July 20, 2008
TECHNOS QUARTERLY Winter 1994 Vol. 3 No. 4
What's Wrong with This Picture?
By Emily Eakin
To
the average viewer, not much is wrong. But some scientists and public health
officials would say a great deal is wrong with it. Electromagnetic fields
emitted by your child's computer screen could be hazardous to her health.
Here's why and what to do about it.
Ever since the late 1970s, when American epidemiologists began studying the 50- to 100-hertz electromagnetic fields (EMFs) emitted by power lines and computers, debate has been ongoing over whether this extremely low frequency radiation can cause or promote cancer. In 1979, an epidemiologist in Denver observed that children who lived in homes located close to power lines had an elevated incidence of leukemia. More recently, some researchers have argued that the low doses of radiation emitted by computer visual display terminals (VDTs) could also be a potential health risk—a risk that may depend, in part, on how much time we spend at our computers, how we position our computers relative to our bodies, and how far away from the screen we sit.
Today, according to a July 1993 survey by the National Education Association, 90 percent of public schools and 52 percent of classrooms have computers. Although students may still spend about six times as many hours in front of a TV set as they spend in front of a school computer every week, their contact with the universe of electronic information is accelerating. Multimedia CD-ROMs, a booming educational software industry, and the Internet—with its data banks, library catalogs, and virtual classes—are making the computer increasingly the center-piece of classroom learning.
One index of the rapidly growing technology and education market is a variety of new publications targeted at schools and young VDT operators. In May 1994, a consortium of Massachusetts software manufacturers in collaboration with education professionals released The Switched-On Classroom, a step-by-step guide to acquiring and implementing video display technology in the state's public schools. By September, several new magazines had begun wooing the estimated 15 million American households with both kids and computers.
From the technology how-to manual to the consumer publications, the dominant tone is one of boundless enthusiasm. There is little talk of any VDT health hazards. In The Switched-On Classroom, typical case studies include a Monson, Massachusetts, elementary school that rotates students through computer stations for daily course work in math, science, and language arts, and a Revere, Massachusetts, magnet school where each classroom is equipped with a multipurpose wall outlet that hooks up computers, cable TV, satellite programs, VCRs, and two-way broadcast video. The first issue of Family PC, a monthly that made its debut in September, tells parents how to make sure their kids are getting enough computer time at school and offers instructions on how to turn the family PC into a Halloween party game.
Health Hazards
But while the computer industry continues to supply schools and homes with
indispensable new technology and to propose creative ways to use it, the rumblings
over health hazards persist. There is a wealth of scientific data to consider
before we plug in and switch on. All electrical equipment, including computers,
produces EMFs of varying degrees of intensity. In most cases, the fields fall
off rapidly with distance from the source, but when a person stands under
a power line or close to an electrical appliance, a weak current is induced
in the body. The 50- to 100-hertz fields emanating from power lines and VDTs
fall into the extremely low frequency (ELF) range. And unlike radiation at
much higher frequencies, such as x-rays and ultraviolet light, these fields
have commonly been considered benign.
When the 1979 Denver power line-leukemia study was published, most scientists were skeptical of its conclusions. Surely, many believed, other factors such as air pollution or socioeconomic class could explain the elevated cancer rates. But by 1990, the Denver study had been replicated by several—initially disbelieving—epidemiologists, and new studies were under way to investigate cancer rates among electricians and telephone line workers, adults with high chronic occupational EMF exposure.
Meanwhile, the connection between power lines and computers had been made in 1982 when Karel Marha, a biophysicist in Canada, announced that VDTs, like power lines, emit 60-hertz EMFs. Furthermore, he noted, these fields are pulsed—the currency is turned on and off 60 times a second—unlike naturally occurring sources of electric and magnetic radiation, such as sunlight. The pulsed fields from VDT monitors, Marha reported, produce potentially harmful biological effects.
