Epidemiological studies of mining populations exposed to nonasbestiform amphibole dusts were summarized. The study groups consisted of taconite miners in Minnesota who were exposed to amphiboles such as cummingtonite (17499080), grunerite (14567614), actinolite (77536664), and hornblende (12178426); miners at the Homestake gold mine in South Dakota who were exposed to cummingtonite, grunerite, actinolite, tremolite (14567738), and hornblende; miners at the Sydvaranges iron mine in Norway who were exposed to cummingtonite, grunerite, actinolite, and hornblende; and Labradoran iron miners who were exposed to cummingtonite, grunerite, and other amphiboles. Mortality studies found no evidence of asbestos like effects such as deaths from lung cancer or mesothelioma at any of the mining sites. Statistically significant elevations of mortality from silicosis were seen in the Homestake mine and from a mixed dust pneumoconiosis in the Labrador iron mines. This was attributed to exposure to silica (14808607) and combined exposure to iron oxides plus silica, respectively. The author concludes that no evidence of asbestos like effects has been found in four mining operations where occupational exposure to nonasbestiform amphibole fibers has been confirmed. There does not appear to be any reason to control exposures to nonasbestiform amphiboles in a manner similar to that required for asbestos.