Foster, K. R. (Pennsylvania, University) Guy, A. W. (Washington,
University)
Journal Title: Scientific American Volume: 255 Page:
32-39
Published: Sep 01, 1986
Corporate Source:
(Corporate Source(s) Not Available)
Pages: 8
Contract Number: None
NASA Subject Category: MAN/SYSTEM TECHNOLOGY AND LIFE
SUPPORT
Abstract:
No firm biophysical data have been found to support a definite lower limit to
microwave exposure below which no harm can occur in humans. The means by which
hazardous levels have been identified are reviewed, along with the techniques being
applied to establish new, lower acceptable radiation levels in the U.S. The military
exerted the original efforts to define exposure limits to assess health risks for
radar operators. The first public exposure limits were an average power density of
100 W/sq m. Recent ANSI recommendations are to lower the levels to about 0.4 W per kg
of body weight, a figure weighted by the frequency used. It has experimentally been
proven that bursts of 10-500 kW microwave energy produce audible clicks in a human
head because of the thermal expansion of tissue. Continued exposure to the new ANSI
standard has been experimentally shown to cause malignant tumors in rats. The EPA is
currently reviewing the available data as a prelude to promulgating new regulations
in 1987.H=ReOpen Alphabetically
Guy, A. W. (Washington,
University)
