In 1996 the American Physical Society, responding to a request from the National Research Council, was asked to examine the potential health hazards of power lines. One of the concerns was that electromagnetic background fields of 2 milligauss might cause cancer (for comparison the earth’s magnetic field is 500 milligauss and fields generated by human physiological processes are hundreds of thousands of times less than 2 milligauss). Monitors of outdoor exposure for children to wear were marketed to parents. “Some city regulations sought to constrain B fields to less than 2 milligauss”. The report, which was a comprehensive study of the alleged dangers, included both molecular and epidemiologic studies and found that no adverse health effects could be attributed to these low fields.
One of the conclusions emphasized that physical calculations rule out carcinogenic effects because at physiological temperatures thermal noise fields in human cells are larger than the background fields from power lines.1, 2 Thus the political agenda, concerned with fear of carcinogenic mechanisms arising from low level magnetic fields, lost credibility. However, about 10 years later claims for health effects from mattress pads equipped with small magnets were marketed. A study of this was funded by National Institute of Health’s Center for Complementary and Alternative Medicine and claims for their benefits were published in alternative medicine journals.3
Some of the rationale for the claims were ludicrous. I attended one sales pitch which claimed their mattress magnets were better because they incorporated only North Poles. About the same time, small 300 gauss magnets, began to appear on the shelves of drug stores. In 2007 a lawsuit brought by the National Council against Health Fraud against advertisers of these products was successfully settled. I was one of the persons who agreed to appear as an expert witness if needed. The Federal Trade Commission also threatened to prosecute purveyors who claimed healthful benefits for these products.