Diana Barbera, a filmmaker and mother of four, turned to the Internet when she heard that Fairfax County school officials wanted to put a towering pole of wireless phone antennas at the middle school two of her children attend.

Barbera, 38, of Clifton learned that the federal government says that people near such poles encounter low levels of radio-frequency radiation but that they would have to be next to the antennas -- usually about 100 feet in the air -- to be exposed to potentially dangerous levels. She also read that some scientists question whether long-term exposure also may be harmful to people on the ground.

The way Barbera sees it, the mere possibility is reason enough to ban placement of the antennas near schools. With another Fairfax parent, Karl Polzer of Falls Church, she began speaking out against proposed cellular antenna poles before the School Board. This month, they launched www.protectschools.org.

"People are so cautious about their kids. We buckle them up and strap bike helmets on, but there's no way I can protect them from this," Barbera said. "In 20 or 30 years, if we find out this stuff is harmful, it's too late. I'd rather err on the side of caution."

As cell phones increasingly become routine, the towers and poles that hold the antennas needed to send cellular signals are popping up next to fire stations, on the roofs of government buildings and in church steeples.

Fairfax County schools have installed poles with cell phone antennas at six schools and one administrative building, officials said. There are plans to add them at several additional schools. In most cases, the poles double as light posts at football fields.

With each telephone carrier paying to rent the space, the towers are an easy moneymaker for nonprofits. Fairfax schools receive an initial $25,000 payment for each new pole and $5,000 each time another cellular phone company adds an antenna to a pole. The companies also pay about $2,000 in rent each month, which is split between the school system and Milestone Communications, the Reston-based company that manages the contracts for the schools.

Montgomery County schools have poles at one high school and one middle school. In Prince William County, there are cellular poles at two high schools.

Officials at the Federal Communications Commission said research has shown that it is safe to live or work in the shadow of a wireless phone antenna, provided the structure meets federal standards. Bruce Romano, associate chief at the FCC's office of engineering and technology, said government experts keep up with the latest research, adding, "We haven't seen anything that raises any concerns."

John E. Moulder, director of radiation biology at the Medical College of Wisconsin in Milwaukee, agrees. Moulder said that on a daily basis, people come into contact with energy from television and radio broadcasting, emergency communications systems and tiny amounts from sources such as microwave ovens and garage door openers.

In his opinion, the low levels of energy around cellular towers pose no risk. "There is no reason . . . to expect that fields that low would have any impact at all," said Moulder, who added that there is a tower near his home.

But there is debate in the scientific community about whether enough is known to proclaim cell towers safe. Last month, the International Association of Fire Fighters, a union representing firefighters in the United States and Canada, agreed to seek funding to study the issue and voted to stop adding towers until that work is completed.

In a letter supporting Polzer and Barbera, Henry Lai, a University of Washington bioengineering professor, acknowledged that the level of radiation around a cellular tower is "typically very low" and "generally considered to be harmless."

But Lai, who studies the effects of radiation, said not enough research had been done on prolonged exposure, particularly on children, who can be more sensitive to environmental factors. He said some research indicates that people who live near towers suffer from headaches and learning problems.

Lai said it's common sense to keep the poles away from schools or day-care centers until more is known. "I'm not saying there's definitely harm," Lai said. "I'm saying there's a possibility."

Gunnar Heuser, a California physician, said that his examination recently of six firefighters who worked at stations with cell towers found that they had some brain impairments. The firefighters had trouble sleeping, headaches and trouble with their balance, he said.

Heuser acknowledges that no conclusions can be made from his work because he looked at only six people, and all of them could have been exposed to other hazards at work. But he said he is seeking funding for further testing.

Fairfax County school officials said environmental experts with the school system make a point of keeping up with the latest research and are confident that the towers are safe.

Polzer and Barbera said they expect to come before the School Board again and will visit with PTAs and community associations.

James B. Burch, a Colorado State University professor who teaches environmental and occupational epidemiology, said that he is not certain that the antennas can harm people who are near them for a long time but that he would not want his children to attend a school that had a cellular pole.

"I don't think it's clear at all," Burch said. "People call and say, 'They are building a cell tower in my neighborhood. Is there any effect?' I tell them I can't say for sure if there is a hazard. Nobody really knows."

Diana Barbera and Karl Polzer are lobbying Fairfax County schools to halt development of cell towers on campuses such as Centreville High School's.