Researchers warn people who think that smokeless tobacco is safe. Tobacco exposes the user to the same amount of another group of dangerous chemicals as the smoke of five cigarettes.
The research on polycyclic aromatic hydrocarbons (PAH) in smokeless tobacco adds to existing evidence that smokeless contains two-dozen other carcinogens that cause oral and pancreatic cancers.
"This study once again clearly shows us that smokeless tobacco is not safe. Our finding places snuff on the same list of major sources of exposure to polycyclic aromatic hydrocarbons as smoking cigarettes," said Dr. Irina Stepanov, who led the research team.
The researchers have earlier found a total of 28 carcinogens in smokeless tobacco, and continued exposure to these over a period of time can lead to cancer.
"Now we have found even more carcinogens in snuff," said Stepanov.
In addition to the increased risk of cancer, she noted that chronic use of snuff leads to nicotine addiction, just as with cigarette smoking.
Stepanov said that until recently, scientists believed that only trace amounts of PAH existed in snuff because the tobacco was not burned when used. This assumption proved to be wrong.
"Even though smokeless tobacco use does not involve burning, moist snuff is getting contaminated with PAH during its manufacturing," said Stepanov.
The most likely source of this contamination with PAH is the curing process that is used to turn tobacco leaves into snuff. This process is called 'fire-curing', and it puts tobacco into direct contact with the smoke generated by smoldering hardwoods-a rich source of various PAHs.
The findings were presented at 238th National Meeting of the American Chemical Society (ACS).