Sandy Travis walks down leafy President Street near her home in the Eastport section of Annapolis and points out neighbors' houses.
"That woman has cancer, that person has cancer, and that person has cancer. And there's a transformer right over there," she says, singling out a utility pole across the street.
Although scientists disagree on whether the electromagnetic fields generated by power lines can cause cancer, Travis says she wants a lot more answers before Baltimore Gas & Electric Co. expands the substation two blocks from her house and strings new power lines in her neighborhood.
"I take walks," explains Travis, a free-lance writer and mother of a 17-month-old girl, Katy. "And if they put a line overhead I don't know if I'm going to feel like walking."
BG&E; officials say Travis and her neighbors have nothing to fear. And they warn that there could be blackouts this winter if the substation is not expanded to supply power to the rapidly growing Annapolis Neck area.
But BG&E;'s $3 million expansion of the Tyler Avenue substation has been snagged by the public concern growing nationwide over electromagnetic fields, or EMFs. The project has been held up a month while the Annapolis City Council listened to six hours of often technical testimony from BG&E; witnesses and opponents in a pair of hearings this week and last month.
"There is insufficient data to lead you to the conclusion that these fields cause cancer," said Linda Erdreich, an epidemiologist from New York who testified Monday night for BG&E.;
But, in a comment typical of neighbors opposing the project, Keith Oliver, a local environmentalist, told the aldermen: "You've heard there is insufficient evidence to conclude that EMF causes cancer, but I also believe there is insufficient evidence to conclude that EMF does not cause cancer."
For more than a decade, scientists have debated -- often heatedly -- whether electric and magnetic fields given off by electricity are harmful to humans. Some researchers have suggested they may be dangerous, but many others are skeptical, noting that the fields generated by neighborhood power lines, appliances and household wiring are often weaker than those produced naturally by earth's gravity.
A draft report issued last fall by the U.S. Environmental Protection Agency, which concludes that EMFs are a "possible, but not proven, cause of cancer in humans," has heightened the dispute. Some are urging the government to regulate magnetic field levels, while others have assailed the report as "crackpot science," as one critic put it.
HUGE POTENTIAL IMPACT
Proving that electromagnetic fields are harmful could have tremendous impact on society, since they are generated by virtually everything, from power lines and transformers to video display terminals and common household appliances such as hair dryers, toasters and televisions.
Electric utilities have a major interest in the issue, since power lines crisscross the country. BG&E;, for instance, has 52,000 miles of overhead distribution and transmission lines in central Maryland and another 26,500 miles of underground wires and cables, according to spokesman John Metzger.
While differing on whether EMFs are a health risk, many scientists agree that they should be investigated more because of epidemiological studies linking them statistically to cancers, particularly childhood leukemia, brain tumors and even breast cancer in men.
One such study, conducted by Genevieve Matanoski of Johns Hopkins University, found that New York telephone line workers got cancer -- including two very rare cases of male breast cancer -- at twice the rate of other phone company employees.
A California study funded by the utility industry found recently that children who lived nearest to neighborhood power lines were 2 1/2 times as likely to have leukemia as were children who lived farther away. Frequent use of hair dryers and watching black-and-white televisions also were linked with increased leukemia risks in the preliminary results, released in February.
Utility officials counter that there are just as many studies finding no EMF-cancer links as there are those making positive connections. And they note that statistical associations do not mean EMFs actually cause cancer.
There are more than 100 studies under way to try to settle the dispute, but scientists on both sides say it could be three or four years at least before much more is known.
With public concern growing, some local and state officials already have begun to regulate EMF exposure. Seven states limit electric field strength at the edge of transmission line rights of way, while New York and Florida limit magnetic fields, which are more often associated with health effects, according to Editorial Research Reports. Officials in Alexandria, Va., concerned about EMF exposures ordered that overhead power lines on narrow residential streets there be buried underground, at a cost of $2 million.
NO HAZARD HERE?
In Maryland, the Public Service Commission has ruled that "current scientific evidence shows no human health hazard from overhead transmission lines," according to PSC spokesman Frank Fulton.
The Maryland panel refused to block or reroute a 500-kilovolt transmission line linking Montgomery and Howard counties in 1989, despite concerns raised by the People's Counsel about possible EMF hazards to nearby residents. Nothing has been brought to the PSC's attention since then to change its position, Fulton said, though he also said he was unaware of EPA's draft report.
"It's something that just can't be pushed aside and ignored forever," counters People's Counsel John Glynn, who conceded that the evidence against EMFs two years ago was "not definitive, but it was cause for concern."
