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Managing Health Effects of Beryllium Exposure
7
Designing a Beryllium Exposure-and Disease-Management Program for Workers in the Air Force
Beryllium sensitization (BeS), chronic beryllium disease (CBD), and lung cancer are the principal health concerns related to exposure to beryllium. Because of a lack of quantitative risk information on low exposure and uncertainties associated with factors that contribute to the development of CBD (see Chapter 3), the committee was unable to identify a chronic inhalation exposure level that is unlikely to produce BeS or CBD. Therefore, the committee recommended, in Chapter 3, that an exposure- and disease-management program be implemented to manage potential health risks posed by exposure to beryllium. This chapter provides some general guidelines for designing a preventive program.
EXISTING MEDICAL SCREENING OR SURVEILLANCE PRACTICES
Published beryllium exposure-management programs are summarized in Table 7-1. Deubner and Kent (2007) describe Brush Wellman’s extensive beryllium-management program. The goals of the program are to keep beryllium work areas clean; to keep beryllium out of the lungs, off the skin, and off clothing in the work process, in the work area, and on the plant site; and to keep workers prepared to work safely. On the basis of surveillance data, the program reduced BeS from 18% (before program implementation) to 1.1% in 24 months. Cummings et al. (2007) present an analysis of sensitization rates before and after the implementation of Brush Wellman’s enhanced beryllium-management program. They also document a BeS reduction associated with the program. The postimplementation sensitization rate was 1%, similar to that in the study by
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Managing Health Effects of Beryllium Exposure
TABLE 7-1 Summary of Published Beryllium Exposure-Management Programs
Workers
Program Components
Comments
Reference
Brush Wellman workers
Respiratory protection
Dermal protection
Work-area and plant hygiene practices
Worker training
Program implementation reduced BeS to 1.1% in new workers
Deubner and Kent 2007
Atomic-weapons workers in United Kingdom
Engineering controls
Respiratory protection
Work-area hygiene practices
Medical surveillance for CBD
Program generally keeps exposures below 2 µg/m3 Only one case of CBD in 400 workers
Johnson et al. 2001
Beryllium workers
For workers:
Understand risks
Avoid inhalation and skin contact
Avoid dust-suspending activities
Participate in medical surveillance
NIOSH 2008
For employers:
Knowing beryllium content of all materials
Substitution of less hazardous materials, if feasible
Minimizing number of workers exposed
Engineering controls
Keeping airborne concentrations as low as possible
Exposure monitoring
Risk communication
Confining beryllium contamination to work area
Respiratory protection
Dermal protection
Medical surveillance
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Managing Health Effects of Beryllium Exposure
DOE and DOE contractor workers with potential beryllium exposure
Baseline inventory to identify operations and locations of potential beryllium contamination
Hazard assessment
Initial exposure monitoring
Limitation of access to areas containing beryllium
Reduction and minimization of exposures through engineering and work-practice controls
Keeping exposures below PEL of 2.0 μg/m3
Provision of respirators when requested by workers
Setting of action level at 0.2 μg/m3 (8-h TWA)
Maintaining removable surface contamination below 3 μg/100 cm2 in designated beryllium-handling areas and below 0.2 μg/100 cm2 when released to the public or for nonberyllium use
For all areas exceeding action level, provision of protective respiratory, clothing, and other equipment; periodic monitoring; regulation of access to that area; installation of hygiene facilities and institution of hygiene practices; posting of warning signs
Medical surveillance of all beryllium-associated workers
Training of workers who could potentially be exposed
Counseling of workers who have diagnosis of BeS or CBD
Offer of medical-removal protection to sick or sensitized workers
Accurate records of all information gathered
Monitoring of the effectiveness of the program and provision of performance feedback
10 CFR 850
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Managing Health Effects of Beryllium Exposure
Deubner and Kent. The sensitization rate in preimplementation workers was 8%. Johnson et al. (2001) described a beryllium-management program for atomic-weapons establishments in the United Kingdom. That program is similar to the Brush Wellman program. Its adoption reduced exposures to less than 2 µg/m3. The facility has documented only one case of CBD, which was detected by using a medical monitoring program that did not include the beryllium lymphocyte proliferation test (BeLPT). That CBD case is considered unique in that it probably occurred as a result of a systemic reaction to beryllium oxide contamination of a cut. This facility does not routinely evaluate BeS with the BeLPT, so the effect of the program on sensitization and early-stage CBD is unknown.
