Safety Questions Now Include Headsets
By: Matthew E. Brunnworth
- Aegis Corporation
January, 1998, Aegis was the
first company to publicly address headset safety issues by informing
its dealers and customers about the issues described in this White
In April, 2000, the British consumer
magazine, Which?, reported that hands-free kits for cellular phones do not
reduce the amount of radio frequency radiation being absorbed by the brain
as many people believe. They claimed the wire leading from the phone acted
like an antenna and increased the amount of radiation penetrating the head
by more than 300% when compared with placing a cellular phone against the
ear. Although their test methods were inconsistent with current regulatory
test procedures, newspapers worldwide published their findings.
In July, 2000, and in response to
the Which? report, the British government commissioned an independent
laboratory, SARTest, to perform a series of SAR (Specific Absorption Rate)
tests that are consistent with current regulatory test procedures used
worldwide to measure and define the safety of cellular phones. The
validity of SAR test procedures as the criteria for determining cellular
phone safety is being debated globally.
Using these procedures, SARTests
reported a reduction in the amount of radiation penetrating the head when
using a headset of 90%. On the basis of this report, the British
government reported that hands-free kits reduce phone radiation exposure
and advised consumers to use them as safety devices. A similar report
released by Australian scientists reported a reduction of 70%.
Overall, these findings revealed
a 390% variance.
Which? continued their
investigations and commissioned another series of tests by the same
laboratory that conducted their initial tests, ERA Technology LTD., in
October, 2000, using five different phones and two different hands-free
kits per phone. The test fixtures were presumably positioned in the way
that most people would use a cellular phone and a hands-free kit: the
phone positioned at or about waist level and the earpiece inserted in the
ear with the wire hanging freely. First, measurements were taken with the
phone handset next to the ear of a dummy head, and then taken again using
a hands-free kit. During testing, the phones were moved up and down to
vary the distance between the antenna mast and the earpiece. A follow up
report released in November reported their findings that hands-free kits
can reduce the amount of radiation penetrating the brain under a specific
condition, however they can increase it by up to 350% under most
conditions. They also reported why their findings were so different from
SARTests and those of the government.
The critical factor
ERA’s laboratory took thousands of
measurements to confirm the earlier test results and identify what was
causing the differences. They stated the critical factor was that the wire
of the hands-free kit served as an antenna and the distance between the
phone’s antenna mast and the earpiece was a considerable factor for the
amount of radiation traveling up the wire and emitted through the
earpiece. At certain distances, there was a tuning effect that increased
the electrical field at the headset’s earpiece.
The radiation levels for all 10
hands-free kits varied between distances of 40 and 80cm. There were two
areas where the level of the signal at the ear was highest (from 40-47cm
and again between 58-75cm), and one area where the level was lower (from
47-58cm). In positions where the levels were higher, they were between
46 - 259% higher than the phones themselves. In positions where the
emissions were lower, the scale of the changes were between 8 - 97% for many
positions of a phone and hands-free kit worn in normal use, the tests
detected higher emissions from the kits than when the phones were held
against the head. The testing did reveal that while hands-free kits can
reduce the emission levels in one position, they also significantly
increase in all others tested.
The premise behind SAR is that if body tissue heats up beyond a
certain level, it can be dangerous. This is frequently referred to as
thermal level and using this approach as the sole criteria for determining
the safety of cellular phones and headsets has significant shortcomings.
First, there is irrefutable evidence that phone radiation affects
protective biological mechanisms in the body far below what can be
measured at the thermal level. Second, SAR does not consider long-term
biological effects, but only observable behavioral effects induced in
laboratory animals for the brief amount of time a phone or headset is
tested. But perhaps the greatest testament that SAR standards should not
be used is that none of the health disorders attributed to cellular phone
radiation are thermally induced and all of them have a long incubation
SAR tests are based upon a
calculated amount of energy that can safely be absorbed by the body,
measuring energy in watts per kilogram that one gram of body tissue
absorbs. It is calculated by measuring the maximum radio signal level
inside the head and applying this value to a formula to calculate a SAR.
Tests are performed by inserting
an electric-field test probe into a dummy head filled with a gel-like
liquid that simulates the same electrical proprieties as brain tissue. In
this case, it measures how much the brain heats up when a cellular phone
is placed against the head and when a hands-free kit is used. Although in
the process of being standardized as the method for rating radio frequency
radiation from cellular phones, it is widely debated because it measures
brain temperature increases after exposure for a brief amount of time and
not actual radiation emissions. This is one of the primary reasons why
AegisGuard™ Radiation Shields were tested using ASTM test procedures
instead of SAR.
have concluded SAR levels are not the critical consideration because the
radio frequency can be a far more damaging element than the amount of
radiation absorbed. For example, a group of Spanish researchers released a
report in late 1999 stating this method of calculating cellular phone
emissions substantially underestimates their effects on human tissue.
