摘要:

Probabilistic risk analysis, based on the identification of failure modes, points to technical malfunctions and operator errors that can be direct causes of system failure. Yet component failures and operator errors are often rooted in management decisions and organizational factors. Extending the analysis to identify these factors allows more effective risk management strategies. It also permits a more realistic assessment of the overall failure probability. An implicit assumption that is often made in PRA is that, on the whole, the system has been designed according to specified norms and constructed as designed. Such an analysis tends to overemphasize scenarios in which the system fails because it is subjected to a much higher load than those for which it was designed. In this article, we find that, for the case of jacket‐type offshore platforms, this class of scenarios contributes only about 5% of the failure probability. We link the PRA inputs to decisions and errors during the three phases of design, construction, and operation of platforms, and we assess the contribution of different types of error scenarios to the overall probability of platform failure. We compute the benefits of improving the design review, and we find that, given the costs involved, improving the review process is a more efficient way to increase system safety than reinforcing the structur

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01302.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This study integrates previous research methodologies to compare the risk perceptions and responses to risk messages of agency personnel and neighbors of Superfund sites in Michigan. The integration attempted and the focus on risk messages are shaped by a critical review of the social amplification conceptual framework. The study involved all four agency groups and three groups of site neighbors actively involved in Superfund planning across the state. The first part of the study utilized the psychometric techniques of hazard rating and hazard profiles that had not previously been used in studies involving stakeholders. While agency personnel responded similarly to experts in previous studies, the responses of individuals in the neighbor groups reflected experience with toxic sites and were dissimilar to previous ratings by the general public. The second part of the study consisted of a hypothetical toxic site scenario that focused on specific risk messages at different times in the site history. Results indicate that the difference in perception of risk occurs after the first testing at a site, and that dramatic differences arise between agency and resident groups regarding the credibility of information sources and the need for independent testing. A general lack of trust in the Superfund program was demonstrated by all groups. The results indicate that problems of institutional credibility and program adequacy cannot be addressed by better risk comunication.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01303.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This paper reports on an experiment to test the hypothesis that people respond better to risk communication that reflects more closely the conditions of their social and cultural lives. The experiment used the case of radon to determine whether technical or narrative forms of risk communication were more effective at drawing people's attention, imparting information, and modifying behavior. Two series of articles on radon were placed in the local newspapers of two Massachusetts communities. Homeowner attitudes, knowledge, and responses were monitored in baseline and follow‐up telephone surveys. A third community was selected for comparison. The newspaper series were developed on the basis of previous research and six focus groups conducted with homeowners. Thetechnicalseries presented authoritative, factual risk information, in the scientific style of the passive voice with generalized and impersonal language. Thenarrativeseries consisted of dramatized accounts of individuals making decisions about radon testing and mitigation, written in a more personal style. The findings from the focus groups confirm the results of previous studies, but the small size of the follow‐up samples was a limiting factor in drawing definitive conclusions about the relative effectiveness of the two formats. The experiment demonstrates the difficulty of any risk communication effort on radon and underscores the need for good research design. The study illustrates the need for further research on the role of sociological and cultural factors in the public perception and response to r

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01304.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

To investigate the extent to which personal values and experiences among scientists might affect their assessment of risks from dioxin, radon, and environmental tobacco smoke (ETS), we conducted an experiment through a telephone survey of 1461 epidemiologists, toxicologists, physicians, and general scientists. Each participant was read a vignette designed to reflect the mainstream scientific thinking on one of the three substances. For half of the participants (group A) the substance was named. For the other half (group B), the substance was not named but was identified only as Substance X, Y, or Z. Knowing the name of the substance had little effect on the scientists’ evaluation of dioxin, although those who knew the substance to be dioxin were more likely to rate the substance as a serious environmental health hazard (51% vs. 42%,p= 0.062). For radon, those who knew the substance by name were significantly more likely to consider it an environmental health hazard than were those who knew it as substance Z (91% vs. 78%,p<0.001). Participants who knew they were being asked about ETS rather than substance X were significantly more likely to consider the substance an environmental health hazard (88% vs. 66%,p<0.001), to consider the substance a serious environmental health hazard (70% vs. 33%,p<0.001), to believe that background exposure required public health intervention (85% vs. 41%,p<0.001), and to believe that above‐background exposure required public health intervention (90% vs. 74%,p<0.001). These findings suggest that values and experiences may be influencing health risk assessments for these substances, and indicate the need for more study of this phenome

