Electrical and Magnetic Fields
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Electric and Magnetic Fields
Electric and magnetic fields are generated by all power sources,
including conductors, wiring, tools, and appliances. The fields increase
with the magnitude of the power source, but dramatically decrease with
distance from the source conductor or wiring.
Electric fields and magnetic fields are independent of each other.
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Electric fields result from the energization of the wiring.
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Magnetic fields result from the flow of power (current) as it
serves the load being applied.
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Electric fields are reduced by distance, by mutual cancellation
(placing the wires as close together as possible without creating an arc
between them) or by placing objects or insulation between the wire and
the exposure location. Magnetic fields are reduced by distance, by
mutual cancellation, or by specific types of shields. However, they are
not reduced by most objects between them and the source wires.
Health effects
The incidence of cancer has not increased with the increased use of
electricity in the United States or any other country that measures
incidence rates. Scientists and doctors have found no testable
hypothesis that demonstrates a possible mechanism by which power fields
can cause adverse health effects, cancer, or any other disease or
debilitating condition.
The effects of fields from power lines have been the object of
research since the late 1950s. Over 26,000 research reports have been
generated in that time, and none report adverse health cause and effect.
High exposures in controlled laboratory tests have not created any
adverse cause-and-effect relationship.
A 1979 study in Denver, Colorado, reported on preliminary research
of possible environmental factors associated with childhood cancer.
Since then, at least a dozen similar studies have been completed in an
effort to determine the relationship. More than half of the studies
reported no association. Those that did report a possible association
have not been reproducible in later studies that were larger and better
controlled.
Using the raw data on fields and exposures collected in the dozen
studies, the International Agency for Research on Cancer concluded that
there may be a possible association between a single, rare form of
childhood cancer and magnetic fields. If the possibility does exist, it
is a very low probability and a mechanism for causation is not known.
Examples of Common Sources of Magnetic Fields
Hair dryers
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300 mG* at 6 inches
1 at 1 foot
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700 mG at 6 inches
70 at 1 foot
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Electric razors
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100 mG at 6 inches
20 at 1 foot
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600 mG at 6 inches
100 at 1 foot
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Blenders
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70 mG at 6 inches
10 at 1 foot
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100 mG at 6 inches
20 at 1 foot
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Can openers
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600 mG at 6 inches
150 at 1 foot
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1500 mG at 6 inches
300 at 1 foot
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Coffee makers
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7 mG at 6 inches
immeasurable at 1 foot
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10 mG at 6 inches
1 at 1 foot
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Dishwashers
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20 mG at 6 inches
10 at 1 foot
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100 mG at 6 inches
30 at 1 foot *milligauss
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Microwave ovens
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80 mG at 6 inches
10 at 1 foot
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100 mG at 6 inches
20 at 1 foot
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Mixers
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100 mG at 6 inches
10 at 1 foot
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600 mG at 6 inches
100 at 1 foot
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Electric ranges
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30 mG at 6 inches, 8 at 1 foot
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200 mG at 6 inches, 30 at 1 foot
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Refrigerators
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2 mG at 6 inches
2 at 1 foot
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40 mG at 6 inches
20 at 1 foot
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Vacuum cleaners
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300 mG at 6 inches
60 at 1 foot
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700 mG at 6 inches
200 at 1 foot
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Analog clocks
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15 mG at 1 foot
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30 mG at 1 foot
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Baby monitors
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6 mG at 6 inches
1 at 1 foot
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15 mG at 6 inches
2 at 1 foot
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Battery chargers
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30 mG at 6 inches
3 at 1 foot
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50 mG at 6 inches
4 at 1 foot
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Hand drills
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150 mG at 6 inches
30 at 1 foot
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200 mG at 6 inches
40 at 1 foot
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Power saws
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200 mG at 6 inches
40 at 1 foot
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1,000 mG at 6 inches
300 at 1 foot
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Copy machines
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90 mG at 6 inches
20 at 1 foot
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200 mG at 6 inches
40 at 1 foot
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Fax machines
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6 mG at 6 inches
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9 mG at 6 inches
2 at 1 foot
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Fluorescent lights
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40 mG at 6 inches
6 at 1 foot
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100 mG at 6 inches
30 at 1 foot
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Pencil sharpeners
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200 mG at 6 inches
70 at 1 foot
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300 mG at 6 inches
90 at 1 foot
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Computers with color monitors
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14 mG at 6 inches
5 at 1 foot
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20 mG at 6 inches
6 at 1 foot
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Additional sources of information
Reviews of EMF research:
• American Medical Association, Council on Scientific Affairs. Effects
of Electric and Magnetic Fields. Chicago: American Medical
Association (December 1994).
• National Institute for Occupational Safety and Health, National
Institute of Environmental Health Sciences, U.S. Department of Energy.
Questions and Answers: EMF in the Workplace, Electric and Magnetic
Fields Associated with the Use of Electric Power. Report No.
DOE/GO-10095-218 (September 1996).
• National
Radiological Protection Board. ELF Electromagnetic Fields and the
Risk of Cancer. Volume 12:1, Chilton, Didcot, Oxon, UK, OX11 ORQ (2001).
• National Research Council, Committee on the Possible Effects of
Electromagnetic Fields on Biologic Systems. Possible Health Effects of
Exposure to Residential Electric and Magnetic Fields. Washington:
National Academy Press (1997).
• National
Institute of Environmental Health Sciences. Report on Health Effects
from Exposure to Power-Line Frequency Electric and Magnetic Fields, NIH
Publication No. 99-4493. Research Triangle Park, National Institute of
Environmental Health Sciences (1999).
Online sources of information:
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About NIEHS EMFRAPID
Symposiums/Meetings
External Resources
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Reports
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EMF
Basics
Reviews basic terms about electric and magnetic
fields.
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Evaluating
Potential Health Effects
Explains how scientific studies are conducted and
evaluated to assess possible health effects.
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Results
of EMF Research
Summarizes results of EMF-related research
including epidemiological, clinical, and laboratory studies.
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Your
EMF Environment
Discusses typical magnetic exposures in homes and
workplaces and identifies common EMF sources.
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EMF
Exposure Standards
Describes standards and guidelines established by
state, national, and international safety organizations for some EMF
sources and exposures.
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National
and International EMF Reviews
Presents the findings and recommendations of major
EMF research reviews including the EMF RAPID Program.
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References
Selected references on EMF topics.
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This booklet was originally printed in 1995 as part of the EMF RAPID
Program. After completion of the program, the booklet was updated to
include the results from the EMF RAPID Program as well as the results of
recent major research studies and various expert panel reviews. We hope
you find this booklet useful and informative. The update of this booklet
would not have been possible without the concerted and generous help of
contributors and reviewers. We greatly appreciate their participation.
We also acknowledge the U.S. Department of Energy as our partner in the
EMF RAPID Program and the electric utility industry for its partial
sponsorship of this program that included funding for the revision of
this booklet.
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