Chrysotile vs. Libby Amphibole
Important differences in physiological responses to fiber types are being observed.
Because of their flexible morphology, Chrysotile fibers were the most commonly used commercial fiber type.
Most of the medical science we have learned has been based on disease caused by Chrysotile fibers, not Amphibole.
Unlike other ARD populations, diffuse highly inflamed pleuritis has an increased incidence in Libby Amphibole disease, causing intense chest pain, rare in Chrysotile disease.
Significant lung disease from Chrysotile typically presents after prolonged occupational exposure.
Disease caused by Chrysotile typically manifests as pleural disease with primary progression being evident as increased interstitial fibrosis, with chest pain and rapid progression being rare.
Chrysotile Fibers are less bio-persistent, having a shorter half life than amphiboles, disease latency is typically around 10 years from exposure.
Disease from LA results from lower cumulative exposure, often times primarily environmental.
Disease caused by LA typically manifests as progressive pleural disease with minimal to mild interstitial fibrosis.
Amphibole fibers have extended bio-persistence, LA diseases typically have a latency of 10-40 years.
Vermiculite, a non-toxic fibrous mineral rock formation, was discovered in Lincoln County, Montana, in 1916 by E.N. Alley. Alley formed the Zonolite Company and began commercial production of vermiculate in 1921. Virtually all vermiculite mined from Zonolite Mountain was contaminated with one of the more toxic forms of asbestos called Libby Amphibole asbestos.