Scientists agree it contains the same cocktail of harmful compounds that smokers inhale, more than 55 cancer-causing chemicals including formaldehyde, arsenic and the powerful toxin benzoapyrene. They also agree that nonsmokers inhale and digest the toxic smoke just as their smoking counterparts do, albeit in smaller quantities. Traces of chemicals found only in tobacco turn up in biological studies of nonsmokers frequently exposed to cigarette smoke.
Tobacco causes increasingly stiff and narrow arteries that precipitate a heart attack.
Its chemicals create long-lasting genetic mutations that blossom into lung cancer. During the past, biologists and courts have wrestled with the question, occasionally arriving at different answers. Fueled by regulators' zeal to hold the tobacco industry accountable for America's epidemic of smoking-related illness, the legal and scientific debate has intensified during the last five years. And geneticists, epidemiologists and molecular and cellular biologists point to a growing body of research on secondhand smoke. A 1998 study, published in the Journal of the American Medical Association, found secondhand smoke increased the rate at which nonsmokers' arteries clog or harden by 20 percent.