I looked into the hazards of microwave energy quite a while back
(mid-60s), when I was a radar technician. Some of the old-timers in
Alaska had routinely warmed their hands by putting them in front of the
feedhorn, but enlightenment had taken place by the time I was involved,
and systems were interlocked to prevent accidental exposure. (I worked
on heavy ground radar, with peak output power of about 5 MW, and average
power of several kW.)

As far as I could determine, plain heating was the only bad effect that
had been found. The main potential for damage was the eyes, where there
are apparently not enough blood vessels to carry away the heat very
fast. Internal organs were vulnerable to very high rate doses, because
of the relative lack of nerves to communicate the problem before it got
serious. They hadn't found any cases of permanent sterility, in spite of
the pervasive fear. Heat can kill any sperm present at the time of the
exposure, leading to temporary sterility, which is likely the source of
the belief. Otherwise, all it was found to do is warm you up. As long as
the heat doesn't build up too much, there was no lasting harm.

I'm sure there's been a great deal of research since then -- both
microwave ovens and cell phones have become ubiquitous in the
intervening years. I believe some research has shown potential harm in
long-term cell phone use with the antenna very close to the head, but
don't know if anyone knows the mechanism -- or how good the research is.

So my view of microwave energy is that it's something to take care with,
but not to irrationally fear.

Roy Lewallen, W7EL

Reg Edwards wrote:
A few years back I opened the highish-level kitchen microwave oven door and
felt what seemed to be a warm breeze of air on my face and especially round
my eyes.

I immediately recognised the sensation felt when standing in the beam from
the non-rotating dish of a 3 GHz, 50 Kwatt radar equipment during WW2, some
50 years before.

I very fast switched all power OFF. The safely mechanism must have been
defective. It may have been a good thing my XYL had not opened it.

There were no after-effects except on my bank balance for a new oven of
different make.
----
Reg.