First of all, it does not mean that using a cellphone will definitely give you cancer, but it might. The panel looked at a number of studies and decided to label cellphone radiation as "possibly carcinogenic" -- the same label given to some dry cleaning chemicals and pesticides like DDT. The announcement's a big deal to those who've been calling cellphones dangerous for years, but some experts still remain unconvinced.
"This is very good news. We're happy about it," said Ellie Marks.
For Marks, the World Health Organization's finding is not a surprise. She's been warning of the dangers of cellphone radiation since her husband was diagnosed with a brain tumor in 2008.
"A malignant glioma in his right frontal lobe, a little bit toward the back. He had held a cellphone to his head since 1987 to his right ear," said Marks.
Doctors wrote at t he time it was probable that Alan's tumor stemmed from his long term mobile phone use. He underwent surgery to remove the tumor, but still suffers from health problems. Now, his wife says the cellphone industry can't deny the possibility that his doctors were right.
"One of their many sound bites is that the WHO says there's no link between cellphones and gliomas and acoustic neuroams and other brain tumors. They're not going to be able to say that anymore," said Marks.
But there are still skeptics, including U.C. Berkeley physics professor Richard Muller, Ph.D.
"There's no cancer risk from using a cellphone. The real risk in using a cellphone is crashing while you're driving," said Muller.
Muller says there's just no conclusive evidence linking cellphones directly to human tissue damage and the numbers don't bear out.
"We know how to calculate cancer from levels of radioactivity and when we apply that calculation to Fukushima, we get a cert number of deaths. We apply it to Three Mile Island, we get a cert number of deaths. We apply it to cellphones, we get a certain number of deaths -- it's zero," said Muller.
But engineer Lloyd Morgan of the Environmental Health Trust says the anecdotal evidence, from dozens of cases documented in studies from Europe and Japan, is enough cause for concern.
"Hold it to the right side, that's where the tumor is. The evidence is really overwhelming," said Morgan.
And Morgan says regulators would do well to take the WHO findings seriously.
"This is a 10-point earthquake for our public health agencies," said Morgan.
The cellphone industry association responded by saying the team that did the study had not conducted any new research. Instead, it just reviewed previous studies. In the past, they point out the group has expressed similar health concerns about the dangers of pickled vegetables and coffee.