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Background: The beryllium lymphocyte proliferation test (Be-LPT) measures beryllium-specific cellular immune response, and is useful in medical surveillance of beryllium sensitivity and chronic beryllium disease (CBD)., Methods: Current and former employees (n = 12,194) of 18 United States Department of Energy (DOE) sites were tested for beryllium sensitization at four laboratories with Be-LPT expertise. Beryllium sensitized individuals were offered evaluations for CBD. The sensitivity, specificity, and positive predictive value (PPV) of the Be-LPT were determined, as was inter- and intra-laboratory agreement., Results: False positives were calculated to be 1.09%, with a laboratory range of 0.00-3.35% for the 10-year investigation. Be-LPTs performed on inter-laboratory split blood specimens from sensitized individuals showed a false negative rate of 31.7%. The intra-laboratory repeatability of abnormal Be-LPT results ranged from 80.4-91.9%. The sensitivity of the Be-LPT was determined to be 0.683, with a specificity of 0.969. The PPV of one abnormal Be-LPT was 0.253., Conclusions: The Be-LPT is efficacious in medical surveillance of beryllium-exposed individuals. The PPV of the Be-LPT is comparable to other widely accepted medical tests. Confirmation of an abnormal result is recommended to assure appropriate referral for CBD medical evaluation., (Copyright 2004 Wiley-Liss, Inc.)

The prevalence of beryllium sensitization and chronic beryllium disease by job category was examined among individuals tested in the Rocky Flats Beryllium Health Surveillance Program. The program offered ongoing beryllium health surveillance for any current or former employee who believed they may have been exposed to beryllium at the Rocky Flats Environmental Technology Site. Of the 18,589 living individuals contacted, 7,573 requested participation and 6,614 (87.3%) eventually participated. Of this group, 78.2 percent were found to have verifiable job and building histories. The beryllium lymphocyte proliferation test was used to identify beryllium-sensitized individuals. Sensitization and chronic beryllium disease rates were analyzed with respect to gender, building work location(s), and length of employment at Rocky Flats. Several job categories and buildings were strongly associated with the 81 cases of chronic beryllium disease and the additional 154 cases of beryllium sensitization in this population. Beryllium sensitization was highest among beryllium machinists, 11.4 percent (odds ratio = 3.04, compared to the remainder of those tested, 95 % confidence interval = 1.48, 3.97) and health physics technicians, 11.9 percent (odds ratio = 2.87, 95% confidence interval = 1.12, 7.36). However, odds ratios were also increased among custodial employees, 5.64 percent (odds ratio = 1.30, 95% confidence interval = 0.92, 1.85) and other job titles that were thought to have only minimal potential for exposure to beryllium.

The Rocky Flats Beryllium Health Surveillance Program (BHSP), initiated in June 1991, was designed to provide medical surveillance for current and former employees exposed to beryllium. The BHSP identifies individuals who have developed beryllium sensitivity using the beryllium lymphocyte proliferation test (BeLPT). A detailed medical evaluation to determine the prevalence of chronic beryllium disease (CBD) is offered to individuals identified as beryllium sensitized or to those who have chest X-ray changes suggestive of CBD. The BHSP has identified 27 cases of CBD and another 74 cases of beryllium sensitization out of 4268 individuals tested. The distribution of BeLPT values for normal, sensitized, and CBD-identified individuals is described. Based on the information collected during the first 3 1/3 years of the BHSP, the BeLPT is the most effective means for the early identification of beryllium-sensitized individuals and to identify individuals who may have CBD. The need for BeLPT retesting is demonstrated through the identification of beryllium sensitization in individuals who previously tested normal. Posterior/anterior chest X-rays were not effective in the identification of CBD.

The first case of chronic beryllium disease (CBD) at the Rocky Flats Environmental Technology Site (Rocky Flats) was diagnosed in a machinist in 1984. Rocky Flats, located 16 miles northwest of Denver, Colorado, is part of the United States Department of Energy (DOE) nuclear weapons complex. Research and development operations using beryllium began at Rocky Flats in 1953, and beryllium production operations began in 1957. Exposures could have occurred during foundry operations, casting, shearing, rolling, cutting, welding, machining, sanding, polishing, assembly, and chemical analysis operations. The Beryllium Health Surveillance Program (BHSP) was established in June 1991 at Rocky Flats to provide health surveillance for beryllium exposed employees using the Lymphocyte Proliferation Test (LPT) to identify sensitized individuals. Of the 29 cases of CBD and 76 cases of beryllium sensitization identified since 1991, several cases appear to have had only minimal opportunistic exposures to beryllium, since they were employed in administrative functions rather than primary beryllium operations. In conjunction with other health surveillance programs, a questionnaire and interview are administered to obtain detailed work and health histories. These histories, along with other data, are utilized to estimate the extent of an individual's exposure. Additional surveillance is in progress to attempt to characterize the possible risks from intermittent or brief exposures to beryllium in the workplace.

This paper demonstrates that current standards used by the Occupational Safety and Health Administration (OSHA) to establish an area free from potential beryllium contamination may be inadequate. Using the Beryllium Antibody Assay, it was shown that workers exposed to former beryllium work areas, thought to be sanitized and to meet OSHA standards, experienced statistically significant rises in blood beryllium antibody titers. This finding raises the question of whether the equipment currently required to protect workers in beryllium-laden environments is sufficient. The project mission of decommissioning/decontaminating the former nuclear weapons plant at Rocky Flats Environmental Technology Site (RFETS), instituted in 1992, has necessitated development of new technology directed toward safe and responsible cleanup. Challenges have been posed not only by the need to dispose of radioactive and chemical waste, but also by the problem of cleaning up hazardous metals such as the element beryllium. Beryllium was used extensively in research and the manufacture of nuclear weapons components at Rocky Flats for over 40 years. Since inhalation of this element can induce chronic beryllium disease (Eisenbud and Lisson, 1983), an antibody assay was developed to screen workers for internal exposure to beryllium. Exposure is indicated by a titer of antibodies greater than two standard deviations above a normal population control (defined as the mean titer of pooled samples from 51 individuals with no known exposure to beryllium) and a p-value of < 0.05. This paper describes two new applications for the assay: risk assessment and health surveillance. Case study 1 involves a team of three workers who cleaned a beryllium plenum and whose beryllium antibody titers provided a quantitative assessment of their exposure. Case study 2 describes the use of the antibody assay to determine the probable manner in which one worker was exposed to beryllium while performing his duties as an architectural engineer.