As the number of computers in the workplace multiplied during the early 1980s, unusual clusters of health problems among VDT users cropped up repeatedly. The first documented complaints involved eye problems: blurry vision, nearsightedness, even cataracts. A second wave of complaints involved clusters of female computer workers in different parts of the country who reported high numbers of abnormal pregnancy results, including spontaneous abortions, miscarriages, and congenital birth defects. In 1984, after the National Institute for Occupational Safety and Health (NIOSH) investigated several of these cases, Dr. J. Donald Millar, the institute's director, testified before a congressional subcommittee on health and safety that, based on available scientific evidence, “VDTs do not present a radiation hazard to the VDT operator or to the developing fetus.” Nevertheless, Dr. Millar affirmed, plans were under way for a NIOSH study on the reproductive health of VDT workers. As it turned out, the United States was already lagging behind the rest of the computerized world. By 1987, two Swedish studies and one Spanish study had found significant malformations in mice and chick embryos that had been exposed to EMFs similar to those emanating from computer monitors.
The problem pregnancies and the animal fetus studies seemed to substantiate Karel Marha's thesis about the negative biological effects of EMFs from computers. But the official response to these findings was very different in Sweden than it was in the United States. Marha had insisted that EMF emissions could be controlled effectively without much effort. He suggested that computer manufacturers incorporate shielding devices into their monitors' basic design and that users sit farther away from the screens. In 1986, the Swedish government established an emissions limit for computer monitors in the public sector, called MPRI. But in this country, the findings were met with virtual silence from both the press and the government. In fact, the federally funded NIOSH study on reproductive health had suffered repeated setbacks and was still in the planning stages.
Yea or Nay?
Today, frustratingly little has changed. Sweden is on to its second, more
stringent VDT emissions guideline, MPRII, while the U.S. government has yet
to take an official stand on the issue. For New Yorker writer Paul
Brodeur, who brought this issue to the public's attention in several long
articles in 1989, the government's failure to take swift action on EMFs amounts
to nothing less than a federal cover-up. For other experts, it is the inevitable
result of working on an issue about which there is much scientific debate,
no conclusive evidence, and considerable big business interest at stake.
A major problem with the epidemiological studies on power lines and childhood cancers and on VDT use and female reproductive health, for example, is that the relative risks (the increased probability of disease in the exposed population) are small—often within a 1.5 to 2.5 range—so their significance remains controversial. By contrast, studies on smoking and lung cancer obtain relative risks in the range of 20 to 30. Some experts fear that small positive effects could be the result of subtle bias in an experiment's design or could reflect the influence of other, unknown variables. A paper published in 1991 by David Jackson, a particle physicist at the University of California at Berkeley, for example, challenges the association between emissions and cancer. Jackson compared data on the consumption of electric power in this country with data on the incidence of cancer over the course of the century. He found that although per capita electrical consumption has increased by 2,000 percent, cancer rates (with the exception of respiratory cancers largely attributed to smoking) have remained stable.
To complicate matters further, no consistent dose-response relationship between emissions and health effects has been established. We still don't know how much radiation for how long is bad for us. In the Denver cancer studies, children's EMF exposure was not measured but only estimated according to the voltage of the power lines near their homes. Actual exposures would vary depending on one's location within the house and the amount of electricity in use at a given time.
Recently, however, several studies have emerged that support the existence of a dose-response relationship. In 1992, Finnish researchers found that women whose computers emitted fields between 4 and 9 milligauss (the unit for measuring magnetic fields) had twice as many miscarriages as women whose computer emissions were below 4 milligauss. The length of exposure was also a factor. The highest rate of miscarriages occurred in the group of women who used higher emission computers for more than 10 hours a week. The results of an important study from Sweden's Karolinska Institute released the same year also found a significant dose-response relationship between magnetic field exposure and childhood leukemia.
In the United States, there were different findings. In 1991, the results of the NIOSH study of reproductive health and female VDT workers were published in The New England Journal of Medicine. No increased risk of spontaneous abortion was discovered in the control population.
