The long-running debate over possible health hazards from sources of electromagnetic radiation (EMR), such as radars and television stations, has taken a new turn. Several recent studies of radar and communications workers regularly exposed to high levels of EMR have revealed evidence of possible radiation-induced cancers and brain damage.

The findings are tentative–some have not yet been published or replicated–and their implications are uncertain. Microwave specialists emphasize that the results may not hold much significance for the general public exposed only to low levels of the non-ionizing microwaves.

Nonetheless, few experts are prepared to discount the studies completely, or to say with certainty that they apply only to high exposures. “There’s a body of work now pointing strongly to health hazards,” says Louis Slesin, editor of Microwave News, an industry newsletter that first reported many of the findings. “It’s circumstantial, yes, but it’s all coming together. What we don’t know yet are what the danger thresholds are.”

The most important of the studies, and according to Slesin the largest epidemiological study on non-ionizing radiation ever completed, examined every case of cancer reported among career Polish military personnel between 1971 and 1980. Dr. Stanislaw Szmigielski of Poland’s Center for Radiobiology and Radioprotection discovered that soldiers–especially young ones–who had been exposed to high, long-term doses of microwaves and radiofrequency radiation were more than three times as likely to contract cancer as others with little or no exposure. The cancers clustered in blood-forming organs, lymphatic tissues, and thyroids.

Several studies have previously linked EMR with cancer, but the evidence has been spotty and often unpersuasive to specialists. Szmigielski’s findings, if they stand up to peer review, could mark a major change. He has alredy called for efforts to replicate them in another “well-defined, well-controlled” population. However, as far as U.S. researchers know, no such attempt is now planned anywhere in the world.

Another disturbing report comes from Sweden. Dr. Hans-Arne Hansson of the University of Goteborg examined about a dozen long-time military radar technicians who had begun to display symptons of central-nervous-system damage. Radar workers have long complained of headaches, dizziness, and vision problems–so-called “microwave sickness”–but no one has ever established a definitive causal link. Hansson may have discovered a clue: he found that the workers’ cerebrospinal fluid contained abnormal proteins. Such changes indicate a variety of diseases involving degeneration of the nervous system.

A recent study at Maryland’s Department of Health and Mental Hygiene, of the death certificates of almost 1,000 white males killed by brain tumors, raised similar concerns. Dr. Ruey Lin and his colleagues found that a 50 percent higher than expected proportion of the men had been electrical workers: utilities’ servicemen, electronic engineers, and the like. Such workers are commonly exposed to EMR from power lines and similar sources, although generally at lower intensities and frequencies than radar technicians. The electrical workers also tended to die younger than the nonexposed sample.

Interpreting the Study Results

Scientists have problems interpreting these studies. Chief among them is the variety of other health hazards the various populations could have faced. “With that kind of study, you just can’ say that it’s the radio-frequency radiation that’s producing the effect,” says Arthur W. Guy, director of the University of Washington’s Bioelectrical Research Laboratory. Guy notes that a host of materials associated with electrical and electronic work–soldering fluxes, some ceramic insulators, solvents, and even older cathode-ray tubes that produce ionizing radiation–are known promoters of cancer and thus could skew epidemiological results.

It’s unclear, as well, what level of EMR the populations might have received. “Let’s assume, for discussion, that the Polich work is absolutely correct,” says Dr. F. Kristian Storm, a California cancer specialist reviewing the voluntary EMR exposure standards set up by the American National Standards Institute. “Then I would say, what can I do about it? I have no idea what exposure those people got. That work doesn’t tell us what a dangerous level of exposure is.”

Unfortunately, the largest experiment on the health effects of EMR on animals, performed in a pathogen-free environment at an exposure level deemed safe by ANSI’s standard, isn’t reassuring either. In a five-year experiment that ended in mid-1984, Arthur Guy discovered that rats exposed to pulsed microwaves developed almost four times as many malignant tumors as unexposed controls, chiefly in the endocrine and adrenal systems.

If reliable, these results would mean that the ANSI standard, along with many state standards based on it, is too high. Guy himself says his results are inconclusive. The distribution of different types of tumors shows statistical quirks, and the researchers suspect that stress–possibly caused by the animals’ constant exposure to microwaves–might cause many of the tumors, especially the adrenal ones.

Guy would like other researchers to try to replicate this study in light of the new epidemiological data. However, no such efforts seems forthcoming. The air force supported Guy’s $4.5 million study, and has no plans at present for more such work. Moreover, one place where such a study might have been done–EPA’s EMR bioeffects laboratory in Research Triangle Park, N.C.–faces extinction under the Reagan administration’s FY 1986 budget.

Many people decry this lack of research, given the public’s suspicion of EMR sources. Across the country citizens’ groups are opposing the siting of facilities such as satellite earth stations and microwave relays. “More and more people are raising questions, and there’s nothing conclusive to show,” says Slesin of Microwave News. “Everybody could lose; the public, industry, everybody.” Storm, at least, thinks the new studies, however questionable, might prove beneficial in the long term. “It’s kind of like a cloud with a silver lining,” he says. “It may scare some people into funding better research in this field.”