The potential link between mobile telephones and brain cancer could be similar to the link between lung cancer and smoking, something tobacco companies took 50 years to recognize, according to US scientists' warning.

Scientists are currently split on the level of danger the biological effects of the magnetic field emitted by cellular telephones poses to humans.

However, society "must not repeat the situation we had with the relationship between smoking and lung cancer where we ... waited until every 'i' was dotted and 't' was crossed before warnings were issued," said David Carpenter, director of the Institute of Health and Environment at the University of Albany, in testimony before a subcommittee of the US House of Representatives Committee on Oversight and Reform.

The potential link between mobile telephones and brain cancer could be similar to the link between lung cancer and smoking -- something tobacco companies took 50 years to recognize, US scientists have warned. Scientists are currently split on the level of danger the biological effects of the magnetic field emitted by cellular telephones poses to humans. [Agencies]

"Precaution is warranted even in the absence of absolutely final evidence concerning the magnitude of the risk", especially for children, said Carpenter.

Ronald Herberman, director of the University of Pittsburgh Cancer Institute -- one of the top US cancer research centers, said that most studies "claiming that there is no link between cell phones and brain tumors are outdated, had methodological concerns and did not include sufficient numbers of long-term cell phone users."

Many studies denying a link defined regular cell phone use as "once a week," he said.

"Recalling the 70 years that it took to remove lead from paint and gasoline and the 50 years that it took to convincingly establish the link between smoking and lung cancer, I argue that we must learn from our past to do a better job of interpreting evidence of potential risk," said Herberman.

A brain tumor can take dozens of years to develop, the scientists said.

Carpenter and Herberman both told the committee the brain cancer risk from cell phone use is far greater for children than for adults.

Herberman held up a model for lawmakers showing how radiation from a cell phone penetrates far deeper into the brain of a five-year-old than that of an adult.