Perhaps most worrisome, though, are the preliminary results of the multinational Interphone study sponsored by the International Agency for Research on Cancer, in Lyon, France. (Scientists from thirteen countries took part in the study, the United States conspicuously not among them.) Interphone researchers reported in 2008 that after a decade of cell-phone use, the chance of getting a brain tumor—specifically on the side of the head where you use the phone—goes up as much as 40 percent for adults. Interphone researchers in Israel have found that cell phones can cause tumors of the parotid gland (the salivary gland in the cheek), and an independent study in Sweden last year concluded that people who started using a cell phone before the age of 20 were five times as likely to develop a brain tumor. Another Interphone study reported a nearly 300 percent increased risk of acoustic neuroma, a tumor of the acoustic nerve.

As more results of the Interphone study trickled out, I called Louis Slesin, who has a doctorate in environmental policy from MIT and in 1980 founded an investigative newsletter called Microwave News. "No one in this country cared!" Slesin said of the findings. "It wasn't news!" He suggested that much of the comfort of our modern lives depends on not caring, on refusing to recognize the dangers of microwave radiation. "We love our cell phones. The paradigm that there's no danger here is part of a worldview that had to be put into place," he said. "Americans are not asking the questions, maybe because they don't want the answers. So what will it take?"

To understand how radiation from cell phones and wireless transmitters affects the human brain, and to get some sense of why the concerns raised in so many studies outside the U.S. are not being seriously raised here, it's necessary to go back fifty years, long before the advent of the cell phone, to the research of a young neuroscientist named Allan Frey.

In 1960, Frey, then 25, was working at General Electric's Advanced Electronics Center at Cornell University when he was contacted by a technician whose job was to measure the signals emitted by radar stations. At the time, Frey had taken an interest in the electrical nature of the human body, specifically in how electric fields affect neural functioning. The technician claimed something incredible: He said he could "hear" radar at one of the sites where he worked.

Frey traveled to the facility and stood in the radar field. "And sure enough, I could hear it, too," he said, describing the persistent low-level hum. Frey went on to establish that the effect was real—electromagnetic (EM) radiation from radar could somehow be heard by human beings. The "hearing," however, didn't happen via normal sound waves perceived through the ear. It occurred somewhere in the brain itself, as EM waves interacted with the brain's cells, which generate tiny electrical fields. This idea came to be known as the Frey effect, and it caused an uproar in the neuroscience community.

The waves that Frey was concerned with were those emitted from the nonionizing part of the EM spectrum—the part that scientists always assumed could do no outright biological damage. When Frey began his research, it was assumed that the only way microwaves could have a damaging biological effect was if you increased the power of their signals and concentrated them like sword points—to the level where they could cook esh. In 1967, this resulted in the first popular microwave oven, which employed microwave frequencies at very high power, concentrated and contained in a metal box. Aside from this engineered thermal effect, the signals were assumed to be safe.