Abstract
Composite materials such as carbon fiber/epoxy composites are becoming an increasingly important structural component of modern aircraft. The release of carbon fibers from their epoxy matrix during combustion has generated concern from both a personal exposure hazard standpoint and from an electrical equipment hazard standpoint. This study reports the results of air sampling for particulates conducted after the crash and burn of an aircraft containing approximately 590 kg (1300 lb) of carbon fiber composites. Air samples were taken for fiber counts by optical microscopy, by respirable and nonrespirable gravimetric analysis, and for gravimetric analysis using a personal cascade impactor. The results indicated that particulate levels from undisturbed wreckage were minimal. Particulate levels at or over recommended exposure limits were generated when the wreckage was disturbed for investigation and site remediation. The generated particulates were mainly of a nonrespirable size (greater than 10 µm). Particulates observed daring optical microscopy analysis for fiber counting did not appear to be carbon fibers. Current recommended personal protective procedures seemed to offer adequate protection from Particulate levels detected for on-site personnel.