Risk-Risk Balancing for Hazardous Waste Workers: Alternative Work, Traffic Fatalities, and Unemployment

Previous studies have shown that the fatality rate among hazardous waste remediation workers is likely to exceed the fatality rate averted among the public by remediation. The implication is that much hazardous waste remediation is inappropriate on a strictly risk-based basis. Such analyses ignore the fact that the same hazardous waste workers would be engaged in other work with similar or perhaps greater safety risks, and that in any case the single greatest cause of occupational fatalities is traffic accidents, hence distance traveled may be a more important predictor than type of work performed.     

Estimated Risk of Occupational Fatalities Associated with Hazardous Waste Site Remediation

This study presents a method to assess short term traumatic fatality risks for workers involved in hazardous waste site remediation to provide a quantitative, rather than qualitative, basis for evaluating occupational exposures in remediation feasibility studies. Occupational employment and fatality data for the years 1979–1981 and 1983 were compiled from Bureau of Labor Statistics data for 11 states. These data were analyzed for 17 occupations associated with three common remediation alternatives: excavation and landfill, capping, and capping plus slurry wall. The two occupations with the highest death rates, truck driver and laborer, contributed most to total exposure hours in each alternative. Weighted average death rates were produced for each alternative and multiplied by respective total person-years of exposure. The resultant expected number of fatalities was converted, using the Poisson distribution, to the risk of experiencing at least one fatality, as follows: 0.149 for excavation and landfill, 0.012 for capping, and 0.014 for capping plus slurry wall. These risks were discussed in light of the need to obtain more reliable and comprehensive data than are currently available on the occupational safety and health risks associated with hazardous waste site remediation and the need for a more scientific, quantitative approach to remediation decisions involving risks to workers.     

Moral imagination in long-term care workers

Our study focused on the cultural construction of dying and death in long-term care facilities. This article centers on direct care workers' perspective of residents' deaths. The data on which this article is based were gathered in a multi-year, multi-site study through formal ethnographic interviews, informal conversations, and on-site observations of residents and staff members. During fieldwork, we noticed an aptitude of direct care workers to deal with residents' deaths, which we named "moral imagination." The term is borrowed from other disciplines to describe a "way of seeing" residents. The case studies presented--that of three direct care workers: a dietary aide, a nurse aide, and an assistant activities director--are suggestive of workers in each category. Our study offers implications for future research concerning direct care workers' value to residents' quality of life. We also propose questions for long-term care facilities about standards of formal caregiving at the end of life.     

Human Health Risks Associated with Asbestos Abatement

Upperbound lifetime excess cancer risks were calculated for activities associated with asbestos abatement using a risk assessment framework developed for EPA's Superfund program. It was found that removals were associated with cancer risks to workers which were often greater than the commonly accepted cancer risk of 1 x 10(-6), although lower than occupational exposure limits associated with risks of 1 x 10(-3). Removals had little effect in reducing risk to school populations. Risks to teachers and students in school buildings containing asbestos were approximately the same as risks associated with exposure to ambient asbestos by the general public and were below the levels typically of concern to regulatory agencies. During abatement, however, there were increased risks to both workers and nearby individuals. Careless, everyday building maintenance generated the greatest risk to workers followed by removals and encapsulation. If asbestos abatement was judged by the risk criteria applied to EPA's Superfund program, the no-action alternative would likely be selected in preference to removal in a majority of cases. These conclusions should only be interpreted within the context of an overall asbestos risk management program, which includes consideration of specific fiber types and sizes, sampling and analytical limitations, physical condition of asbestos-containing material, episodic peak exposures, and the number of people potentially exposed.     

What Risks Are Chinese People Concerned About?

