Release of Aerosols during Sawing and Milling of Beryllium Metal and Beryllium Alloys

Risk of beryllium sensitization in a low-exposed former nuclear weapons cohort from the Cold War era

BACKGROUND

The nuclear weapons industry has long been known as a source of beryllium exposure.

METHODS

A total of 1,004 former workers from a nuclear weapons assembly site in the Midwest were screened for sensitization to beryllium (BeS). The screenings were part of the Department of Energy (DOE) Former Worker Program established in 1996.

RESULTS

Twenty-three (2.3%) workers were found sensitized to beryllium and this prevalence was comparable to other DOE sites. Occasional, direct exposure to beryllium through machining and grinding of copper-beryllium (Cu-Be) 2% alloy tools was found to increase the risk of sensitization compared to background exposure (OR = 3.83; 95% CI: 1.04-14.03) with a statistically significant trend (P = 0.03) revealing that particular jobs are associated with sensitization. Exposure potential in this study was estimated based on job titles and not personal exposure information.

CONCLUSIONS

These results confirm the need to screen workers using beryllium alloy tools in other industries and for consideration of altering work practices.

Beryllium aerosol characteristics in the magnesium and aluminum transformation industry in Quebec: a comparison of four different sampling methodologies

To examine the influence of the sampling method on beryllium (Be) exposure assessment, a study was conducted in foundries and smelters to contrast the performance of five different dust sampling devices. Six sampling surveys were conducted in four different settings, and both personal and fixed station samples were collected using the following sampling heads: IOM samplers (inhalable dust), 35-mm plastic cassettes (total dust), aluminum SKC cyclones (respirable dust), 8-stage Sierra cascade impactors, and 12-stage MOUDI impactors. In total, beryllium concentrations were determined for 66/68 inhalable dust samples, 62/62 total dust samples, 56/57 respirable dust samples, 54/64 8-stage Sierra samples, and 19/25 12-stage MOUDI samples. In the magnesium foundry and aluminum smelters, the concentrations obtained during specific tasks could exceed the actual permissible exposure limit of the province of Quebec (0.15 microg/m(3)) or of the ACGIH threshold limit value (TLV) (0.05 microg/m(3)). The median of median dust concentration ratios computed from the sampling heads at the fixed station decreased as follows: IOM (1.00) > Sierra (0.76) > 37-mm cassette (0.61) > MOUDI (0.48) > respirable (0.12). The same trends were observed with the ratios of the median of median Be concentrations at the fixed station but with a larger scattering within sampling heads as follows: IOM (1.00) > Sierra (0.69) > 37-mm cassette (0.64) > MOUDI (0.54) > respirable (0.19). The median of median ratios of dust (IOM (1.00) > Sierra (0.56) > 37-mm cassette (0.35) > respirable (0.06)) and Be (IOM (1.00) > Sierra (0.66) > 37-mm cassette (0.48) > respirable (0.11)) in dust were lower, and there was less scattering for the 37-mm cassette and SKC cyclone used during breathing zone sampling than for the same sampling heads at the fixed station. Inhalable aerosol measurements should remain the tool for estimating the risk of exposure to beryllium in these settings until a clear dose response is established for these sampling heads.

Beryllium: A Modern Industrial Hazard

Beryllium exposure can cause a granulomatous lung disease in workers who develop a lymphocyte-mediated sensitization to the metal. Workers in diverse industries are at risk because beryllium's properties are critical to nuclear, aerospace, telecommunications, electronic, metal alloy, biomedical, and semiconductor industries. The occupational air concentration standard's failure to protect beryllium workers is driving many scientific and occupational health advances. These developments include study of bioavailability of different physicochemical forms of beryllium, medical surveillance to show effectiveness of skin protection in preventing sensitization in high-risk processes, gene-environment interaction, transgenic mice for use in experimental research, and risk-based management of industrial exposures in the absence of effective exposure-response information. Beryllium sensitization and disease prevention are paradigms for much broader public health action in both occupational and general population settings.

Bérylliose Pulmonaire Chronique : un modèle d’interaction entre environnement et prédisposition génétique (1re partie)

INTRODUCTION

The physico-chemical properties of beryllium (Be) are crucial for high technology industries. The inhalation of beryllium may cause, in certain individuals, a specific sensitisation (BeS) and lead, in some of them, to a pulmonary granulomatosis called chronic pulmonary berylliosis (CPB).

BACKGROUND

Although there is no linear relationship between the level of exposure to Be and the risks of BeS and CPB, the highest exposures are associated with an increased risk. The specific influences of the chemical composition, the solubility and different types of Be on the risk of BeS an CPB are poorly understood. Insoluble particles of small diameter are probably associated with an increased risk. Many studies have reported the role of a genetic predisposition in the risk of BeS and CPB. At present the role of HLA-DPB1 Glu69 in sensitisation to Be is the best studied.

CONCLUSION

Sensitisation to Be and CPB result from the combination of exposure and predisposing genetic polymorphisms. CPB is a model for the understanding of the pathology of certain ideopathic pulmonary granulomatoses such as sarcoidosis.

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 microns and < 1 micron in aerodynamic diameter. Cumulative exposure was calculated as sigma (job title exposure estimate x years in job title). Individual lifetime-weighted (LTW) exposure was calculated as sigma [(job title exposure x years in job title) divided by 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 micrograms/m3-years in the cases versus 1.2 micrograms/m3-years in the controls for total exposure, and 1.7 micrograms/m3-years in the cases versus 0.5 microgram/m3-years in the controls for exposure to particles < 6 microns 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 microgram/m3 in both groups. The median LTW exposure to particles < 6 microns was 0.20 microgram/m3 in the cases compared with 0.14 microgram/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 microgram/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.

Aerosols generated during beryllium machining

Some beryllium processes, especially machining, are associated with an increased risk of beryllium sensitization and disease. Little is known about exposure characteristics contributing to risk, such as particle size. This study examined the characteristics of beryllium machining exposures under actual working conditions. Stationary samples, using eight-stage Lovelace Multijet Cascade Impactors, were taken at the process point of operation and at the closest point that the worker would routinely approach. Paired samples were collected at the operator's breathing zone by using a Marple Personal Cascade Impactor and a 35-mm closed-faced cassette. More than 50% of the beryllium machining particles in the breathing zone were less than 10 microns in aerodynamic diameter. This small particle size may result in beryllium deposition into the deepest portion of the lung and may explain elevated rates of sensitization among beryllium machinists.