Demolition of Gypsum Wallboard with Asbestos-Containing Mastic

This paper reports a series of laboratory and field tests that measured the asbestos (chrysotile) fibers released during demolition of gypsum wallboard (GWB) that contained small amounts of chrysotile in the joint mastic. The tests include contractors’ data from two actual demolitions, a controlled demolition of a wall segment, and bench top laboratory tests of gypsum wallboard samples. The results of all these tests indicated that many fibers are released during GWB demolition, but few if any of the fibers were chrysotile. The use of electron microscopy demonstrated that less than 2% of the fibers counted from laboratory and controlled demolitions using light microscopy procedures was asbestos. The actual field demolitions, which included asbestos containing material other than GWB, indicated that less than 4% of the fibers counted using light microscopy procedures was asbestos.