The aim of this study is to investigate public perceived risk on various issues in present-day China. Two surveys were conducted in urban China in 1996 and 1998. In the first survey, risk perceptions of different occupational groups are compared. Gender differences within each occupational group are also analyzed. In the second survey, participants with diverse employment status were recruited. The overall risk rankings of both surveys indicate great concern with risks that threaten national stability and economic development, and less concern with high-technology risk such as threat from a nuclear power plant. It is also found that employees from high-profit firms are more concerned about macroscopic catastrophic risks, whereas laid-off workers and employees from money-losing enterprises are more concerned about daily life or self-concerned risks. The importance of actual exposure to risk, mass media coverage, culture, and psychometric dimensions are discussed.     

Cancer Dose-Response Modeling of Epidemiological Data on Worker Exposures to Aldrin and Dieldrin

The paper applies classical statistical principles to yield new tools for risk assessment and makes new use of epidemiological data for human risk assessment. An extensive clinical and epidemiological study of workers engaged in the manufacturing and formulation of aldrin and dieldrin provides occupational hygiene and biological monitoring data on individual exposures over the years of employment and provides unusually accurate measures of individual lifetime average daily doses. In the cancer dose-response modeling, each worker is treated as a separate experimental unit with his own unique dose. Maximum likelihood estimates of added cancer risk are calculated for multistage, multistage-Weibull, and proportional hazards models. Distributional characterizations of added cancer risk are based on bootstrap and relative likelihood techniques. The cancer mortality data on these male workers suggest that low-dose exposures to aldrin and dieldrin do not significantly increase human cancer risk and may even decrease the human hazard rate for all types of cancer combined at low doses (e.g., 1 g/kg/day). The apparent hormetic effect in the best fitting dose-response models for this data set is statistically significant. The decrease in cancer risk at low doses of aldrin and dieldrin is in sharp contrast to the U.S. Environmental Protection Agency's upper bound on cancer potency based on mouse liver tumors. The EPA's upper bound implies that lifetime average daily doses of 0.0000625 and 0.00625 g/kg body weight/day would correspond to increased cancer risks of 0.000001 and 0.0001, respectively. However, the best estimate from the Pernis epidemiological data is that there is no increase in cancer risk in these workers at these doses or even at doses as large as 2 g/kg/day.     

Estimated Cancer Risk Associated with Occupational Asbestos Exposure

This paper estimates the number of workers in the United States who were occupationally exposed to asbestos during and after World War II and assesses the impact of this exposure on overall cancer mortality. The results suggest that over half of the estimated 7–8 million potentially exposed workers employed between 1940 and 1970 may still be alive and at risk of dying from some form of asbestos-related cancer. While the maximum number of excess cancer deaths associated with this occupational exposure is likely to occur sometime in this decade, such deaths will continue to be seen for many years thereafter. At their peak, these deaths may account for an estimated 3% of the annual cancer death toll, with an associated range of 1.4–4.4%.     

Leukemia Risk Associated with Benzene Exposure in the Pliofilm Cohort. II. Risk Estimates

The detailed work histories of the individual workers composing the Pliofilm cohort represent a unique resource for estimating the dose-respoonse for leukemia that may follow occupational exposure to benzene. In this paper, we report the results of analyzing the updated Pliofilm cohort using the proportional hazards model, a more sophisticated technique that uses more of the available exposure data than the conditional logistic model used by Rinsky et al. The more rigorously defined exposure estimates derived by Paustenbach et al. are consistent with those of Crump and Allen in giving estimates of the slope of the leukemogenic dose-response that are not as steep as the slope resulting from the exposure estimates of Rinsky et al. We consider estimates of 0.3-0.5 additional leukemia deaths per thousand workers with 45 ppm-years of cumulative benzene exposure to be the best estimates currently available of leukemia risk from occupational exposure to benzene. These risks were estimated in the proportional hazards model when the exposure estimates of Crump and Allen or of Paustenbach et al. were used to derive a cumulative concentration-by-time metric.     

