Only 4% of the articles produced by the tobacco industry said that passive smoking was unhealthful, compared with 65% of other journal articles. 72% of these same reports argued that secondhand smoke wasn't harmful, compared with 20% of independent journal articles, with the remainder being neutral on the subject. The results of these tobacco industry lead symposia did not undergo the standard scientific process of peer review, yet can be fond in the databases of medical literature.
Despite the tobacco industry's attempt to persuade the public, the evidence is overwhelmingly clear; secondhand smoke poses a major health risk. Secondhand smoke has been classified by the EPA as a known cause of lung cancer in humans and is estimated to cause approximately 3,000 lung cancer deaths in nonsmokers each year. A non-smokers risk of developing cancer from secondhand smoke or ETS is about 100 times greater than from outdoor cancer causing pollutants. For any given non-smoker, the lifetime risk of getting lung cancer remains small, 4 to 5 in 1,000 ordinarily, 6 to 7 in 1,000 if he or she has a smoking spouse. A spouse's smoking alone produced an overall 30% increase in lung cancer risk. Women with the greatest lifetime exposure (smoking parents, spouse, friends, and coworkers) had a 225% increase in risk of lung cancer. Exposure to secondhand smoke is so commonplace that the EPA ranks secondhand smoke as the third known cause of lung cancer, after active smoking and indoor radon exposure.
Despite all the attention given to lung cancer, it may not be the most significant health effect of secondhand smoke. It has been shown that secondhand smoke causes more disease than first imagined. About 47,000 Americans will die from heart disease caused by secondhand smoke this year and another 150,000 will suffer non-fatal heart attacks. The effects of passive smoke are our country's third leading preventable cause of death after direct smoking and alcohol.