Microsoft Corporation NPD-1GW User Manual

[ 175 ]

Appendix B Message from the FDA 

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.

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 guidelines 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.

The research done thus far has produced conflicting results, and many studies have 

suffered from flaws in their research methods. Animal experiments investigating the 

effects of radiofrequency 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 

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 

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 long-

term exposures, since the average period of phone use in these studies was around 

three years.

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 this measurement, such as the angle 

at which the phone is held, or which model of phone is used.