Site Activities

The most critical public health hazards are associated with a particular form of asbestos mined near Libby, Montana, a small town in the extreme northwest corner of the state. The rock quarried here from1920 to 1990 is termed Libby amphibole and was used to produce vermiculite through a process known as exfoliation.

The best available records of shipments of this rock are for the period of 1964 to 1990 when more than 4.1 million tons were shipped to at least 254 sites across the United States. It is estimated that 95 percent of these shipments went to 105 sites – 28 of which have been investigated by ATSDR and the various state and local public health agencies.

The results of these studies comprise the Summary Report of 28 Sites.