43
Base stations are thus not the subject of the safety questions discussed in
this document.
3. What kinds of phones are the subjects of this update?
The term “mobile phone” refers here to hand-held mobile phones with built-
in antennas, often called “cell,” “mobile,” or “PCS” phones. These types of
mobile phones can expose the user to measurable radiofrequency energy
(RF) because of the short distance between the phone and the user's head.
These RF exposures are limited by Federal Communications Commission
safety guidelines that were developed with the advice of FDA and other
federal health and safety agencies. When the phone is located at greater
distances from the user, the exposure to RF is drastically lower because a
person’s RF exposure decreases rapidly with increasing distance from the
source. The so-
called “cordless phones,” which have a base unit
connected to the telephone wiring in a house, typically operate at far lower
power levels, and thus produce RF exposures far below the FCC safety
limits.
4. What are the results of the research done already?
The research done thus far has produced conflicting results, and many
studies have suffered from flaws in their research methods. Animal
experiments investigating the effects of radiofrequency energy (RF)
exposures characteristic of mobile phones have yielded conflicting results
that often cannot be repeated in other laboratories.
A few animal studies, however, have suggested that low levels of RF could
accelerate the development of cancer in laboratory animals. However,
many of the studies that showed increased tumor development used
animals that had been genetically engineered or treated with cancer-
causing chemicals so as to be predisposed to develop cancer in the
absence of RF exposure. Other studies exposed the animals to RF for up
to 22 hours per day. These conditions are not similar to the conditions
under which people use mobile phones, so we don’t know with certainty
what the results
of such studies mean for human health. Three large epidemiology studies
have been published since December 2000. Between them, the studies
investigated any possible association between the use of mobile phones
and primary brain cancer, glioma, meningioma, or acoustic neuroma,
tumors of the brain or salivary gland, leukemia, or other cancers. None of
the studies demonstrated the existence of any harmful health effects from
mobile phone RF exposures. However, none of the studies can answer
questions about long-term exposures, since the average period of phone
use in these studies was around three years.
5. What research is needed to decide whether RF exposure from
mobile phones poses a health risk?
A combination of laboratory studies and epidemiological studies of people
actually using mobile phones would provide some of the data that are
needed. Lifetime animal exposure studies could be completed in a few
