Some additional comments on the "possibility" that EMF is a humancarcinogen

["Dukelow, James S Jr" <jim.dukelow@pnl.gov>]

Continuing a discussion on the "possibility" that low-frequency 
electromagnetic fields might or might not cause human health effects, 
Fritz A. Seiler and Joe Alvarez wrote on Monday, July 20, 1998 7:45 PM 

>  It is obvious from the context of the EMF discussion that it
>  addresses an issue where suspicion is no longer the issue.
>  (Additional reference, pointed out to us by Dick Wilson is:
>  National Academy of Sciences, "Possible Health Effects of
>  Exposure to Residential Electric and Magnetic Fields".
>  Washington D.C. National Academy Press, 1996, $39.95)
>  The culprit EMF was tried and found innocent. ' Innocent',
>  mind you, rather than 'not guilty'.
>  
>  Normally, the finding of 'not guilty' is not sufficient to allay
>  suspicion.  Statistically, the 'not guilty' verdict means that
>  below a given confidence level, 1 - alpha,  the null
>  hypothesis 'not guilty' cannot be rejected.  It does,
>  however, also mean that, at a significance level alpha,
>  the null hypothesis may not be valid, and thus a residual
>  suspicion remains.
>  
>  As we have pointed out before, risk management needs
>  to be flexible, in particular with respect to the confidence
>  levels.  In several cases , we have advocated levels as low
>  as 60% or even 50%, if costs and attendant risks are low.
>  It all depends on the interpretation of the perceived
>  threat and the action contemplated.
>  
>  For a general case, as you correctly point out, if one of the
>  two conditions for a cause-effect relationship is not met, the
>  situation is somewhat fluid, and different actions may be
>  indicated.  In our opinion the action should be based on a
>  cost-risk-benefit analysis of all relevant alternatives.
>  
>  As you agree, in the case of the EMF/cancer link, the
>  situation is different insofar as both conditions are not met.
>  Most importantly, any evidence for a physical-chemical/
>  biological mechanism of causation is lacking.  To our way
>  of thinking, this exonerates EMF, i.e., it declares it to be
>  "innocent" which is quite a different situation from being
>  found "not guilty".
>  
>  Nevertheless, EMF is subjected to continued suspicion on
>  the part of  certain persons and thus the press.  In effect
>  EMF is subjected to the media asking questions of the
>  misleading type "When are you going to stop causing
>  cancer?"  ("Have you stopped beating your wife yet?")
>  
>  We appreciate and and support the position that you
>  advocate, Tony, but  would like to see the proviso added
>  that corresponding actions have to be selected and
>  justified by cost-risk-benefit analyses.
>  
>  Joe Alvarez
>  Auxier & Associates, Inc.
>  10317 Technology Dr., Suite 1
>  Knoxville, TN 37932
>  jalvarez@auxier.com
>  Tel: 423-675-3669
>  FAX: 423-675-3677
>  
>  ************************
>  
>  Fritz A. Seiler, Ph.D.
>  Principal
>  Sigma Five Associates
>  P.O. Box 14006
>  Albuquerque, NM 87191-4006
>  Tel.     505-323-7848
>  Fax.    505-293-3911
>  e-mail: faseiler@nmia.com
>  

With regard to the whether EMF is "not guilty" or "innocent", it might 
be worthwhile to quote at some length from the Executive Summary of the 
NAS report that Richard Wilson recommended to Seiler and Alvarez and 
that Seiler and Alvarez recommended to RADSAFE readers.  The entire 
document is online at the National Academy of Science web site 
<www.nas.edu>, althought the user interface for reading or downloading 
NAS reports is so clunky that it suggests the Academy would really 
prefer that they not be read. 

The Committee on the Possible Effects of Electromagnetic Fields on 
Biological Systems was charged "to review and evaluate the existing 
scientific information on the possible effects of exposure to electric 
and magnetic fields on the incidence of cancer, on reproduction and 
developmental abnormalities, and on neurobiologic response as reflected 
in learning and behavior."  They were instructed to focus on exposure 
modalities found in residential settings.

Their conclusions included (and I am picking and choosing those 
conclusions that suggest that "not guilty" is a more appropriate 
judgment than "innocent"):

"The conclusion of the committee is that the current body of evidence 
does not show that exposure to these fields presents a human health 
hazard."

 <snip>

"At exposure levels well above those normally encountered in 
residences, electric and magnetic fields can cause biologic effects 
(promotion of bone healing is an example)."

 <snip>

"An association between residential wiring configuration (call wire 
codes, defined below) and childhood leukemia persists in multiple 
studies, although the causitive factor responsible for that 
statistical association has not been identified.  No evidence links 
contemporary measurements of magnetic-field levels to childhood 
leukemia."

 <snip>

"These studies found the highest wire-code category is associated with 
a rate of childhood leukemia (a rare disease) that is about 1.5 times 
the expected rate."

 <snip>

"Magnetic fields measured in the home after diagnosis of disease in a 
resident have not been found to be associated with an excess incidence 
of childhood leukemia or other cancers."

"The link between wire-code rating and childhood leukemia is 
statistically significant (unlikely to have arisen from chance) and 
robust in the sense that eliminating any single study from the group 
does not alter the conclusion that the association exists."

