alternating or direct current
is used, electric and magnetic fields result. Alternating Current (AC)
expands and collapses 120 times every second or 60 cycles-per-second
MHz). AC changes polarity and emanates extremely low frequency
fields (ELF-EMF). Electric and magnetic fields are measured by V/m and
A/m respectively (Volts & Amps per meter). High voltage electric
are audible but magnetic fields of equal intensity are silent. Magnetic
fields can emanate from unshielded power lines, wires, equipment,
distribution lines, transformers, feeders, switchgears, and heaters
saturate people, buildings, and most metals without audible or visible
signs. Questions regarding EMF health hazards have been explored for
last 20 years. The initial findings were negligible but recent
improvements have led to graver concerns.
planet Earth who may be exposed to EMFs above 2 mG. Although the
home measures less than 1 mG and constitutes ‘no exposure,’ power
and many work environments can exceed the safety threshold for EMF
Studies have shown that men and young children are the most susceptible
to hazards related to EMF exposure.
Systems can be installed in the home to mitigate magnetic field
to less than 2 mG. Thorny shrubs can be planted around transformers to
discourage children from playing on or near high voltage equipment.
subjected to strong EMFs such as those projected by VDT/CRT (computer
can take precautions to reduce the effects of EMF exposure. Awareness
EMF sources and the potential danger may inspire the public to exercise
The current state of
has not yet reached epidemic or even alarming levels, excluding
those that have died or sustained EMF-aggravated diseases. Because
medical bodies in the US have only given limited validity to
conditions, Communication Channels may not be available except through
private sponsorship. 18 Federal agencies are sponsoring extensive
to validate EMF-related concerns while the American Medical Association
has remained relatively passive regarding EMF exposure studies.
Melatonin among Aging Volunteers
Kripke, Ph.D., UC San Diego, La Jolla, California.
It has been
may suppress melatonin and mediate morbidity and mortality. The problem
is particularly severe for elderly people who have low melatonin. The
that melatonin prevents aging, e.g., aging related to free-radical
and cancer, has recently received sensational news coverage. The
will collect home EMF recordings to combine with data being collected
other projects on melatonin excretion and bedtime light levels and
if EMF is a substantial regulator of melatonin production.
An evaluation form
to determine: 1. What was the reader previously aware of EMFs? 2. Is
reader interested in EMF research? 3. Is the reader currently subjected
to potentially hazardous EMF environments at home or work? 4. Will the
reader use or reject the information once informed? 5. Would the reader
like to be updated on EMF related issues?
Electric homes require more power than fossil fuel (gas and oil) heated
Breast cancer among men in electrical occupations are double that of
Children living near power lines double the risk of contracting
and/or brain tumors.
Adults can contract breast cancer, depression, and suffer a variety of
negative health effects.
Less than 2mG is not considered exposure to EMF by current standards.
Voltage produces an electric field: Current produces a magnetic field.
An appliance that is plugged in has an electric field, even when the
is turned off.
The only medically acknowledged causes of leukemia are ionizing
benzene, viruses, other chemicals and drugs that suppress bone marrow
Epidemiologists in other States and Countries have connected EMF to
and brain cancer.
A recent meta-analysis of occupational EMF exposure and brain cancer
that workers in electrical occupations had a 10% to 20% higher risk
to 1.2 times the risk) of developing brain cancer compared to
Magnetic fields decrease dramatically about one arm's length away from
The Human brain is also an electrical device but the current is much
Standard epidemiologic practice uses a 2 mG safety threshold to define
broad categories of exposure.
in nature? _____________________________
What illnesses may have
to EMFs? _____________________________
Why is a doctor’s
on EMFs? ______________________________
Are homes safe?
What action can
Does EMF cause cancer?
How do you minimize
What is the difference
and the Earth’s
Was this presentation
Would you like periodic
related news? If yes,
in many forms
radio waves, and EMFs are all forms of electromagnetic energy that
our bodies in different ways. Welding operations, for example, can
electro-magnetic energy in the ultraviolet, visible, infrared, and
frequency range, in addition to power-frequency EMFs. Microwave ovens
60Hz fields at several hundred milligauss. Although microwave ovens are
designed to shield us from an average internal cooking frequency of
billion Hz, we are not shielded from the 60Hz EMF. The Earth produces
in the form of static fields like those generated by DC electricity.
occurring EMFs are produced by thunderstorms and electrical atmospheric
activity. The Earth’s magnetic field averages 500 mG and are produced
electric currents flowing deep within the Earth's core. EMFs pertain to
alternating rather than static electric fields. The existence of
occurring EMFs do not negate EMF-related health concerns since direct
(DC) does not induce AC in a stationary object.
