The US Surgeon General has released a new report titled How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease, which finds that even occasional smoking or secondhand smoke causes immediate damage to the body that can lead to serious illness or death. The report is available at http://www.surgeongeneral.gov/library/tobaccosmoke/index.html
For more information about the report, see this US HHS press release: http://www.hhs.gov/news/press/2010pres/12/20101209a.html
For information and resources to quit smoking, visit www.tobaccofreemaine.org