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Appendix B: A message from the U.S. Food and Drug Administration
FCC also regulates the base stations that the wireless phone networks rely upon. While these
base stations operate at higher power than do the wireless phones themselves, the RF
exposures that people get from these base stations are typically thousands of times lower than
those they can get from wireless phones. Base stations are thus not the subject of the safety
questions discussed in this document.
3. What kinds of phones are the subject of this update?
The term wireless phone refers here to hand-held wireless phones with built-in antennas,
often called cell mobile or PCS phones. These types of wireless 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 wireless 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 pre-disposed 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 wireless 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 wireless 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 wireless 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 wireless
phones poses a health risk?
A combination of laboratory studies and epidemiological studies of people actually using
wireless phones would provide some of the data that are needed. Lifetime animal exposure
studies could be completed in a few years. However, very large numbers of animals would be
needed to provide reliable proof of a cancer promoting effect if one exists. Epidemiological
studies can provide data that is directly applicable to human populations, but 10 or more years
follow-up may be needed to provide answers about some health effects, such as cancer. This
is because the interval between the time of exposure to a cancer-causing agent and the time
tumors develop - if they do - may be many, many years. The interpretation of epidemiological