Here’s an excerpt:
Scientists say they identified a strong oral carcinogen in smokeless tobacco and called for federal regulation of the substance (S)-NNN, one of a family of compounds called nitrosamines, in these products.
“This is the first example of a strong oral cavity carcinogen that’s in smokeless tobacco,” he said. “Our results are very important in regard to the growing use of smokeless tobacco in the world, especially among younger people who think it is a safer form of tobacco than cigarettes. We now have the identity of the only known strong oral carcinogen in these products.”
you can read the rest of the article here: http://www.ada.org/news/7510.aspx