RISKS-LIST: RISKS-FORUM Digest  Friday 4 June 1993  Volume 14 :
Issue 70

       FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED
SYSTEMS
  ACM Committee on Computers and Public Policy, Peter G.
Neumann, moderator

 Contents:
Re: Did they have an address for Hillary? (Olivier MJ
Crepin-Leblond,
   Sidney Markowitz)
Health effects of VDTs - an update (Kenneth R Foster)

The RISKS Forum is a moderated digest discussing risks;
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CD RISKS:<CR>GET RISKS-i.j<CR>" (where i=1 to 14, j always TWO
digits).  Vol i
summaries in j=00; "dir risks-*.*<CR>" gives directory;
"bye<CR>" logs out.
The COLON in "CD RISKS:" is essential.  "CRVAX.SRI.COM" =
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-----------------------------------------------------------------
-----

Date: Fri, 4 Jun 1993 19:43:37 +0100
From: Olivier MJ Crepin-Leblond <[email protected]>
Subject: Re: Did they have an address for Hillary?

Paul Robinson ([email protected]) writes:

> I wanted to see if there was anything:
>
> % telnet
> telnet> open whitehouse.gov 25
> Trying 198.137.240.100 ...
> Connected to whitehouse.gov.
> Escape character is '^]'.
> 220 SMTP/smap Ready.
> helo
> 250 Charmed, Im sure.
> vrfy hillary
> 250 <hillary>
>
> "250" in this case, is an "ok" indicating the mail-server
receiving
> the request considers the address to be valid.  So try that,
then:
>
>    [email protected]

Alas, this will most probably not work.
If you type

vrfy foobar
250 <foobar>
vrfy tdarcos
250 <tdarcos>          [ Eh Paul ? Didn't know you worked there
:-) ]

etc.

In fact, anything is accepted by the mailer, so that no new
address can be
traced before it is officially released. A finger request at that
site returns
a standard message; a "rup" of that site (to see "if the
President is busy
reading your beloved messages" :) returns a "port mapper
failure".

Still not ready to give up ?

Okay, how about trying "talk [email protected]" ?
The reply is: "No talk daemon on requested machine"

I leave it to RISKS readers to find out if
[email protected]
is on Internet Relay Chat (IRC).  :-)

Olivier M.J. Crepin-Leblond, Digital Comms. Section, Elec. Eng.
Department
Imperial College of Science, Technology and Medicine, London SW7
2BT, UK
      Internet/Bitnet: <[email protected]> - Janet:
<[email protected]>

 [Also noted by
    [email protected] (Bill Brykczynski)
    Dave Bachmann <[email protected]>
    [email protected] (Tom E. Perrine)
    Frederick W. Wheeler <[email protected]>
    [email protected]
    "Jonathan I. Kamens" <[email protected]>
    Pat Place   [email protected]
    [email protected]
    Jerry McCollom <[email protected]>
    "Albert Peters" <[email protected]>
    Peter J. Scott <[email protected]>  ]

------------------------------

Date: Fri, 4 Jun 93 14:59:19 -0700
From: [email protected] (Sidney Markowitz)
Subject: Re: Hillary's e-mail address

Someone in the White House must be paying attention to RISKS
Digest.

In RISKS-14.69, Paul Robinson showed

>> telnet> open whitehouse.gov 25
[...]
>> vrfy hillary
>> 250 <hillary>

I just tried it and got back

vrfy
500 Command unrecognized

It looks like they sealed off this possible security risk.

 [Also noted by "Albert Peters" <[email protected]>.
 Perhaps we need to add the White House to the RISKS LIST!  PGN]

------------------------------

Date: Wed, 2 Jun 93 09:30:24 -0400
From: [email protected] (Kenneth R Foster)
Subject: health effects of VDTs - an update

I am uploading a chapter from our new book Phantom Risk:
Scientific Inference
and the Las (MIT Press June 1993, Foster, Bernstein, Huber, eds.)
Hopefully
it adds something to the public concern about health effects of
VDTs - and
maybe some users will buy the book!  K. R. Foster
([email protected]).

