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FDA Update

The U.S. Food and Drug Administration’s Center

for Devices and Radiological Health Consumer Update

on Mobile Phones

FDA has been receiving inquiries about the safety of mobile phones,

including cellular phones and PCS phones. The following summarizes

what is known--and what remains unknown--about whether these

products can pose a hazard to health, and what can be done to minimize

any potential risk. This information may be used to respond to questions.

Why the concern?

Mobile phones emit low levels of radiofrequency energy (i.e.,

radiofrequency radiation) in the microwave range while being used. They

also emit very low levels of radiofrequency energy (RF), considered non-

signiﬁcant, when in the stand-by mode. It is well known that high levels

of RF can produce biological damage through heating effects (this is how

your microwave oven is able to cook food). However, it is not known

whether, to what extent, or through what mechanism, lower levels of RF

might cause adverse health effects as well. Although some research has

been done to address these questions, no clear picture of the biological

effects of this type of radiation has emerged to date. Thus, the available

science does not allow us to conclude that mobile phones are absolutely

safe, or that they are unsafe. However, the available scientiﬁc evidence

does not demonstrate any adverse health effects associated with the use

of mobile phones.

What kinds of phones are in question?

Questions have been raised about hand-held mobile phones, the kind

that have a built-in antenna that is positioned close to the user's head

during normal telephone conversation. These types of mobile phones are

of concern because of the short distance between the phone's antenna--

the primary source of the RF--and the person's head. The exposure to RF

from mobile phones in which the antenna is located at greater distances

from the user (on the outside of a car, for example) is drastically lower

than that from hand-held phones, because a person's RF exposure

decreases rapidly with distance from the source. The safety of so-called

"cordless phones," which have a base unit connected to the telephone

wiring in a house and which operate at far lower power levels and

frequencies, has not been questioned.

How much evidence is there that hand-held mobile phones

might be harmful?

Brieﬂy, there is not enough evidence to know for sure, either way;

however, research efforts are on-going. The existing scientiﬁc evidence is

conﬂicting and many of the studies that have been done to date have

suffered from ﬂaws in their research methods. Animal experiments

investigating the effects of RF exposures characteristic of mobile phones

have yielded conﬂicting results. A few animal studies, however, have

suggested that low levels of RF could accelerate the development of

cancer in laboratory animals. In one study, mice genetically altered to be

predisposed to developing one type of cancer developed more than twice

as many such cancers when they were exposed to RF energy compared to

controls. There is much uncertainty among scientists about whether

results obtained from animal studies apply to the use of mobile phones.

First, it is uncertain how to apply the results obtained in rats and mice to

humans. Second, many of the studies that showed increased tumor

development used animals that had already been treated with cancer-

causing chemicals, and other studies exposed the animals to the RF

virtually continuously--up to 22 hours per day.

For the past ﬁve years in the United States, the mobile phone industry has

supported research into the safety of mobile phones. This research has

resulted in two ﬁndings in particular that merit additional study:

1 In a hospital-based, case-control study, researchers looked for an

association between mobile phone use and either glioma (a type of

brain cancer) or acoustic neuroma (a benign tumor of the nerve

sheath). No statistically signiﬁcant association was found between

mobile phone use and acoustic neuroma. There was also no

association between mobile phone use and gliomas when all types of

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