Avoiding secondhand smoke should be a primary goal for anyone who wants to avoid smoking-related health problems, including lung cancer. Containing hundreds of dangerous chemicals — including dozens known to cause cancer — secondhand smoke is an ongoing threat to the health of those exposed to it through burning cigarettes, exhaled smoke and even residue on the clothing of smokers. Since the mid-1960s, approximately 2.5 million non-smoking Americans have died from secondhand smoke exposure, and experts estimate that exposure can increase the chances of developing lung cancer by 20-30 percent — statistics that could provide smokers with added incentives to give up the habit, says the OSUCCC – James’ Michael Wert, MD. “If smokers are unable or unwilling to stop for themselves, you can ask them if they're willing to stop for other family members, particularly children,” he says. There is no minimum safe amount of secondhand smoke exposure.”