A Novel Approach for the In-Situ Chemical Elimination of Chrysotile from Asbestos-Containing Fireproofing Materials

We report here the development of a method for the chemical digestion of chrysotile asbestos in asbestos-containing fireproofing to levels lower than the regulatory threshold. The resulting fireproofing, no longer defined as asbestos-containing, can remain in place with properties intact. In the process, chrysotile fibers are digested without generating excessive gaseous byproducts, and the foam-based delivery system essentially eliminates release of airborne fibers. New X-ray diffraction methods quantified chrysotile levels with far greater precision than standard optical microscopic methods. Full-scale field testing confirmed the laboratory phase of the project. Fire testing of the treated fireproofing showed th at the treated material functions as well as the original fireproofing.