Intended for healthcare professionals

Rapid response to:

News Extra [these Stories Appear Only On The Web]

UK recommends adoption of international guidelines on exposure to electromagnetic fields

BMJ 2004; 328 doi: (Published 01 April 2004) Cite this as: BMJ 2004;328:790

Rapid Response:

Electromagnetic Radiation and Health

It's very true that "uncertainties remain" regarding electromagnetic
effects on biological systems.

The most serious confusion in the field of radiation protection,
extended from ionizing understandings to nonionizing realities, is that
the heating of tissue is the only important effect.

It is certainly true that heating can be harmful, and that exposure
to microwaves or other radiofrequency (RF) radiation that raises tissue
temperature can cause injury or death. The problem is that levels of
exposure NOT raising tissue temperature also can be harmful; lacking an
easy thermometer to insert, "experts" in this field become confused and
try to ignore the possibility of harm.

An example worth study is that of microwave hearing, a phenomenon in
which low-level radar pulses or other RF can be heard as a tinnitus-like
hiss, sputter, or sizzle, or, at high pulse power, as distinct clicks or
pops. Readers interested in this phenomenon may want to read the first
serious study of it in A. H. Frey's, "Human auditory system response to
modulated electromagnetic energy" (J. of Applied Physiology, 1962, 17(2),
689 - 692).

A debate raged in Science magazine in the late-1970's (see Science,
1980, 209, 1144 - 1145 and trace the references back), and the side
advocated by Frey et al unfortunately was not argued as well as it should
have been. The result was that many readers were satisfied that there was
no effect of RF except a thermal (or, thermal-rate) one.

However, it can be shown that the many-times replicated microwave
hearing effect can not possibly be solely because of a thermal or thermal-
rate effect, and thus that there must be a direct effect of some kind on
the cochlea.

Other findings that RF can cause harm of one kind or another below
temperature-raising levels have been published from time to time, but none
is so well supported by the evidence as is microwave hearing.

It is unfortunate that the UK has taken the easy way out--the way of
putting in the thermometer and closing the eyes--well, maybe keeping just
one eye a little open.

A proper revision of RF exposure limits should include a description
of the parameters of delivery causing the tinnitus of microwave hearing,
and perhaps other effects more than merely bothersome. More research
definitely is needed on this subject, and it is not at all precautionary
to say that it's OK to just go about the business of wirelessing
everything while asserting that nothing is known.

Competing interests:
None declared

Competing interests: No competing interests

09 April 2004
John M. Williams
(business owner)
Markanix Co., P. O. Box 2697, Redwood City, CA 94064