AMERICAN scientists have warned Congress of the risks of brain cancer from mobile phone use, highlighting the potential threat to children who use them.

They said most studies claiming no link between mobiles and tumours were out of date and did not take into account how much the phones were used today.

And they called for warning labels on mobile phones.

"We urgently need more research," said David Carpenter, director of the Institute of Health and Environment at the University of Albany, in testimony before the House Subcommittee on Domestic Policy.

"We must not repeat the situation we had with the relationship between smoking and lung cancer."

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Cancer Institute, said most studies "claiming that there is no link between mobile phones and brain tumours are outdated, had methodological concerns and did not include sufficient numbers of long-term mobile phone users".

Many studies denying a link "defined regular cell (mobile) phones as `once a week`," Mr Herberman said.

"I cannot tell this committee that cell phones are definitely dangerous. But, I certainly cannot tell you that they are safe."

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

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

"Every child is using cell phones all of the time, and there are three billion cell phone users in the world," Mr Herberman said.

He added that, like the messages that warn of health risks on cigarette packs, mobile phones "need a precautionary message".

Noting that numerous US studies have not found a definitive cancer-phone link, Mr Carpenter asked: "Are we at the same place we were with smoking and lung cancer 30 years ago?"

The committee were shown several European studies, particularly surveys from Scandinavia - where the mobile phone was first developed - which show that the radiation emitted by mobile phones have definite biological consequences.

For example, a 2008 study by Swedish cancer specialist Lennart Hardell found that frequent mobile phone users are twice as likely to develop a benign tumour on the auditory nerves of the ear most used with the handset, compared with the other ear.

In addition, a paper published this month by the Royal Society in London found that adolescents who start using mobile phones before the age of 20 were five times more likely to develop brain cancer at the age of 29 than those who didn`t use a mobile phone.

AFP