The research done thus far has produced conflicting results, and many studies have suffered from flaw in their research methods. Animal experiments investigating the effects of radio frequency energy (RF) exposures characteristic

of wireless phones have yielded conflicting 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 pre-disposed to develop cancer in the absence

of RF exposure. Other studies exposed the animals to therefore for up to 22 hours per day. These conditions are not similar to the condition 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, tumor 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.

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 te interval between the time of exposure to a cancer-causing agent and the time tumors develop - if they do - may be many

years. The interpretation of epidemiological studies is hampered by difficulties in measuring actual RF exposure during dat-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.

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 effect of exposure to

radio frequency 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 and 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 abroad assessment of additional research needs in the context of the latest research development around the world.

How can I find out how much radio frequency energy exposure I can get by using my wireless phone?

The Federal Communications Commission (FCC) requires that wireless phones sold in the United States demonstrate compliance with human exposure limits adopted by FCC in 1996. The relative amount of RF energy absorbed in the

head of a wireless telephone-user is given by he Specific Absorption Rate (SAR). The FCC requires wireless phones to comply with a SAR safety limit of 1.6 watts per kilogram (1.6 W/kg).

Information on SAR for phone models authorized since June 2, 2000, can be obtained by using the FCC identification (ID) number for that model. The FCC ID number is usually printed somewhere on the case of the phone, but it may

be on the battery pack. Follow the directions to enter the FCC ID number and obtain the SAR information of "Grant of Equipment Authorization." Grants authorized prior to 1998 are not part of the electronic database.

Phones certified by the Cellular Telecommunications And Internet Association (CTIA) are required to provide SAR information to consumers in the instructional materials that come with the phones.

What has the FDA done to audit the radio frequency energy coming from wireless phones?

After FCC grants permission for a particular cellular telephone to be marketed, FCC will occasionally conduct "post-grant" testing to determine whether the wireless phone conforms with FCC regulatory requirements. The most

important post-grant test, from a consumer's perspective, is testing of the R emissions of the hone. FCC measures the Specific Absorption Rate (SAR) of the phone, following a very rigorous testing protocol. As is true for nearly any

scientific measurement, there is a possibility that the test measurement may be less than or greater than the actual RF emitted by the phone. This difference between the RF test measurement and actual RF emission is because test

measurements are limited by instrument accuracy because test measurement and actual use environments are different, and other variable factors. This inherent variability is known as "measurement uncertainty." When FCC

conducts post-grant testing of a wireless phone, FCC takes into account any measurement uncertainty to determine whether regulatory action is appropriate. This approach ensures that when FCC takes regulatory action, it will have

a sound, defensible scientific basis.

FDA scientific staff reviewed the methodology used by FC to measure wireless phone RF, and agreed it is an acceptable approach.

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