The view is impressive, if strange. A forest of about two dozen huge towers supports an intricate web of antenna wires that together pump many hundreds of kilowatts into the atmosphere from a site 25 kilometers north of Rome. The antennas are the Vatican's portal to the world: signals from two medium-wave transmitters reach all of Italy at all times, while those from 27 shortwave antennas are beamed at selected parts of the world in different languages at varying times. (Only two of the shortwave antennas transmit at any given time.) Thus, papal speeches, news programs, and religious events are dispatched in 40 languages to all the corners of the world, making this complex as important to the Vatican as the Voice of America and Radio Free Europe were to the United States at the height of the Cold War.

But to the inhabitants of Cesano and neighboring communities, the antennas, some transmitting at an effective 600 kilowatts, represent not only a blight on the landscape and something of a nuisance—hearing the Pope's voice picked up by your front-door intercom is not always appreciated—but also a possible health threat [see photo, "Radio Spikes"].

When the antennas were erected in 1951 on a 3.9-square-kilometer plot, the surrounding area, known as Santa Maria di Galeria, was still largely rural. But during the last few decades the area has been built up, and now an estimated 60 000 people live within a radius of 10 km of the transmitters. In 2000, a small number of cases of childhood leukemia, first reported by a local physician, were blamed by residents on the strong radio-frequency fields generated by the Vatican antennas.

This past May, an Italian court imposed suspended 10-day prison sentences on two Vatican officials responsible for operating the transmitters, a cardinal and a priest, for the "dangerous showering of objects"—meaning the antennas' electromagnetic waves. (The term "electromagnetic radiation" has not made it yet into Italy's legal vocabulary.) In addition, environmental groups and committees representing the local population will be awarded damages in a separate civil action, though the figures have yet to be determined.

Local residents and environmentalists have sought to have the Vatican close down the complex since 2000. Several years ago, an Italian environmental minister, Willer Bordon, organized field strength measurements and found that the Vatican's radio transmitters violated Italy's radiation standards, which are much stricter than those in other parts of the world. He threatened to cut off electric power to the site; in response, Vatican Radio reduced the time it was on the air and transferred some radio transmission to other sites.

The Vatican's situation improved in 2002, when courts ruled that the Italian government had no jurisdiction over the transmitters because of the Vatican's status as an independent state. But in 2003, Italy's Supreme Court overturned those rulings, which resulted in the two Vatican officials' having to stand trial [see photo, "Divine Right of Way?"]

What does science say? While the complaints against Vatican Radio were bouncing back and forth in the Italian courts, the regional government commissioned an epidemiological study of leukemia incidence in the area around the disputed antennas. A team of researchers led by Paola Michelozzi of the Local Health Authority, in Rome, reported in 2002 that the incidence of childhood leukemia from 1987 to 1998 was twice the expected rate, but the actual numbers were very small. The results, published in the American Journal of Epidemiology, indicated that instead of the expected 3.7 cases in the population of 60 000, there had been eight. Because of the small number, Michelozzi considers the result statistically insignificant. But a somewhat more disconcerting finding in her study made a stronger impression on critics of the Vatican, members of the press, and even some experts.

Michelozzi's survey determined that if leukemia incidence was measured in concentric circles around the radio complex, rates dropped off with increasing distance from the transmitters. Based on that finding, a court-appointed expert science panel in the legal proceeding against the Vatican concluded, questionably, that "the weight of evidence...is much more in favor of the existence of a [cancer] risk" and that it "is in favor of a causal relationship." That assessment, together with the Vatican's violation of Italian power limits, is what prompted the guilty verdict last May against the Vatican officials.

Similar studies of populations around radio and television transmitters have been conducted during the past two decades in several countries, including the United States, Switzerland, the Netherlands, and New Zealand. But all these studies are crippled by the very low normal incidence of leukemia, the need to study very large populations, and the technical difficulty of accurately determining actual exposure levels. "The situation has not changed that much. If you look at the string of recent epidemiological studies, they are still equivocal," says Keith Florig, a specialist in risk analysis and radiation protection at Carnegie Mellon University, in Pittsburgh. Florig expressed surprise at the court's ruling in the Vatican case.

Others agree that the ruling was premature. "I'm quite concerned about a rush to judgment based on a less-than-adequate understanding of the scientific issues," says Wayne Overbeck, a specialist in the legal aspects of communications at California State University, in Fullerton. (Overbeck, a ham radio operator, takes precautions to avoid exposing himself and other people to excess RF radiation.)

Local inhabitants, on the other hand, reacted to the Italian court's finding with jubilation. "We are satisfied; we had to suffer the arrogance of the Vatican for years," one resident told the press. Representatives of Vatican Radio, maintaining that the radiation levels are safe, said that they found the judgment unjust and plan to appeal it.