Sialoglycoprotein (SG) on the surface of rat red blood cells (RBC) were labeled with gold-conjugated wheat germ agglutinen (WGA). Before labeling, RBC's were treated with aliquots of chrysotile asbestos. Asbestos fibers firmly adhere to red cell surfaces. A decrease in the number of SG-WGA complexes was observed on the surface of asbestos treated RBC's. It is proposed that positively charged Mg ions in the chrysotile fibers bind to negatively charged sialic acid molecules on the red cell surface. This interaction leads to cell distortion, loss of some membrane components, consequent translocation of intracellular ions and finally, hemolysis. The hypothesis is being tested in vitro with morphologic and biochemical techniques. These methods will be applied to pulmonary components such as macrophages and epithelial cells which are known to interact with inhaled chrysotile asbestos.