by Sarah Lane

In response to our local power company’s proposed construction of a new electrical substation and installation of high voltage power lines in the downtown core area, I decided to investigate possible health and safety concerns related to electromagnetic fields (EMFs), those electrical and magnetic emissions created by all the electrical devices in our lives, from appliances to giant electric towers. I knew the conventional wisdom that there is no definitive link shown through research between EMFs and cancers, including childhood leukemia. But I’ve also walked underneath high voltage towers and felt my hair rise on my head from the charge, and I’ve heard the cracking and snapping and popping of the wires. So I unplugged conventional wisdom and decided to turn on some of the real variety.

From the Horse’s Mouth

The power company in question, Puget Sound Energy, offers on its website a page dedicated to electric and magnetic fields (http://www.pse.com/safetyReliability/electricsafety/pages/electricSafety.aspx?tab=1&chapter=10). There is some good basic information here and in the links provided. One key bit of information is the measurement units. We can’t talk about what we can’t see, like electric and magnetic fields, without a way to measure it:

• Electric field strength is measured in volts per meter (V/m).
• Magnetic field is measured in microstesla (µT).

How High Can You Get?

Both PSE and the World Health Organization (follow the link from the PSE page) present in terms of these units the human exposure guidelines recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). (Keep in mind that these units are based on the European standard of alternating currents at 50 Hz, which means that the reversal of current direction and thus the reversal of the electromagnetic field direction occurs in 50 cycles per second. In the United States we use 60 Hz.) The ICNIRP says that humans should be exposed to no more than 5,000 V/m and 100 µT. These limits are based on behavioral changes observed in studies with animals.

It is important to remember that we are exposed to electric fields all the time, so our exposure is already higher than 0 V/m. For example, the electric field strength of a refrigerator (at 50 Hz) is 120 V/m, and of a hair dryer (again, at 50 Hz) it is 80 V/m. The guideline of 5,000 V/m includes the exposure we already have. Underneath high voltage power lines we can be exposed to as much as 10,000 V/m all at once, more than double the ICNIRP recommended maximum exposure.

The same holds true for magnetic field. For example, we are continuously exposed to the Earth’s magnetic field, measured at up to 70 µT—still below the guideline of 100 µT. Beneath power lines, magnetic field can reach densities of up to 20 µT, which although by itself below the ICNIRP limit, greatly exceeds the density of 0.2 µT found in homes away from power lines.

Breaking Down

Low-frequency electric fields affect us all the time just as the electrical processes within our own bodies do. High frequency fields can cause more serious consequences.

Qanta are particles that carry electromagnetic waves. At higher frequencies, wavelengths are shorter and carry more energy. At very high frequencies qanta can carry so much energy that the bonds among molecules begin to break. High frequencies like this are found in radio frequency fields, which are created by microwave ovens, radio and cell towers, high voltage power lines, and radar, for example. In radio frequencies because electric and magnetic fields are so closely related, they are often measured in terms of power density, expressed in watts per square meter (W/m²).

Those Pesky Variables

As both PSE and WHO are quick to remind (and thorough about it), there are many variables involved in the potential effects of EMFs:

• the strength of exposure
• the length and frequency of exposure
• the size and body composition of the person
• the orientation of the body toward the field
• the health of the person
• the distance of the person from the source of exposure
• in the case of electric fields, the presence of barriers, such as metal or trees or walls, that can shield a person from the electric waves

These variables make it difficult for scientists to determine what EMF exposure is safe. The WHO explains one way that ICNIRP handles these variables: “According to ICNIRP, radiofrequency and microwave exposures should be averaged over time to address cumulative effects. The guidelines specify a time-averaging period of six minutes and short-term exposures above the limits are acceptable.”

Reading Between the Power Lines

The PSE page quotes the World Health Organization as saying that “Despite extensive research, to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to human health.” Indeed, WHO very, very carefully emphasizes the low risk of low-level exposure to EMFs. But they also remind readers, and PSE does not quote them on this, that “It is not disputed that electromagnetic fields above certain levels can trigger biological effects.” And they emphasize that no studies have been conducted to assess long-term exposure to low levels.

WHO also carefully explains why so much research into this matter continues even though many studies have failed to show a definitive link between cancer (and other health effects) and exposure to EMFs:

Human health studies are very good at identifying large effects, such as a connection between smoking and cancer. Unfortunately, they are less able to distinguish a small effect from no effect at all. If electromagnetic fields at typical environmental levels were strong carcinogens, then it would have been easy to have shown that by now. By contrast, if low level electromagnetic fields are a weak carcinogen, or even a strong carcinogen to a small group of people in the larger population, that would be far more difficult to demonstrate. In fact, even if a large study shows no association we can never be entirely sure that there is no relationship. The absence of an effect could mean that there really is none. But just as well it could mean that the effect is simply undetectable with our method of measurement. Therefore, negative results are generally less convincing than strong positive ones. [emphasis all mine]

The Issue That Towers Before Us

In our community, we already have high voltage power lines running by one of the community middle schools. The proposed new lines would run by either the high school, a middle school, and a daycare or down a busy a street with a high residence density, including apartments, townhomes, and community cohousing.

The reason offered by PSE for their proposal to build is to address a slight increase in energy needs. In our relatively progressive community, the increase in energy that the proposed station and power lines is intended to address could be managed easily through a community-wide effort at reducing energy consumption. Already more than 700 families have volunteered to have their electric heat cut off by the power company during times of peak usage that overtax the grid. It seems that given the long list of unknowns and knowns cited by both PSE and the World Health Organization, the only reasonable course of action is to change our energy behavior before we willingly risk the potential for changes to our molecular structures.

© 2010 ProgressiveKid

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