The RISKS Digest
Volume 6 Issue 5

Thursday, 7th January 1988

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Please try the URL privacy information feature enabled by clicking the flashlight icon above. This will reveal two icons after each link the body of the digest. The shield takes you to a breakdown of Terms of Service for the site - however only a small number of sites are covered at the moment. The flashlight take you to an analysis of the various trackers etc. that the linked site delivers. Please let the website maintainer know if you find this useful or not. As a RISKS reader, you will probably not be surprised by what is revealed…


o Re: PCs die of New Year Cerebration
John Owens
Paul F Cudney
o Source code vs. attacks — Avoidance techniques
David Collier-Brown
o Ham Radiation and Cancer
Barry Ornitz [long]
Martin Ewing
Douglas Jones
o Info on RISKS (comp.risks)

Re: PCs die of New Year Cerebration

Thu, 07 Jan 88 12:43:11 EST
Scot E. Wilcoxon writes:

>One of my clients has just reported to me that a certain brand of
>PC-compatibles which they sold in 1984 suddenly stopped working when 1988
>was reached...

Just to avoid any confusion, it is quite unlikely that Scot is referring
to a PC-compatible at all, but to a problem with Sun Microsystems UNIX
workstations.  Recent versions of the operating system had a bug in
the time of day code which caused a warning message at boot time and
problems setting the time _in a leap year_.

(The bug was caused by an expression with a side effect being passed
as an argument to a macro which evaluated the expression twice.)

Sun has published the fix on various mailing lists and USENET groups;
if you have the problem and don't have the patch, send mail to

-John Owen, Virginia Tech Communications Network Service  
OWENSJ@VTVM1.BITNET                      +1 703 961 7827

Leaping Clocks

Paul F Cudney <Cudney@DOCKMASTER.ARPA>
Thu, 7 Jan 88 00:02 EST
... Although resolved in just a few days, [this problem] highlights our 
assumption that workstation "owners" are OS-wise (or can obtain competent
assistance).  With the ubiquitous spread of ever more complex systems,
shouldn't we be demanding self-validating system maintenance tools useable
by un-OSphisticated users?

Source code vs. attacks — Avoidance techniques

David Collier-Brown <geac!daveb@uunet.UU.NET>
6 Jan 88 18:50:12 GMT
  Chris Torek <>, comments:
  What, then, are we to do?  Form a software users' union?  (I am
  only half joking.)  I would very much appreciate receiving source
  code to the binaries I must run..

In fact, the Honeywell Large Systems User's Group is such a union, and votes
semi-annually on features to be required or to be removed from Honeywell (now
-Bull) software.  One of the fallbacks from requiring improved maintenance, is
to require source code. This also is the normal behavior when HW when a system
is to be taken off maintenance (ie, one normally gets either maintenance or
source, but not both).

David Collier-Brown, Geac Computers International Inc., 350 Steelcase
Road, Markham, Ontario, CANADA, L3R 1B3 (416) 475-0525 x3279

Ham Radiation and Cancer

barry ornitz <ucbcad!ames.UUCP!rochester!kodak!ornitz@ucbvax.Berkeley.EDU>
Wed, 6 Jan 88 23:07:43 EST
[The following is an article I posted on the subject of Cancer and Electro-
magnetic Radiation.  I have received several replies on my posting; two
disputed Dr. Milham's statistics based on Poisson distributions, and one mailed
an article on Milham's previous article in 1985 in Lancet.   Barry]

In yesterday's newspaper, I noticed with great interest an article entitled

          "Link suggested between cancer,  electromagnetic fields."

The article had the byline of the Associated Press, Tacoma, WA.  It was
stated in the article that "amateur radio operators in two states appear to
die at abnormally high rates from several forms of cancer, suggesting a
possible link between cancer and electromagnetic fields, according to data
collected by a state epidemiologist."  This article appears to be prompted
by work published in the American Journal of Epidemiology by Dr. Samuel
Milham Jr. of the Washington Department of Social and Health Services.
According to the article, Dr. Milham studied the deaths of 2,485 Washington
and California amateur (ham) radio operators between 1979 and 1984.  Based
on a population this size, he found the following data:

                               Expected                  Actual
     Cause                      Deaths                   Deaths
     ------------------------  -----------------------  -----------
     Leukemia                     29                       36
     Lymphatic & Blood Forming
         Organ Cancers            72                       89
     Prostate Cancer              67.6 (!)                 78

I am not sure about the statistical differences between these numbers, but I am
certain that a trained epidemiologist would check the statistical significance
of his data before publishing.  Dr. Milham is further reported to have
concluded that "amateur radio operator licensees in Washington state and
California have significant excess mortality due to acute myloid leukemia,
multiple myeloma and perhaps certain types of malignant lymphoma."