Several approaches for screening or surveillance of beryllium workers can be found in the scientific literature (see Table 7-2 for some examples). Most of the studies have focused on evaluating the performance of the BeLPT, and were not designed to determine the appropriate selection of tests and the optimal frequency of testing for medical surveillance and screening. As indicated in the table, a questionnaire has been used in most of the studies to include occupational history, occupational exposure, and medical information (such as smoking history, previous respiratory disease, respiratory and dermatologic symptoms, fatigue, weight loss, and medication use). Use of the BeLPT has been included in most surveillance and screening programs since the test has been available; an exception is the UK atomic weapons facility, where the BeLPT was used until the middle 1980s and is now only used on request (Johnson et al. 2001).
CONSIDERATIONS FOR THE AIR FORCE
The committee had little information on current or former workers and the extent or structure of the workforce with potential beryllium exposure, such as enlisted personnel, civilian employees, and subcontractors. The prevalence of BeS or CBD (if any) in Air Force personnel is not known, inasmuch as the service has not performed any systematic surveillance of its workers for BeS or CBD. Thus, the proposed beryllium exposure- and disease-management program described below is a general outline of a program that should be tailored to the Air Force’s needs as more information becomes available.
Figure 7-1 shows a framework for minimizing personnel exposure and risks posed by exposure to aerosolized beryllium in the Air Force. Key aspects of the framework are discussed below, and general recommendations for monitoring and testing are provided. The first years in which the management program is in place will include a period of information-gathering, when more is learned about the type of workplace settings with beryllium exposure in the Air Force and about the prevalence of BeS and CBD, if any, in the settings. With time, the initial testing and monitoring practices should be refined as more information is gathered on the specific risks of BeS and CBD in the Air Force and as any new research findings appear in the scientific literature. In addition, the
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TABLE 7-2 Medical Screening Tests Used in Beryllium-Exposed Populations
Workers
Cross-Sectional or Repeated Test Intervals
Tests
Reference
Aluminum smelter
Annual
Qx, spirometry, BeLPT
Taiwo et al. 2008
Beryllium-material production
At hire; 3, 6, 12, 24 mon
BeLPT
Deubner and Kent 2007
Brush Wellman plants
At hire; 3, 6, 12, 24, 48 mon
BeLPT
Donovan et al. 2007
Ceramic
At hire; 3, 6, 12, 24, 48 mon
BeLPT
Cumming et al. 2007
Copper-beryllium alloy distribution
CS
Qx, BeLPT
Stanton et al. 2006
Copper-beryllium alloy
CS
Qx, BeLPT
Schuler et al. 2005
Nuclear facility
CS
Qx, spirometry, CXR, BeLPT
Sackett et al. 2004
DOE nuclear facility
CS
Qx, CXR, BeLPT
Welch et al. 2004
Machining
Every 2 y (new and rehired within 3 mon of starting)
Qx, BeLPT
Newman et al. 2001
UK atomic-weapons facility
Monthly spirometry, annual CXR
Clinical and physical examinations, spirometry, CXR (BeLPT used until middle 1980s, then only if requested)
Johnson et al. 2001
Mining and milling
Quarterly or annual PFT, including DLCO and CXR since 1969, then 1996-1997 Qx and BeLPT
PFT, CXR, later BeLPT, Qx
Deubner et al. 2001a
Ceramic
Annual Qx, PFT, CXR; CS BeLPT in 1992, 1998
Qx, CXR, PFT, BeLPT
Henneberger et al. 2001
Metal alloy and oxide
CS
Qx, BeLPT
Kreiss et al. 1997
Ceramic
CS
Qx, BeLPT, CXR
Kreiss et al. 1996
Nuclear
Two tests at 3-y intervals
Qx, CXR, BeLPT
Stange et al. 1996b
Ceramic
CS
Qx, BeLPT, CXR
Kreiss et al. 1993a
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Managing Health Effects of Beryllium Exposure
Workers
Cross-Sectional or Repeated Test Intervals
Tests
Reference
Nuclear
CS
Qx, BeLPT, CXR, spirometry
Kreiss et al. 1993b
Nuclear machining
CS
Qx, BeLPT, CXR, spirometry
Kreiss et al. 1989
Beryllium factory
Every 3 y since 1977
Qx, spirometry, CXR, blood gases
Kriebel et al. 1988
Mine and mill
Twice at 3-y intervals
Spirometry, BeLPT
Rom et al. 1983
Abbreviations: BeLPT, beryllium lymphocyte proliferation test; CS, cross-sectional; CXR, chest x ray; DLCO, carbon monoxide diffusing capacity; DOE, Department of Energy; PFT, pulmonary-function test; Qx, questionnaire.
findings from the management program should be used to consider whether it would be prudent to evaluate beryllium exposures and potential risks to former Air Force workers.
