London, March 16 (IANS): Scientists have claimed to have established that a cancer-triggering compound - speculated till now to be present in smokeless tobacco products (STPs) - is not a prevalent contaminant in contemporary smokeless tobacco products.

The main STPs are snus (khaini), chewing tobacco, moist snuff, dry snuff, plug and pellet products.

Hydrazine is used as a sucker growth inhibitor on tobacco crops. Suckers are side shoots which, if not removed, affect the quality and yield of the tobacco plant.

Hydrazine is classified as a possible human carcinogen by the International Agency for Research on Cancer which can have negative effects on the central nervous system, liver and kidneys.

"Our results indicate that hydrazine is not a prevalent contaminant of contemporary STPs. In the minority of cases where hydrazine might possibly be present, the levels are substantially lower than those reported previously," said Kevin McAdam, principal scientist at British American Tobacco, a leading tobacco group.

Scientists at British American Tobacco in collaboration with professor Brad Rodu of the University of Louisville, undertook a comprehensive survey of toxicants in STPs.

They developed and carefully validated a highly sensitive method for determining levels of hydrazine in STPs.

The researchers used the validated method to analyse hydrazine content in a wide range of commercial STPs from the USA and Sweden.

None of the STPs were found to contain hydrazine above the current limits.

Close investigation identified the possible presence of trace levels of hydrazine in 34 of 70 samples; while in others, there was no evidence of hydrazine being present.

The trace elements were at such low levels that they cannot be quantified using currently available analytical techniques, the British American Tobacco said in a statement.

Hydrazine is on the list of US Food and Drug Administration's (FDA) "Harmful and Potentially Harmful Constituents" list.