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Cross-Sectional Study on Respiratory Morbidity in Workers After Exposure to Synthetic Amorphous Silica at Five German Production Plants: Exposure Assessment and Exposure Estimates

Morfeld, Peter; Taeger, Dirk; Mitura, Heike; Bosch, Axel; Nordone, Adrian; Vormberg, Reinhard; McCunney, Robert; Merget, Rolf

Journal of Occupational and Environmental Medicine: January 2014 - Volume 56 - Issue 1 - p 72–78
doi: 10.1097/JOM.0000000000000055
Original Articles

Objectives: Synthetic amorphous silicas (SASs) are nanostructured polymorphs of silicon dioxide. We compared two different exposure assessments.

Methods: This study estimated cumulative exposure to inhalable SAS dust in 484 male workers from five German SAS-producing plants. Two procedures (P1 and P2) were applied. P1 was based on an expert assessment. P2 was a multiple exposure assessment (15 scenarios) anchored by a recent measurement series (1375 personal measurements of inhalable SAS dust concentration) and used expert assessments.

Results: Cumulative exposure estimates for P1 averaged 56.9 mg/m3·yrs (range, 0.1 to 419); for a selected P2 scenario, the mean was 31.8 mg/m3·yrs (range, 0.4 to 480), (P < 0.0001). Averages varied between the 15 P2-scenarios from 12.6 to 109.6 mg/m3·yrs. Different time trends for SAS concentrations were observed.

Conclusions: Both approaches suffer from considerable uncertainties that need to be considered in epidemiological studies.

Supplemental Digital Content is Available in the Text.

From the Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries AG (Mr Morfeld), Essen, Germany; Institute and Policlinic for Occupational Medicine (Mr Morfeld), Environmental Medicine and Prevention Research, University of Cologne, Cologne, Germany; Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (Mr Taeger and Mr Merget), Institute of the Ruhr-Universität Bochum (IPA), Bochum, Germany; AQura GmbH (Mr Mitura), Hanau, Germany; Wacker Chemie AG (Mr Bosch), Burghausen, Germany; Cabot Corporation (Mr Nordone), Boston, Mass; Evonik Industries (Mr Vormberg), Hanau, Germany; and Massachusetts Institute of Technology (Mr McCunney), Boston, Mass.

Address correspondence to: Peter Morfeld, Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries AG, Rellinghauser Straße 1-11, 45128 Essen, Germany (

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The authors declare no conflicts of interest.

Copyright © 2014 by the American College of Occupational and Environmental Medicine