On-site detection of asbestos at the surface of building materials wasted at disaster sites by staining.

We have developed a method to detect asbestos by staining the surface of building materials in order to quickly detect asbestos-containing building materials at disaster sites. After staining, asbestos was easily detected by the color and characteristic shape of the images observed under a stereomicroscope. The type of asbestos was confirmed to be chrysotile by polarized light microscopy, X-ray diffraction patterns, and Raman spectra. The percentage of the area of asbestos at the surface of building materials was also determined by an image analyzer after the dye staining, and the distribution percentage of asbestos increased with its total concentration in the building material. Three-dimensional X-ray computed tomography images showed that asbestos was mainly distributed at the surface of building materials. This result suggests that the asbestos at the surface of debris of building materials is more easily and sensitively detected than total asbestos analysis by pulverization. The present method was applied to detect and determine asbestos in debris of building materials wasted at temporary storage sites after disaster and on the wall of a building in use. Therefore, this method can contribute to the classification of asbestos-containing and non-asbestos-containing building materials at disaster sites and demolition sites, as well as to preliminary inspections for the detection of asbestos-containing building materials before demolition of houses and buildings.