Mike writes again from Tannersville, Pennsylvania: "Thanks for the good information. I have one final question. I don't mean to get too medical on you but when you say the fibers don't stay in the body that long - does the fiber dissolve into the body or how would it be removed from the body?"

Answer: You got it, Mike; the fibers actually dissolve. Solubility, or the ability of the fibers to be removed from the lung once inhaled, is important to preventing harmful effects. In contrast to other fibers that may persist in the body for decades, ordinary insulation wool glasses are quite soluble in the body and are removed in a period of weeks or months. For more on solubility, check the New Research on Glass Fibers page on the Owens Corning Web site.