Conflicting Interests
What do we make of these conflicting results? Are some studies more reliable
than others? How can we tell? For the Swedes, the latest batch of EMF research,
although not definitive proof of a health hazard, was the impetus for formulating
an official position on emissions. In September 1992, Sweden's National Board
for Industrial and Technical Development declared that it would “act
on the assumption that there is a connection between exposure to power frequency
magnetic fields and cancer, in particular childhood cancer.” In the United
States, no such statement is expected soon.
“The anxiety of the public on this issue is enormous,” says Dr. David Carpenter, dean of the School of Public Health at the State University of New York in Albany, “and we're hiding our heads in the sand. Too many of the players have a conflict of interest.” As Dr. Carpenter points out, much of the American research into EMFs has been financed by federal agencies or major utility companies, a situation that may affect the kinds of questions that are asked and the way results are interpreted. Berkeley physicist Jackson's investigation of cancer data and electricity consumption was supported in part by the Department of Energy. Not coincidentally, the same agency is a major benefactor of the Oak Ridge Associated Universities (ORAU), an academic consortium dedicated to developing America's technology infrastructure that was hired by a federal committee on radiation research and policy to conduct an independent scientific review of EMF health hazards. In 1992, the ORAU panel concluded that extremely low frequency EMF “does not constitute a public health problem” and that “in the broad scope of research needs in basic science and health research, any health concerns over exposures to ELF-EMF should not receive a high priority.”*
(*From the Executive Summary of “Health Effects of Low Frequency Electric and Magnetic Fields,” June 1992. Prepared by an ORAU Panel for the Committee on Interagency Radiation Research and Policy Coordination.)
This sort of mitigating language comes as a relief to utility companies and manufacturers of electrical equipment who could possibly face retroactive liability for their customers' health problems. Two years ago, a Florida man sued a cellular telephone company, claiming that his wife's death from brain cancer was due to EMFs emitted by her phone. Recently, several cancer patients have sued utility companies whose power lines run through their backyards. Although none of the suits has been won by the complainants, Dr. Carpenter predicts it is only a matter of time before the computer industry becomes a target of litigation as well. If the federal government were to acknowledge EMFs as a serious potential health hazard and enforce emissions limits, some manufacturers could face exorbitant costs in order to make their products compliant with the law.
Despite possibly biased funding sources for epidemiological studies, aggressive lobbying on the part of utilities and computer companies, and the poor record of federal agencies on conducting research, it is not clear that the government is deliberately broadcasting misinformation about EMFs. Even if an association between EMFs and health effects could be proved, a viable theory about how the fields interact with the human body to promote or cause cancer is still lacking.
Dr. David Savitz, an epidemiologist at the University of North Carolina at Chapel Hill who replicated the 1979 Denver power line study, disagrees with the ORAU panel's conclusions but insists there is “room for legitimate differences.” Cautiously optimistic about the progress of EMF research, Dr. Savitz suspects that VDTs will not turn out to be a major health risk. “Evidence for a hazard is suggestive but uncertain for power lines and electrical workers,” he observes. “In the extrapolation of that information for VDTs, the concern goes down markedly.”
A Prudent Policy
The point is that we are working in the realm of educated guesses. We just
don't know enough about what kind of dose at which frequencies is dangerous.
In the absence of a national standard on EMFs, however, concerned consumers
have fashioned their own policies of prudent avoidance, and public schools
have been among some of the most visible advocates of precautionary measures.
In 1991, the New York City Board of Education adopted stringent guidelines
on computer emissions, becoming the first public institution in the country
to do so. The reasoning was simply that computers are here to stay and might
as well be made as safe as possible. “There is no other electrical appliance
used by so many people for so many hours a day that produces such an enormous
range of electromagnetic radiation,” observes Michael Mason, a consultant
on EMF issues who helped devise the New York City Board of Education's policy
on VDTs.
There are easy, inexpensive precautions we can take with VDTs while waiting to find out the extent of the health risks. For computer manufacturers, the costs of making monitors compliant with MPRII is minimal, less than 10 dollars per monitor. The liquid crystal display (LCD) monitors often used with laptops are a viable alternative. Although they involve expensive technology, LCD monitors typically do not generate significant emissions and have recently become available for use with desktop models. In addition, the design of the computer work station can play a crucial role in reducing exposure, because most of the emissions come from the back and sides of a monitor and tend to fall off rapidly with distance.
