Currents of Fear: In Which Power Lines Are Suspected of Causing Cancer

Voodoo Science,
by Robert Park

These days — when so many people believe crazy conspiracy theories, refuse life-saving vaccines, promote alternative medicine, fret about perceived 5G cell phone hazards, and postulate implausible microwave weapons to explain the Havana Syndrome — we need to understand better how science interacts with society. In particular, we should examine similar controversies in the past to see what we can learn. In this post, I review the power line/cancer debate of the 1980s and 90s. I remember it well, because it raged during my graduate school days. The dispute centered on the physics Russ Hobbie and I describe in Chapter 9 of Intermediate Physics for Medicine and Biology.

To tell this tale, I’ve selected excerpts from Robert Park’s book Voodoo Science: The Road from Foolishness to Fraud. The story has important lessons for today. Enjoy!

In 1979, an unemployed epidemiologist named Nancy Wertheimer obtained the addresses of childhood leukemia patients in Denver and drove about the city looking for some common environmental factor that might be responsible. What she noticed was that many of the homes of victims seemed to be near power transformers. Could it be that fields from the electric power distribution system were linked to leukemia? She teamed up with a physicist named Ed Leeper, who devised a “wiring code” based on the size and proximity of power lines to estimate the strength of the magnetic fields. Together they eventually produced a paper relating childhood leukemia to the fields from power lines…

In June of 1989, The carried a new three-part series of highly sensational articles by Paul Brodeur… on the hazards of power-line fields…. The series reached an affluent, educated, environmentally concerned audience. Suddenly, Brodeur was everywhere: the Today show on NBC, Nightline on ABC, This Morning on CBS, and, of course, Larry King Live on CNN. In the fall, Brodeur published the New Yorker series as a book with the lurid title Currents of Death. A new generation of environmental activists, led by mothers who feared for their children’s lives, demanded government action…

By [1995], sixteen years had passed since Nancy Wertheimer took her historic drive around Denver. An entire industry had grown up around the power-line controversy. Armies of epidemiologists conducted ever larger studies; activists organized campaigns to relocate power lines away from schools; the courts were clogged with damage suits; a half dozen newsletters were devoted to reporting on EMF [electromagnetic fields]; a brisk business had developed in measuring 60 Hz magnetic fields in homes and workplaces; fraudulent devices of every sort were being marketed to protect against EMF; and, of course, Paul Brodeur’s books were selling well…

It was into this climate that the Stevens Report was released by the National Academy of Sciences in 1996 with it unanimous conclusion that “the current body of evidence does not show that exposure to these fields presents a human health hazard.”… The chair of the review panel, Charles Stevens, a distinguished neurobiologist with the Salk Institute, [explained] the difficulty of trying to identify weak environmental hazards. Scientists had labored for seventeen years to evaluate the hazards of power-line fields; they had conducted epidemiological studies, laboratory research, and computational analysis. “Our committee evaluated over five hundred studies,” Stevens said, “and in the end all we can say is that the evidence doesn’t point to these fields as being a health risk…”

On July 2, 1997, the National Cancer Institute (NCI) finally announced the results of its exhaustive epidemiological study, “Residential Exposure to Magnetic Fields and Acute Lymphoblastic Leukemia in Children”… It was the most unimpeachable epidemiological study of the connection between power lines and cancer yet undertaken. Every conceivable source of investigator bias was eliminated. There were 638 children under age fifteen with acute lymphoblastic leukemia enrolled in the study along with 620 carefully matched controls, ensuring reliable statistics. All measurements were double blind… [The study] concluded that any link between acute lymphoblastic leukemia in children and magnetic fields is too weak to detect or to be concerned about. But the most surprising result had to do with the proximity of power lines to the homes of leukemia victims: the study found no association at all. The supposed association between proximity to power lines and childhood leukemia, which had kept the controversy alive all these years, was spurious-just an artifact of the statistical analysis. As is so often the case with voodoo science, with every improved study the effect had gotten smaller. Now, after eighteen years, it was gone completely.

Power Line Fears,

Originally published at

Professor of Physics at Oakland University and coauthor of the textbook Intermediate Physics for Medicine and Biology.