Anthophyllite asbestos from Staten Island, New York: Longitudinal fiber splitting.

Asbestos ore was sampled from a historical anthophyllite mine in Staten Island, New York. High-resolution transmission electron microscopy (HRTEM) was used to image the structure of nineteen fibers of the anthophyllite asbestos. The anthophyllite was characterized by a high level of chain width disorder, involving wide chain multiplicity faults (CMFs) that were frequent in fibers, randomly spaced, and ranged from one to eight chains in width. This chain width disorder was manifest by streaking of electron diffraction rows of chain width. The anthophyllite asbestos fibers were found to be produced by longitudinal splitting rather than crystal growth. Such splitting is a function of cleavage along CMFs rather than crystal boundaries. The morphology of the fibers is consistent with anthophyllite asbestos mined in Finland associated with lung cancer and mesothelioma. These findings may have regulatory implications.