It must be sampled by a Certified Asbestos Hazard Evaluation Specialist and analyzed by a laboratory for asbestos content. The EPA and the department of Health both agree that any building material with asbestos content above 1% is to be considered asbestos containing material. OSHA on the other hand defines asbestos as asbestos, there is no cut off for 1%. This can get tricky, so the bottom line is "if there is asbestos at any percent you must follow the OSHA standards, but if it is above 1% then you must comply with OSHA, EPA, and the Department of Health".
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