Asbestos containing materials become a health hazard once they are disturbed. Intact, asbestos fibers embedded within construction materials, components, and rock are inert and do not pose a health hazard; however, once they are disturbed, through physical contact such as land grading or building renovation and demolition activities, asbestos fibers may be rendered airborne. The California Air Resources Board has identified asbestos as a toxic air contaminant.  

Asbestos Brochure