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."