Asbestos is a naturally occurring mineral, used by humans since ancient times but not extensively until the 1940s. After World War II and for the next 30 years, it was widely used as a construction material in schools and other public buildings. The United States Environmental Protection Agency (EPA) estimates that there are asbestos-containing materials in most of the primary and secondary schools as well as in most public and commercial buildings in the nation. It is estimated that 27 million Americans had significant occupational exposure to asbestos between 1940 and 1980. Asbestos has been popular because it is readily available, low in cost, and has very useful properties. It does not burn, conducts heat and electricity poorly, strengthens concrete products into which it is incorporated, and is resistant to chemical corrosion. It has been used in building materials as a thermal and electrical insulator and has been sprayed on...