Vehicle Emission Unit Risk Factors for Transportation Risk Assessments

When the transportation risk posed by shipments of hazardous chemical and radioactive materials is being assessed, it is necessary to evaluate the risks associated with both vehicle emissions and cargo-related risks. Diesel exhaust and fugitive dust emissions from vehicles transporting hazardous shipments lead to increased air pollution, which increases the risk of latent fatalities in the affected population along the transport route. The estimated risk from these vehicle-related sources can often be as large or larger than the estimated risk associated with the material being transported. In this paper, data from the U.S. Environmental Protection Agency's Motor Vehicle-Related Air Toxics Study are first used to develop latent cancer fatality estimates per kilometer of travel in rural and urban areas for all diesel truck classes. These unit risk factors are based on studies investigating the carcinogenic nature of diesel exhaust. With the same methodology, the current per-kilometer latent fatality risk factor used in transportation risk assessments for heavy diesel trucks in urban areas is revised and the analysis expanded to provide risk factors for rural areas and all diesel truck classes. These latter fatality estimates may include, but are not limited to, cancer fatalities and are based primarily on the most recent epidemiological data available on mortality rates associated with ambient air PM-10 concentrations.     

Compressed Natural Gas Bus Safety: A Quantitative Risk Assessment

This study assesses the fire safety risks associated with compressed natural gas (CNG) vehicle systems, comprising primarily a typical school bus and supporting fuel infrastructure. The study determines the sensitivity of the results to variations in component failure rates and consequences of fire events. The components and subsystems that contribute most to fire safety risk are determined. Finally, the results are compared to fire risks of the present generation of diesel-fueled school buses. Direct computation of the safety risks associated with diesel-powered vehicles is possible because these are mature technologies for which historical performance data are available. Because of limited experience, fatal accident data for CNG bus fleets are minimal. Therefore, this study uses the probabilistic risk assessment (PRA) approach to model and predict fire safety risk of CNG buses. Generic failure data, engineering judgments, and assumptions are used in this study. This study predicts the mean fire fatality risk for typical CNG buses as approximately 0.23 fatalities per 100-million miles for all people involved, including bus passengers. The study estimates mean values of 0.16 fatalities per 100-million miles for bus passengers only. Based on historical data, diesel school bus mean fire fatality risk is 0.091 and 0.0007 per 100-million miles for all people and bus passengers, respectively. One can therefore conclude that CNG buses are more prone to fire fatality risk by 2.5 times that of diesel buses, with the bus passengers being more at risk by over two orders of magnitude. The study estimates a mean fire risk frequency of 2.2 x 10(-5) fatalities/bus per year. The 5% and 95% uncertainty bounds are 9.1 x 10(-6) and 4.0 x 10(-5), respectively. The risk result was found to be affected most by failure rates of pressure relief valves, CNG cylinders, and fuel piping.     

Risk Analysis of Finnish Peacekeeping in Kosovo

The research team interviewed over 90 Finnish battalion members in Kosovo, visited 22 units or posts, registered its observations, and made any necessary measurements. Key persons were asked to list the most important risks for occupational safety and health in their area of responsibility. Altogether, 106 accidents and 40 cases of disease resulted in compensation claims in 2000. The risks to the peacekeeping force were about twice those of the permanent staff of military trainees in Finland. Altogether, 21 accidents or cases of disease resulted in sick leave for at least 3 months after service. One permanent injury resulted from an explosion. Biological, chemical, and physical factors caused 8 to 9 occupational illnesses each. Traffic accidents, operational factors, and munitions and mines were evaluated to be the three most important risk factors, followed by occupational hygiene, living conditions (mold, fungi, dust), and general hygiene. Possible fatal risks, such as traffic accidents and munitions and explosives, received a high ranking in both the subjective and the objective evaluations. One permanent injury resulted from an explosion, and two traffic accidents involved a fatality, although not of a peacekeeper. The reduction of sports and military training accidents, risk-control programs, and, for some tasks, better personal protection is considered a development challenge for the near future.     

