At CPS Energy, the safety and health of our customers has always been an important focus. Over the last few decades, the public has become concerned that there might be health risks associated with electric and magnetic fields (EMF). This is not a new issue. Researchers have been studying EMF for more than 20 years.

What are Electric and Magnetic Fields?
Electric and magnetic fields are invisible lines of force associated with the use of electricity. Voltage in any wire creates an electrical field around the wire. Magnetic fields, on the other hand, are produced by current. For example, when you plug in an ordinary lamp, voltage enters the cord, creating an electrical field. Current flows through the lamp cord when you turn it on, emitting a magnetic field as well as the already present electric field. It is important to know that EMF readings, measured in milliGauss (mG), decrease with distance.

Where are Electric and Magnetic Fields Found?
Electric and magnetic fields, which are produced by natural and man-made sources, are around us every day. They surround any wire conducting electricity, from everyday appliances such as televisions, toasters and alarm clocks to the transmission lines that carry electricity long distances.

The earth is the largest natural source of magnetic fields. Its magnetic field causes a compass needle to point north and it enables birds to migrate. Lightning is also a common natural source of electric fields.

Can These Fields Be Blocked?
Electric fields can be blocked by trees, the ground, buildings and other objects. Magnetic fields, however, are not significantly affected and they pass through most common objects.

Are These Fields Harmful?
There is currently no conclusive evidence proving EMF poses a risk. Early studies suggested a link between magnetic fields and certain types of cancer, including leukemia, among children and utility workers. While some studies reported a slightly higher incidence of disease among populations with high exposures to magnetic fields, other studies have presented conflicting information or have suggested that no convincing evidence linking magnetic fields to cancer exists at all.

What Does the EMF Research Indicate?
After more than 20 years of research, experts are still unable to tell us whether EMF exposure poses a risk. Although, recent research suggests if there is a risk, it is relatively insignificant. In a recent study from the Institute for Environmental Toxicology at the University of Michigan, Dr. Lawrence Fisher states, “All in all, this study indicates that, if there is an association between magnetic fields and cancer, it is very weak.”

The results of a United States government investigation found that scientific data laying out a link between EMF and cancer was inconclusive. The results of this research were published in several journals in 1992. The U.S. National Institute of Health panel concluded that more than 20 studies in the years since this research have found little evidence that EMF causes cancer.

However, over the past few years, several long-term studies have been completed. Because of the breadth of the study groups and the quality of modern research technologies, these are considered to be the most definitive.

A team of investigators led by E.R. Schoenfeld of Stony Brook University published the results of a study of electric and magnetic fields and breast cancer in the July 2003 issue of the American Journal of Epidemiology. The study found no statistically significant link between breast cancer and EMF exposure.

The latest large-scale investigation of EMF and childhood leukemia, conducted by Mary L. McBride and her colleagues at the British Columbia Cancer Agency, concluded that there is little evidence to link the risk of childhood leukemia to exposure to EMF. The study surveyed five Canadian Provinces: British Columbia, Alberta, Saskatchewan, Manitoba, and Quebec.

The National Institute of Environmental Health Sciences (NIEHS) releases its report in 1999 after Congress passed the Energy Policy Act in 1992. The NIEHS report states, “The scientific evidence suggesting that EMF exposures pose any health risk is weak. While the support from individual studies is weak, the epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia that for childhood leukemia. In contrast, the mechanistic studies and the animal toxicology literature fail to demonstrate any consistent pattern across studies although sporadic findings of biological effects (including increased cancers in animals) have been reported. No indication of increased leukemias in experimental animals has been observed.

IN 1989, the National Cancer Institute (NCI) initiated a study of residential magnetic field exposures and childhood acute lymphoblastic leukemia (ALL). NCI concluded, “Our results provide little evidence that living in homes characterized by high-measured, time-weighted average magnetic field levels or by the highest wire-code category increases the risk of ALL in children.” This study provides one of the largest comprehensive measures of magnetic field exposure to children in their homes. The complete findings were published July 3, 1997 in the New England Journal of Medicine.

How Are Magnetic Fields Measured?
Magnetic fields can be measured in milliGauss with a device known as a gaussmeter. Measurements taken by the gaussmeter are helpful in determining the relative strengths of magnetic fields from a variety of sources found in our everyday environments.

What Are Common Magnetic Field Measurements?
You may be surprised to learn that people generally receive more exposure from the wiring in their homes and appliances than from distribution or transmission lines – simply because they are closer to the sources in their homes. Magnetic field levels vary depending on the type of electricity source and the distance from it. Intensity decreases dramatically as you move away from the source. Consequently, magnetic fields near some common household appliances are greater than those measured directly beneath a high-voltage transmission line.

If you would like CPS Energy to come to your home and conduct an EMF reading, call (210) 353-2222.

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