A typical US home
mG to 4 mG with a median of 0.6 mG. Above 2 mG represents the basis for
exposure studies. The closer one is to an EMF emission source, the
the exposure. EMF exposure is measured with a gaussmeter in units of
(mG). An mG equals one-thousandth of a Gauss (G). Europe uses a
(µT) where 1 mG equals 0.1 µT [see appendix]. Electric
exist passively around an appliance, even if the appliance is turned
– it only needs to be plugged in. To conduct their studies, researchers
placed gaussmeters at waist level with a probe positioned as close to
worker as possible. Spot measurements were also taken to locate and
the most prominent EMF emission sources.
Since 1982, several
surveys and studies of cancers have reported a higher than expected
of leukemia cases among people who worked in certain "electrical"
compared with people who work in other occupations. In these studies,
"electrical worker" category included electrical engineers, phone line
workers, TV and radio repairers, power station operators, electricians,
and welders. Other studies have reported associations between brain
incidence among workers in these same occupations. Scientists have also
examined the possibility that some workers may be "electrosensitive"
others are not. More precise data is derived as new variables are used
to expand existing analytical methods.
defects were reported at several workplaces in the United States and
due to video display terminals (VDT). VDT emissions include X-rays,
radiation, visible light, infrared radiation, radio frequency fields,
EMFs, chemicals (PCBs), air ions, and static fields. VDTs emit pulsed
fields in the very low frequency (VLF) range from 15,000 to 30,000 Hz.
A 1982 Spanish laboratory experiment discovered malformations in
embryos that were exposed to pulsed magnetic fields at low frequencies.
A Finish study concluded that VDT’s emitting 50 Hz above 3 mG were
for an excessive number of miscarriages among women subjected to those
EMF conditions. The U.S. government has no VDT exposure/emission
but Swedish guidelines impose no more than 2 mG at a distance of 30
(11.8 inches) from the VDT surface. US standards have not been released
due to technological deficiencies rather than insufficient medical and
According to the
Administration (FDA), electromagnetic interference can affect various
devices, including electronic cardiac pacemakers and implantable
Current research now includes higher-frequency sources such as cellular
telephones, citizens band radios, wireless computer linkages, microwave
signals, radio, television broadcast and paging transmitters. Some
suggests that metal equipment located near a magnetic field source can
greatly enhance the intensity of the field from that source. Some
medical implants (such as pins, nails, screws, and plates) can be
by high static magnetic fields from magnetic resonance imaging (MRI)
and aluminum refining processes. Sources such as welding equipment,
lines at electricity generating plants, and rail transport equipment
produce lower-frequency EMFs strong enough to create interference in
medical devices. The occupational threshold limit developed by the
Conference of Governmental Industrial Hygienists state that workers
cardiac pacemakers should not be exposed to a 60-Hz magnetic field
than 1 gauss (1000 mG) or an electric field greater than 1 kilovolt
volts) per meter.
EMFs promote cancerous activity in cells that are already precancerous
but do not necessarily initiate the cancer process. Recent studies have
shown that EMF exposure can promote tumor development in animals.
is a hormone secreted under nocturnal conditions by a small gland
to the brain called the pineal gland. Melatonin has been found to slow
growth of some cancer cells to include breast cancer. The state of
has initiated statewide research and education programs to increase EMF
awareness. Many utilities companies in California have taken action to
reduce EMF emissions in new facilities. The Harvard Center for Risk
in an April 1995 analysis of EMF’s suspected linkage to leukemia and
concluded that, "there is enough evidence to raise concern."
Dr. Samuel Milham
conducted the first
study in 1982 to examine the causes of death among deceased men in
occupations in the State of Washington. Among "electrical workers," he
discovered that the mortality rate due to leukemia was higher than
when compared to other causes. In 1990, Drs. Loomis and Savitz gathered
data from 16 states to study the causes of death in U.S. workers.
workers" had a higher incidence of brain cancer, but not leukemia.” A
study led by Dr. Gilles Thériault at McGill University in
in 1994 reported that workers with a higher cumulative exposure to
fields were three times more likely to develop acute myeloid leukemia.
Dr. Birgitta Floderus, a researcher at the Swedish National Institute
Working Life studied EMF exposure in 1,015 different workplaces in
The study involved 1,600 people in 169 different occupations. Floderus
reported that EMF exposure increased the risk for chronic lymphocytic
Men under the age of 40 that were exposed to more than 2 mG also
an increased risk for brain tumors. A separate Swedish study conducted
by Alfredsson and colleagues in 1996 found an excess risk of
leukemia among railway engineers and conductors. Two years prior,
had reported similar conditions among Swedish railway workers.