Job insecurity in temporary versus permanent workers: Associations with attitudes, well-being, and behaviour

Recent research suggests that the relationship between job insecurity and psychological outcomes is more negative among permanent compared with temporary workers. We investigate possible interaction effects between job insecurity and type of contract (temporary versus permanent) for various psychological outcomes (job satisfaction, organizational commitment, life satisfaction, and self-rated performance), some of which have received little attention. We aim to explain these interaction effects, while taking into account the heterogeneous nature of temporary workers in terms of tenure, employment prospects, and wish to do temporary employment. We argue that permanent workers expect higher levels of job security; job insecurity breaches permanent workers' but not temporary workers' expectations. This may relate to unfavourable outcomes. Similarly, the heterogeneous nature of temporary workers may relate to job security expectations and thus to reactions to job insecurity. This study was conducted on a sample of 477 temporary and permanent workers from various occupational sectors in Belgium. The results suggested that the interaction effect between job insecurity and contract type may be limited to job satisfaction and organizational commitment. Furthermore, permanent workers had higher expectations about job security. Breach of these expectations furthermore mediated the relationship between job insecurity and all outcomes, except for self-rated performance. However, the heterogeneity indicators were found to be unrelated to job security expectations.     

Dose-Response and Risk Assessment of Airborne Hexavalent Chromium and Lung Cancer Mortality

This study evaluates the dose-response relationship for inhalation exposure to hexavalent chromium [Cr(VI)] and lung cancer mortality for workers of a chromate production facility, and provides estimates of the carcinogenic potency. The data were analyzed using relative risk and additive risk dose-response models implemented with both Poisson and Cox regression. Potential confounding by birth cohort and smoking prevalence were also assessed. Lifetime cumulative exposure and highest monthly exposure were the dose metrics evaluated. The estimated lifetime additional risk of lung cancer mortality associated with 45 years of occupational exposure to 1 microg/m3 Cr(VI) (occupational exposure unit risk) was 0.00205 (90%CI: 0.00134, 0.00291) for the relative risk model and 0.00216 (90%CI: 0.00143, 0.00302) for the additive risk model assuming a linear dose response for cumulative exposure with a five-year lag. Extrapolating these findings to a continuous (e.g., environmental) exposure scenario yielded an environmental unit risk of 0.00978 (90%CI: 0.00640, 0.0138) for the relative risk model [e.g., a cancer slope factor of 34 (mg/kg-day)-1] and 0.0125 (90%CI: 0.00833, 0.0175) for the additive risk model. The relative risk model is preferred because it is more consistent with the expected trend for lung cancer risk with age. Based on statistical tests for exposure-related trend, there was no statistically significant increased lung cancer risk below lifetime cumulative occupational exposures of 1.0 mg-yr/m3, and no excess risk for workers whose highest average monthly exposure did not exceed the current Permissible Exposure Limit (52 microg/m3). It is acknowledged that this study had limited power to detect increases at these low exposure levels. These cancer potency estimates are comparable to those developed by U.S. regulatory agencies and should be useful for assessing the potential cancer hazard associated with inhaled Cr(VI).     

Residential Building Codes,Affordability, and Health Protection: A Risk-Tradeoff Approach

Residential building codes intended to promote health and safety may produce unintended countervailing risks by adding to the cost of construction. Higher construction costs increase the price of new homes and may increase health and safety risks through income and stock effects. The income effect arises because households that purchase a new home have less income remaining for spending on other goods that contribute to health and safety. The stock effect arises because suppression of new-home construction leads to slower replacement of less safe housing units. These countervailing risks are not presently considered in code debates. We demonstrate the feasibility of estimating the approximate magnitude of countervailing risks by combining the income effect with three relatively well understood and significant home-health risks. We estimate that a code change that increases the nationwide cost of constructing and maintaining homes by $150 (0.1% of the average cost to build a single-family home) would induce offsetting risks yielding between 2 and 60 premature fatalities or, including morbidity effects, between 20 and 800 lost quality-adjusted life years (both discounted at 3%) each year the code provision remains in effect. To provide a net health benefit, the code change would need to reduce risk by at least this amount. Future research should refine these estimates, incorporate quantitative uncertainty analysis, and apply a full risk-tradeoff approach to real-world case studies of proposed code changes.     

