There is a stigma that comes with lung cancer that it is a smoker’s disease. Many other exposures can cause a person to develop lung cancer. Railroad workers who never smoked may have developed lung cancer due to breathing diesel exhaust, asbestos dust, silica/sand, second-hand tobacco smoke and other toxic substances during their career. Many of these substances add together to raise the risk of developing cancer from any one exposure alone. For a railroad worker who smoked cigarettes, the additional railroad exposures may have multiplied the risk from the cigarette smoking alone.