A search was conducted to determine the best practices available to insure that asbestos ontaining materials could be identified and handled properly. However, this project did not investigate the technical feasibility of using roofing tear-off wastes containing asbestos in ecycling or energy recovery projects.
Only materials found to be free of asbestos were rocessed for use in the trials conducted. Chipping of the shingle materials is normally ccomplished using a high speed hammermill. During the processing of shingles at two ecycling facilities, air sampling was conducted to determine the amount of total and espirable fibers to which workers might be exposed. Results showed that • All total fiber esults measured below OSHA’s 8-hour time-weighted average (TWA) Permissible Exposure Limit (PEL) for asbestos of 0.1 f/cc
• None of the fiber samples analyzed by TEM showed any asbestos fibers
• All respirable fiber samples measured below the 8-hour TWA value of 0.05 f/cc for durable respirable fibers
• All respirable particulate & respirable crystalline silica results were non detectable & well below their respective OSHA PELs.
Of 355 loads of tear-off materials received at the processing center in 2007, six (1.69%)
were found to contain a detectable amount of asbestos using EPA Method 600. This is
in alignment with experience in other studies as mentioned above.
Experience gained during this project using EPA Method 600 suggests that screening
roofing tear-off waste streams for the presence of asbestos is technically feasible,provided that:
• Contractor and processor personnel can be adequately trained to recognize different types of roofing materials in loads of tear-off
Loads of tear-off wastes from different sites of generation are not combined prior to testing;
• Only materials from residential tear-offs are accepted. (Materials from commercial or industrial sites are more likely to include asbestos containing materials.);
• Proper handling techniques and PPE are used in proximity to untested materials;
• A sample of each type of shingle, underlayment and other roofing material present in each load is taken and tested independently (not composited);
• Loads are staged separately until testing results are obtained;
• A plan is in place and implemented that will insure that materials found to contain asbestos are sequestered, stored and disposed of in accordance with all applicable EPA, OSHA and other rules and regulations, including proper recordkeeping.
This project demonstrated that sampling and analysis of tear-off wastes using the above procedures on materials prior to processing s adequate to insure that the processed materials are free of asbestos. In all cases, testing of the materials after processing (chipping, sieving, etc.) showed no detectable asbestos.