FIGURE 7-1 Beryllium exposure- and disease-management program.
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Managing Health Effects of Beryllium Exposure
Exposure Assessment
A detailed exposure assessment is a key element of a beryllium-management program. The exposure-assessment strategy should be modeled after the recommendations contained in the American Industrial Hygiene Association’s manual for assessing and managing occupational exposures (Ignacio and Bullock 2006). Briefly, the strategy should begin with an initial job or task characterization. The purpose of the initial characterization is to identify all jobs and tasks that have a potential for skin or respiratory beryllium exposure. Beryllium-containing materials should be characterized as to where they are used or were used in the past, their alloy content, their potential for contact that could lead to dermal or inhalation exposure, and the presence of any exposure controls. After the basic characterization, exposures should be assessed with air and surface sampling. As noted in Chapter 2, there are several analytic approaches for detecting airborne beryllium. Air samples are typically measured by either flame atomic absorption spectroscopy or inductively-coupled plasma atomic emission spectrometry, but other methods are available (see Chapter 2). Given the available Air Force sampling data, a method should be chosen that maximizes analytical sensitivity. For jobs or tasks identified as having detectable airborne beryllium, consideration should be given to determining the beryllium particle size distribution by using stationary or personal cascade impactors. Determining the particle size distribution may require pooling samples related to a given job or task to provide detectable quantities of beryllium. Beryllium surface sampling should conform with standard practices (such as the Department of Energy’s Chronic Beryllium Disease Prevention Program, 64 Fed. Reg. 68854 [1999]). Samples with surface beryllium exceeding background levels of removable contamination on equipment surfaces should be investigated for the source of contamination. The goal of sampling is to identify jobs that entail detectable airborne or dermal exposure. Workers in those jobs should be targeted for exposure reduction and medical monitoring.
Exposure Reduction and Prevention
Measures should be taken to prevent skin and respiratory exposure to beryllium to the greatest extent possible. The control measures detailed in the National Institute for Occupational Safety and Health (NIOSH 2008) draft document on Preventing Chronic Beryllium Disease and Beryllium Sensitization and similar resources from DOE (10 CFR 850) and Brush Wellman (Deubner and Kent 2007). The measures include the following:
Know the beryllium content of all materials in the workplace. The manufacturers or suppliers of materials containing more than 0.1% beryllium are required to provide this information on material-safety data sheets. Upstream-
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production information might be needed to assemble a comprehensive list of materials used by the Air Force and its subcontractors.
Substitute less hazardous materials for those containing beryllium whenever feasible.
Keep airborne concentrations of beryllium as low as possible because no safe exposure limit for beryllium is known.
Minimize the number of workers exposed to beryllium dusts, fumes, and contaminated surfaces.
Install, use, and maintain effective engineering controls for processes that create beryllium dusts and fumes.
Monitor airborne beryllium concentrations to document the effectiveness of efforts to reduce airborne exposure.
Inform workers about the risks of BeS, CBD, and lung cancer and the proper procedures for working with beryllium-containing materials.
Keep beryllium dusts and fumes confined to the immediate work area.
Avoid the use of cleaning methods that may cause dust to become resuspended in air (for example, dry sweeping, use of compressed air, and other dust-generating methods).
Prevent beryllium dusts and other contamination from leaving beryllium work areas on equipment or workers’ skin, clothing, shoes, and tools.
Identify and clean areas in and outside the beryllium work zone that may have become contaminated before these recommendations were implemented.
Establish and maintain an appropriate respiratory-protection program.
Establish and maintain a skin-protection program to protect workers’ skin from contamination with beryllium dusts and solutions by keeping work surfaces and work areas clean; providing work gloves, long-sleeved shirts, long pants, and shoes that remain at the workplace; and providing showering and changing facilities.
