionalities with respect to cleanup do exist, but appear to be more a function of the nature of the process of designation of NPL sites in the early 1980s rather than a result of actions connected with cleanup plans per se. Further investigations are needed at alternative geographic scales to discern the sensitivity of patterns of inequity to distance from the sites.     

Practical Methods for Meeting Remediation Goals at Hazardous Waste Sites

Risk-based cleanup goals or preliminary remediation goals (PRGs) are established at hazardous waste sites when contaminant concentrations in air, soil, surface water, or groundwater exceed specified acceptable risk levels. When derived in accordance with the Environmental Protection Agency's risk assessment guidance, the PRG is intended to represent the average contaminant concentration within an exposure unit area that is left on the site following remediation. The PRG, however, frequently has been used inconsistently at Superfund sites with a number of remediation decisions using the PRG as a not-to-exceed concentration (NTEC). Such misapplications could result in overly conservative and unnecessarily costly remedial actions. The PRG should be applied in remedial actions in the same manner in which it was generated. Statistical methods, such as Bower's Confidence Response Goal, and mathematical methods such as "iterative removal of hot spots," are available to assist in the development of NTECs that ensure the average postremediation contaminant concentration is at or below the PRG. These NTECs can provide the risk manager with a more practical cleanup goal. In addition, an acute PRG can be developed to ensure that contaminant concentrations left on-site following remediation are not so high as to pose an acute or short-term health risk if excessive exposure to small areas of the site should occur. A case study demonstrates cost savings of five to ten times associated with the more scientifically sound use of the PRG as a postremediation site average, and development of a separate NTEC and acute PRG based on the methods referenced in this article.     

Citizen Perceptions of Risks Associated with Moving Radiological Waste

Much has been written about public support or opposition to the siting of hazardous waste facilities and more generally about concern for radioactive contamination. Much less has been written about the perceived risks of citizens'specific concerns about the transportation of radiological waste to temporary or permanent sites. This study reviews the existing literature in the area and presents new data on the subject from an Idaho survey. The new data indicates: (1) age, gender, and knowledge are the key variables predicting opposition to the transportation of such waste, (2) the primary concern among the opposing and unsure public is the planned use of trucks to move the TRU waste, and (3) respondents have high degrees of trust in officials who make decisions based on technical knowledge, are charged with the safety of transporting TRU waste, and who respond to mishaps. These attitudes need to be understood by policymakers and administrators when designing and implementing waste-transportation programs.     

Consideration of Background Exposures in the Management of Hazardous Waste Sites: A New Approach to Risk Assessment

The current approach to health risk assessment of toxic waste sites in the U.S. may lead to considerable expenditure of resources without any meaningful reduction in population exposure. Risk assessment methods used generally ignore background exposures and consider only incremental risk estimates for maximally exposed individuals. Such risk estimates do not address true public health risks to which background exposures also contribute. The purpose of this paper is to recommend a new approach to risk assessment and risk management concerning toxic waste sites. Under this new approach, which we have called public health risk assessment, chemical substances would be classified into a level of concern based on the potential health risks associated with typical national and regional background exposures. Site assessment would then be based on the level of concern for the particular pollutants involved and the potential contribution of site contaminants to typical background human exposures. While various problems can be foreseen with this approach, the key advantage is that resources would be allocated to reduce the most important sources of human exposure, and site remediation decisions could be simplified by focussing on exposure assessment rather than questionable risk extrapolations.     

Financing Liabilities Under Superfund

One of the more critical environmental risk areas involves the financing of cleanup costs associated with past improper disposal of hazardous wastes. These costs will run into the tens of billions of dollars. The federal Superfund program and related state programs are the driving forces for cleaning up hazardous waste. Under Superfund, the government collects taxes and coordinates cleanup strategies, and searches for potentially responsible parties (generators, disposers, transporters) to assist in financing the cleanup. To lessen the financial impact, responsible parties are looking to their liability insurers to provide coverage under old general liability insurance policies. Insurance companies contend that Superfund liabilities are not covered under liability policies. The paper examines the various financing methods and liabilities produced by Superfund. Particular emphasis is placed on developments in the courts which are resulting in a significant shift in the financial responsibilities to the insurance industry. Broad estimates of the financial impact of Superfund liabilities are developed. Finally, several public policy issues, which are raised by the topics exmained in this paper, are discussed.     

