Doctors know the origin, but they haven't got a cure. Allegheny County patients frequently don't develop mesothelioma symptoms until several years after they've been exposed to asbestos, a known cause of the rare cancer. Most mesothelioma patients, diagnosed at the rate of 2,000 to 3,000 people annually, came in contact with asbestos at work.
Asbestos is a natural substance found in soil, water and air. Manufacturers, attracted to the heat and chemical resistant properties of the mineral fibers, incorporated asbestos in a multitude of everyday products. Banned in 55 countries today, the use of asbestos in the U.S. is restricted but hasn't disappeared entirely.