It’s been 20 years since Congress tried to settle the debate over power-line health risks.
In the 1992 Energy Policy Act, lawmakers instructed the U.S. Department of Energy and the National Institute of Environmental Health Sciences to lead a five-year investigation into the health effects of electric and magnetic fields, or EMFs.
The process involved scores of scientists from dozens of disciplines, from electrical engineers to molecular biologists. The results were compiled in a 500-plus-page report written at a nine-day meeting in Brooklyn Park, Minn., and released in 1998.
It concluded — despite studies in the 1980s suggesting a link — that two decades of research showed only a “weak association” between EMF exposure and childhood leukemia, and no link between EMF exposure and adult cancers.
For all its depth and breadth, though, the institute’s report was hardly the final word for transmission line opponents. Health fears regularly come up during power-line disputes, most recently with the CapX2020 project.
“It’s a hearty perennial,” says John Farley, a UNLV physics professor who has followed the controversy for decades.
While worries about cell phone EMFs have received more attention in recent years, Farley said he still gets emails once every week or two from people asking whether it is safe to buy a home near a power transmission line.
“I say I don’t think it’s a problem,” says Farley.
Magnetic fields are measured using a unit called a gauss (named after German physicist Carl Friedrich Gauss).
We’re naturally exposed to between 300 and 500 milligauss from the Earth’s magnetic field, says Farley. The precise amount depends on your proximity to the planet’s magnetic poles. The magnetic field at ground level from a power line, by comparison, is usually only 1 or 2 milligauss.
“The additional magnetic field from the power line is maybe 1 percent or less than the magnetic field you get from just standing around on Earth,” says Farley. “I just don’t think it’s an issue.”
Meanwhile, an MRI exposes people to a magnetic field of about 10 million milligauss.
So why are power-line fears so persistent? Farley has a few theories.
One: people don’t trust experts. “There’s a distrust of experts, and to a certain extent it’s a healthy thing. The experts have reassured us about things that weren’t true at all,” says Farley. “So now, even if the experts are telling the truth, some people don’t believe them.”
Secondly, “People don’t know what a magnetic field is, unless you’ve had a physics class,” says Farley.
And lastly, you can’t prove a negative. “The problem is you can never prove there is absolutely no risk,” says Farley.
You can, however, compare the known risk to other risks, he says. “Last time I checked, something like 35,000 Americans are killed each year in auto accidents,” says Farley. “But no one’s ever going to say ‘never get in a car.'”
Concerns about power-line health effects first originated from a flawed and never-reproduced study in 1979, says Farley. They’ve persisted for decades, despite the lack of scientific evidence.
The fears were popularized by a series of New Yorker articles by Paul Brodeur, who later wrote a book called Currents of Death. In 1995, a PBS Frontline investigation called Currents of Fear questioned Brodeur’s reporting.
“The researchers have been researching this for a couple of decades and they haven’t found anything,” says Farley. “Either there’s no effect — and it’s hard to prove there is absolutely no effect — or the effect is small enough that you don’t have to worry about it.”
Photo by Emily Hoyer via Creative Commons