Computer Models Used to Support Cleanup Decision-Making at Hazardous and Radioactive Waste Sites

Massive efforts are underway to clean up hazardous and radioactive waste sites located throughout the United States. To help determine cleanup priorities, computer models are being used to characterize the source, transport, fate, and effects of hazardous chemicals and radioactive materials found at these sites. Although the U.S. Environmental Protection Agency (EPA), the U.S. Department of Energy (DOE), and the U.S. Nuclear Regulatory Commission (NRC)have provided preliminary guidance to promote the use of computer models for remediation purposes, no agency has produced directed guidance on models that must be used in these efforts. As a result, model selection is currently done on an ad hoc basis. This is administratively ineffective and costly, and can also result in technically inconsistent decision-making. To identify what models are actually being used to support decision-making at hazardous and radioactive waste sites, a project jointly funded by EPA, DOE, and NRC was initiated. The purpose of this project was to: (1)identify models being used for hazardous and radioactive waste site assessment purposes; and (2)describe and classify these models. This report presents the results of this study. A mail survey was conducted to identify models in use. The survey was sent to 550 persons engaged in the cleanup of hazardous and radioactive waste sites; 87 individuals responded. They represented organizations including federal agencies, national laboratories, and contractor organizations. The respondents identified 127 computer models that were being used to help support cleanup decision-making. There were a few models that appeared to be used across a large number of sites (e.g., RESRAD). In contrast, the survey results also suggested that most sites were using models which were not reported in use elsewhere. Information is presented on the types of models being used and the characteristics of the models in use. Also shown is a list of models available, but not identified in the survey itself.     

The Role of Risk and Future Land Use in Cleanup Decisions at the Department of Energy

As a result of the legacy of the Cold War, the Departments of Energy and Defense are involved in massive cleanup and remediation projects. While health risk to humans and ecological receptors is perceived to be the basis for remediation, this assumption is rarely examined. In this article, we examine the role of risk and future land-use designations in cleanup decisions, using the Department of Energy's self-assessment of 36 sites. We then discuss the risk-related tools that might be required to address the cleanup challenge. Much of the current cleanup program is driven by compliance with federal and state statutes and regulations, presumably to protect human health and the environment. Compliance, however, is not synonymous with cleanup. Although some of these laws and regulations take risk into account, the lack of site-specific data on exposures and risk scenarios, and the lack of attention to future land use or end states, has often resulted in disconnects between risk and cleanup goals, risk and final end states, and cleanup levels and end state or subsequent land use. Partly, these disconnects result from the need for a range of technical, economic, sociological, and public policy tools to address the issues. A better transfer of information among and within Department of Energy facilities, operations offices, and DOE headquarters is required. Further, linking cleanup decisions and goals with the final end state involves a number of risk tradeoffs, including (1) ecological versus human health, (2) worker versus public health, (3) among competing contaminated areas, (4) among temporal patterns of cleanup, (5) among different ecological receptors (plants vs. animals, one animal vs. another), and (6) among the sites across the DOE complex. For the nation, balancing among risks is essential within sites and among Department of Energy sites, as well as among other remediation sites (such as those of Department of Defense and Superfund sites).     

Risks of Hazardous Waste Sites versus Asteroid and Comet Impacts: Accounting for the Discrepancies in U.S. Resource Allocation

Approximately $6 billion is spent annually in the United States on the cleanup of sites regulated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, or Superfund). The current health risks posed by such sites are thought to be quite small; the expenditures are justified primarily as protecting hypothetical future residents of these sites. Approximately 0.05% of this amount, or $3 million, is spent annually by the U.S. government on the detection of asteroids or comets that could strike the earth. Such damaging impacts do occur from time to time--most recently in 1908 in an unpopulated region of Siberia--but no person is confirmed ever to have died as a result. Anticipated impacts over the course of 1 million years would yield deaths that, when annualized, total approximately 4,000 per year. The risk reduction goal for CERCLA is 15 orders of magnitude greater than that for asteroid/comet detection. A modest increase in resources devoted to asteroid detection would greatly increase the chances of early detection of a threatening object, allowing an effective defense to be attempted. This article argues that the much lower risk-to-resources ratio for CERCLA cleanups than for asteroid and comet detection can be explained by four primary factors: (1) the regard for future generations, since CERCLA benefits mainly the unborn; (2) concrete fears, since toxics are much more feared than asteroids or comets; (3) the source of the threat, since toxic contamination is caused by human beings, unlike impacts from space objects; and (4) the greater political constituencies for hazardous waste cleanup than for space object detection.     

