Potential significance of airborne fiber dimensions measured in the US refractory ceramic fiber manufacturing industry

Background To determine dimensions of airborne fibers in the U.S. refractor y ceramic fiber (RCF) manufacturing industry, fibers collected though perso nal air sampling for employees at RCF manufacturing and processing operatio ns have been measured. Methods Data were derived from transmission electron microscopy analyses of 118 air samples collected over a 20-year period. Results Characteristics of sized fibers include: diameter measurements of < 0.19 to 1.0 mu m, of which 75% are less than 0.6 mu m; and length ranging from < 0.6 to > 20 mu m, with 68% of fibers between 2.4 and 20 mu m. Conclusions Exposures in RCF manufacturing include airborne fibers with dim ensions (diameter < 0.1-0.4 mu m, length < 10 mu m) historically associated with biological effects in pleural tissues. Air sampling data and a review of studies relating fiber size to pleural effects in animals and humans su pport the belief that information on fiber dimensions is essential for stud ies with synthetic vitreous fibers. Am. J. Ind. Med. 36:286-298, 1999. (C) 1999 Wiley-Liss, Inc.