SAR hands-free kit test
To find out why the SAR tests showed
hands-free kits reducing radiation levels being absorbed, Which? also
employed the services of SARTests. Although the test procedures were
similar to those used by ERA, they found differences in the way they were
applied to testing hands-free kits. One consideration was the dummy head
used at ERA’s facilities had an outer ear to accurately maintain a
relative position for the phones and the hands-free kits; the test head at
SARTest did not. An important difference was the SAR test fixture was on a
wide platform that did not position the hands-free kit in the position
most people would normally use. In fact, SAR measurements were taken with
the phone lying on the platform, basically at shoulder height, with the
wire coiled around or alongside of it. During testing, the wire was moved
as much as possible and significantly increased SAR levels measured at the
ear from the hands-free kits.
significant difference is that with the SAR test system, the probe scans
the entire inside cavity of the dummy head and only provides a measurement
for the area where the highest radiation level appears. With the kits, the
highest emissions were at the ear; with the phones, it was at the jaw and
cheek. ERA tested the phone and the hands-free kit earpiece at the same
location, inside the head at ear level. Unlike ERA’s test, the SAR test
system does not provide a reading for radiation emissions at the ear
(close to the brain) for phones, only inside the dummy head.
Handle with care
Cellular phone radio waves are
non-ionizing radiation. At high levels, such as those found in radar and
microwave ovens, they can heat and severely damage living tissue. Similar
to principle of mounting television antennas on rooftops, a phone
transmits and receives better signals from head height than at waist
level. According to phone manufacturers, hands-free equipment was designed
for convenience, such as allowing writing or typing while listening to the
phone and to reduce the possibility of accidents while driving. They were
not designed to reduce radiation emissions.
The controversial issue is
whether cellular phone radiation is dangerous to your health, and does the
use of a hands-free kit increase or decrease that risk. Most people will
attach the phone at the waist and connect a headset to it, causing the
phone to increase it’s output power, which is an important consideration.
This raises concern for unprotected body tissue at the waist level, such
as the liver and kidneys, which have excellent conductivity and absorb
radiation faster than the head due to a lack of surrounding bone. When a
hands-free kit is attached to a cellular phone, electrical currents are
conducted and induced on the wire, exposing internal organs and channeling
the radiation more effectively through the ear piece.
What scientists know
For years, electromagnetic radiation
has been suspected of causing a wide range of disorders, ranging from
dizziness to genetic damage. Opinions differ between researchers on the
effects of radio frequency radiation because of non-standardized testing
procedures and materials. Traditionally, they have been separated into two
categories: thermal (high energy) and non-thermal (low energy). Scientists
understand the brain heats up when using a cellular phone, but the actual
long-term biological effects of radio frequency radiation haven’t been
determined, and they will not be determined for quite some time.
Researchers worldwide are investigating non-thermal radiation to discover
if there are ill-health effects, and there have been studies confirming
effects upon the body far below what can be measured at the thermal level.
Medical researcher Dr. Bruce
Hocking claims that cellular phones are likely to disturb nerve functions.
He has reported a marked difference in the responsiveness of nerves
behind, and just in front of, the ear after using of a cellular phone.
Swedish medical investigators
conducted a two year study of patients with brain tumors.
They concluded that cellular phone users of analog phones (the kind
most commonly found in the U.S.) are at an increased risk of developing
brain tumors, which are most likely to appear on the side of the head
where users hold their phones.
Unlike analog phones however, digital
phones use pulsed
transmissions that some scientists believe are more dangerous.
Cellular phones may present a
danger even when they are not in use.
Dr. Roger Coghill, a British biologist, found that cellular phones
on standby mode lowered the white blood cells to 10% of normal activity
after exposure to radio frequency radiation.
A team of researchers in Spain
claim the effects of cellular phone radiation could be 20% higher than
previously thought. By
studying more realistically shaped computer models of cells, they
discovered electric fields are amplified across the cell membrane, a
factor that had not been considered in other studies.
It was also found that the angle of the cell in relation to the
source of radiation is important, and that interactions between
neighboring cells can significantly modify the electric field within each
Researchers have discovered that
electromagnetic radiation can cause subtle, short-term biological effects,
including changes in brain wave patterns during sleep.
Although cancer studies have so far been inconclusive,
organizations including the National Cancer Institute and World Health
Organization are investigating the issue. Many experts caution it’s too
early to give cellular phones a clean bill of health, and it is important
to understand that cancers represent a small number of the heath effects
attributed to cellular phone radiation.
Change of heart
In December 2000, the British government reversed their endorsement
advising consumers to use hands-free kits as a safety device that reduces
cellular phone radiation exposure to the brain. The government sent out
leaflets stating, “…The effectiveness of hands-free kits is uncertain”,
and requested its citizen’s take a precautionary approach to cellular
phones, particularly with children.
In May, 1995 and again in February,
2000, the FDA made no commitments concerning the effects of
electromagnetic radio frequency radiation by saying “There is currently
insufficient scientific basis for concluding either that wireless
communication technologies are safe, or that they pose a risk to millions
Top of Page