San Diego — The electricity transmission industry has long recognized that surrounding underground power lines with a metal shield is the most effective way to block their emissions of magnetic field radiation. But on August 3 of last year, San Diego Gas and Electric senior governmental liaison Jany Staley sent an e-mail to Nathan Bruner saying, "We will NOT shield. There is [sic] no convincing studies that for the expense this methodology works." She followed the e-mail up with a letter to Bruner saying the same thing and explaining methods SDG&E uses.

Bruner is the City of San Diego's power undergrounding program administrator. He passed Staley's e-mail and letter on to Joan Tukey, president of the California Alliance for Utility Safety and Education. Tukey, in turn, sent copies of the messages to a member of her organization, retired local attorney Hal Tyvol.

Since Staley intended her original memorandums to clarify what SDG&E would do in a planned Carmel Valley park project, Tyvol paid little attention to them, even though they involved 138- and 230-kilovolt power lines. But in July, Staley's neighbor, Jeff Gunn, had gone in with an SDG&E "measurement guy" to read electromagnetic-field radiation emissions on Dale Street in North Park. According to Tyvol, Gunn waited several weeks to put leaflets on people's doors that read, "There are super-high radiation readings on Dale Street, and they're trying to kill us."

Gunn sounded the alarm because the city and SDG&E have been planning to extend the power lines on Dale Street into his neighborhood. Both he and Tyvol live in South Park on 29th Street.

The standard measurement units of electromagnetic-field radiation are called "gausses" and "milligausses" (one thousandth of a gauss). When Tyvol got Gunn's leaflet, he went to Dale Street and took electromagnetic-field radiation readings with his own gauss meter. The figures he got there, he says, were 200 milligausses above the trench the power cables are in, 40 milligausses at 10 feet away, and 10 milligausses at 35 feet away -- the distance residences typically are set back from the lines. "Those are very high levels, as high as overhead lines give off," says Tyvol, who reports the California Health Services Department recommends no more than 3 milligausses at the edge of residences.

"People think burying power lines reduces electromagnetic-field radiation substantially," Tyvol continues. "But earth alone doesn't cut it. The radiation can go through it and through asphalt and concrete. The only thing that stops it is metallic shielding."

By late August, Tyvol had put Staley's "We do NOT shield" together with the Electromagnetic-field-radiation readings he obtained on Dale Street. In the meantime, he notes, SDG&E "refuses to answer customer questions whether metallic shielding was used with the cable installed [on Dale]."

On behalf of the Alliance for Utility Safety and Education, Tyvol filed a December 3 complaint to the California Public Utilities Commission about SDG&E's project on Dale and 29th Streets and the plans to extend it farther south. He charges in the complaint that SDG&E failed to use metallic shielding on the underground cables in the first phase of its installations in the area. (The California Public Utilities Commission requires that all cables operating at voltages higher than 5000 volts be shielded with metal coverings.)

San Diego Gas and Electric has plans to underground most of a double 138-kilovolt power line from a substation in Mission Valley to Main Street near San Diego Bay, according to Tyvol. The history of the problem began on May 16, 2000, when the San Diego City Council granted SDG&E permission to underground the cable in a one-mile corridor, or "district," along 30th Street between University Avenue and Olive Street. That corridor extends 150 feet on either side of 30th Street's centerline, Tyvol says.

But on September 20 that same year, SDG&E wrote to assistant city manager Frank Belock saying it had chosen an alternate route for the project, according to documents in Tyvol's possession. The company wanted to move the undergrounding from 30th one block west to the corridor that runs along Dale Street.

The city's Belock granted SDG&E's request to relocate its undergrounding project. The company began the project in the summer of 2002 and by 2003 completed work to the northern edge of South Park. In his complaint to the Public Utilities Commission, Tyvol writes, "It should be noted [that] 30th Street is a through street, mixed commercial and residential, with city bus traffic. On the other hand...Dale Street [is] a narrower, almost exclusively residential side street, with no through traffic."

In changing the site of its undergrounding, SDG&E went outside the boundaries of the district that the city originally granted the utility in 2000. Since SDG&E did not return to the city council to change the district, according to Tyvol's complaint, it acted without proper authority. By taking its work out of the district, the company also lost an exemption from environmental review. Public Utilities Commission regulations allow this exemption if overhead power lines are buried in the same district. Since the district changed, however, residents of the affected area have the right to file a protest with the commission to require the utility to submit its work to environmental review. Residents in this case, says Tyvol, were not given the chance to protest.

Tyvol's complaint alleges that SDG&E did not give local residents a Public Utilities Commission notice of its undergrounding project either. If it had stayed within the originally granted district, the company would not have had to provide the notice. Though city officials did send out a notice of the undergrounding project to residents of 30th Street, they did not send a notice to those on Dale Street.

"The Public Utilities Commission notice is the important one," says Tyvol. "San Diego Gas and Electric had to post handbills on the streets affected, and two notices of the work had to be published in the newspaper. In the newspaper notices, a summary statement of how they were going to reduce electromagnetic-field emissions, along with the procedure to protest, had to appear. Those notices were not given."

Tyvol inadvertently discovered SDG&E's failure to give the Public Utilities Commission notices. After learning how high electromagnetic-field emissions were on Dale Street, he wrote to the city's planning department requesting the "advice letter" that the notices had gone out. (Utilities are required to file such advice letters with the commission, the California Energy Commission, and the local planning director.)

"I wrote a formal request to see the advice letter," says Tyvol, "because officials take you more seriously that way. But I had to follow up, because they lost my letter. They're nice people in the planning department but not very organized. Eventually they discovered that they never received the advice letter I inquired about."

Finally, Tyvol's complaint to the Public Utilities Commission charges that, in its Dale Street project, SDG&E did not take the steps to mitigate electromagnetic radiation that the utility's own "design manual" says have some impact. The company did not bury the power cables in the center of the streets, but closer to their eastern edges. The company dug only a three-foot-deep trench to bury the lines, so that by the time the lines were placed on the bottom of the trench, they were 24 inches from the surface, the minimal depth the law allows. When Pacific Gas and Electric undertook a similar project in San Francisco, says Tyvol, the Public Utilities Commission required it to bury the cables 11 feet deep, to keep them farther away from pedestrians.

In the meantime, a national debate rages over how harmful electromagnetic-field radiation is to humans. Hal Tyvol admits that no "conclusive" proof exists that the radiation is dangerous. But he cites a 2002 report by the California Department of Health Services that "it is more probable than not" that radiation is a factor in the development of childhood leukemia, miscarriages, brain cancer, and Lou Gehrig's disease. Other studies have established a "statistically significant correlation" between radiation emissions and the diseases. "The power industry," says Tyvol, "admits to the correlations but argues the diseases may come from other factors, such as pollution, and not from electromagnetic fields. The problem is that you can't do laboratory testing on people like you can on rats."

Stephanie Donovan, a senior communications manager for SDG&E, responds, "The issue is an emotional one. The danger can't be ruled out. But most studies don't demonstrate that it exists." Donovan referred me to a link on SDG&E's webpage. It reads in part: "Without exception, the major scientific reviews of the [electromagnetic- field] research literature have reported that the body of data, as large as it is, does not demonstrate that exposure to power-frequency magnetic fields causes cancer or other health risks, although the possibility cannot be dismissed.... Has science proved [electromagnetic-field radiation] is harmless? No, scientific uncertainty remains and research is ongoing."

That must be the reason that California's Public Utilities Commission insists that utilities put metal shielding around cables carrying more than 5000 volts of power.