Can the TRW provide any suggestions or examples on when it might be warranted to conduct indoor dust or air sampling at sites based on residential yard soil results?
• The primary factors that would seem to pose the greatest potential for impacting the indoor of homes would be 1) close proximity of residences to the exfoliation facility, resulting in airborne deposition of asbestos fibers into the home or 2) presence of waste material, known to have high concentrations of Libby amphiboles, on the exterior of the residential property resulting in the potential for physical tracking of fibers into the home. In the past, EPA has focused on properties that had the highest concentrations of asbestos in surface material, the highest frequency of positive detections, and those closest to the exfoliation facility.
