Smoking is by far the leading cause of lung cancer. Tobacco smoke causes more than 8 out of 10 cases of lung cancer, according to the American Cancer Society. Tobacco products contain harmful carcinogens (cancer causing agents) that can damage the cells in the lungs. The longer a person has been smoking and the more cigarettes a day smoked, the greater the chances are of contracting lung cancer. Exposure to secondhand tobacco smoke, which is called involuntary or passive smoking, can also increase the risk of developing lung cancer. If a person stops smoking before lung cancer develops, the lung tissue slowly returns to normal
Even though smoking is mostly responsible for causing lung cancer, it is not the sole cause of it. Asbestos exposure can also cause lung cancer. People who work with asbestos are already in danger of getting lung cancer, and by smoking, the risk is greatly increased. Although the manufacturing of asbestos has slowed down significantly due to government regulations, it is still present in some products and old buildings. However, if left undisturbed, asbestos poses no danger. Asbestos is only dangerous when it has been disturbed and its raw form (fibers) is released into the air and breathed in.
