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Safety Guidelines
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 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