Questions
What are electric and magnetic fields (EMF) and where do they come from?
Electric and magnetic fields are invisible force fields created by both natural and man-made sources. A natural source is the earth's magnetic field. Manmade sources include household or building wiring, electrical appliances and electric power transmission and distribution facilities.
Electric fields
An electric field occurs wherever a voltage is present. Electric fields are created around appliances and wires wherever a voltage exists. Electric field strength is measured in volts per meter (V/m). The strength of an electric field decreases at greater distances from the source.
Electric field strength is measured in volts per meter (V/m). The strength of an electric field decreases at greater distances from the source.
Magnetic fields
Magnetic fields are created whenever electrical current flows. Magnetic field strength is often measured in milliGauss (mG). Magnetic field strength from power lines depend on many factors including the design of line, the amount of current the line carries, and the distance away the line.
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Are electric and magnetic fields a health hazard?
Three decades of research has not established that a human health hazard exists from long-term EMF exposures. Questions remain about whether EMF exposure at home or work is linked to some diseases such as childhood leukemia. While scientific research is continuing, a quick resolution of the remaining scientific uncertainties is not expected. Coordinated international research has resolved many questions about specific diseases. While some health authorities have identified magnetic field exposure as a possible human carcinogen, they acknowledge that additional research will be necessary before a more definitive conclusion can be made.
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What are Southern California Edison and public officials doing about EMF?
Since the question of whether EMF exposures cause human health problems was raised, SCE has been committed to resolving the issue in a socially responsible manner. If there is a problem, SCE wants to know about it and find ways to serve our customers in a safe, practical manner. SCE has funded EMF health research and has conducted and supported engineering research on field reduction techniques since the 1970's. Over the past three decades, SCE has consistently worked with government agencies on efforts to resolve unanswered scientific questions and develop consistent and reasonable EMF policies. In the absence of any clearly established health risks, federal health authorities have suggested that cost-effective, avoidance and preventive measures are appropriate to address public EMF exposures. In its 1999 Report to Congress, the National Institute of Environmental and Health Sciences (NIEHS) stated: "the conclusion of this report is insufficient to warrant aggressive regulatory concern." Instead, it recommended that: "The power industry should continue its current practice of siting power lines to reduce exposures and continue emphasis on educating both the public and providers of electricity about ways to reduce exposure.
Recognizing both public concern and scientific uncertainty over possible health effects from EMF exposure, the California Public Utilities Commission (CPUC) adopted a precautionary approach to reduce EMF exposures in 1993 (and updated in 2006). While keeping electrical safety and good engineering practice as first priority, investor-owned electric utilities in California utilize designs to reduce magnetic fields created by new and re-built electric facilities. Whether reducing exposure has any health benefit is not known, so these designs are implemented either at no added cost, or a low percentage (4%) of the project cost.
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Are there any official EMF exposure limits?
While there are no federal or California established limits for EMF exposure, some nongovernmental organizations have issued advisory limits. These limits, however, are much higher than the relatively low levels of EMF found in homes, schools, and offices, or even the EMF exposures being studied in relation to childhood leukemia. The advisory limits apply only to short term EMF exposures far higher than those in residential or typical occupational settings. For example, the International Commission on Non-Ionizing Radiation Protection recommends that the general public not be exposed to magnetic field levels above an average of 833 milliGauss (mG). In contrast, the average magnetic field level found in U.S. homes is approximately 1 mG. Field levels within inches of some appliances can range in the 10’s or 1000’s of mG and diminish to below 1 mG within a few feet. Field levels directly underneath larger transmission line are often below 100 mG under normal operating conditions.
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Where can I find help with EMF related issues?
SCE can provide an EMF information package and free EMF measurements to our customers upon request. In Southern California, call 800-200-4723, or send an e-mail with your name, mailing address and phone number to almontar@sce.com.
