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VDT Radiation Danger
Summ: D. Lauffer
The New Yorker recently ran a series of articles under the
heading of "The Annals of Radiation" by Paul Brodeur. They
covered research and the industry responses to possible dangers
from a variety of radiation sources. The articles covered power
lines, microwave sources and Video Display Terminals. Brodeur
relies heavily on the work of several epidemiologists,
microbiologists and the maverick, Louis Slesin, editor of the
Microwave News and the VDT News. The VDT article appeared in the
6-26-89 issue of the New Yorker (an issue with skateboarders on
the cover if you are looking in the local library). Since I do
not have training in either medicine or electrical engineering, I
am only offering a very brief, uncritical summary of the VDT
article.
Brodeur points out that the groups most likely to fund
research into radiation dangers are the military and computer and
electronics manufacturers. All of these have a vested interest in
downplaying health hazards associated with regular use of VDTs
both by the public and by their own personnel. The medium most
likely to spread detailled information about hazards would be the
newspapers, who have reporters, editors and clerks who take
classified ads all of whom might hold them responsible for health
risks. The Columbia Journalism Review has documented the lack of
coverage by the press in articles in 1981 and 1984. Additionally,
there is documentation that NIOSH and the FDA have been lax in
pursuing problems in this area, even though they had announced
studies of the problem.
The major hazards no longer involve the X-Rays which had
been emitted by the CRTs and consumer TVs in the past. They seem
to lie in the magnetic radiation emitted by transformers
associated with the changing image on the VDT. Epidemiologists
have noted high incidence of miscarriages among VDT operators.
This seems to correspond to research on Extra Low Frequency
radiation (ELF) and Very Low Frequency radiation (VLF) which are
emitted by components such as the fly-back transformer in the
VDT. These components are often near the outside of the device,
and are even more likely to send radiation to the sides or to the
back of the terminal.
Embroylogy research on chickens by Delgado, who has taught
at Yale, indicated that serious changes were caused in early
development by 100Hz magnetic radiation. The results were
confirmed in a Swedish study, which led to banning VDTs which are
not shielded for VLF in Sweden as of 1988. IBM now markets a VDT
(only available in Scandinavian Countries) which meets VLF
guidelines. Other research has found that as little as 15 minutes
of exposure to ELF accelerates DNA/RNA transfer in insects. This
would indicate a potential for problems in fetal development for
early stage pregnant women who work at VDTs.
An additional area of problems is the role of magnetic
fields in these ranges in the increased incidence of childhood
cancer. These are usually associated with power lines near
residences. Epidemiologists have also noted increased incidence
of cancer in adult VDT operators.
Recommendations
When VLF-shielded terminals become available, these should be
given strong consideration for new purchases and
replacements.
When ELF-shielded terminals become available, these should be
also given strong consideration for new purchases and
replacements. These will require transformer shielding in Mu-
metal.
This is not a problem with liquid crystal displays LCD, such
as are found in Laptop Computers.
With the present generation of equipment you should sit 28
inches in front, and about 40 inches away from any other
terminal.
Waiver of responsibilty
I am still not sure that I understand all this material, and
I am in no position to critique the positions taken. However,
I'd rather be aware of the possibilities and and be conservative
in my approach to my own safety. If this is like other lengthy
articles in the New Yorker, it should be published in book form
shortly. It will be very interesting to see what sort of
reception the wider dissemination of these ideas gets, both from
the industry and the press.
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