          From PHANTOM RISK:  SCIENTIFIC INFERENCE AND THE LAW
            K. R. FOSTER, D.E. BERNSTEIN, P. W. HUBER, EDS.
                          MIT PRESS JUNE 1993

          Miscarriage and Video Display Terminals:  An Update

                           Kenneth R. Foster
                        Dept. of Bioengineering
                              Univ. of PA
                            Phila. PA 19104
                      [email protected]

The link between miscarriages and use of video display terminals
(VDTs) became
a public issue around 1980 with the reports of clusters of
reproductive
mishaps in women users of VDTs.  In 1986 I traced the development
of the VDT
debate (Foster 1986).  Now, six years later (and a decade after
the
controversy began), I describe the current state of the issue.
    All together, about a dozen clusters were reported.  These
included 7
adverse outcomes of 8 pregnancies at the offices of the solicitor
general in
Ottawa; 10 out of 19 at the offices of the attorney general in
Toronto; 7 of
13 at the Air Canada offices at Dorval Airport, Montreal; 8 of 12
at Sears,
Roebuck in Dallas, Texas; 10 of 15 at the Defense Logistics
Agency in Atlanta;
3 of 5 at Pacific Northwest Bell in Renton, Washington; and 5 of
5 at Surrey
Memorial Hospital in Vancouver.  The problems included birth
defects,
spontaneous abortions, respiratory problems in the newborns,
Down's syndrome,
spina bifida, and premature birth.
    Despite attempts by health authorities to investigate the
matter, the
clusters were never adequately explained.  I have been able to
locate reports
of a follow-up investigation by the U.S. Army Environmental
Hygiene Agency of
the cluster at the Defense Logistics Agency (Tezak 1981), and by
the Centers
for Disease Control (1981) of the cluster at Sears, Roebuck.
Both verified
the existence of a cluster; neither established any apparent link
to the
women's use of VDTs.
    The interpretation of a cluster is problematic.  Any
unexpected grouping
of problems (a cluster) may indicate some problem of public
health
significance.  More commonly, investigation by health authorities
of a
reported cluster fails to identify a problem that can be remedied
by public
health measures.  However tragic the outcomes may be to the
people involved,
the grouping of cases may have been a statistical event with no
epidemiologic
significance.  Roughly one pregnancy in five ends in spontaneous
abortion (the
reported rates vary widely, depending on how early pregnancy is
diagnosed);
roughly one child in a hundred is born with a major birth defect.
Simple
calculations will show that many clusters will occur every year
among the 10
million North American women who use VDTs.  The issue, so easily
raised, took
a decade to resolve.
    In the remainder of this chapter, I will summarize two lines
of evidence
related to the possible reproductive risks from use of VDTs.  The
first is the
many studies on possible teratological effects of electromagnetic
fields; the
second is the series of progressively more sophisticated
epidemiologic studies
searching for a possible link between adverse pregnancy outcomes
and use of
VDTs.

Electromagnetic Fields

Public concern about VDTs has focused on several factors.  As
judged by
contemporary newspaper articles, initial fears concerned possible
X-ray
emissions from the terminals, no doubt reflecting the scare in
the late 1960s
about X-ray emission from color television sets (Foster 1986).
However,
measurements by several government agencies on thousands of
terminals showed
that X-ray emissions are extremely low and in the overwhelming
majority of
cases are unmeasurable (Zuk et al. 1983).  Emissions of
ultraviolet, visible,
and infrared radiation are also small, and far below recommended
exposure
limits.  VDTs produce no measurable microwave radiation,
notwithstanding one
early (incorrect) report by an investigator to the contrary.
    In their coverage of the issue, the lay media has frequently
mentioned
possible effects of low-frequency magnetic fields that are
present near the
terminals.  These fields include components at power-line
frequency (50-60 Hz)
associated with the power supply, and fields with a more complex
time
dependence from the coils that move the electron beam around the
screen.
    The power-frequency fields from VDTs are comparable with
those from other
appliances; at a distance of 30 cm from the terminal, typical
field strengths
are a few v/m (electric field) and 4-7 Mg (magnetic flux density)
(Jokela et
al. 1989).
    The fields from the beam deflection coils are more complex.
If displayed
on an oscilloscope, they would resemble a sawtooth wave with a
repetition
frequency of approximately 20 Khz (for the coils responsible for
horizontal
beam movement) and 60 Hz (vertical motion).  The field from the
vertical
deflection coil has a peak amplitude of about 10-15 Mg at a
distance of 30 cm
from the screen (Jokela et al. 1989); that from the horizontal
deflection coil
is smaller but at a higher frequency.  The corresponding electric
field
strength is typically a few volts per meter at a distance of 30
cm from the
terminals.  These field strengths are far below the levels
associated with
known hazards of electromagnetic fields (excessive heating of
tissues or nerve
excitation and shock) and far below recommended exposure limits.