In 1990, Norwegian
and Andersen reported that breast cancer occurred more frequently among
men who worked in electrical occupations in Norway. The number of cases
totaling 12 could not be dismissed as natural. Dr. Genevieve Matanoski
of Johns Hopkins University conducted another study 1991 to determine
or not EMF exposure could be linked to breast cancer in men. She
two cases of breast cancer among 900 men who worked in a central
station of a New York telephone company. Since male breast cancer is a
very rare (about 1:100,000 per year in the US), finding two cases in a
group that small was unusual. In 1992, Dr. Dana Loomis at the
of North Carolina, studied the death records of men in 24 states and
a higher than expected proportion of breast cancer among electrical
who were less than 65 years old. In 1993, Dr.
cancer incidence among Danish workers and reported that breast cancer
more frequently than expected in men who had continuous EMF exposure. A
solid basis upon which to associate EMF to breast cancer among women
not be developed because the breast cancer rate among women is
higher then men, regardless of occupation.
A study published in
that workers in Finland and in California, primarily seamstresses,
and tailors, sustained three times the risk of developing Alzheimer's
as did other workers. This was the first study to examine the possible
association between EMF exposure and Alzheimer's disease.
EMF exposure can
inside a car
or bus when it nears power lines. Car batteries do not create an EMF
since they are direct current, but alternators generate AC power that
an EMF at other than 60 Hz. Diesel-electric trains operate on AC.
taken aboard operating trains exceeded 50 mG -- 48 units above the
threshold. A US-sponsored exposure assessment found train operator
ranged from 0.4 mG (Boston high speed trolley) to 31.1 mG (North Jersey
transit). Workers who maintain electrified rail lines in the
United States sustain exposure at both 25 Hz and 60 Hz. The National
for Occupational Safety and Health (NIOSH) reveals that such workers
exposures that range between 3 to 18 mG, depending on how often trains
pass the work site.
There is enough
continued exploration of EMFs affects on Human health. Although the
varies from study to study, the common denominators leading to adverse
health conditions found in each case deserves careful treatment and
are sufficient data for there to be real concern -- the concern is not
Sir Richard Doll,
May 22, 1995
Exposures of Workers in Los Angeles
table displays the mean measurements (the sum of all measurements in
divided by the number of measurements taken).
et al., 1994
that in Los Angeles, electrical workers had higher EMF exposures than
did in other jobs.
on Non-Ionizing Radiation Protection (ICNIRP) is an organization of
scientists from 40 nations who specialize in radiation protection.
G (5,000 mG)
to 24 hours per day
G (1,000 mG)
hours per day
G (10,000 mG)
electric fields of 10-30 kV/m, field strength (kV/m) multiplied by
exceed 80 for the whole working day. Whole-body exposure to magnetic
to 2 hours
per day should not exceed 50 G.
for EMF Exposure
Limit Values for EMF Exposure, American Conference of Governmental
Conference of Governmental Industrial Hygienists (ACGIH) is a
organization that facilitates the exchange of technical information
worker health protection. It is not a government regulatory agency.
should not exceed
to 100 Hz
kV/m or below
G (10,000 mG)
dictates the use of protective devices (e.g. suits, gloves, insulation)
for Low-Frequency EMFs
show the frequencies used in the following table
Ultra low frequencies
0, below 3 Hz
Extremely low frequencies
Very low frequencies
illustrates, EMF strength diminishes quickly as distance from the
Measurements Averaged Over a Workday
magnetic fields measured in mG
men in Sweden
in theoretical subjects
repair and assembly
workers in various industries
workers without computers
workers with computers
off the job (home, travel, etc.)
maintenance and repair technicians
industry workers in Finland
range is between the 5th and 95th percentiles of daily average
for an occupation.
compiled by NIOSH. See the Reference section.
data summarized in this table came from various sources, all of which
listed in the References section.
equipment used in manufacturing
exposures measured at
drill press, etc.
DC current (with an
galvanizes metal parts
electric line and
high static field
ULF from the ladle's
rooms (relay &
high static field,
near power center
cables in floor
about the magnitude of other frequencies measured can be found in the
reports from which data for this table were drawn. They are listed in
in volts per meter (V/m) or in kilovolts per meter (kV/m).
1 kV = 1000 V
in units of gauss (G) or tesla (T). Gauss is the unit most commonly
in the United States. Tesla is the internationally accepted scientific
term. One tesla equals 10,000 gauss.
1 T = 10,000 G
involve magnetic field intensities that are only a fraction of a tesla
or a gauss, these are commonly measured in units of microteslas
or milligauss (mG). A milligauss is 1/1000 of a gauss. A microtesla is
1/1,000,000 of a tesla.
1 G = 1000 mG
1 T = 1,000,000 µT
To convert a
(µT) to milligauss (mG), multiply by 10.
1 µT = 10 mG
0.1 µT = 1 mG
Robert B. Goldberg,
Information Ventures, Inc.
IVI Online provides
about health issues of critical concern to all of us. We cover the
health challenges, including electric and magnetic fields (EMF),
and pesticides, chemicals and other hazards in the workplace,
EMF in the
NATIONAL INSTITUTE FOR
SAFETY AND HEALTH
NATIONAL INSTITUTE OF
U.S. DEPARTMENT OF
25 sources listed on 3 pages, not attached. The above 3 are new.
High tension wires