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A P P E N D I X
Do wireless phone accessories that claim to shield the head from RF radiation
work?
Since there are no known risks from exposure to RF emissions from wireless
phones, there is no reason to believe that accessories that claim to shield the
head from those emissions reduce risks. Some products that claim to shield
the user from RF absorption use special phone cases, while others involve
nothing more than a metallic accessory attached to the phone. Studies have
shown that these products generally do not work as advertised. Unlike "hand-
free" kits, these so-called "shields" may interfere with proper operation of the
phone. The phone may be forced to boost its power to compensate, leading to
an increase in RF absorption. In February 2002, the Federal trade Commission
(FTC) charged two companies that sold devices that claimed to protect
wireless phone users from radiation with making false and unsubstantiated
claims. According to FTC, these defendants lacked a reasonable basis to
substantiate their claim.
How does FCC Audit Cell Phone RF?
After FCC grants permission for a particular cellular telephone to be marketed,
FCC will occasionally conduct "post-grant" testing to determine whether
production versions of the phone are being produced to conform with FCC
regulatory requirements. The manufacturer of a cell phone that does not meet
FCC's regulatory requirements may be required to remove the cell phone from
use and to refund the purchase price or provide a replacement phone, and may
be subject to civil or criminal penalties. In addition, if the cell phone presents
a risk of injury to the user, FDA may also take regulatory action. The most
important post-grant test, from a consumer's perspective, is testing of the RF
emissions of the phone. 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 cell 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 FCC to measure cell
phone RF, and agreed it is an acceptable approach, given our current
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