In Vitro and In Vivo Studies

Two lines of evidence are related to the question of possible
reproductive
risk from VDTs: animal studies and epidemiologic observations on
human
populations.  I consider the first and most confusing of these:
animal tests
for possible teratogenic effects of low-frequency magnetic
fields.
    In 1982 Delgado and colleagues reported that chicken eggs
exposed to
pulsed magnetic fields showed a striking number of malformations
in the
embryos inside (Delgado et al. 1982; Ubeda et al. 1983).  The
fields were
comparable in strength with those from VDTs but weaker than the
earth's
magnetic field.  Further, the investigators claimed, small
changes in the
waveshape of the field made a large difference in the rate of the
malformations that were induced.  Four independent attempts to
confirm the
findings were unsuccessful (Maffeo et al. 1984; Stuchly et al.
1988;
Sandstrom et al. 1986; Sisken et al. 1986).
    Delgado's findings were widely reported in the lay media,
often with
speculation about their possible significance to hazards from
fields from VDTs
and other appliances.  The unsuccessful attempts at replication
received
little media attention.

Project HenHouse

To address the questions that the Delgado studies raised, the US
Office of
Naval Research commissioned at great expense a multi- laboratory
replication
of the original study, under the name Project HenHouse.  Six
laboratories in
the United States, Canada, and Europe conducted replicate
experiments, using
the same techniques, identical exposure apparatus, and precisely
measured
fields (Berman et al. 1990).  Each experiment involved the
exposure of
fertilized chicken eggs to pulsed magnetic fields, and subsequent
examination
of the embryos.
    The outcome of Project HenHouse was very puzzling.  Four of
the
laboratories--including that of colleagues of Delgado--found no
statistically
significant differences in the rate of malformations in the
exposed versus
control eggs.  A fifth laboratory reported a
borderline-significant increase.
The sixth reported a statistically significant increase (but a
smaller one
than originally reported by Delgado et al.).  If the results of
all six
studies are combined, they indicate a borderline significant
increase in rate
of malformations in the exposed eggs--in contrast with the very
striking
effect originally reported by Delgado et al. (Berman et al.
1990).
    Thus, the results of Project HenHouse were neither clearly
positive nor
clearly negative.  The simplest interpretation is that five of
the six studies
were negative, and that the one positive study was different in
some important
respect from the other five.  Whether the sixth was in error or
whether there
is something important in its results is a question that cannot
at present be
answered.
    The latest development in this episode is the preliminary
report by
Litovitz et al. (1992) of a teratogenic effect of weak magnetic
fields on
chicken eggs.  Litovitz claimed that the critical variable of
exposure is the
"coherence" of the field.  As of this writing these results have
not been
published; whether they will be confirmed and accepted by other
scientists
remains to be seen.
    In retrospect, Delgado's study probably did not merit the
widespread
attention it received.  The biological system (fertilized chicken
eggs)
differs too much from human embryos for the test to have much
value for risk
assessment; on the other hand it is too complex to be of much use
for basic
scientific research on mechanisms of interaction of fields with a
biological
systems.  Chickens are not inbred, and are notoriously variable
in the
frequency of chick malformations and fertility of eggs.  Finally,
a project
officer from the Office of Naval Research who visited Delgado's
lab (Thomas C.
Rozzell, private communication) told me that the initial
experiment was
crudely done and the applied fields were poorly characterized.
    After ten years of research on the "Delgado effect" with so
little to
show for it, funding agencies and most scientists have lost
interest in the
matter.  As well they should.

