By Vassia Barba Lung cancer – which is often associated with smoking – can in fact pose a significant health hazard even to those who have never touched a cigarette in their life. While smoking remains the primary cause, other risk factors include exposure to environmental pollutants such as radon gas, secondhand smoke, and occupational hazards. Data from the American Cancer Society showed that about 20% of lung cancer deaths in the US every year are in people who never smoked. Nonsmokers, defined as individuals who either have never smoked or have smoked fewer than 100 cigarettes in their lif…