 <snip>

"Studies have not identified the factors that explain the association 
between wire codes and childhood leukemia."

"Because few risk factors for childhood leukemia are known, formulating 
hypotheses for links between wire codes and disease is very difficult.  
Although various factors are known to correlate with wire-code ratings, 
none stands out as a likely causitive factor.  It would be desirable 
for future research to identify the source of the association between 
wire codes and childhood leukemia, even if the sources has nothing to 
do with magnetic fields."

"In the aggregate, epidemiological evidence does not support possible 
associations of magnetic fields with adult cancers, pregnancy outcome, 
neurobehavioral disorders, and childhood cancers other than leukemia."

 <snip>

"Ambient levels of 60-Hz (or 50-Hz in Europe and elsewhere) magnetic 
fields in residences and most workplaces are typically 0.01-0.3 
microTesla ...."

"Higher levels are encountered directly under high-voltage transmission 
lines and in some occupational settings.  Some appliances produce 
magnetic fields of up to 100 microTesla or more in their vicinity.  For 
comparison, the static magnetic field of the earth is about 50 
microTesla.  Magnetic fields of the magnitude found in residences 
induce currents within the human body that are generally much smaller 
that the currents induced naturally from the function of nerves and 
muscles.  However, the highest field strengths to which a resident might 
be exposed (those associated with appliances) can produce electric 
fields within a small region of the body that are comparable to or even 
larger than the naturally occuring fields."

 <snip>

"Because the mechanisms through which electric and magnetic fields 
might produce adverse health effects are obscure, the characteristics 
of the electric and magnetic fields that need to be measured for 
testing the linkage of these fields to disease are unclear.  In most 
studies, the root-mean-square (rms) strength of the field, an average 
field-strength parameter, has been measured on the assumption that this 
measurement should relate to whatever field characteristics might be 
most relevant.  As noted earlier, wire-code categories have been used 
in many epidemiological studies as a surrogate measurement of the 
actual exposure."

 <snip>

"Reproducible changes have been observed in the expression of specific 
features in the cellular signal-transduction pathways for magnetic 
field exposures on the order of 100 microTesla and higher."

 <snip>

"At field strengths greater than 50 microTesla ..., credible positive 
results are reported for induced changes in intracellular calcium 
concentrations and for more general changes in gene expression and in 
components of signal tranduction."

 <snip>

"One area with some laboratory evidence of health-related effects is 
that animals treated with carcinogens show a positive relationship 
between intense magnetic-field exposure and the incidence of breast 
cancer."

 <snip>

"Neuroendocrine changes associated with magnetic-field exposures have 
been reported; however, alterations in neuroendocrine function by 
magnetic-field exposure have not been shown to cause adverse health 
effects."

"the majority of investigations of magnetic-field effects on pineal-
gland function suggests that magnetic fields might inhibit nighttime 
pineal and blood melatonin concentrations; in those studies, the 
effective field strengths varied from 10 microTesla ... to 5.2 
milliTesla ...." 

 <snip>

And finally, from the body of the report (pp. 25-26):

"Various characteristics of electric and magnetic fields, other than 
their rms magnitude at 60 Hz, might be responsible for their 
interaction with biologic systems (e.g., harmonics, transients, and 
temporal and spatial changes).  Knowledge of which characteristic (if 
any) of the exposure fields is important in the interaction would 
permit reliable exposure assessment in epidemiologic studies.  Lack of 
knowledge of the relevant field characteristic makes comprehensive 
human exposure assessment nearly intractable.  Nevertheless, a majority 
of studies have been conducted with the tacit assumption that the 60-Hz 
magnetic field (rms averaged and cumulative over time) is directly 
related to the exposure of interest."

Well, repeating the caveat that I have quoted the NAS report 
selectively, I would argue that the situation with EMF and health 
effects is not a simple or straightforward as Seiler and Alvarez 
assert.  In fact the carefully-worded conclusion of the 
Wilson/Seiler/Alvarez-recommended NAS report 

   "The conclusion of the committee is that the current body of 
   evidence does not show that exposure to these fields presents a 
   human health hazard." 

is not that far removed from the conclusions of the recent National 
Institutes of Environmental Health Sciences panel that Seiler and 
Alvarez are unhappy about. 

The NIEHS panel voted 19-9 that EMF was a "possible human carcinogen".  
Eight members of the panel said that because of conflicting studies 
they could not decide whether EMF should be regarded as potential 
carcinogens.  One member of the panel voted that EMF was not a human 
carcinogen.  The 19 positive voters chose not to vote that EMF was a 
"known human carcinogen" or that it was a "probable human carcinogen".

It is worth repeating here the epidemiology catch phrase that "Absence 
of evidence is not evidence of absence".  One of the best recent 
examples of the wisdom of the catch phrase is found in the first 10 
years of so of Mad Cow disease in the UK.  The British government 
asserted repeatedly (and more or less truthfully) that there was no 
scientific evidence that Mad Cow could be transmitted from beef and 
dairy products to humans and repeatedly assured the British public that 
beef and dairy products were perfectly safe (which the government did 
not know and which has, apparently, turned out not to be true). 

Best regards.

Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov

These comments are mine and have not been reviewed and/or approved by 
my management or by the U.S.Department of Energy.