Other Animal Studies

Since the early 1980s, at least 17 animal studies have been
searched for
effects of pulsed magnetic fields on animal embryos.  (Berman
1990 provide a
comprehensive review.)  The literature is very inconsistent, with
some studies
reporting effects and others (including attempts to replicate
earlier positive
findings) finding none.  Berman concludes
    ... we cannot clearly relate an increase in the
    incidence of abnormal embryos resulting from exposure
    to pulsed magnetic fields to any patterns of pulse
    frequency, field intensity, pulse shape, or rate of
    change in the intensity.... Until the important
    variables in pulsed magnetic fields are determined and
    the mechanism of effects is identified, it may not be
    possible to extrapolate such effects to humans. (1990, p.
47).

    This conflates two issues.  The first is the absence of any
clearly
reproducible phenomena.  Until some reproducible phenomenon
appears, with some
defined relation between dose and response, that can be
consistently observed
by independent investigators, it will be difficult to draw any
conclusions
from the data.  The second is the relevance of these results to
human health,
assuming that the effects themselves are real.  That depends on
the biological
similarity between the animal subjects and humans, the exposure
conditions,
and other factors.  Whether these studies will point to a
mechanism for human
injury is, at present, a matter of speculation.

Epidemiologic Evidence

A much clearer picture has emerged from the epidemiologic
studies.  By now, a
dozen epidemiologic studies have been conducted in the United
States, Canada,
Finland, Sweden, and elsewhere on reproductive problems
associated with use of
VDTs.  (A good, but dated, review is Blackwell and Chang 1988.)
They have
been overwhelmingly--but not totally--negative, finding no links
between use
of VDTs and spontaneous abortion or birth defects.
    The studies vary widely in their methods, and I will not
review them in
detail here.  Table 6.1 summarizes their results in terms of the
relative
risk, which is the risk (probability) of an undesired consequence
in a VDT
user, divided by the probability of the same consequence for an
otherwise
similar nonuser (see chapter 1).  The table also shows the 95
percent
confidence intervals, i.e. margins of sampling error in the
studies.
Virtually all of the results indicate no increase in risk
associated with use
of VDTs.  But some of these studies did report positive or
equivocal findings,
which has helped to keep the issue alive.  The most widely
publicized of these
studies was that of Goldhaber et al. (1988), who reported a
1.8-fold increase
in risk of miscarriage among women who worked with VDTs for more
than 20 hours
a week during their first trimester of pregnancy.  This increase
was at the
edge of statistical significance.
    Goldhaber's study was generally well done, but it had one
major weakness
that resulted from its retrospective design.  To determine the
subjects' use
of VDTs during pregnancy, the investigators sent them a
questionnaire, as much
as three years after their pregnancies.  The investigators did
not
independently verify the subjects' actual use of the terminals.
At the time
the study was conducted, the possible reproductive hazards of
VDTs were well
publicized; it is likely, as the investigators themselves
suggested, that
women with adverse pregnancy outcomes might have been more likely
than other
women to report using VDTs.  Goldhaber's study was widely
reported in the lay
media, without the careful reservations of the investigators, and
usually
without mention of the negative findings of the other studies.
    The most recent, and undoubtably the best, study on
reproductive risk of
VDTs was published early in 1991 in the New England Journal of
Medicine by
Schnorr and colleagues.  The investigators, working for the
National Institute
for Occupational Safety and Health (NIOSH), conducted a
retrospective cohort
study that compared groups of telephone operators who used VDTs
with telephone
operators in otherwise similar jobs who did not.  The
investigators found no
link between spontaneous abortion and use of VDTs during the
first trimester
of pregnancy.  Whether this study will end the VDT debate remains
to be seen.
    The epidemiologic literature on the VDT-miscarriage question
frequently
mentions the great difficulty of measuring reproductive risk.
These problems
are not reflected in the 95 percent confidence intervals in the
table, which
show only the statistical uncertainties due to sampling error.
    For example, several of the papers listed in the table
discuss at length
the problem of reporting bias, which might be introduced if not
all of the
subjects in a study were equally likely to report use of VDTs
during their
pregnancies.  Two studies (Goldhaber et al. 1988; McDonald et al.
1988)
mentioned this as a possible explanation for a small apparent
excess of
miscarriages among VDT users.
    Another problem is the difficulty of reliably detecting
miscarriages that
occur early in pregnancy.  Because of this difficulty, an
investigator has a
choice of including only miscarriages that occur after a month or
more of
