Everyone with a microwave oven knows that radio waves can heat up water molecules, which is handy when you’re making Mac and Cheese for the kids but a little more problematic when you spend hours every day with a cell phone pressed to your ear. Are cell phones a health hazard?

In May the $24 million Interphone study was finally released, after 10 years of study in 13 countries with 13,000 participants. The Interphone study included 2,708 cases of glioma and 2,409 of meningioma, another type of brain tumor, with a total of over 5,634 controls —from 13 countries. Eligible cases were patients diagnosed between 2000 and 2004. (Meningioma was not linked to cell phone use.) It is the largest study of cell phone and tumors ever done.

The point of the study was to determine once and for all whether cell phones represent a health hazard. The conclusion: “Overall, no increase in risk of glioma or meningioma (a specific brain cancer thought to be promoted or triggered by cell phone radiation) was observed with use of mobile phones.” However the report went on to state, “There were suggestions of an increased risk of glioma at the highest exposure” and those tumors are more likely to show up on the side of the head on which the user typically holds the phone.

As one of the researchers said at a press conference announcing the release of the report, “We have not demonstrated that there is increased risk but neither have we demonstrated that there is an absence of risk. These findings of increased risk in the heaviest users suggest a possible association but we don’t have enough scientific evidence.” The results, on the surface, are unclear.

Cause for Concern

On closer inspection the Interphone study isn’t as equivocal as it first appears. If you’re willing to dig through the data, Appendix 2 paints a considerably less nuanced picture than the report itself. As Microwave News points out,

“Although not included in the paper, [Appendix 2] offers a way to look at the risks free of some of the bias that so muddled the published results. It also provides a window on the controversy that deadlocked the Interphone group for four years.”

The report—and Appendix 2—clearly show higher incidence of cancer among “heavy cell phone users”, defined as those using cell phones more than 30 minutes per day—a pretty low number for your average teenager.

“Those who used a mobile phone for ten or more years were found to be twice as likely to develop a brain tumor. This increased risk is statistically significant. Indeed, the risk is higher for all three indices of exposure —years of use, total talk time and total number of calls. There even appears to be a dose-response relationship, with the highest risk among the heaviest users.”

Check out the data below:

As with any study there are built in biases that need to be factored into any conclusion. “You can see patterns in the data that show some risk, but the issues of selection and recall bias make me concerned,” said one of the study’s researchers. Siegal Sadetzki, the Israeli member of Interphone, told Microwave News, “The data are not strong enough for a causal interpretation, but they are sufficient to support precautionary policies,” she said. Elisabeth Cardis, who leads the Interphone project, took a less equivocal stand: “To me, there’s certainly smoke there. Overall, my opinion is that the results show a real effect.”

The Rush to Legislate

Politicians have been quick to start promoting “precautionary policies.” At the same time some industry groups have been quick to push back.

Specific absorption rate (SAR) is a measure of how RF energy is absorbed by the body. It measures how much tissue is heated up, which is one way that cells can be damaged. In the U.S., the FCC limits legal SARs to 1.6 watts per kilogram. Cell phones vary considerably in output, typically ranging from 0.1-1.5 watts per kilogram. The prudent thing to do is to buy a cell phone with the lowest SAR. Or talk less on the phone and use a Bluetooth headset when you do.

SAR is easy to measure, unlike cell mutations that clearly can cause cancer whereas heat by itself probably doesn’t. SAR is just a proxy for a missing metric. The only way you can determine an RF/cancer correlation is by long-term epidemiological studies like the Interphone study.

In June  San Francisco passed its Cell Phone Right to Know Ordinance, mandating that all cell phones sold in the city must clearly show the SAR figure for the phone. This information is available if you look hard enough, but it’s not easy to find. San Francisco just wants it to be front and center so consumers can make more informed decisions.

That isn’t the way the Cellular Telephone Industries Association (CTIA)—sees it. “The wireless industry is committed to consumer choice,” trumpeted the CTIA, which by Alice in Wonderland logic sees San Francisco as somehow impeding by providing more information upon which to base those choices. The CTIA almost immediately sued the city of San Francisco claiming that hey, all cell phones are safe because the FCC says they are:

“The ordinance challenges the Federal Communication Commission’s (FCC) determination that all FCC-compliant wireless handsets are safe by mandating that retailers post Specific Absorption Rate (SAR) values. The ordinance misleads consumers by creating the false impression that the FCC’s standards are insufficient and that some phones are “safer” than others based on their radiofrequency (RF) emissions… The FCC has determined that all wireless phones legally sold in the United States are ‘safe.’”

There, now don’t you feel better already? Just ignore the quotes around ‘safe’.

 SF Initiative Goes National

The CTIA notwithstanding, San Francisco’s ordinance is gaining momentum. On June 30 Rep. Dennis J. Kucinich (D-OH) announced his intent to introduce a bill in congress making an SAR labeling a national law, at the same time establishing a new national research program to study cell phones and health.

“Some studies find links. Some don’t,”  said Kucinich.” But studies funded by the telecommunications industry are significantly less likely to find a link between cell phones and health effects. We need a first class research program to give us answers.” Meanwhile, “a labeling law will ensure that cell phone users can decide for themselves the level of risk that they will accept.”

As soon as Kucinich files his bill you can be sure that the CTIA will be in there fighting and suing for your right not to be confused by too much information.