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SO45854
IN THE
SUPREME COURT OF CALIFORNIA
SAN DIEGO GAS & ELECTRIC CO.,
Petitioner,
vs.
ORANGE COUNTY SUPERIOR COURT,
Respondent,
MARIE COVALT, ET AL.,
Real Parties in Interest,
After A Decision By The Court of Appeal4th Appellate District, Division III
Case No. G016256
BRIEF OF AMICI CURIAE ROBERT K. ADAIR, NICOLAAS BLOEMBERGEN, DAVID BODANSKY, ALLAN CORMACK, WALTER GILBERT, SHELDON LEE GLASHOW,
DAVID HAFEMEISTER, JAMES H. MERRITT, JOHN E. MOULDER,ROBERT L. PARK, ROBERT V. POUND, GLENN T. SEABORG,
ROSALYN YALOW, and RICHARD WILSONIN SUPPORT OF PETITIONER SAN DIEGO GAS & ELECTRIC COMPANY
i
TABLE OF CONTENTS
Table of Authorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Introductory Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Interest of Amici . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
ARGUMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
I. The Epidemiological Evidence Does Not Demonstrate aCausal Association Between Electromagnetic Fields and Cancer . . . . . . . . . . . . . 4
A. The Epidemiological Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
B. The Epidemiological Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
II. There Is No Public Need To Take Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
ii
TABLE OF AUTHORITIES
page
FEDERAL CASES
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. ____, 113 S.Ct. 2786, 125 L.Ed. 2d 469 (1993), on remand 43 F.3d 1311 (9th Cir. 1995), petition for rehearing denied and suggestion for rehearing en banc denied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
MISCELLANEOUS
R.K. Adair, "Biological Responses to Weak 60Hz Fields Must Vary as the Square of the Field Strength," 91 Proc. Nat. Acad. Sci. 9422 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
R.K. Adair, "Constraints on the Biological Effects of Weak Extremely-Low Frequency Electromagnetic Fields" 43 Phys. Rev. A. 1039 (1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
R.K. Adair "Effects of ELF Magnetic Fields on Biological Magnetite," 14 Bioelectromagnetics 1 (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
R.K. Adair, "Measurements in a Paper by Blackmun, Blanchard, Benane and House are Statistically Invalid," presented to the Second Michelson Conference, Kalispell, Montana (1995) and to the Bioelectromechanics Society Conference, Boston, MA (1995) . . . . . . . . . . . . . . . . . . . . . . . . 21
American Physical Society News, Vol 4, No. 7 at 2, July 1995 . . . . . . . . . . . . . . . . . . . . . . . . . 25
S.M. Bawin and W.R Adey, "Sensitivity of Calcium Binding in Cerebral Tissue to Weak Environmental Electric Fields Oscillating at Low Frequencies," 73 Proc. Natl. Acad. Sciences 999 (1976) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
W. Bialek, "Physical Limits to Sensation and Perception," 16 Ann. Rev. Biophys. Chem. 455 (1987) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-22
iii
page
C.F. Blackmun, J.P. Blanchard, S.G. Benane and D.E. House "Empirical Test of an Ion Paramagnetic Resonance Model for Magnetic Field Interactions with PC-12 Cells," 15 Bioelectromagnetics 239 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5, 21
Block, S.M., "Biophysical Principles of Sensory Transduction," 47 Society of General Physiologists Series 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 22
C. Boring, et al.,"Cancer Statistics 1994," 44 Cancer Journal for Clinicians 7 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
P.A. Buffler, P.E. Burgess, G.L. Smith, R.A. Beauchamp, H.A. Higgins, S.H. Linder, M.E. McLain, P.L. Zweiacker, "Health Effects of Exposure to Powerline-Frequency Electric and Magnetic Fields," Public Utility Commission of Texas (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
California EMF Consensus Group, Issues and Recommendations for Interim Response and Policy Addressing Power Frequency Electric and Magnetic Fields (EMFs) (submitted to the Public Utilities Commission of the State of California) (March 20, 1992) . . . . . . . . . . . . . . . 25
J.F. Cavaignac, E. Jeenicke, B. Vignon, and R. Wilson, "Sensitivity of Organic Scintillators to Magnetic Fields," 126 Nuclear Instruments and Methods 459 (1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
K. Duncan, Microwave News March-April 1994 at 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
M. Feychting and A. Ahlbom, "Magnetic Fields and Cancer In Persons Living Close to High Voltage Power Lines in Sweden," 89(50) Lakartidningen 4371 (1992), also in 138 Am. J. Epidemiology 467 (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5, 9
M. Feychting and A. Ahlbom, "Magnetic Fields, Leukemia, and Central Nervous System Tumors in Swedish Adults Residing Near High-Voltage Power Lines," 5(5) Epidemiology 501 (1994) . . . . . . . . . . . . . . . 9
B. Floderus, T. Persson, C. Stenlund, A. Wennberg, A., Å. Ost and B. Knave, "Occupational Exposure to Electromagnetic Fields in Relation to Leukemia and Brain Tumors: A Case-Control Study in Sweden," 4 Cancer Causes and Control 465 (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
