EDITOR'S NOTE - The harnessing of electricity has caused profound changes in the environment, bathing modern society with invisible forces called electromagnetic fields. But only in recent years did scientists start to suspect these fields might promote cancer and perhaps other health problems. The first of a three-part series, ''Fields of Peril,'' examines this emerging environmental concern.

Undated (AP) _ By LEE SIEGEL AP Science Writer

GARDEN GROVE, Calif. (AP) - In the basement of a Pacific Bell telephone office, 11 of 65 workers developed cancer in recent years, and three died. Yet on the second floor, not one of 75 employees had the disease.

Some of the stricken staffers suspected their cancers might be caused by electromagnetic fields - invisible forces produced by anything electrical, from workplace equipment and power lines to hairdryers and can openers.

They feared dangerous doses of electromagnetic radiation were emanating from an adjacent power room where incoming electricity was converted to run phone systems.

''There was so much paranoia going on in the office,'' said Judy Parker, a 47-year-old data processing worker with breast cancer. ''People were asking 'Who's next?' One after another after another of us kept coming down with cancer. I do believe these electromagnetic fields could very possibly have something to do with it.''

A company investigation failed to implicate any environmental cause, including asbestos recently removed from the building. But Pacific Bell says it didn't think to measure electromagnetic fields, either from the power room or employees' computer video screens.

As in a growing number of cases across the country, people concerned about the fields were left to wonder.

Inconclusive but increasing evidence from a number of studies suggests workers in electrical industries develop cancer at unexpectedly high rates after prolonged exposure to electric and magnetic fields, known collectively as electromagnetic fields, or EMFs.

Yet the possible hazard isn't limited to the workplace. Virtually everyone is bombarded with EMFs - at home, at the mall, even outdoors. Power lines, home appliances and office equipment all emit the fields.

Studies have associated prolonged EMF exposure with higher rates of cancer in children. Inconclusive studies also link EMFs with other health problems, including birth defects, miscarriages, nervous system and behavioral problems, and possibly immune system disorders.

Some scientists consider the studies linking EMFs and health problems badly flawed. They say it's ridiculous to believe human lives are endangered by radiation that is weaker than the Earth's magnetic field or the natural electrical activity in the human body.

Skeptics also note that research has failed to reveal a biological explanation of how EMFs could promote cancer. And if such a risk does exist, they say, it is much smaller than other environmental hazards such as smoking.

But even ''low risks applied to a lot of people are unacceptable,'' said Raymond Neutra, chief of special epidemiological studies for California's Department of Health Services.

The potential consequences reach beyond human health.

If researchers eventually determine electromagnetic fields are harmful, it could cost industry billions of dollars to fight lawsuits and redesign electric power facilities, appliances and workplace equipment.

''We're talking about rewiring America,'' said Ram Mukherji, an electromagnetism expert at Southern California Edison, a power company. ''We may have to reduce our standard of living.''

The potential costs of personal injury lawsuits filed by cancer patients and others against utilities and other companies ''are just incredible,'' said San Francisco attorney Stephen M. Snyder. ''They would dwarf things we've dealt with so far like Agent Orange, the Dalkon Shield and asbestos.''

But so much about EMFs and their effects is unknown.

Unlike cigarette smoke and toxic chemicals, there is evidence that electromagnetic radiation may not be worse in larger doses, so government agencies say they can't yet determine what levels are safe or unsafe.

The Environmental Protection Agency abandoned its research into EMFs a few years ago for budgetary reasons, leaving it in large part to the utility industry, which has the most to lose if the hazard proves real, Seattle lawyer Michael Withey said.

The industry's Electric Power Research Institute funds about half the $15 million spent annually on EMF research, said Greg Rauch, an institute project manager. The EPA resumed a small amount of research - $750,000 worth - during the current fiscal year, agency spokesman Dave Ryan said. The federal Energy Department also is financing studies.

Scientists say it's unclear whether EMFs generated by common household current, which is measured at a frequency of 60 hertz, pose a peril.

A 1990 draft EPA report identified 60-hertz magnetic fields from power lines and perhaps other sources in the home as a ''possible, but not proven'' cause of cancer in humans.

The agency said studies were inconclusive as to the dangers of electromagnetic radiation in the higher, so-called radio-frequency fields, such as radio and television signals. It did, however, urge more study of elevated rates of leukemia discovered in recent years among amateur radio operators.

Radio-frequency fields are generated by radio and TV transmitters, cordless and cellular phones, microwave communication equipment and cooking ovens, and a variety of medical devices.

The EPA staff initially recommended classifying 60-hertz fields as ''probable human carcinogens'' and radio-frequency fields as ''possible'' carcinogens.

But those recommendations were deleted by Dr. William Farland, director of EPA's Office of Health and Environmental Assessment, because he felt existing evidence didn't justify the conclusions.

While scientists sort the evidence, the EMF issue is appearing more frequently in power line construction battles, personal injury and other lawsuits, and in government.

Citizens worried about fields have gone to court or regulatory agencies to fight planned or existing power lines and other facilities in Seattle, Los Angeles, Boca Raton, Fla., Houston and elsewhere.

Florida has adopted standards limiting magnetic field intensities near transmission lines. The issue is being studied by officials in California, New York, Oregon and Maryland. Restrictions on new power lines were imposed last year in Whatcom County, Wash., and East Greenwich, R.I.

In one notable case, the Klein Independent School District in Texas forced Houston Lighting & Power to spend $8.6 million to remove a transmission line from school property.

Because electromagnetic risks remain debatable, utilities are winning most lawsuits in which workers or others blame cancer, miscarriages and birth defects on EMF exposure, said Tom Watson, a utility industry lawyer in Washington.

But there are exceptions.

Last year, Boeing Co. worker Robert Strom won a $500,000 settlement in Seattle after arguing his leukemia was caused by occupational exposure to electromagnetic pulses used to test missiles. Boeing agreed to monitor 700 exposed workers.

New York attorney Stanley J. Levy said plaintiffs receiving settlements in radio-frequency electromagnetic cases included a civilian Navy repair technician from Connecticut who blamed his pancreatic cancer on radar exposure, a New York phone repairman who attributed his cancer to radar transmitters, and military personnel who developed cataracts after working on radar equipment.

And even if the utility industry wins most of its EMF battles, the victories do little to alleviate public fears that these invisible waves are responsible for cancer hot spots - clusters of cancer cases in workplaces or neighborhoods, reported in cities ranging from Darrington, Wash., to Rochester, N.Y., to Portland, Ore., to Guilford, Conn.

In virtually every cluster, health investigators couldn't establish any link to the fields. Instead, they attributed the disease to other possible factors such as toxic substances or said the seemingly high numbers of cancer cases weren't excessive or happened by chance.

In the Garden Grove phone company case, investigators noted the sick workers faced several health risks, including asbestos plumbing insulation. Truck exhaust was sucked into the basement by faulty ventilation. Some lung cancer patients smoked cigarettes. Others had family histories of cancer.

''I don't think working in that office had a thing to do with it,'' said Jim Stout, Pacific Bell's safety director.

Most of the employees moved from the basement after the building's other two floors were remodeled. But 15 or 20 administrators still work there, said Charles Wallin, who managed the basement database center.

''Pacific Bell should investigate it further and not try to link it to some outside cause,'' said phone maintenance administrator Stephanie Madison, a union steward for the Communications Workers of America.

''That basement is the common denominator. But it's a liability issue, and I don't think they want to discover that.''

Next: How One Community Coped With Uncertainty