Forty-one public schools in Colorado were drawn at random and surveyed for asbestos-containing materials. After bulk samples of possible asbestos materials from the schools were collected and analyzed, the K2 asbestos screening test was used to eliminate samples that did not contain asbestos. Samples with positive results on the K2 test were analyzed by an outside laboratory by polarized light microscopy. The risk of potential exposure presented by these materials was then assessed for each site from which a sample was taken. Of 113 samples collected, results were negative for asbestos for only 10.6 percent by the K2 test. Of the 101 samples for which results were positive, 56 actually contained 1 or more forms of asbestos. Twelve of these 56 samples were from sprayed material; the remaining 44 were from other materials containing asbestos. Of the 41 schools sampled, 31 had asbestos materials in one of more locations. The potential exposure values for these materials ranged from very low to very high, but the majority had high-exposure potentials. Estimates based on the survey of the 41 schools indicated that 63 to 89 percent of the public schools in Colorado have asbestos materials that present potentially serious hazards, not only to the children, teachers, and staff, but also to members of the community who use the school buildings after regular school hours.