According to the EPA Website, exposure to asbestos increases the risk of mesothelioma, lung cancer and asbestosis. That risk exacerbated smoking and spending years in work sites known to be constructed with the toxin.
The CDC claims there is no safe amount of asbestos exposure, however, logically the more time workers spent in the presence of the material, the more likely they are to develop cancer. Thus, major health effects are known to be directly caused by asbestos exposure including lung cancer, pulmonary fibrosis, adenocarcinoma and mesothelioma.
Curiously, the EPA has not taken measures to eradicate the toxin as safety advocates say they should. The European counterparts have all done so, but the US still has a number of hot spots around the country. Asbestos still exists in homes, schools, hospitals, factories, and other workplaces. New cancer cases are diagnosed each year.