A. James Ruttenber

Beryllium particulate exposure and disease relations in a beryllium machining plant.

We examined the relationship between exposure to beryllium and the presence of beryllium sensitization (BeS) and chronic beryllium disease (CBD) in a cohort of workers in a beryllium precision machining facility. Twenty workers with BeS or CBD (cases) were compared with 206 worker-controls in a case-control study. Exposure for each job title was measured using cascade impactors placed in the workers’ breathing zone to measure total beryllium exposure and exposure to particles <6 &mgr;m and <1 &mgr;m in aerodynamic diameter. Cumulative exposure was calculated as &Sgr; (job title exposure estimate × years in job title). Individual lifetime-weighted (LTW) exposure was calculated as &Sgr; [(job title exposure × years in job title) ÷ total years employment)]. Workers in the case group were more likely to have worked as machinists (odds ratio, 4.4; 95% confidence interval, 1.1 to 17.5) than those in the control group. The median cumulative exposure was consistently greater in the cases compared with the controls for all exposure estimates and particle size fractions, although this was not statistically significant. The median cumulative exposure was 2.9 &mgr;g/m3-years in the cases versus 1.2 &mgr;g/m3-years in the controls for total exposure, and 1.7 &mgr;g/m3-years in the cases versus 0.5 &mgr;g/m3-years in the controls for exposure to particles <6 &mgr;m in diameter. With cumulative exposure categorized into low-, intermediate-, and high-exposure groups, the odds ratios were 2.4 (95% confidence interval, 0.7 to 8.2) for the intermediate-exposure group and 1.2 (95% confidence interval, 0.4 to 4.2) for the high-exposure group compared with the low-exposure group. The median LTW exposure was 0.25 &mgr;g/m3 in both groups. The median LTW exposure to particles <6 &mgr;m was 0.20 &mgr;g/m3 in the cases compared with 0.14 &mgr;g/m3 in the controls. The differences in cumulative and LTW exposure were not statistically significant. None of the 22 workers with LTW exposure <0.02 &mgr;g/m3 had BeS or CBD. Twelve workers (60%) in the case group had LTW exposures >0.20. In conclusion, increased cumulative and LTW exposure to total and respirable beryllium was observed in workers with CBD or BeS compared with the controls. These results support efforts to control beryllium exposure in the workplace.

Exposure Databases and Exposure Surveillance: Promise and Practice

Based on recent developments in occupational health and a review of industry practices, it is argued that integrated exposure database and surveillance systems hold considerable promise for improving workplace health and safety. A foundation from which to build practical and effective exposure surveillance systems is proposed based on the integration of recent developments in electronic exposure databases, the codification of exposure assessment practice, and the theory and practice of public health surveillance. The merging of parallel, but until now largely separate, efforts in these areas into exposure surveillance systems combines unique strengths from each subdiscipline. The promise of exposure database and surveillance systems, however, is yet to be realized. Exposure surveillance practices in general industry are reviewed based on the published literature as well as an Internet survey of three prominent industrial hygiene e-mail lists. Although the benefits of exposure surveillance are many, relatively few organizations use electronic exposure databases, and even fewer have active exposure surveillance systems. Implementation of exposure databases and surveillance systems can likely be improved by the development of systems that are more responsive to workplace or organizational-level needs. An overview of exposure database software packages provides guidance to readers considering the implementation of commercially available systems. Strategies for improving the implementation of exposure database and surveillance systems are outlined. A companion report in this issue on the development and pilot testing of a workplace-level exposure surveillance system concretely illustrates the application of the conceptual framework proposed.

Lung Fibrosis in Plutonium Workers

Abstract Newman, L. S., Mroz, M. M. and Ruttenber, A. J. Lung Fibrosis in Plutonium Workers. Radiat. Res. 164, 123–131 (2005). There have been few systematic studies of the non-malignant health effects of α-particle radiation in humans. Animal studies and a report on plutonium-exposed workers from Russia suggest an association between high doses to the lung from plutonium exposure and the development of fibrotic lung disease. Prompted by a case of lung fibrosis in a retired plutonium worker, we tested the hypothesis that plutonium inhalation increases the risk for developing chest radiograph abnormalities consistent with pulmonary fibrosis. We conducted a retrospective study of nuclear weapons workers that included estimating absorbed doses to the lung with an internal dosimetry model. Our study population consisted of 326 plutonium-exposed workers with absorbed lung doses from 0 to 28 Sv and 194 unexposed workers. We compared the severity of chest radiograph interstitial abnormalities between the two groups using the International Labour Organization profusion scoring system. There was a significantly higher proportion of abnormal profusion scores among plutonium-exposed workers (17.5%) than among unexposed workers (7.2%), P < 0.01. Lung doses of 10 Sv or greater conferred a 5.3-fold risk (95% CI 1.2–23.4) of having an abnormal chest X ray consistent with pulmonary fibrosis when compared with unexposed individuals after controlling for the effects of age, smoking and asbestos exposure. This study shows that plutonium may cause lung fibrosis in humans at absorbed lung doses above 10 Sv.

