The report reviews control technology applicable to asbestos emissions from open sources including asbestos mines, mills, and manufacturing waste piles. It combined a literature review with visits to asbestos mining and manufacturing operations, and considered climatology, location, and topography. The study, which included preliminary field sampling, produced a comprehensive bibliography on emissions control. The health effects of asbestos exposure were reviewed from two aspects: the significance of fiber size, and the effect of non-occupational exposure. Fiber size considered to be most harmful is still not established and, while non-occupational exposure probably does not lead to asbestosis, evidence relates it to increased incidence of cancer. Data analyses indicated that asbestos can be detected at considerable distances from a given source. It was concluded that, because of their proximity to populations, asbestos manufacturing waste piles are a threat to public health more serious than asbestos mining.