Runaway Reactions, Their Courses, and the Methods to Establish Safe Process Conditions

The purpose of this paper is to describe the various process deviations which can cause a runaway reaction to occur, and to discuss the experimental information necessary for risk assessment, the choice of a safe process, and the mitigation of the consequences of the runaway reaction. Ten typical hazardous process situations have been identified, considering various modes of initiation, homogeneous and heterogeneous, Arrhenius, and autocatalytic reactions. Each possible hazardous process deviation is illustrated by examples from the process industry and/or relevant experimental information obtained from laboratory experiments.     

Why aren't managers concerned about occupational stress?

To explain the rarity of workplace stress management interventions, it is thought that managers are not concerned with the risks of occupational stress to health and job performance. Some writers consider either (1) deficiencies in theory, and/or (2) deficiencies in methodology to be the cause of this apparent lack of concern. The aim of this paper is to illustrate another perspective on this issue; that of risk perception. Two perspectives on risk perception are discussed; the psychometric view and the cultural view. The psychometric view suggests that senior managers may underestimate the risks associated with stress. The cultural view suggests that managers may consider stress management to be inappropriate, since individuals, not organizations, should be responsible for coping with stress. Both perspectives indicate that very few managers may consider stress to be a risk that should be actively managed by the organization. The associated disciplines of risk management and particularly risk communication are discussed to suggest ways to overcome lack of managerial interest in stress management.     

Assessing Cross-Media Impacts: A Comparative Risk Approach

The Oregon Department of Environmental Quality has developed a Cross-Media Comparative Risk Assessment model to address certain regulatory concerns. The model generates a Human and Ecological Risk Index for a facility releasing toxins into the environment. The risk indices are based on chemical fate and transport predictions, toxicity, population density, and ecological sensitive areas. The model can be used to rank facilities for inspection or as a tool to assess the progress of pollution prevention programs. Regulatory permitting departments can use the model to address the cross-media transfer of pollutants from one environmental compartment to another. The versatility of the model allows adaptation to each specific users needs.     

Ethics, Decision Analysis, and Public Risk

In any analysis of a decision problem involving public risks, ethical implications are introduced. In some cases, these ethical implications may be introduced simply because an analysis is being done. Additional ethical implications may be inherently part of the methodology being utilized or introduced into the specific analysis of the decision problem. In this paper, we investigate where and how ethical implications enter when using the methodology of decision analysis to examine problems involving public risks. We conclude that the methodology of decision analysis is sufficiently robust to allow for numerous different ethical viewpoints to be accounted for in any specific analysis. Stated alternatively, decision analyses of public risks can be conducted in a manner consistent with utilitarianism, deontological theories, libertarianism, egalitarianism, and so forth. However, any specific analysis has embedded within it numerous ethical implications. This suggests that the careful ethical scrutiny of analyses involving the methodology of decision analysis should be placed on the specific application and not on the methodology per se or on the fact that an analysis is undertaken.     

Benefit Analysis for Natural Hazards

The objective of this paper is to develop the ex ante perspective for benefit analysis with natural hazards. It defines an ex ante evaluation of the economic benefits that arise from policies designed to reduce either the risk of or the detrimental effects associated with a natural hazard. In the process the paper compares the ex ante and ex post perspectives and discusses the prospects for implementing the framework by measuring the valuation concepts that are developed.     

ESTIMATING THE COMMON MEAN OF A BIVARIATE NORMAL POPULATION

For estimating the common mean of a bivariate normal distribution, Krishnamoorthy & Rohatgi (1989) proposed some estimators which dominate the maximum likelihood estimator in a large region of the parameter space. We consider some modifications of these estimators and study their risk performance.     

Eliciting and Classifying Concerns: A Methodological Critique

Two methodological steps in the study of peoples'concerns are elicitation and classification. Elicitation of concerns through analytical methods such as surveys can be supplemented with techniques that perform more diversively. We present two examples of how this can be accomplished: one in the expert community and one in the lay community. A classification taxonomy is a subjective choice of the researcher and it can only be evaluated against the stated objectives of the research. We present a classification schema that is explicitly oriented toward diagnosing the substantive needs of public discourses about risk decision making. To illustrate how concerns can be elicited in a social setting and how this classification tool can be applied, we report on a public participation exercise in New Jersey where citizens discussed the impacts of land application of sewage sludge at an experimental farm.     

Characterising the Perceived Risks and Benefits of Some Health Issues

Previous work on perceived risk, particularly a study by Fischhoff et al. (1978), is critically examined with reference to its applicability to specific health related issues. Judgments were obtained from 159 subjects of 15 health-related items in terms of perceived risk, benefit, and a number of risk characteristics based on the Fischhoff et al. research. In addition, demographic details concerning sex of respondent, seat belt usage, smoking status, and birth order were collected. Using regression analyses it was found that the direction of the risk-benefit relationship was dependent on the issue being judged. Risk was found to be better explained by ratings of likelihood of mishap and likelihood of death as a consequence of mishap. Benefit was poorly explained by the risk characteristics and demographic data. However, subject group characteristics were shown to be important influences on risk and benefit perception in certain situations. The implications of these results for understanding behavioral decisions involving risk in relation to specific activities are discussed.     

Probabilistic Risk Analyses: NRC Programs and Perspectives

The historical basis and more recent activities and products of probabilistic risk analysis (PRA) in the Atomic Energy Commission and Nuclear Regulatory Commission (NRC) are reviewed. Current NRC program activities and objectives are described. The author's opinions on the best uses of PRA are presented.