Worker Education and Training Programs
Worker education and training programs should be in place and should include education of all new and current workers with potential for beryllium exposure as to health risks of beryllium, appropriate exposure reduction, and use of skin and respiratory protective equipment. Such programs have been implemented in a beryllium-products manufacturing plant (Deubner and Kent 2007) and in the Department of Energy’s CBD-prevention program (DOE 2001). A similar program should be tailored to the Air Force’s work settings and workforce. Such a program could be coordinated with informing workers about the surveillance and medical-management program. The information provided should include the role of various screening and surveillance tests, risks related to the tests, and the health and occupational implications of positive test results. Education and training materials should developed to include information about
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the medical and employment implications of the results of the BeLPT test and about potential long-term health risks after exposure ends.
Identifying Workers Who Have Beryllium Sensitization or Chronic Beryllium Disease
On the basis of the initial exposure evaluation, Air Force workers with exposure to beryllium—including civilian employees, onsite subcontractors, and workers who may be exposed incidentally—should be evaluated for possible BeS, and those with confirmed BeS should be further evaluated for CBD (see Figure 7-2). The medical screening program, including the BeLPT and diagnosis and management of workers with BeS and CBD, is described in greater detail below. Data from the screening program should be entered into the centralized database to facilitate evaluation of the effectiveness of the program and guide modifications (see discussion below).
FIGURE 7-2 Medical monitoring approach.
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Limiting the Number of Beryllium Workers
Limiting the number of workers exposed to beryllium in the Air Force is consistent with the industrial-hygiene hierarchy of controls. The workers should not only be skilled in operations involving beryllium but be trained in and committed to the safe use of beryllium and control of beryllium exposure as part of the overall beryllium-management plan. Medical screening and surveillance can then be targeted to the workers. Some aspects of this approach have been described in a report of an enhanced preventive model in a large beryllium-products manufacturing plant (Deubner and Kent 2007). The authors described limiting the number of workers exposed to beryllium and reducing worker turnover in areas of beryllium exposure, and they described a wall-enclosed, restricted access zone. They reported that those measures were implemented until engineering control changes could be completed at the plant. They also described enhanced worker preparation through training, education, and motivation.
Centralized Surveillance Database
Data obtained from the beryllium exposure-assessment and worker-surveillance programs at each Air Force site should be entered into a centralized surveillance database (Figure 7-1). Data should include airborne and surface beryllium-sampling data, job and task information, use of personal protective equipment, and clinical information, such as demographics, smoking, job history, results of the BeLPT, spirometry, and additional testing (for example, high-resolution computed tomography and bronchoscopy). The prevalence of BeS and CBD should be determined, and assessments made of possible associations between prevalence and jobs and tasks or exposure. That information should then be used to refine and modify the program. For example, specific sites or job tasks with a higher prevalence of BeS might require greater attention to exposure control or more frequent medical monitoring. The effectiveness of the exposure-reduction plan on quantitative airborne and surface beryllium-sampling data should also be evaluated. In addition to facilitating assessment of the prevalence of BeS and CBD in Air Force workers and the effectiveness of the program, the database could be used as a resource by investigators. The database should include followup clinical data on all workers identified with BeS and CBD so that questions regarding natural history and risk factors for progression can be addressed.
SPECIFICS OF THE MEDICAL SCREENING PROGRAM
Initial Medical Screening
The committee advises that after workers have undergone education and training, including education as to the potential risks and benefits associated
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with the screening procedures, there be initial screening of all workers with potential for beryllium exposure, including new hires before placement and current employees, and continuing screening of new hires and workers who might be moved from areas of no exposure to areas with potential exposure to beryllium. Each entering and current worker with potential beryllium exposure should receive baseline medical screening that includes a questionnaire, chest radiography, spirometry, and the BeLPT. The questionnaire should include at least demographic information, lifetime workplace exposure history, smoking history, and history of respiratory and dermal disease and symptoms. The BeLPT test should be performed in accordance with the testing algorithm in Appendix B. BeLPT results from initial testing and any necessary retesting should be evaluated and recorded before a worker is allowed to begin work with potential exposure to beryllium.