Before working with the New York City schools, Mason, in collaboration with an architect, had designed offices at the Fund for the City of New York, a nonprofit organization that advises the city and other municipal groups on policy issues. Low emission monitors had not yet come on the market, so Mason improvised a spatial solution. He arranged 43 work stations in such a way that every employee was at least five feet away from the sides or back of another's display. At each cubicle, the keyboard rests in a tray attached to the edge of the desk. This allows the VDT operator to reach the keyboard comfortably while maintaining a 28-inch working distance from the screen. Pregnant workers at the Fund were requested to use one of two LCD desktop monitors purchased from Norway.
When Mason was hired by the New York City public schools in 1991, lower emission monitors were available, but typically only the newest models met levels established by MPRII. At the time, the New York City school system owned 60,000 computers for students and staff and was acquiring 6,000 to 8,000 new models on an annual basis. The school system's computer orders for the following year had already been placed. Under Mason's recommendation, however, the school system warned its vendors that it would not accept delivery of any monitors that failed to meet emissions limits at least as stringent as MPRII. In a pioneering gesture, the vendors responded positively. Wherever necessary, substitute monitors were found, and Mason tested a sample of each model at 53 specified measurement points according to MPRII test protocol to verify compliance.
Money Matters
The New York City Board of Education's successful campaign for low emission
VDTs has paved the way for other school systems and communities to follow
suit. But without support from the federal government, schools may fare unevenly
in their quest for control over EMFs. In wealthier communities, school systems
may be able both to hire a consultant for an EMF evaluation and to pay for
suggested alterations. After the Woodmere Middle School in Hewlett, Long Island,
was found to have some of the highest EMF emissions in the state of New York,
the local school system developed a proposal to build a new $10 million school
at a different site and hired a consultancy firm to do a thorough “magnetic
field survey” in early 1994. As a result of the survey, the school system
spent $50,000 during the summer on adjustments in basic wiring and reconfiguration
of classroom space. Student VDTs will now be positioned at optimum distances
from each other, and in the Early Childhood Center, children will no longer
sit on floor areas situated directly over fluorescent lights on the ceiling
of the floor below. More substantial alterations, including the shielding
of electrical equipment and of classrooms located close to electrical sources,
involve expensive materials and await budgeting approval.
Rebuilding and renovating schools is expensive, but simply purchasing the safest VDT can be costly as well. Today, most of the major U.S. computer manufacturers sell monitors that meet MPRII guidelines, but older, noncompliant models are still on the market. Louis Slesin, the publisher and editor of VDT News, a bimonthly newsletter that addresses computer health and safety issues, warns that public schools may well be stuck with less sophisticated, older models. “A lot of poorer districts can't afford to buy the new computers,” Slesin says, “and many depend on hand-me-downs. We don't know whether there is a risk, but what's happened is that computer companies have begun to fix a problem without ever admitting there was one or what it was.” Unless manufacturers are forced to retract older models, it may be years before MPRII-compliant monitors reach classrooms in some parts of the country. In New York City schools, where the monitors meet the Swedish guidelines, classroom space is at a premium and computer terminals may not always be configured at recommended distances from each other.
Although no one can say for sure whether money spent on reducing EMFs is money wasted, parents, teachers, and schools ought to be informed about both potential health hazards and preventive measures as they make their technology choices. Understanding EMFs and the risks associated with them is part of computer literacy. As Michael Mason points out, if you factor in the costs of medical care, prudent avoidance begins to look like a bargain.
Photos, photo/illustration by Jason Schmidt.
Emily Eakin is a doctoral student in English literature at Columbia University and a freelance writer on social and academic issues. Her work has been published in The Economist, Interview, The New York Times Book Review, and Vanity Fair. Eakin currently works for The New Yorker.
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