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.
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
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this measurement, such as the angle at which the phone is held, or which model
of phone is used.
6. What is FDA doing to find out more about the possible health effects of
wireless phone RF?
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
radiofrequency energy (RF). FDA has been a leading participant in the World
Health Organization International Electromagnetic 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. FDA and the Cellular
Telecommunications & Internet Association (CTIA) have a formal Cooperative
Research and Development Agreement (CRADA) to do research on wireless
phone safety. FDA provides the scientific oversight, obtaining input from experts
in government, industry, and academic organizations. CTIA-funded research is
conducted through contracts to 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.
7. How can I find out how much radiofrequency energy exposure I can get
by using my wireless phone?
All phones sold in the United States must comply with Federal Communications
Commission (FCC) guidelines that limit radiofrequency energy (RF) exposures.
FCC established these guidelines in consultation with FDA and the other
federal health and safety agencies. The FCC limit for RF exposure from wireless
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