A Risk Assessment for Occupational Acrylonitrile Exposure Using Epidemiology Data

The extensive data from the Blair et al.((1)) epidemiology study of occupational acrylonitrile exposure among 25460 workers in eight plants in the United States provide an excellent opportunity to update quantitative risk assessments for this widely used commodity chemical. We employ the semiparametric Cox relative risk (RR) regression model with a cumulative exposure metric to model cause-specific mortality from lung cancer and all other causes. The separately estimated cause-specific cumulative hazards are then combined to provide an overall estimate of age-specific mortality risk. Age-specific estimates of the additional risk of lung cancer mortality associated with several plausible occupational exposure scenarios are obtained. For age 70, these estimates are all markedly lower than those generated with the cancer potency estimate provided in the USEPA acrylonitrile risk assessment.((2)) This result is consistent with the failure of recent occupational studies to confirm elevated lung cancer mortality among acrylonitrile-exposed workers as was originally reported by O'Berg,((3)) and it calls attention to the importance of using high-quality epidemiology data in the risk assessment process.     

Potential exposures and risks from beryllium-containing products.

Beryllium is the strongest of the lightweight metals. Used primarily in military applications prior to the end of the Cold War, beryllium is finding new applications in many commercial products, including computers, telecommunication equipment, and consumer and automotive electronics. The use of beryllium in nondefense consumer applications is of concern because beryllium is toxic. Inhalation of beryllium dust or vapor causes a chronic lung disease in some individuals at concentrations as low as 0.01 microg/m3 in air. As beryllium enters wider commerce, it is prudent to ask what risks this might present to the general public and to workers downstream of the beryllium materials industry. We address this question by evaluating the potential for beryllium exposure from the manufacturing, use, recycle, and disposal of beryllium-containing products. Combining a market study with a qualitative exposure analysis, we determine which beryllium applications and life cycle phases have the largest exposure potential. Our analysis suggests that use and maintenance of the most common types of beryllium-containing products do not result in any obvious exposures of concern, and that maintenance activities result in greater exposures than product use. Product disposal has potential to present significant individual risks, but uncertainties concerning current and future routes of product disposal make it difficult to be definitive. Overall, additional exposure and dose-response data are needed to evaluate both the health significance of many exposure scenarios, and the adequacy of existing regulations to protect workers and the public. Although public exposures to beryllium and public awareness and concern regarding beryllium risks are currently low, beryllium risks have psychometric qualities that may lead to rapidly heightened public concern.     

The Economic Impact of Health Policy Interventions

The rapid aging of the U.S. population, increases in the absolute prevalence of chronic diseases, and the associated rise in the proportion of the GNP expended on medical care all indicate the need for methods to accurately forecast future health care expenditures for specific chronic diseases. Additionally, if these methods are biomedically realistic, they can be used to evaluate the economic implications of specific prevention strategies designed to reduce chronic disease incidence, prevalence, and mortality. Projection strategies that are not biomedically realistic, such as models that assume that risks for demographic subgroups do not change over time (e.g., "static component" models), though possibly accurate over the short run, are not suitable for assessing the long term effects of specific proposed health policy interventions which are designed to alter risks.
In this paper we present a strategy for forecasting health care costs which is based on a model that represents the natural history of a chronic disease in terms of a preclinical state, a clinical state, case fatality rates, cures, and the implications of exogenous medical factors. Using this model we project that the treatment costs associated with respiratory cancer in the white male population of the U.S. may undergo a two-thirds increase in real dollars over the period 1977 to 2000. About one-half of this increase is due to a demographic shift to an older population structure, with the remainder due to higher respiratory cancer incidence rates in younger cohorts. Alteration of certain parameters of the model to simulate various interventions suggests that about three-quarters of the cost of this disease could be eliminated, though realization of any significant part of this savings would require a lengthy phase-in period.     

