Research unveiled at the recent national meeting of the American Chemical Society has identified additional hazardous ingredients in smokeless tobacco, which already was known to include more than two dozen dangerous substances.

In fact, researchers said that a single portion of smokeless tobacco exposes users to five times more carcinogenic polycyclic aromatic hydrocarbons (PAH) than smoking a cigarette.  "Our finding places snuff on the same list of major sources of exposure to polycyclic aromatic hydrocarbons as smoking cigarettes," said researcher Irina Stepanov, Ph.D.

PAHs are typically associated with grilling meat and burning of organic materials; researchers said that the PAHs in smokeless tobacco may come from the tobacco-curing process.