The Associated Press article also quoted Leonard Sagan, program manager for
radiation studies at the Electric Power Research Institute in Palo Alto, CA.
Sagan warned that studies like Dr. Milham's could be misinterpreted, and that
the "findings could be simple associations that have nothing to do with cancer
causes among people who work with electricity."

Having been an amateur radio operator for over twenty-three years, and having
been concerned with the safety of exposure to non-ionizing, radio frequency
electromagnetic energy as a small portion of my job, I have a few comments
about this article.  Before I begin, I should state that my title of Dr. is not
a medical one, but rather a PhD in Engineering.  I should also state that I
have not yet read the article in the American Journal of Epidemiology.

The medical effects of exposure to electromagnetic radiation have been shown to
be frequency dependent.  This is logical since as the wavelength of radiation
approaches the dimensions of the human body, absorption of the radiation is
enhanced due to more efficient coupling into the body.  At higher frequencies
(shorter wavelengths), typically in the microwave region, the electromagnetic
radiation is absorbed near the surface of the body.  The ANSI standards for
exposure to radio frequency energy take this information into account, placing
the most strict requirements on frequencies in the VHF (very high frequency)
region.  Amateur use of the VHF spectrum, while dating back over fifty years,
has primarily been negligible until twenty years ago.  Amateur transmitter
power levels in the VHF region have generally been much lower than the power
levels used in the high frequency bands.  Antenna placement for VHF, in terms
of wavelengths from the amateur's operating position, is generally high.  These
three facts would tend to cancel the increased hazard of VHF radiation.  To
test Milham's hypothesis further, a study of FM broadcast engineers, commercial
two-way radio technicians, and television transmitter engineers should be
performed since these persons are all exposed to various levels of VHF
radiation.  The highest field strengths to which amateur radio operators are
normally exposed come from the near field antenna radiation during high
frequency operation.  Power levels of up to two kilowatts may be used with
antenna placement often below a wavelength.  It should be noted that exposure
to this power level is intermittent in most amateur operation.  If Milham's
hypothesis is correct, broadcast technicians and engineers for commercial AM
and especially short wave broadcast stations, as well as military communication
operators should show even higher levels of cancer deaths than hams.  Operation
on microwave frequencies by amateur radio operators is rare; furthermore, I
would expect any cancers caused by microwaves to be other than deep tissue
cancers.  A study of the eyes for cataracts would be in order, too, since
microwave exposure generally causes eye problems prior to additional damage in
the human body.

I believe that other causality should be investigated by the medical profession
before Dr. Milham's conclusions are accepted.  I would expect that the amateurs
studied by Dr. Milham were mostly individuals who had been hams for many years.
An analysis including the length of time that the amateurs were licensed (or at
least active) would be in order.  I believe that this analysis would show some
increased mortality (adjusted for age, of course) for the older hams.  If this
increased mortality exists, I feel that other environmental factors should be
studied in addition to exposure to electromagnetic fields.

Until twenty-five to thirty years ago, much of the amateur radio equipment in
use was home constructed.  The construction of electronic equipment at this and
especially prior years, exposed the amateur to a number of chemical hazards,
many of which were not known as hazards at the time.  For example, I would
expect to see higher than normal levels of metals in older hams such as tin,
lead, bismuth, antimony, and cadmium (from soldering); mercury (from broken
rectifier tubes and relays); barium, beryllium, and rare earth oxides (from
broken vacuum tubes and phosphors from cathode ray tubes); radium (from
luminescent dials); selenium (from rectifiers); and manganese and zinc (from
batteries).  Likewise these hams would have been exposed to rosin fumes
containing numerous organic acids (from soldering), paint solvents and cleaning
fluids such as benzene and carbon tetrachloride, phenol (from burnt phenolic
insulators), and asbestos.  Even more insidious, however, was the exposure to
transformer and capacitor impregnating oils.  These oils often contained
poly-chlorinated biphenyls (PCB's) as flame retardants, sometimes in quite high

These chemical hazards were not unique to amateur radio operators only.  Other
electronic hobbyists as well as people manufacturing electronic equipment would
have been exposed to similar hazards.  I feel that it would be prudent to
compare mortality rates of workers in oil-filled capacitor manufacturing plants
to those of the hams studied [for example, the Sangamo capacitor plant in
Pickens, SC, which until several years ago was a major user of PCB oils].

