title: Fiber size and number in workers exposed to processed chrysotile asbestos, chrysotile miners, and the general population.
abstract: We analyzed chrysotile and chrysotile-associated amphibole (largely tremolite) asbestos fibers in 21 workers exposed to various types of processed (milled) chrysotile ore, 20 long-term chrysotile miners, and 20 members of the general population (controls). Significantly greater amounts of both chrysotile and tremolite were found in processed-ore workers and miners than in controls. On average, the mean fiber lengths and aspect ratios for the mining and processed-ore-exposed workers were similar and were significantly greater than the values seen in the controls; within the processed-ore group, there was a marked variation in these parameters, and some workers appeared to be exposed to fairly long, thin fibers. It was found empirically that the fiber size data, and to a lesser extent the concentration data, could be used to classify workers accurately into those with processed-ore exposure and controls. We conclude that fiber sizes in the lungs of processed-ore-exposed workers are similar to those of chrysotile miners and are considerably longer than those found in the general population; some processed-ore workers have longer fibers which might be responsible for higher disease incidences in certain working groups; tremolite accompanies chrysotile in a variable proportion of workers exposed to processed chrysotile products and might be important in the genesis of mesothelioma in such workers; and mineralogic analysis will usually detect exposure even when chrysotile has largely disappeared from lung tissue.
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D001194:Asbestos / Q000032:analysis*; D017636:Asbestos, Amphibole; D017632:Asbestos, Serpentine; D001344:Autopsy; D006801:Humans; D008168:Lung / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008906:Mining; D012824:Silicic Acid / Q000032:analysis
chemical_list: D000395:Air Pollutants, Occupational; D017636:Asbestos, Amphibole; D017632:Asbestos, Serpentine; D001194:Asbestos; D012824:Silicic Acid; C005846:tremolite