Mesothelioma, a rare form of cancer, affects the lining of the cavities around the lungs, stomach, and heart. The only known cause of mesothelioma in the U.S. is exposure to asbestos fibers. Mesothelioma usually does not appear until 10 to 40 years after a person first inhales asbestos fibers. Asbestos exposure also contributes to the development of lung cancer, other cancers (stomach, colon, rectal, esophagus, larynx, and pharynx), asbestosis, and pleural disease. Many people have been exposed to asbestos fibers at work. There is also a risk to workers’ families because the fibers may be transported home on clothing, vehicles, etc. Likewise, people who live near sites using asbestos (e.g., refineries, power plants, factories, shipyards, steel mills, building demolition sites) are also at risk because of environmental exposure.