Outcome of Initial Medical Screening
Initial findings of the questionnaire, chest radiography, and spirometry should be reviewed by an appropriately trained medical provider to determine appropriate job placement and medical followup. Results of the BeLPT test (according to the algorithm in Appendix B) will determine whether the worker is sensitized to beryllium. Those who are not sensitized and have no other findings of concern should be monitored regularly. The frequency of all screening measures cannot be advised with confidence, because no studies have evaluated the optimal interval between screenings. Table 7-2 illustrates the measures that have been used for screening and the intervals used. For examples, the questionnaire has been administered at intervals of 3-12 months, and chest radiography at intervals of 1-3 years at different facilities. Similarly, the frequency of the BeLPT cannot be advised with confidence, because no published studies have addressed it. Some studies have identified development of BeS within 4-8 months of first beryllium exposure in new hires in some work settings, but the clinical importance of detection at 4 months rather than at 1 year has not been determined. In the absence of a clear current estimate of risk in the Air Force, it is suggested that there be initial screening and that the frequency of repeat screening be guided in part by the extent of abnormalities detected. The frequency and extent of monitoring will probably depend on several factors, including information on exposure and the risk of BeS and CBD identified on initial screening. Initially, when there may be some uncertainty as to the risk to the workforce, it would be reasonable to consider annual medical monitoring for those with potential beryllium exposure. The data obtained from exposure assessment and medical monitoring should be collected centrally and reviewed regularly to allow determination of work areas and types of jobs carrying exposure risks and to allow some determination as to the degree of risks of BeS and CBD in exposed workers. Such knowledge should lead to better exposure controls and may allow modification of the program to optimize the frequency of medical monitoring and to
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determine the relative effectiveness of modes of screening. Others have suggested that the optimal frequency of medical monitoring may be between 1 and 5 years after the initial assessment (Maier 2001; Judd et al. 2003).
BeLPT results that are not reported as normal should be addressed as outlined in Appendix B. An abnormal BeLPT result, unexplained abnormalities seen in chest radiography or spirometry, unexplained respiratory symptoms, or other symptoms should lead to further medical assessment. Potentially, there can be an adverse effect on workers of almost any medical investigation, including emotional stress during a wait for test results. Identification of radiographic abnormalities that may not have true clinical significance can lead to more invasive tests (such as bronchoscopy or open lung biopsy), which have associated risks.
If a worker with evidence of BeS is undergoing further evaluation for possible CBD, investigations would probably include full pulmonary-function tests and high-resolution computed tomography (HRCT) scans of the chest, which pose minimal risk. Bronchoscopy with bronchoalveolar lavage and biopsies poses greater risk and, although generally a sensitive method of diagnosing CBD, may not be appropriate or necessary for all workers with BeS. For example, a worker with an abnormal HRCT scan showing diffuse opacities or pulmonary-function abnormalities might, after evaluation of the risks and benefits related to bronchoscopy, obtain a presumptive diagnosis without undergoing bronchoscopy. A worker with BeS who is asymptomatic and has normal pulmonary-function test results, carbon monoxide diffusing capacity, and HRCT may not want to undergo bronchoscopy, unless abnormalities are found in a regular followup. A worker with BeS or other medical screening results that suggest CBD should be offered removal from beryllium exposure (discussed further below).
Outcome of Further Clinical Evaluation
After the clinical evaluation, there are three possible outcomes:
No CBD and no BeS. These workers will be advised that they can continue their previous jobs and have routine periodic medical screening. Other medical conditions (not related to beryllium) identified in the clinical evaluation should be managed as they would be for non–beryllium-exposed workers.
BeS but no CBD. There is insufficient evidence to determine clearly the effect of continuation of work in an area with potential beryllium exposure for those with BeS. Although BeS is a predictor of CBD, it is not known whether (and by how much) additional beryllium exposure increases the risk of progression to CBD. That uncertainty should be communicated to a sensitized worker, who should be given the opportunity to work in areas without further beryllium exposure with medical removal protection. Workers with BeS who wish to con-
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tinue to work in an area with potential beryllium exposure should be closely monitored to detect CBD.
CBD. Workers with CBD should discontinue work in areas that have beryllium exposure because of concern about worsening the disease. Although the effect of continuing exposure to beryllium at relatively low concentrations has not been clearly shown, the potential for CBD to become serious suggests that, given the current state of knowledge, it is prudent to avoid further beryllium exposure. Workers with CBD should continue to receive regular medical followup. Workers with CBD who discontinue work with beryllium should receive medical removal protection. If workers understand the risk and elect to continue exposure, their exposure should be kept as low as feasible, and they should have regular medical followup and regular advice about the risk of disease progression.