In conclusion, I believe that other causal relationships between cancer deaths
and amateur radio operators may more adequately explain Milham's data.  I
propose that Milham or other epidemiologists expand their study to include the
other occupations I have suggested above.  I further propose that age-adjusted
mortality rates be calculated for the existing data to determine whether length
of exposure or date of exposure is significant and whether chemical exposure of
these hams might be significant.  I am certain that electromagnetic radiation
has effects on the human body, but I do believe that electromagnetic radiation
is not the major cause of the increase in cancer deaths as stated by Dr.Milham.

For those persons interested in further study on the effects of electromagnetic
radiation, I would suggest the American National Standards Institute document
ANSI C95.1-1982, Safety Levels with Respect to Human Exposure to Radio
Frequency Electromagnetic Fields, 300 kHz to 100 GHz.  This standard contains
an appendix listing numerous references on the biological effects of
radio-frequency electromagnetic fields.  A number of other standards exist for
radio-frequency and microwave exposure; many of these are listed in the
Microwave Engineer's Handbook, Vol. 2.

If anyone has read Dr. Milham's original article, I would appreciate their
sending me the exact title and the date of publication so I might have our
library order a copy.  I would also appreciate the comments of other amateurs
as well as physicians on this subject.  Please email responses directly to me
and I will summarize or cross-post your replies to both rec.ham-radio and (many hams on ARPA receive their postings via an automatic mailing list
rather than a newsgroup).

Thanks and 73 [ham radio jargon for best regards].
                                   Barry L. Ornitz   WA4VZQ

Dr. Barry L. Ornitz   UUCP:...!rochester!kodak!ornitz
Eastman Kodak Company, Eastman Chemicals Division Research Laboratories
P. O. Box 1972, Kingsport, TN  37662       615/229-4904

Risks of Amateur Radio

Martin Ewing <msesys@DEImos.Caltech.Edu>
Wed, 6 Jan 88 17:37:01 PST
I also noted Dr Milham's study of ham radio operators vs cancer
statistics.  The press report was undoutably mangled, but as a sometime
radio amateur, I can add some questions and comments. 

Was there any analysis of the actual RF exposure to the amateurs?
Typical amateur radio operations involves <<50% of time spent in actual
transmission.  Typical frequencies range from 3.5 to 220 MHz, and power
levels from 5 W to 1 kW.  Emission modes vary, but single-sideband voice
is most common up to 30 MHz; SSB duty cycles are <<100% even when
transmitting.  Antennas range from large yagi arrays on high towers to
loaded 1/4 wave "rubber duckies" held next to the head while using VHF
handheld equipment.  Many licensees are inactive, too. 

Was there any demographic control?  Ham operators have a peculiar
distribution, with "peaks" among young-adult techies and retired
middle-class WASP males. 

Hams expose themselves to various other potential hazards: solvents
and smoke during soldering, PCBs from transformer and capacitor oils,
etc.  Why should one suspect RF exposure in particular? 

Apparently the study came out in a reputable journal, so it may
deserve a better review than the AP (and we) are giving it. 

Martin Ewing, Caltech 

Re: Ham radios and non-ionizing radiation

Douglas Jones <>
Wed, 6 Jan 88 11:16:58 CST
Eric Townsend's note raises the possibility of a
  >  link between cancer and electromagnetic fields
in the context of a study of cancer cases among ham radio operators.

I would not be surprised to find a link between ham radio operation and cancer
for a completely unrelated reason:  Ham radio operators tend to work with
electronics, exposing them to many interesting chemicals in the process,
including lead vapor from hot solder and vaporized solder flux, not to mention
coil dope, red glypt, and other oddities.  Older ham radio equipment
frequently contained large oil-filed capacitors (possibly containing PCB
oils), and who can forget the ozone smell caused by the high plate voltages
used by pre-1970 transmitters.

I don't mean to imply that there is no risk associated with the high fields
around a radio transmitter, after all, you can cook hot-dogs by putting them
inside the antenna impedence matching coils, but there are other possible
causes of the small increase in cancer risk that was observed.

A good experiment to test these risks would be to look at the cancer rate
among model railroaders.  They also solder things and work with related
chemicals, but the electric fields they are exposed to are produced by a
source with a maximum power of 12 watts (12 volts at one amp, DC power to
the track).
                Douglas Jones

Please report problems with the web pages to the maintainer