Limits of Knowledge and the Limited Importance of Trust

Perceived risk and related attitudes have been implicated as major factors in many of the difficult policy problems that face modern society (nuclear power, genetically modified food, etc). Experts often argue that no or very small risks are involved; people are still worried. Why? The standard answer is lack of trust. Data on trust and risk perception, however, point to only a weak relationship between the two (r approximately 0.3). It is suggested here that the reason for the surprisingly minor importance of trust is that people believe that there are clear limits to how much science and experts know. Results are presented from studies of risk perception of the public, experts, and politicians. Politicians and members of the public believe that there are many unknown effects of technology and such beliefs were strongly related to their perceived risk. Experts on nuclear waste, on the other hand, seemed to believe that little is unknown in their field of expertise. Regression analyses of risk perception showed the unknown‐effects factor to be a more important explanatory factor than trust for the public and politicians.     

Perceived Risks of Radioactive Waste Transport Through Oregon: Results of a Statewide Survey

Transportation of hazardous materials, and particularly radioactive wastes, on public highways has become an important risk management issue. The unfavorability of public attitudes regarding hazardous and nuclear wastes signals the potential for strong public opposition to programs for transporting these materials. This paper presents the results of a survey conducted to assess public reactions to a long-term nuclear waste transport program planned to follow a route through a portion of rural Oregon. The survey assessed a number of key risk perception issues, including perceived health and safety risks of nuclear waste transport, relative risks of transport vs. storage at an existing site, trust in state officials, and satisfaction with life in communities along the transport route. The survey identified a number of attitudes and concerns that need to be understood and considered by those in charge of designing and implementing the waste-transportation program.     

Trust and Risk Communication in High-Risk Organizations: A Test of Principles from Social Risk Research

This study explored the effects of open communication about occupational risks on workers' trust beliefs and trust intentions toward risk management, and the resilience of these beliefs and intentions to further risk information. An experimental survey of 393 student nurses showed the importance of open communication in the development of worker trust in risk management. Consistent with the trust asymmetry principle, we found that the increase in trust beliefs following open communication was weaker than the reduction in trust following a lack of communication. Further, the level of trust developed through communication (or lack of) influenced the way that subsequent risk information was processed. Negative risk information reduced trust beliefs in nurses with already low levels of trust while positive risk information increased trust beliefs only in those with already high levels. A similar pattern of results emerged for nurses' trust intentions, although the magnitude of these effects was weaker. The implications of these findings for occupational risk management are discussed.     

Estimating Risk Assessment Exposure Point Concentrations when the Data Are Not Normal or Lognormal

The U.S. Environmental Protection Agency (EPA) recommends the use of the one-sided 95% upper confidence limit of the arithmetic mean based on either a normal or lognormal distribution for the contaminant (or exposure point) concentration term in the Superfund risk assessment process. When the data are not normal or lognormal this recommended approach may overestimate the exposure point concentration (EPC) and may lead to unecessary cleanup at a hazardous waste site. The EPA concentration term only seems to perform like alternative EPC methods when the data are well fit by a lognormal distribution. Several alternative methods for calculating the EPC are investigated and compared using soil data collected from three hazardous waste sites in Montana, Utah, and Colorado. For data sets that are well fit by a lognormal distribution, values for the Chebychev inequality or the EPA concentration term may be appropriate EPCs. For data sets where the soil concentration data are well fit by gamma distributions, Wong's method may be used for calculating EPCs. The studentized bootstrap-t and Hall's bootstrap-t transformation are recommended for EPC calculation when all distribution fits are poor. If a data set is well fit by a distribution, parametric bootstrap may provide a suitable EPC.     

When Can Scientific Studies Promote Consensus Among Conflicting Stakeholders?

