Skip Navigation LinksHome > November 2012 - Volume 54 - Issue 11 > Mesothelioma Associated With Commercial Use of Vermiculite C...
Journal of Occupational & Environmental Medicine:
doi: 10.1097/JOM.0b013e318250b5f5
Original Articles

Mesothelioma Associated With Commercial Use of Vermiculite Containing Libby Amphibole

Dunning, Kari K. PhD; Adjei, Stephen MD, MPH; Levin, Linda PhD; Rohs, Amy M. MD, MS; Hilbert, Tim MS; Borton, Eric MS; Kapil, Vikas DO, MPH; Rice, Carol PhD; LeMasters, Grace K. PhD; Lockey, James E. MD, MS

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Objectives: To describe asbestos-related mortality among manufacturing workers who expanded and processed Libby vermiculite that contained amphibole fiber.

Methods: Standardized mortality ratio was calculated for 465 white male workers 31 years after last Libby vermiculite exposure.

Results: Two workers died from mesothelioma, resulting in a significantly increased standardized mortality ratio of 10.5 (95% confidence interval, 1.3 to 38.0). These workers were in the upper 10th percentile of cumulative fiber exposure, that is, 43.80 and 47.23 fiber-years/cm3, respectively. One additional worker with cumulative fiber exposure of 5.73 fiber-years/cm3 developed mesothelioma but is not deceased. There were no other significantly increased standardized mortality ratios.

Conclusions: Workers expanding and processing Libby vermiculite in a manufacturing setting demonstrated an increased risk for the development of mesothelioma following exposure to the amphibole fiber contained within this vermiculite ore source.

©2012The American College of Occupational and Environmental Medicine


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