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between the phone’s antenna—the primary source of the RF—and
the person’s head. The exposure to RF from mobile phones in
which the antenna is located at greater distances from the user (on
the outside of a car, for example) is drastically lower than that from
hand-held phones, because a person’s RF exposure decreases
rapidly with distance from the source. The safety of so-called
“cordless phones,” which have a base unit connected to the
telephone wiring in a house and which operate at far lower power
levels and frequencies, has not been questioned.
How much evidence is there that hand-held mobile phones might be
harmful?
Briefly, there is not enough evidence to know for sure, either way;
however, research efforts are on-going.
The existing scientific evidence is conflicting and many of the
studies that have been done to date have suffered from flaws in
their research methods. Animal experiments investigating the
effects of RF exposures characteristic of mobile phones have
yielded conflicting results. A few animal studies, however, have
suggested that low levels of RF could accelerate the development
of cancer in laboratory animals. In one study, mice genetically
altered to be predisposed to developing one type of cancer
developed more than twice as many such cancers when they were
exposed to RF energy compared to controls. There is much
uncertainty among scientists about whether results obtained from
animal studies apply to the use of mobile phones. First, it is
uncertain how to apply the results obtained in rats and mice to
humans. Second, many of the studies that showed increased tumor
development used animals that had already been treated with
cancer-causing chemicals, and other studies exposed the animals
to the RF virtually continuously—up to 22 hours per day.
For the past five years in the United States, the mobile phone
industry has supported research into the safety of mobile phones.
This research has resulted in two findings in particular that merit
additional study:
In a hospital-based, case-control study, researchers looked for an
association between mobile phone use and either glioma (a type of
brain cancer) or acoustic neuroma (a benign tumor of the nerve
sheath). No statistically significant association was found between
mobile phone use and acoustic neuroma. There was also no
association between mobile phone use and gliomas when all types
of types of gliomas were considered together. It should be noted
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atmosphere and obey all signs and instructions. Sparks in such
areas could cause an explosion or fire resulting in bodily injury or
even death.
Areas with a potentially explosive atmosphere are not always
clearly marked. They include fueling areas such as gasoline
stations; below deck on boats; fuel or chemical transfer or storage
facilities; vehicles using liquefied petroleum gas(such as propane
or butane); areas where the air contains chemicals or particles,
such as grain, dust, or metal powders; and any other area where
you would normally be advised to turn off you your vehicle engine.
FDA Consumer Update
FDA has been receiving inquiries about the safety of mobile
phones, including cellular phones and PCS phones. The following
summarizes what is known—and what remains unknown—about
whether these products can pose a hazard to health, and what can
be done to minimize any potential risk. This information may be
used to respond to questions.
Why the concern?
Mobile phones emit low levels of radiofrequency energy (i.e.,
radiofrequency radiation) in the microwave range while being used.
They also emit very low levels of radiofrequency energy (RF),
considered non-significant, when in the stand-by mode. It is well
known that high levels of RF can produce biological damage
through heating effects (this is how your microwave oven is able to
cook food). However, it is not known whether, to what extent, or
through what mechanism, lower levels of RF might cause adverse
health effects as well. Although some research has been done to
address these questions, no clear picture of the biological effects of
this type of radiation has emerged to date. Thus, the available
science does not allow us to conclude that mobile phones are
absolutely safe, or that they are unsafe. However, the available
scientific evidence does not demonstrate any adverse health
effects associated with the use of mobile phones.
What kinds of phones are in question?
Questions have been raised about hand-held mobile phones, the
kind that have a built-in antenna that is positioned close to the
user’s head during normal telephone conversation. These types of
mobile phones are of concern because of the short distance