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well. FDA shares regulatory responsibilities for wireless phones with the Federal Communica-
tions Commission (FCC). All phones that are sold in the United States must comply with FCC
safety guidelines that limit RF exposure. FCC relies on FDA and other health agencies for safety
questions about wireless phones. FCC also regulates the base stations that the wireless phone net-
works rely upon. While these base stations operate at higher power than do the wireless phones
themselves, the RF exposures that people get from these base stations are
typically thousands of times lower than 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 guide-
lines 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 conicting results, and many studies have suffered from
aws in their research methods. Animal experiments investigating the effects of radiofrequency
energy (RF) exposures characteristic of wireless phones have yielded conicting 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.
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 difculties in measuring
actual RF exposure during day-to-day use of wireless phones. Many factors affect this measure-
ment, such as the angle at which the phone is held, or which model of phone is used.
6. What is FDA doing to nd 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 inuential 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 sci-
entic 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 nd 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 telephones is set at a Specic Absorption Rate (SAR) of 1.6 watts per kilo-
gram (1.6 W/kg). The FCC limit is consistent with the safety standards developed by the Institute
of Electrical and Electronic Engineering (IEEE) and the National Council on Radiation Protection
and Measurement. The exposure limit takes into consideration the body’s ability to remove heat
from the tissues that absorb energy from the wireless phone and is set well below levels known to
have effects. Manufacturers of wireless phones must report the RF exposure level for each model
of phone to the FCC. The FCC website (http://www.fda.gov (under “c” in the subject index, select
Cell Phones > Research)) gives directions for locating the FCC identication number on your
phone so you can nd your phone’s RF exposure level in the online listing.
8. What has FDA done to measure the radiofrequency energy coming from wireless
phones?
The Institute of Electrical and Electronic Engineers (IEEE) is developing a technical standard for
measuring the radiofrequency energy (RF) exposure from wireless phones and other wireless
handsets with the participation and leadership of FDA scientists and engineers. The standard,
“Recommended Practice for Determining the Spatial-Peak Specic Absorption Rate (SAR) in the
Human Body Due to Wireless Communications Devices: Experimental Techniques,” sets forth the
rst consistent test methodology for measuring the rate at which RF is deposited in the heads of
wireless phone users. The test method uses a tissue-simulating model of the human head. Standard-
ized SAR test methodology is expected to greatly improve the consistency of measurements made
