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APPENDIX
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 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 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
neu-roma, 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.