While scientific studies may help conflicting stakeholders come to agreement on a best management option or policy, often they do not. We review the factors affecting trust in the efficacy and objectivity of scientific studies in an analytical‐deliberative process where conflict is present, and show how they may be incorporated in an extension to the traditional Bayesian decision model. The extended framework considers stakeholders who differ in their prior beliefs regarding the probability of possible outcomes (in particular, whether a proposed technology is hazardous), differ in their valuations of these outcomes, and differ in their assessment of the ability of a proposed study to resolve the uncertainty in the outcomes and their hazards—as measured by their perceived false positive and false negative rates for the study. The Bayesian model predicts stakeholder‐specific preposterior probabilities of consensus, as well as pathways for increasing these probabilities, providing important insights into the value of scientific information in an analytic‐deliberative decision process where agreement is sought. It also helps to identify the interactions among perceived risk and benefit allocations, scientific beliefs, and trust in proposed scientific studies when determining whether a consensus can be achieved. The article provides examples to illustrate the method, including an adaptation of a recent decision analysis for managing the health risks of electromagnetic fields from high voltage transmission lines.     

Technical and Democratic Values in Risk Analysis1

So, we can argue that the lay public are not fools in their attitudes about risk. That nonexperts should show more concern over hazardous waste facilities in their neighborhoods than radon levels in their homes is not a sign of irrationality (because aggregate and individual risks are greater from the radon), but simply a sign that nonexperts are working from a different set of criteria. These criteria are incorporated in what I call the democratic model. The democratic model evaluates risk based on its social and political consequences, such as possible disruption in the social fabric or a loss of communality. Lay criteria for assessing the impact of risk decisions are not explicit, like the those of the risk analyst, but are embedded in cultural values. Similarly, lay evaluations of risk incorporate substantive and procedural democratic values, such as the acceptability of processes for making decisions, the ethics of the distribution of risk, and the capacity to control a source of risk in the community's interests. Finally, the democratic model relates judgments about risks to the competence (Can we trust them?) and the legitimacy (Should we trust them?) of the social institutions that impose and control those risks. The public's judgments about risk are not inferior, but different, and arguably richer than those of the experts.     

Role for Risk Communication in Closing Military Waste Sites

Lessons learned from environmental and occupational hazard risk management practices over the past 30 years have led the Department of Defense to explore alternative risk management approaches. Policies for cleanup of environmentally hazardous waste sites are undergoing examination and are being reframed. A Demonstration Risk Communication Program is described which incorporates principles that integrate risk-based scientific information as well as community values, perceptions, and needs in a democratic process that includes the public as an active participant from the earliest stages. A strong scientific foundation for assessment and characterization of risk is viewed as necessary but not sufficient; the public's values must be actively integrated into the negotiated criteria. The Demonstration Program uses a model to prepare the participants and to guide them through the process. A five-step process is presented: (1) create risk communications process action team including at least one member of the specific site audience; (2) professionally train participants on team dynamics including interpersonal communication skills; (3) train risk communicators to deliver a cogent presentation of the message to secure a decision acceptable to both the government and the public; (4) identify existing biases, perceptions, and values held by all participants; and (5) develop risk message incorporating science and values. The process action team approach assumes the participants enter into the effort with the goal of improved environment and safeguarded public health. The team approach avoids confrontational or adversarial interactions and focuses on a dialogue from which a negotiated team response develops. Central to the program is the recognition that communication is only effective when the dialogue is two-way.     

Varying Risk Comparison Elements: Effects on Public Reactions

Expanding a limited empirical base on effects of risk comparisons, a pilot experiment explored how varying elements of such comparisons might influence public response. The scenario used was a hypothetical trial of an asbestos-installing firm for putting students and staff at a junior high school at "unreasonable risk," first used by Slovic et al. (1990). Study participants played the role of jurors in the trial, asked to rate the risk, the firm's guilt, whether it should be made liable for future health effects, whether the school should be occupied in its current condition, and whether the asbestos should be removed at a cost of 3 million dollars. Opportunity samples of New Jersey residents (n= 309) received information intended to vary four comparison attributes: number of dimensions of comparison; single versus multiple ways of expressing mortality; a narrative to explain and justify the risk comparison; and the hypothetical role of the participant (juror vs. parent). The dependent variable was a hazard scale constructed from four of the five postcomparison judgments. ANOVA found format variations swamped in their effect by concern about asbestos, with the absence of a narrative and the parental role being the only attributes that increased negative risk reactions. Multiple regression analyses found that multidimensionality, narrative, role, and the presence of any risk comparison at all had significant effects when these (plus death formats) were the only independent variables. However, only multidimensionality (which increased negative reactions) retained significance when asbestos concern, risk beliefs (no safe level of exposure to a carcinogen; any exposure leads to cancer), and demographic variables were added to the analysis. Concern and risk beliefs alone explained 33% of variance in hazard scores; adding demographics and risk comparison variables only raised explained variance to 36% (having children at home and being exposed to multidimensional risk comparisons raised scores; age and income lowered them). The results underline the potentially small effect of risk comparison information on risk views (at least between subjects), but offer some insight into aspects of message design left unexplored in empirical literature to date.     

