Section 388.862 - Measurement of asbestos levels; methods(1) The measurement of asbestos levels shall be made by either or both of the following methods: (a) Optical phase contrast microscopy in the manner described in the measurement protocol provided by the United States occupational safety and health administration in 29 C.F.R. part 1910.(b) Transmission electron microscopy (TEM) in the manner described in the nonmandatory TEM protocol in appendix A to subpart E of part 763 of title 40 of the Code of Federal Regulations, counting only fibers longer than 5 microns.(2) If the results of a laboratory analysis of air samples obtained using optical phase contrast microscopy as described in subsection (1)(a) indicate that asbestos levels exceed .01 fibers per cubic centimeter, air samples shall be recollected and analyzed using an electron microscope pursuant to subsection (1)(b), and the results of the laboratory analysis of air samples obtained using transmission electron microscopy control.(3) If both methods are used and a question arises as to the presence of fibers that may not be asbestos, a measurement made by transmission electron microscopy controls.1993, Act 51, Imd. Eff. 6/1/1993.