BG&E; has been questioned before about the possible health effects of its power lines. The issue was raised last year in connection with new high-voltage transmission lines the utility wanted to string across Loch Raven Reservoir in Baltimore County.
But Eric H. Bauman, BG&E;'s new EMF issues manager, says studies suggesting a statistical link between EMF and cancer are "speculation," and he notes that scientists have been unable cause cancer in laboratory animals exposed to EMF.
In any case, BG&E; officials say, the Annapolis substation expansion will not increase electromagnetic fields in the neighborhood. Even though the facility's power-supply capacity will double from 32,000 kilowatts to 64,000 kilowatts, BG&E; officials say the fields generated by the added equipment will offset each other.
Adding two new circuits to serve the substation also will reduce current on each power line, shrinking the fields they generate, utility engineers say.
But Travis suggests that the city should do an independent study of BG&E;'s claims, or at least require the utility to submit a lot more information to back them up.
"Getting an education from BG&E; is like asking the tobacco industry what they think of smoking cigarettes," she says.
Some EMF readings near the substation and along neighborhood power lines already exceed the levels at which cancer risks are increased, based on the EPA report.
BG&E; crews measured EMF levels averaging 10 milligauss or below around the Tyler Avenue substation last month, according to engineer Charles T. Lacey Jr. A milligauss is one-thousandth of a Gauss, a standard unit of measure for magnetic field strength.
The EPA report says that cancer risks seem to be heightened when magnetic fields are stronger than 2 to 3 milli-Gauss.
At one house, which stands just 10 or 15 feet from the substation's fence, the EMF levels were 5 or 6 milligauss, Lacey said, while readings near overhead power lines along Hanson and President streets in the neighborhood ranged as high as 9 to 12 milligauss. Travis says a BG&E; crew measured 13 milligauss under the power lines outside her house and about 3 milligauss )) inside her home.
HIGHER CANCER RATES
Even if electromagnetic fields do cause cancer, they are relatively weak carcinogens, says H. Keith Florig, coauthor of an EMF study for the congressional Office of Technology Assessment.
Various studies have found two to three times higher cancer rates among people most exposed to electromagnetic fields. But many of the cancers associated with EMF so far are relatively rare, such as childhood leukemia, which hits 1 in every 14,000 children per year. Doubling that rate would increase the rate to 1 in 7,000.
Cigarette smoking, by comparison, increases the risk of lung cancer by 20 to 60 times, according to an EPA brochure.
Though EMFs may pose a relatively small individual risk of cancer, Florig notes that could translate into "from one to several thousand deaths" nationwide when many people are exposed to EMFs for many years.
Still, he notes, automobile accidents and even radon are blamed for many more deaths than EMFs, even if the worst is assumed about them.
"I don't think that's nearly large enough [a risk] for me to worry about my kids or devote all my attention to," said Florig, a fellow in the center for risk management at Resources for the Future, an energy policy think tank in Washington.
With the jury still out on whether EMFs are dangerous, many experts advise "prudent avoidance," a middle course between doing nothing and drastic action. Some have suggested putting away electric blankets, for instance, because the fields they produce are next to the skin, or not buying homes next to transmission lines, the power cables strung on steel towers that generate intense fields nearby.
In the Annapolis controversy, Florig suggested that BG&E; was being "insensitive" to public concerns about EMF by not presenting city officials with several alternatives to expanding the substation and laying out their costs.
"To spend $30,000 to ask a consultant to draw up these alternatives I don't think is a lot to ask," Florig said, "and I think the value of that information to the community is money well spent."
Travis, for one, questions whether the substation expansion is needed, particularly if energy conservation measures are tried. She has rallied opposition from most of the homeowners living around the substation, from local environmentalists and from three neighborhood associations served by the facility.
"I'm not saying that this causes cancer," she says. "I'm saying that there's enough evidence and enough going on around the country to warrant concern. . . . If you can wait, why not wait?"
BG&E; officials say delays in winning city approval of the project already have forced them to look for stopgap ways of meeting power demands in the area. But they say there are no other suitable locations for the substation, and conservation measures will not reduce power use enough to eliminate need for the expansion. If the mercury drops below normal this winter, they warn, power demand could exceed the substation's capacity by as much as 20 percent.
For Wayne C. Turner, the Republican alderman representing Eastport, the controversy boils down to "whether you go with facts or you go with feelings." Turner, a systems technician with C&P; Telephone Co., says he has not made up his mind yet how he will vote.
The nine-member council is scheduled to decide next month. But of one thing Turner feels certain: "I'm going to lose, no matter which side wins."