pregnancy (and thus missing a large fraction of all
miscarriages), or of
including earlier miscarriages and finding some way to determine
precisely
when the subjects became pregnant.  Most studies choose the
former approach.
    A final difficulty arises from the many different birth
defects that can
occur.  A study that retrospectively examines medical records for
any
association between birth defects and use of VDTs can, therefore,
make many
different comparisons.  However, by the statistical tests that
most scientists
adopt, 1 comparison out of 20 will show a difference that is
statistically
significant--even if there is no real difference in the groups
being compared.
(This problem is discussed in chapter 1, and again in chapter 4.)
    Because of these and other problems, one can never achieve
complete
consistency in epidemiologic studies--but the dozen studies
summarized in the
table come pretty close.  They certainly rule out the large
increases in risk
that some people inferred from the clusters.
    Recently, public concern has shifted to the much more
difficult question
of possible risks from the fields associated with the terminals,
which these
studies do not directly address.  In the NIOSH study, for
example, both the
VDT and non-VDT operators were exposed to similar levels of 60 Hz
electromagnetic fields from the equipment they used.
Consequently, the study
is inconclusive on the question of hazard from fields.  This
point was raised
in a letter to the editor of Science News from the president of a
company that
makes radiation shields for VDTs (Doilney 1991).
    An adequate epidemiologic study on reproductive risk from 60
Hz fields
from VDTs would be very hard to mount.  The NIOSH investigators
measured the
fields from the terminals, and found them to be comparable to
those from many
other sources in the environment.
    The latest development in this issue is a preliminary report
of a Finnish
epidemiologic study (Hietanen et al. 1992) of a 3.5- fold
increase in risk of
miscarriage in VDT operators who were exposed to extremely low
frequency
magnetic fields greater than 9 Mg from the terminals.  The study
has not been
published as of this writing and there is no way to judge its
quality; perhaps
the issue of reproductive risk from VDTs will remain alive.
    Other Problems Associated with Use of VDTs Of greater
concern to many
scientists and health authorities have been diverse ergonomic and
psychosocial
problems associated with the use of computers in the workplace
(World Health
Organization 1989).
    Ergonomic problems include workstation design, glare,
legibility of
display, seating, and keyboard height.  A panel assembled by the
U.S. National
Research Council judged radiation hazards to be highly unlikely,
and focused
in its report on issues such as glare, legibility of video
displays, and
background lighting (National Academy of Sciences 1983).
    Perhaps more important still are psychosocial problems.  To
my mind the
fundamental problem is that many clerical workers using VDTs
simply have lousy
jobs.  A data entry operator who spends the day keying numbers
into a
computer, with every keystroke counted, little opportunity for
personal
interaction, and rigid performance standards to meet might well
experience
emotional and perhaps physical problems.  If only radiation
shielding could
fix such problems!
    Carpal tunnel syndrome (CTS) is a painful condition
associated with
repetitive motions of the hand, that afflicts workers in many
occupations,
including VDT operators.  CTS arises from compression of the
median nerve as
it passes through a small opening (the carpal tunnel) in the
wrist (Spinner et
al. 1989); and can be relieved by a simple operation.  The
problem has been
reported among workers in diverse occupations, including meat
cutting and
clerical workers, but there are few reliable data on its
incidence and the
medical literature on CTS is sketchy and anecdotal.  The syndrome
is clearly a
matter of concern to VDT operators and their employers, and might
be prevented
by better keyboard design or other ergonomic considerations.
Clearly, more
study on CTS is needed.
    Other, less well defined, health problems have been reported
from use of
VDTs (Bergqvist 1989; Council on Scientific Affairs 1987).  Since
the
mid-1980s, there have been scattered reports of rashes and other
skin problems
among VDT users; follow-up studies have been unable to find the
cause of the
problem or associate it with the terminals or other factors in
the office
environment.  This has, however, led to at least one lawsuit (see
"The Legal
Context" at the end of Part I).
    On reviewing the history of the VDT debate, I am struck by
the great
disparity between the ease with which concerns about reproductive
hazards from
the terminals were raised, and the great difficulty in adequately
addressing
them.  The clusters, in retrospect, were probably chance events
of no
epidemiologic significance.  But the question of whether use of
VDTs increases
reproductive risk took ten years and a dozen studies to address,
and (from a
recent preliminary report) it has still not been settled.  It is
time to focus
instead on the more serious ergonomic and psychosocial problems
associated
with use of computers in the workplace.

