The carcinogenicity of asbestos is well documented. Many countries, including Japan, have banned the production and use of asbestos, whereas some other countries, including China, continue to produce and use huge amounts of chrysotile asbestos in construction materials. Even where banned, asbestos continues to create many problems. For example, although domestic asbestos production is negligible in Japan, the country has in the past imported more than 10 million tons of asbestos, most of which remains in buildings and other structures. Asbestos removal and site cleaning have placed an enormous burden on society. Moreover, because of the long latency of asbestos-related diseases, health problems may emerge long after actual exposure. For example, in Amagasaki, Japan in 2005, several cases of mesothelioma were found among residents living in the vicinity of a former asbestos plant.1 This prompted nationwide concern about asbestos, and many similar cases were subsequently discovered and reported from other areas of the country.