A landmark decision in a U.S. city over cellphone use has triggered renewed concerns over the potential health risks associated with our mobile devices.

Last week, the city of Berkeley in California passed an ordinance law forcing phone retailers to place warnings on their products regarding potential exposure to radiation.

The warnings must encourage customers to keep the devices five to 25 millimetres away from their bodies.

Berkeley is the first community in North America to mandate warnings on cellphones.

“We relish the idea of Berkeley being first in the forefront of those efforts to protect the public,” said city councillor Max Anderson.

But the move is raising questions again in the science and tech worlds about the potential for adverse effects from phones, and what users need to know.

Cellphones emit radiofrequency radiation. The closer it is to the body, the higher the dose.

Taking that into consideration, the proposed warning in Berkeley is as follows:

“If you carry or use your cellphone in a pants or shirt pocket, you may exceed guidelines for exposure to radio frequency radiation.”

Concerned that studies are beginning to link cellphone use to fertility problems and cancer, University of Toronto scientist Dr. Anthony Miller says he hopes other municipalities follow suit.

“People need to keep the devices as far away as possible,” Miller told CTV News. “Distance is your friend.”

The U.S. wireless industry however, is expected to challenge the Berkeley law, with Canadian officials insisting the technology is safe at any distance.

“I keep it in my pocket,” said Kurt Eby, director of the Canadian Wireless Telecommunications Association. “Most of my friends do, my family does as well.

“The vast majority of scientific evidence in Canada and around the world does not support any link between RF energy exposure and any negative impact on human health.”

Still, Dr. Miller says consumers need to know about scientific concerns so they can take precautions.

“They could lower exposure, by avoiding holding the phone to head,” he said, adding cellphone users should opt to use ear buds or the speaker phone function.

In Canada, a private member’s bill is proposing the same warnings for retailers here.

With a report by CTV medical specialist Avis Favaro and producer Elizabeth St. Philip