Determinants of perceived occupational stress among Chinese offshore oil workers

This is the first comprehensive study to explore the determinants of perceived sources of occupational stress among workers in the rapidly expanding Chinese offshore oil industry. In this study we surveyed 561 Chinese workers in a state-owned oil company using a questionnaire that measured occupational stress and Type A personality behaviour (TABP), social support and other socio-demographic data. Occupational stress was assessed by the Occupational Stress Scale, adapted from the questionnaire developed in previous studies (Cooper & Sutherland, 1987; Sutherland & Cooper, 1996). Using factor analyses, we identified nine sources of stress: 'interface between job and family/social life'; 'career and achievement'; 'safety'; 'management problems and relationship with workmates'; 'physical environment of workplace'; 'living environment'; 'managerial role'; 'ergonomics'; and 'organizational structure'. We performed hierarchical regression analyses on each source of stress with variables reflecting socio-demographic characteristics, TABP and social support. Better-educated workers perceived more stress from the interface between their job and family or social life and career achievement, but less stress from ergonomics. Type A workers perceived more stress from career achievement and the living environment. Social support was significantly associated with four sources of stress. Workers with different job titles perceived stress from different sources. Our findings imply that, in the stress management of offshore oil workers, different strategies and methods could be applied to different occupational groups, and to workers with different personalities and socio-demographic characteristics.     

Tools for Comparative Analysis of Alternatives: Competing or Complementary Perspectives?

A third generation of environmental policy making and risk management will increasingly impose environmental measures, which may give rise to analyzing countervailing risks. Therefore, a comprehensive analysis of all risks associated with the decision alternatives will aid decision-makers in prioritizing alternatives that effectively reduce both target and countervailing risks. Starting with the metaphor of the ripples caused by a stone that is thrown into a pond, we identify 10 types of ripples that symbolize, in our case, risks that deserve closer examination: direct, upstream, downstream, accidental risks, occupational risks, risks due to offsetting behavior, change in disposable income, macro-economic changes, depletion of natural resources, and risks to the manmade environment. Tools to analyze these risks were developed independently and recently have been applied to overlapping fields of application. This suggests that either the tools should be linked in a unified framework for comparative analysis or that the appropriate field of application for single tools should be better understood. The goals of this article are to create a better foundation for the understanding of the nature and coverage of available tools and to identify the remaining gaps. None of the tools is designed to deal with all 10 types of risk. Provided data suggest that, of the 10 types of identified risks, those associated with changes in disposable income may be particularly significant when decision alternatives differ with respect to their effects on disposable income. Finally, the present analysis was limited to analytical questions and did not capture the important role of the decision-making process itself.     

Residential Radon in Canada: An Uncertainty Analysis of Population and Individual Lung Cancer Risk

Following a comprehensive evaluation of the health risks of radon, the U.S. National Research Council (US-NRC) concluded that the radon inside the homes of U.S. residents is an important cause of lung cancer. To assess lung cancer risks associated with radon exposure in Canadian homes, we apply the new (US-NRC) techniques, tailoring assumptions to the Canadian context. A two-dimensional uncertainty analysis is used to provide both population-based (population attributable risk, PAR; excess lifetime risk ratio, ELRR; and life-years lost, LYL) and individual-based (ELRR and LYL) estimates. Our primary results obtained for the Canadian population reveal mean estimates for ELRR, PAR, and LYL are 0.08, 8%, and 0.10 years, respectively. Results are also available and stratified by smoking status (ever versus never). Conveniently, the three indices (ELRR, PAR, and LYL) reveal similar output uncertainty (geometric standard deviation, GSD approximately 1.3), and in the case of ELRR and LYL, comparable variability and uncertainty combined (GSD approximately 4.2). Simplifying relationships are identified between ELRR, LYL, PAR, and the age-specific excess rate ratio (ERR), which suggest a way to scale results from one population to another. This insight is applied in scaling our baseline results to obtain gender-specific estimates, as well as in simplifying and illuminating sensitivity analysis.