The Risks of "Putting the Numbers in Context": A Cautionary Tale

Despite the warnings of risk communication specialists, members of the technical community often urge that technological risks should be "put in context" by comparisons against risks that are more familiar. Little quantitative evidence is available on the actual behavioral consequences of such risk comparison efforts. In the present study, subjects were presented with two types of information about a hazardous waste incinerator–a simplified statistical summary and a comparison of incinerator risks against the risks of smoking. Statistical information led to a modest increase in the reported willingness to vote in favor of the incinerator in a community referendum, but the comparison against cigarettes led to a slight decrease in support; the difference between the two messages is statistically significant ( p <.001). In combination with other results, this study's findings suggest that an implicit assumption of risk comparisons is in error: Opposition to controversial technologies may have little to do with citizens' levels of information about technology, having more to do with citizens' levels of trust in governmental and industrial actors.     

Major Sources of Exposure to Benzene and Other Volatile Organic Chemicals1,2

The major sources of human exposure to about a dozen volatile organic chemicals (VOCs) have recently been identified.¹ For nearly every chemical, the major sources of exposure are completely different from the major sources of emissions. This finding implies that current environmental regulations and control strategies are misdirected. Important sources of exposure are typically not regulated in any way, whereas unimportant sources are heavily regulated. Vast sums of money are spent on problems involving little risk (e.g., hazardous waste sites), whereas few resources are expended on problems involving higher risk (e.g., indoor air pollution). The following paper summarizes recent findings regarding major sources of exposure to several VOCs. Benzene is selected as a case study. Brief discussions of tetrachloroethylene and paradichlorobenzene are also included.     

Do Reports on Drinking Water Quality Affect Customers' Concerns? Experiments in Report Content

The Safe Drinking Water Act Amendments of 1996 required U.S. utilities to report on drinking water quality to their customers annually, beginning in fall 1999, on the assumption that such reports would alert them to quality problems and perhaps mobilize pressure for improvement. A random sample of New Jersey customers read alternative versions of a water quality report, in an experiment on reactions to water quality information under U.S. Environmental Protection Agency (USEPA) rules. Experiment design was 2 x 3 + 1: two versions each--one with, one without, a violation of a health standard--of a report that was (1) Qualitative (without water quality numbers, thus not meeting USEPA rules); (2) Basic, with minimal information meeting the rules; or (3) Extended, adding reading aids and utility performance information; plus a control instrument without any hypothetical report. Results of ANOVA suggest the reports will have less effect than hoped or feared. These manipulations were successful: people reading the Qualitative versions were less likely to say that the report gave the amounts of substances found in the water, and those reading Violation versions were more likely to report a violation of a health standard. The main differences in responses to the report involved the judged adequacy of the information, and to a lesser extent responses on a Concern scale (constructed from measures of concern, judged risk, clean-up intentions, distrust of utility information, and doubt that the utility was doing all it could to improve water quality). Overall judgments of water quality and utility performance did not change, either relative to the controls or in before versus after responses. Qualitative reports performed worse than others, confirming the decision to have utilities report actual contaminant levels. Extended reports did only slightly better than the Basic versions on these measures. Many respondents had trouble identifying the presence or absence of substance amounts or violations, despite their seeming obviousness (e.g., in a "bottom line" summary on the front page of each report), suggesting many were not processing this information carefully. However, the pattern of responses for those who accurately identified the presence or absence of substance amounts or violations did not differ substantially from that for the group as a whole. Generic risk beliefs (serious local environmental problems; lack of control over risks to one's health) dominated demographic variables, attitudes toward utility water quality or trustworthiness, and the content and format of water quality reports in influencing concern about drinking water quality. Previous empirical and theoretical evidence for lack of change in public risk attitudes due to one-time or infrequent communications--e.g., role of personal experience, perseverance of prior trust or distrust--seems to be confirmed for annual water quality reports.