American scientist Devra Davis is on a worldwide tour to promote her new book Disconnected. In it she lifts the lid on mounting research and an industry intent on burying it.

“I was shocked when I learned that many scientists had raised questions about the safety of cell phones decades ago,” Devra said.

But now the $3 trillion dollar global business with 4.6 billion customers worldwide is facing growing evidence of harmful effects.

“When you're looking at animal studies and cell culture studies and combine that with human studies you see a very compelling case that heavy use of cell phones increases the risk of brain cancer,” Devra said.

In a chilling image, it is shown that mobile phone radiation absorbed into the brain of a five year old and an adult brain. We know that children’s brains are developing and exquisitely sensitive. What's more horrifying is that this model was made by scientists working for the mobile phone industry 10 years ago.

Devra is one of the world's leading epidemiologists and public health experts, she even shares a nobel peace prize with Al Gore.

She is serious about taking action, saying: “If we wait as we did for tobacco and asbestos, 20 - 30 years for proof of human harm, we'll have that proof long after I'm dead and we will then be apologising to our grandchildren for failing to protect them.”

“Cell phone radiation can have profound effects on the way cells work, on the way we reproduce and the health of sperm.”

In Australia there are more mobile phones than people.

“That's why I've written this book.

“I think we can take these steps now to prevent what will be a global public health catastrophe because we never had 100 per cent of people smoking cigarettes and we do have 100 per cent of people using cell phones now in many nations around the world.”

And just like the Tobacco and Asbestos industries, Devra believes the mobile phone industry has tried to control research by holding the purse strings.

“All they do is control the money, control who gets appointed to the committees and then it’s really not that difficult.” Debra said.

A good example? The Australian centre for Radiofrequency Bio Effects Research.

It's received major funding from industry, one of its directors is a Telstra executive and a Telstra scientist is on its research list.

One of its scientists Vites Anderson says mobile phones are safe: “If you were asking me to bet my house on one way or the other, I’d certainly come down on the side saying there probably isn’t any real significant risk.”

But what happens when scientists do find harmful effects? Back in the mid-90’s in a study funded by industry, Henry Li found cell damage in rats after exposure to mobile phone radiation.

“Three-and-a-half years later, and nothing has happened. You wonder what's going on,” Devra said.

“The industry tried to get him fired, tried to get his money taken back, went to the journal that had accepted the article for publication and asked them to unaccept, and then finally hired a public relations firm to quote "war game" the science,” Devra said.

He's not the only one, George Carlo was given $28 million by industry in the United States to research effects.

“When they found we had findings of genetic damage and increased risk of cancer they cut off our money completely,” he said.

10 years ago Today Tonight interviewed Peter French, a scientist for the Centre for Immunology at St Vincent’s Hospital, who was conducting a five-year study funded partly by the mobile industry. He also found cells changed after a small dose of radiation.

“The changes I saw were enough to convince me that this was an interesting area to research and also important,” Peter said.

“The cells shouldn’t change at those sorts of levels, some of the changes we saw were similar to the changes you see in cancer cells.”

But the mobile phone industry that helped pay for his research didn’t see it as important and again the funding for his investigation dried up.

The most recent and largest study of 13,000 people is Interphone. A World Health Organisation initiative involving 13 countries, yet again heavily funded by the industry.

Devra Davis believes that study too was skewed: “They defined a user as a person who made one call a week for six months so although the study overall finds no increase in brain cancer, it found with respect to long term heavy use, using a cell phone heavily for 10 years or more increases the risk of brain cancer.”

Devra's not the first to speak out. In 2008 one of our country's foremost experts on public health Professor Bruce Armstrong from Sydney University broke his silence on Today Tonight.

“I would not want to be a heavy user of mobile phones,” Bruce said.

“What was found there was evidence of a two-fold increase in risk of tumours, acoustic nerve tumours and parotid gland tumours, some of these tumours are certainly fatal.”

Mobile phone salesman David Smith had a tumour as big as a golf ball removed from around his acoustic nerve, he used to speak on his mobile 1 to 2 hours a day.

“I believe mobile phones gave me this tumour and I blame the mobile phone companies,” David said.

Some of our top Neurosurgeons only use their mobile on speaker phone.

Dr Vini Khurana says: “I just don’t think we have the room for error when it comes to brain tumours”.

While Dr Richard Bittar explains: “I think it would be very foolish to assume there is no relationship and not to take precautions”.

But of course the industry still says they’re safe.

Chris Althaus from the Australian Mobile Telecommunications Association says he is not worried about getting a tumour even though he uses his phone every day.

Devra's advice: “Use a speaker phone, use an earpiece, don’t keep the phone on the body, children should not use cell phones except for texting”.