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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 cancercausing 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 do not 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 longterm 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 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 cancercausing 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 high priority animal studies are conducted to address important
questions about the effects of exposure to Radio Frequency (RF) energy. The FDA has been a
leading participant in the World Health Organization International Electro Magnetic Fields (EMF)
Project since its inception in 1996. An influential result of this work has been the development of a
detailed agenda of research needs that has driven the establishment of new research programs
around the world. The project has also helped develop a series of public information documents
on EMF issues. The FDA and the Cellular Telecommunications & Internet Association (CTIA)
have a formal Cooperative Research And Development Agreement (CRADA) to do research on
wireless phone safety. The FDA provides the scientific oversight, obtaining input from experts in
government, industry, and academic organizations. CTIA-funded research is conducted through
contracts with independent investigators. The initial research will include both laboratory studies
and studies of wireless phone users. The CRADA will also include a broad assessment of
additional research needs in the context of the latest research developments around the world.
