(FORTUNE Magazine) – Anders Ahlbom is hardly a revolutionary. Sitting in his tidy, light-filled office at Stockholm's Karolinska Institute medical school, the researcher whose results are frightening a lot of people seems not the least anxious himself. His 1992 study found a significant correlation between exposure to electromagnetic fields around power lines and the incidence of leukemia in children. But he won't take a position on what ought to be done, warning that ''the worst mistake we can make is to overinterpret the data.'' He cautions that the mechanism that caused the cancers remains unknown. On a recent visit to Sweden, FORTUNE interviewed many students of electromagnetic radiation, including epidemiologists like Ahlbom, biophysicists, doctors, and experts from government agencies, unions, and power companies. A number of them pointed out that Ahlbom's study could have been done nowhere else. He had access not only to a comprehensive historical registry of all cancer cases ever reported, but also to detailed logs of electrical loads carried by specific power lines at any given time. Only Sweden keeps such careful records. The Swedish government is already responding. Olov Ostberg, an official at the Agency for Administrative Development, has started to provide ''electrical and magnetic sanitation'' in government offices, removing unnecessary electrical equipment and designing work areas to minimize exposure. By this summer, Swedish regulators expect to propose a ban on construction of houses within about 330 feet of high-tension lines. Electromagnetic fields are the talk of Sweden. But a visitor who expected to hear everyone discussing the risk of cancer found greater concern about a phenomenon called ''electrical allergy'' -- hypersensitivity to electricity. The malady appears to be common nowhere else, but nearly every high-tech workplace in Sweden has people who suffer from it. They generally attribute the onset of symptoms to unremitting work at a video terminal. Eventually, sufferers report a range of allergic reactions, from burning sensations on the skin and headaches to memory loss, nausea, and even complete disorientation. Some can talk for only a few minutes on an ordinary telephone, which uses a minuscule one watt of electrical power. At Ellemtel, a research partnership between Ericsson and Swedish Telecom that likes to consider itself the Bell Labs of Sweden, as many as 30 out of 750 were afflicted in 1990, including a top software engineer. Ellemtel eventually got them all back to work, in part by reducing fields with rewiring and shielding. Many doctors in Sweden believe it's all in the mind -- but not Gunnar Hovsenius, chief environmental researcher for the nation's power companies. Says he: ''I definitely don't believe these problems are psychosomatic in most cases. I have met people willing to do anything to come back to society, but they have no chance.'' In the U.S. the condition is virtually unheard of, but experiments by Charles Graham of the Midwest Research Institute in Kansas City do show clear variations in how people react to electromagnetic exposure. Under pressure from its powerful unions, Sweden began moving toward requiring lower VDT emissions in the mid-1980s -- well before there was any solid evidence for doing so. Now the national VDT standards, called Swedac, are generally accepted worldwide as the ultimate in user safety. (IBM and Apple have adopted them for reduced-emission monitors.) It's too soon to know whether Swedish officials are once again ahead of the curve in limiting exposure to radiation and taking these allergies seriously.