38
Consumer Update on Mobile Phones (Published by U.S. Food and Drug Administration, Center for Devices and
Radiological Health, October 20, 1999.)
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 kind 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 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-