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July 24, 2019

How one chart, 19 years ago, drove the myth that cellphones cause cancer

Daily Briefing

    In 2000, Bill Curry, a consultant and physicist, presented two reports supposedly showing a link between wireless signals and brain cancer, but while his conclusion has since been debunked, the myth of the connection remains pervasive today, William Broad reports for the New York Times.

    Cheat sheets: Evidence-based medicine 101

    The birth of a myth

    About 20 years ago, Broward County Public Schools was considering adding laptops and wireless networks to its classrooms. So it recruited Curry, whose resume included decades of experience at federal and industrial laboratories, to research any potential health risks associated with the technology.

    Curry came back with two reports in which he claimed that the radio waves generated by laptops and wireless networks were "likely to be a serious health hazard," and summarized his concerns in a graph labeled "Microwave Absorption in Brain Tissue (Grey Matter)."

    The graph showed dosages of radiation received by the brain as increasing exponentially once frequencies reached the levels of a wireless signal. "This graph shows why I am concerned," Curry wrote in his reports, which detailed how the radio waves could lead to brain cancer.

    Curry's reports began to circulate among other wireless critics, one of whom was David Carpenter, former dean of the School of Public Health at the State University of New York and current director of the university's Institute for Health and the Environment, Broad writes.

    Carpenter has worked to further the message about the alleged harm of 5G, becoming editor in chief of Reviews on Environmental Health in 2012 and publishing a number of authors who wrote alarming reports about wireless networks, Board reports.

    Carpenter wasn't the only one who believed Curry's findings. In the years after Curry shared his findings with Broward County, his "warning spread far, resonating with educators, consumers, and entire cities," Broad writes.  

    Debunking the myth

    But while Curry had experience in physics and electrical engineering, he had no formal training in biomedical research, and that's where the fault in his graph lies, Broad reports.

    Curry's research looked at studies on how these waves affected tissues isolated in a lab, but failed to take into account the protective effect of human skin, Broad writes.

    Christopher Collins, a professor of radiology at New York University, explained that the skin acts as a barrier to higher radio frequencies, shielding the internal organs from exposure, and Curry's graph failed to account for that "shielding effect."

    In fact, experts say radio waves actually become safer at higher frequencies, rather than more dangerous as Curry concluded. For instance, Marvin Ziskin, an emeritus professor of medical physics at Temple University School of Medicine, agreed, and said many of his experiments have supported the safety of high-frequency radio waves.

    David Robert Grimes, a cancer researcher at the University of Oxford, noted that if radio waves did cause brain cancer, there would be more cases of the disease. "If phones are linked to cancer, we'd expect to see a marked uptick," he said. "Yet we do not."

    Even Carpenter in a recent interview conceded that it could be possible that increasingly high frequencies could have difficulty entering the human body. "There's some legitimacy to that point of view," he said, adding that if the human skin blocks 5G signals, "maybe it's not that big a deal" (Broad, New York Times, 7/16).

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