References

Berg, M.  1988.  Skin problems in workers using visual display
terminals--a
study of 201 patients.  19 Contact Dermatitis 335- 341.

Bergqvist, U.  1989.  Possible health effects of working with
VDUs.  46 Br. J.
Indus. Med. 217-221.

Berman, E., L. Chacon, D. House, B. A. Koch, W. E. Koch, J. Leal,
S. Lovtrup,
E. Mantiply, A. H. Martin, G. I. Martucci, K. H.  Mild, J. C.
Monahan, M.
Sandstrom, K. Shamsaifer, R. Tell, M. A.  Trillo, A. Ubeda, and
P. Wagner.
1990.  Development of chicken embryos in a pulsed magnetic field.
11
Bioelectromagnetics 169- 187.

Berman, E.  1990.  The developmental effects of pulsed magnetic
fields on
animal embryos.  4 Repro. Toxicol. 45-49.

Blackwell, R., and A. Chang.  1988.  Video display terminals and
pregnancy.  A
review.  95 Br. J. Obstet. & Gynaecol. 446-453.

Brandt, L. P. A., and C. V. Nielsen.  1990.  Congenital
malformations among
children of women working with video display terminals.  16
Scand. J. Work
Environ. & Health 329-33.

Bryant, H. E., E. J. Love.  1989.  Video display terminal use and
spontaneous
abortion risk.  18 Int. J. Epidemiol. 132-8.

Butler, W. J., and K. A. Brix.  1986.  Video display terminal
work and
pregnancy outcome in Michigan clerical workers.  In Allegations
of
reproductive hazards from VDUs.  Nottingham UK: Humane Technology
67-91.

Centers for Disease Control, Family Planning Evaluation Division.
981.
Cluster of spontaneous abortions.  Report EPI-80-113-2.

Council on Scientific Affairs.  1987.  Health effects of video
display
terminals.  257 J. Am. Med. Assn. 1508-1512.

Delgado, J. M. R., J. Leal, J. L. Monteagudo and M. G. Gracia.
1982.
Embryological changes induced by weak extremely low frequency
electromagnetic
fields.  134 J. Anat. 533-551.

Doilney, J. A.  1991.  Science News 387.  June 22.  Letter to the
editor.

Ericson, A., and B. Klln.  1986.  An epidemiological study of
work with
video screens and pregnancy outcome: II.  A case- control study.
9 Am. J.
Indus. Med. 459-475.

Foster, K. R.  1986.  The VDT debate.  74 Am. Scientist 163-168.

Goldhaber, M. K., M. R. Polen, and R. A. Hiatt.  1988.  The risk
of
miscarriage and birth defects among women who use visual display
units during
pregnancy.  13 Am. J. Indus. Med. 695-706.

Hietanen, M., M. L. Lindbohm, P. von Nandelstadh, P. Kyyrnen,
and M.
Sallmn.  1992.  Effects of exposure to magnetic fields of VDTs
on
miscarriages (abstr), 1st Congress of the European
Bioelectromagnetics
Association, Brussels, Belgium.  January.

Jokela, K., J. Aaltonen, and A. Lukkarinen.  1989.  Measurements
of
electromagnetic emissions from video display terminals at the
frequency range
from 30 Hz to 1 Mhz.  57 Health Physics 79-88.

Edstrm, R., and B. Klln.  1985.  Dataskarmsarbete och
graviditet.  82
Lakartidningen 687-688.

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