Safety
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 ten or more
156
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 studies is
hampered by difficulties in
measuring actual RF exposure
during day-to-day use of wireless
phones. Many factors affect this
measurement, such as the angle
at which the phone is held, or
which model of phone is used.
6. What is the FDA doing to
find out more about the
possible health effects of
wireless phone RF?
The FDA is working with the U.S.
National Toxicology Program and
with groups of investigators
around the world to ensure that