Beryllium sensitization and disease among long-term and short-term workers in a beryllium ceramics plant.
OBJECTIVE
Workers at a beryllium ceramics plant were tested for beryllium sensitization and disease in 1998 to determine whether the plant-wide prevalence of sensitization and disease had declined since the last screening in 1992; an elevated prevalence was associated with specific processes or with high exposures; exposure-response relationships differed for long-term workers hired before the last plant-wide screening and short-term workers hired since then.


METHODS
Current workers were asked to complete a questionnaire and to provide blood for the beryllium lymphocyte proliferation test (BeLPT). Those with an abnormal BeLPT were classified as sensitized, and were offered clinical evaluation for beryllium disease. Task- and time-specific measurements of airborne beryllium were combined with individual work histories to compute mean, cumulative, and peak beryllium exposures for each worker.


RESULTS
The 151 participants represented 90% of 167 eligible workers. Fifteen (9.9% of 151) had an abnormal BeLPT and were split between long-term workers (8/77 = 10.4%) and short-term workers (7/74 = 9.5%). Beryllium disease was detected in 9.1% (7/77) of long-term workers but in only 1.4% (1/74) of short-term workers (P = 0.06), for an overall prevalence of 5.3% (8/151). These prevalences were similar to those observed in the earlier survey. The prevalence of sensitization was elevated in 1992 among machinists, and was still elevated in 1998 among long-term workers (7/40 = 18%) but not among short-term workers (2/36 = 6%) with machining experience. The prevalence of sensitization was also elevated in both groups of workers for the processes of lapping, forming, firing, and packaging. The data suggested a positive relationship between peak beryllium exposure and sensitization for long-term workers and between mean, cumulative, and peak exposure and sensitization for short-term workers, although these findings were not statistically significant. Long-term workers with either a high peak exposure or work experience in forming were more likely to have an abnormal BeLPT (8/51 = 16%) than the other long-term workers (0/26, P = 0.05). All seven sensitized short-term workers either had high mean beryllium exposure or had worked longest in forming or machining (7/55 = 13% versus 0/19, P = 0.18).


CONCLUSIONS
A plant-wide decline in beryllium exposures between the 1992 and 1998 surveys was not matched by a decline in the prevalence of sensitization and disease. Similar to findings from other studies, beryllium sensitization/disease was associated with specific processes and elevated exposures. The contrast in disease prevalence between long-term and short-term workers suggests that beryllium sensitization can occur after a short period of exposure, but beryllium disease usually requires a longer latency and/or period of exposure. The findings from this study motivated interventions to more aggressively protect and test workers, and new research into skin exposure as a route of sensitization and the contribution of individual susceptibility.
Henneberger
P K
PK
Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, M/S H-2800, Morgantown, WV 26505, USA. pkh0@cdc.gov
Cumro
D
D
Deubner
D D
DD
Kent
M S
MS
McCawley
M
M
Kreiss
K
K
D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000032:analysis; D001607:Berylliosis / Q000453:epidemiology*; D001608:Beryllium / Q000009:adverse effects* / Q000032:analysis; D002516:Ceramics / Q000009:adverse effects / Q000032:analysis; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D004391:Dust / Q000009:adverse effects / Q000032:analysis; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology*; D016014:Linear Models; D008213:Lymphocyte Activation; D016273:Occupational Exposure; D011159:Population Surveillance; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013997:Time Factors
D000395:Air Pollutants, Occupational; D004391:Dust; D001608:Beryllium