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Professor Frank Barnes weighs in on cell phones’ possibly damaging effects.

It’s safe. Then it isn’t. What’s a person with a cell phone to do?

Conflicting reports about the health ramifications of cell phone use play in and out of news headlines. The issue touches nearly everyone. As the world population edges in on 7 billion this year, an estimated 5 billion of us have cell phones.

“The real question is relative risk,” says distinguished professor Frank Barnes of CU’s electrical, computing and energy engineering department. He compares an estimated 3,500 days of diminished lifespan as a result of being an unmarried male, the occupational hazards innate in being a policeman, fireman or miner and the downside of drinking a cup of a coffee a day.

“Given the evidence we have, where do you put cell phones in this risk assessment?” he asks.

Barnes chaired the 2008 National Research Council report for the U.S. Food and Drug Administration that called for stronger research on the potential health effects of exposure to radio-frequency energy from wireless technology, including cell phones, laptops and other handheld devices.

“At this stage, relative to the amount of information we have, it’s relatively low risk,” he says.

But cell phone safety is not proven either. While money has yet to flow into Barnes’ suggested long-term cell phone studies, a World Health Organization review of existing data in June rendered some new conclusions about adverse health effects.

The W.H.O.’s International Agency for Research on Cancer boosted the cell phone alarm level to “possibly carcinogenic to humans.” Concluding that radio-frequency electromagnetic fields are a potential human health threat, the panel of 31 scientists ranked cell phones on par with some pesticides, dry cleaning, coffee and surgical implants.

After considering hundreds of scientific articles, including last year’s extensive 13-European-country Interphone study, scientists found no increased risk of brain tumors among cell phone users of more than 10 years.

However, they cited indications of an increased risk of a rare brain cancer called glioma for those who reported the highest 10 percent of cumulative hours of cell phone use.

Christopher Wild, the agency’s director, issued a statement in line with Barnes’ previous recommendations —�� including a suggestion to limit exposure in the mean time.

“Given the potential consequences for public health of this classification and findings, it is important that additional research be conducted into the long-term, heavy use of mobile phones,” he wrote, urging users to take pragmatic measures to reduce exposure by using hands-free devices or texting.

Barnes says the W.H.O. report has raised the level of concern from nothing to a possible carcinogen, noting there are a lot of things in that category.

“They’ve raised the level to ‘possible,’” he says. “The result is mixed. Nobody understands for sure what’s going on.”

Barnes’ own research, however, reveals other clues.

His lab has shown that by canceling out the Earth’s magnetic field, growth can be inhibited in some cells, including a couple of kinds of cancer. The question becomes whether this can be said about low levels of nonionizing radiation emitted from cell phones.

Barnes laments the fact that long-term studies on cell phones cannot keep up with the pace of companies that sell the devices. Ultimately, he suggests identifying thresholds of exposure might be most helpful since the real debate is over long-term use. These are tricky experiments to do since brain tumors have 10-to-20-year latencies.

“There is data that says cell phones are doing something to the brain,” he says. “Now what [their effects are] is the open question.”

He points to last year’s study in the��Journal of the American Medical Association��that reported brain activity sped up in the area closest to a cell phone antenna. But while the study showed a measurable effect, it did not show or explain harm to the brain, he notes.

“Just because [cell phones are] doing something doesn’t mean they’re bad,” Barnes says.

“A lot of the original [radio frequency] studies were done in the U.S. We did a lot of studies starting in the 1950s through about 1990,” Barnes says. “Many of the results were negative. Basically, we’ve had members of the National Academy [of Science] say that no more money should be wasted in this area.”

With that, new U.S. cell phone studies have largely been stymied and European researchers have taken the lead in studying any effects of cell phones’ radio-frequency energy on the human body.

Contentious as the W.H.O. report may be among industry workers and scientists who say negative data is scant and methodologies have been flawed, the fact remains that cell phone use is increasing at an astronomical rate.

In the past decade, cell phone subscribers in the U.S. have nearly tripled, from 110 million in 2000 to 303 million in 2010. The National Cancer Institute notes that the number of calls per day, call length and the duration of use have also increased. Whether this translates to a direct health threat remains to be seen.