Air samples for asbestos (1332214) were collected at the Certain Teed Products Company (SIC-3292) in Hillsboro, Texas during January, 1966. General, personal, and breathing zone samples were collected from approximately 20 representative operations including pipe preparation, waste crushing, sand blasting, air spraying, general materials handling, and servicing areas. Samples were collected either by the impinger or membrane filter method. Fiber counts ranged from 0.5 to 1.9 million particles per cubic foot (mppcf) for general area samples and from 0.5 to 0.8mppcf for breathing zone samples, by the impinger collection method. Fiber counts ranged from 0.3 to 23.8 fibers per cubic centimeter (F/cc) for personal samples, 0.7 to 30.4F/cc for breathing zone samples, and 2.9 to 26.0F/cc for general areas, by the membrane collection method. Fiber size ranged from 0.2 to 5.8 microns. The greatest dust concentrations were found at waste crushing, pipe finishing, and curing operations and in the warehouse and mixing areas.