Guidelines for conducting the AHERA (Asbestos Hazard Emergency Response Act) TEM (Transmission Electron Microscopy) clearance test to determine completion of an asbestos abatement project. Final report

Asbestos abatement carried out in schools is subject to regulations under the Asbestos Hazard Emergency Response Act of 1986 (AHERA). The AHERA rule (40 CFR Part 763) includes procedures for determining when an asbestos abatement site is sufficiently clean for the containment barriers to be removed. After the abatement site has been subject to a thorough visual inspection, air samples are collected. In most cases, the samples must be analyzed by transmission electron microscopy (TEM). The document provides guidance for conducting the TEM clearance test with emphasis on interpretation of the results. The three components of the test, the Initial Screening Test, the Blank Contamination Test, and the Z-test, are described and illustrated with numerical examples.