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01305.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The 1989 DC‐10 crash at Sioux City, Iowa presented a rare instance in which a potential threat to safety was both (i) intensely publicized over a short period and (ii) also amenable to the unobtrusive measurement of the market reaction it evoked. As such, it allowed a useful case study of the extent and duration of behavior change caused by a frightening event. Using reservations data from travel agencies in five states, this paper estimates the short‐term effects of the Sioux City crash on passenger willingness to fly the DC‐10. The data suggest that, in the first few weeks after the crash, more than one third of travelers who would normally have booked DC‐10 flights chose instead to fly other aircraft. Within 2 months of the disaster, however, DC‐10 bookings rebounded to within 10% of the level that would have been expected had the Sioux City crash not occurred. At no time, apparently, did the airlines that operate DC‐10s use their “yield‐management” computer pricing systems unofficially to lower DC‐10 fares relative to those on o

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01306.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Most public health risk assessments assume and combine a series of average, conservative, and worst‐case values to derive a conservative point estimate of risk. This procedure has major limitations. This paper demonstrates a new methodology for extended uncertainty analyses in public health risk assessments using Monte Carlo techniques. The extended method begins as do some conventional methods—with the preparation of a spreadsheet to estimate exposure and risk. This method, however, continues by modeling key inputs as random variables described by probability density functions (PDFs). Overall, the technique provides a quantitative way to estimate the probability distributions for exposure and health risks within the validity of the model used. As an example, this paper presents a simplified case study for children playing in soils contaminated with benzene and benzo(a)pyrene (B

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01307.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

For risk assessments, the average current residence time (time since moving into current residence) has often been used as a surrogate for the average total residence time (time between moving into and out of a residence). Since the distributions of the two quantities are not necessarily the same, neither are their averages. Housing surveys provide current residence time data; total residence times must, therefore, be inferred. By modeling the moving process, the total residence time distribution can be estimated from current residence time data. Using 1985 and 1987 U.S. housing survey data, distributions and averages for both current and total residence times were calculated for several housing categories. The average total residence time calculated for all U.S. households, 4.6 (se= 0.6) years, is less than half the average current residence time, 10.6 (se= 0.1) years.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01308.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

In this paper we describe a simulation, by Monte Carlo methods, of the results of rodent carcinogenicity bioassays. Our aim is to study how the observed correlation between carcinogenic potency (β or ln2/TD50) and maximum tolerated dose (MTD) arises, and whether the existence of this correlation leads to an artificial correlation between carcinogenic potencies in rats and mice. The validity of the bioassay results depends upon, among other things, certain biases in the experimental design of the bioassays. These include selection of chemicals for bioassay and details of the experimental protocol, including dose levels. We use as variables in our simulation the following factors: (1) dose group size, (2) number of dose groups, (3) tumor rate in the control (zero‐dose) group, (4) distribution of the MTD values of the group of chemicals as specified by the mean and standard deviation, (5) the degree of correlation between β and the MTD, as given by the standard deviation of the random error term in the linear regression of log β on log (1/MTD), and (6) an upper limit on the number of animals with tumors. Monte Carlo simulation can show whether the information present in the existing rodent bioassay database is sufficient to reject the validity of the proposed interspecies correlations at a given level of stringency. We hope that such analysis will be useful for future bioassay design, and more importantly, for discussion of the whole NCI/ NTP pro

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01309.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The regulation and management of hazardous industrial activities increasingly rely on formal expert judgment processes to provide wisdom in areas of science and technology where traditional “good science” is, in practice, unable to supply unambiguous “facts.” Expert judgment has always played a significant, if often unrecognized, role in analysis; however, recent trends are to make it formal, explicit, and documented so it can be identified and reviewed by others. We propose four categories of expert judgment and present three case studies which illustrate some of the pitfalls commonly encountered in its use. We conclude that there will be an expanding policy role for formal expert judgment and that the openness, transparency, and documentation that it requires have implications for enhanced public involvement in scientific and technical

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01310.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1992.tb01311.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY