Washington, Aug 17 - Beware snuff users. Banish the comforting notion that snuff and chewing tobacco are safe because they don't burn and produce smoke like cigarettes.

A study that looked beyond the well-researched tobacco hazards, nitrosamines and nicotine, has discovered a single pinch -- the amount in a portion -- of smokeless tobacco exposes the user to the same amount of another group of dangerous chemicals as the smoke of five cigarettes.

The findings come in the wake of a rise in both marketing and consumption of smokeless tobacco, which many consumers regard as less dangerous than other forms. Estimates suggest that sales of moist snuff in the US have doubled since the 1980s.

The research bolsters existing evidence that smokeless tobacco contains two dozen other carcinogens that cause oral and pancreatic cancers, the scientists say.

'This study once again clearly shows us that smokeless tobacco is not safe,' said Irina Stepanov, Masonic Cancer Centre, University of Minnesota-Minneapolis (UM-M), who led the research team.

'Our finding places snuff on the same list of major sources of exposure to polycyclic aromatic hydrocarbons (PAHs) as smoking cigarettes.