Integrating Workplace Exposure Databases for Occupational Medicine Services and Epidemiologic Studies at a Former Nuclear Weapons Facility

We outline methods for integrating epidemiologic and industrial hygiene data systems for the purpose of exposure estimation, exposure surveillance, worker notification, and occupational medicine practice. We present examples of these methods from our work at the Rocky Flats Plant--a former nuclear weapons facility that fabricated plutonium triggers for nuclear weapons and is now being decontaminated and decommissioned. The weapons production processes exposed workers to plutonium, gamma photons, neutrons, beryllium, asbestos, and several hazardous chemical agents, including chlorinated hydrocarbons and heavy metals. We developed a job exposure matrix (JEM) for estimating exposures to 10 chemical agents in 20 buildings for 120 different job categories over a production history spanning 34 years. With the JEM, we estimated lifetime chemical exposures for about 12,000 of the 16,000 former production workers. We show how the JEM database is used to estimate cumulative exposures over different time periods for epidemiological studies and to provide notification and determine eligibility for a medical screening program developed for former workers. We designed an industrial hygiene data system for maintaining exposure data for current cleanup workers. We describe how this system can be used for exposure surveillance and linked with the JEM and databases on radiation doses to develop lifetime exposure histories and to determine appropriate medical monitoring tests for current cleanup workers. We also present time-line-based graphical methods for reviewing and correcting exposure estimates and reporting them to individual workers.

Development and piloting of an exposure database and surveillance system for DOE cleanup operations

An industrial hygiene exposure database and surveillance system was developed in partnership between National Institute for Occupational Safety and Health (NIOSH)-funded independent investigators and practicing industrial hygienists at the Rocky Flats Environmental Technology Site (RFETS) in Golden, Colo. RFETS is a former U.S. Department of Energy nuclear weapons plant that is now in cleanup phase. This project is presented as a case study in the development of an exposure database and surveillance system in terms that are generalizable to most other industries and work contexts. Steps include gaining organizational support; defining system purpose and scope; defining database elements and coding; planning practical and efficient analysis strategies; incorporating reporting capabilities; and anticipating communication strategies that maximize the probability that surveillance findings will feed back to preventive applications. For each of these topics, the authors describe both general considerations as well as the specific choices made for this system. An important feature of the system is a two-tier task-coding scheme comprising 33 categories of task groups. Examples of grouped analyses of exposure data captured during the system pilot period demonstrate applications to exposure control, medical surveillance, and other preventive measures.

Cleanup worker exposures to hazardous chemicals at a former nuclear weapons plant: piloting of an exposure surveillance system.

Cleanup of former U.S. Department of Energy (DOE) nuclear weapons production facilities involves potential exposures to various hazardous chemicals. We have collaboratively developed and piloted an exposure database and surveillance system for cleanup worker hazardous chemical exposure data with a cleanup contractor at the Rocky Flats Environmental Technology Site (RFETS). A unique system feature is the incorporation of a 34-category work task-coding scheme. This report presents an overview of the data captured by this system during development and piloting from March 1995 through August 1998. All air samples collected were entered into the system. Of the 859 breathing zone samples collected, 103 unique employees and 39 unique compounds were represented. Breathing zone exposure levels were usually low (86% of breathing zone samples were below analytical limits of detection). The use of respirators and other exposure controls was high (87 and 88%, respectively). Occasional high-level excursions did occur. Detailed quantitative summaries are provided for the six most monitored compounds: asbestos, beryllium, carbon tetrachloride, chromium, lead, and methylene chloride. Task and job title data were successfully collected for most samples, and showed specific cleanup activities by pipe fitters to be the most commonly represented in the database. Importantly, these results demonstrate the feasibility of the implementation of integrated exposure database and surveillance systems by practicing industrial hygienists employed in industry as well as the preventive potential and research uses of such systems. This exposure database and surveillance system--the central features of which are applicable in any industrial work setting--has enabled one of the first systematic quantitative characterizations of DOE cleanup worker exposures to hazardous chemicals.

Computer-generated time lines for visualizing and editing epidemiological and biomedical data

Most biomedical data have a temporal dimension. Time-line displays spatialize this dimension and help the viewer comprehend large sets of complex data. If we add ways for users to selectively expand the details of data visible on a time line, even more information can be organized and accessed. Design issues for this kind of display include: how to display time scales that are often wider than the physical display space; how to display events with brief duration; how to display data for two or more events that overlap in time; how to manage the display of data details; how to allow database editing from a time line; and how to facilitate time-based analytical techniques. We describe a time-line display system that addresses each of these issues, and show how it can be used to organize data for an epidemiological study of parental radiation exposure and childhood leukemia. We also suggest further refinements of the time line technique for other biomedical applications.