"Even additives such as cocoa, long used to flavor cigarettes, can be harmful. 'Studies have indicated that when it's burned, it [produces] a co-carcinogen [a substance that in the presence of a carcinogen increases the risk of cancer],' says Scott Ballin, vice president and legislative counsel for public affairs at the American Heart Association and chairman of the anti-smoking Coalition on Smoking OR Health."
                                                                --Environmental Health Perspectives, Volume 102, Number 9, September 1994