To gather information on work practices and engineering controls that can be effectively used to control occupational exposure to fibrous glass, Calspan Corporation conducted field surveys and a literature search, and consulted with unions, trade groups, and medical experts in the field. Forty field surveys were conducted, including glass textile, glass and mineral wool manufacturers; fine fiber producers and users; glass-reinforced plastic operations; and appliance, filter, and vehicle manufacturers; as well as commercial and residential insulation installers. The variation in conditions from plant to plant with age and sector of the industry (mineral wool, glass wool, glass textiles) is most striking. While most of the newer, glass-textile and glass-wool and mineral-wool plants are well-lit, comfortable, and pay obvious attention to cleanliness, a few of the older mineral-wool plants represent the absolute antithesis of this. In some cases, the air (although of relatively low respirable fiber count according to samples taken by NIOSH) produced an accumulation of fiber on the clothing of the survey personnel and considerable "fiber itch" after the few hours of exposure during surveying.