In Libby, Mont., mining of asbestos-contaminated vermiculite—a natural insulating material—sickened or killed many workers and townspeople in recent decades. Now, a study finds that even 16 years after the vermiculite mine closed, area trees hold substantial amounts of asbestos, rendering them hazardous to a separate group of workers.
Logging is a major employer for people around Libby. With asbestos a potential contaminant in dust, Tony J. Ward of the University of Montana in Missoula and his colleagues wondered whether asbestos from the mining operations might have settled on local trees.