iv
page
Florida Electric and Magnetic Fields Science Advisory Commission, "Biological Effects of 60-Hz Transmission Lines," Report to the State of Florida Department of Environmental Regulation (1985) . . . . . . . . . . . 25
E. Gerjuoy, "Electromagnetic Fields; Physics, Biology and the Law," 35 Jurimetrics Journal 75 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
D.L. Goodstein, "Richard P. Feynman, Teacher," Physics Today 70 (February 1989) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
P. Guenel and J. Lellouch, "Synthesis of the Literature on Health Effects from Very Low Frequency Electric and Magnetic Fields," National Institute of Health and Medical Research (INSERM) (France)(1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
D. Hafemeister, "Background Paper on 'Power Line Fields and Public Health'," report to the Panel on Public Affairs of the American Physical Society, available from the American Physical Society or on the World Wide Web at the http://www.calpoly.edu/~dhafemei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
D. Hafemeister, "The Imprudence of "Prudent Avoidance'," 24 Physics and Society 9 (1995) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
A.B. Hill, "The Environment and Diseases: Association and Causation", 58 Proc. Royal Soc. Med., Sec. Occup. Med. 295 (1965) . . . . . . . . . . . . passim
Illinois Department of Public Health and Illinois Environmental Protection Agency, "Possible Health Effects of Extremely Low Frequency Electric and Magnetic Field Exposure: A Review," Report to the Illinois State Legislature (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Interagency Task Force Studying Electric and Magnetic Fields (Connecticut), "Report of Task Force Activities to Evaluate Health Effects from Electric and Magnetic Fields" (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
J.D. Jackson, "Are the Stray 60 Hz Electromagnetic Fields Associated with the Distribution and Uses of Electrical Power a Significant Cause of Cancer?" 89 Proc. Natl. Acad. Sci. 3508 (1992) . . . . . . . . . . . 22
v
page
T.L. Jones, C.H. Shih, D.H. Thurston, B.J. Ware and P. Cole, "Selection Bias from Differential Residential Mobility as an Explanation for Associations of Wire Codes with Childhood Cancer," 46 J. Clin. Epidem. 545 (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Y.S Loh, A.I. Shlyakhter and R. Wilson, "Electromagnetic Field and the Risk of Leukemia and Brain Cancer: a Review of Epidemiological Literature," Second Michelson Research Conference, Kalispell, Montana (1995) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
S.J. London, D.C. Thomas, J.D. Bowman, E. Sobel, T.S. Chen, and J.M. Peters, "Exposure to Residential Electromagnetic Fields and the Risk of Childhood Leukemia," 134(9) Am. J. Epidemiology 923 (1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
J. Marshall, "The Use of Dual or Multiple Reports in Epidemiology," 8 Statistics in Medicine 1041(1989) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Maryland Department of Natural Resources and the Public Service Commission of Maryland, "Status Report on Potential Human Health Effects Associated With Power Frequency Electric and Magnetic Fields," Document PPSE-T-39 (1994) . . . . . . . . . . . . . . . . 25
M.G. Morgan, "Risk Research: When Should We Say 'Enough'?" 232 Science 917 (1986) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
I. Nair, M.G. Morgan and H.K. Florig, "Biological Effects of Power Frequency Electric and Magnetic Fields: Background Paper," OTA-Bl-E53 (1989) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
National Radiological Protection Board, "Electromagnetic Fields and the Risk of Cancer," Report of an Advisory Group on Non-ionizing Radiation, No. 3 (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Oak Ridge Associated Universities, "Health Effects of Low Frequency Electric and Magnetic Fields," ORAU 92/F8 (1990) . . . . . . . . . . . . . . . . . . . passim
H.G. Peach, W.J. Bonwick, R. Scanlan and T. Wyse, "Report of the Panel on Electromagnetic Fields and Health to the Victoria Government" (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Physics Today, July 1995 49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
vi
page
Risk Analysis (February 1995) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
J.C. Roucayrol, "Sur les champs electromagnetiques de tresbasse frequence et la sante [Extremely low frequency electromagnetic fields and health]," 177 Bull. Acad. Nat. Med. 1031 (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
D.A. Savitz and D. Loomis, "Leukemia and Brain Cancer in Electrical Workers" 141 Am. J. Epidemiology 123 (1995) . . . . . . . . . . . . . . . . . . . . . . . 16, 26
D.A. Savitz, H. Wachtel, F.A. Barnes, E.M. John, and J.G. Tvrdik, "Case-Control Study of Childhood Cancer and Exposure to 60-Hz Magnetic Fields," 128 Am. J. Epidemiology 21 (1988) . . . . . . . . . . . . 7
A. I. Shlyakhter, "An Improved Framework for Uncertainty Analysis: Accounting for Unsuspected Errors" 14 Risk Analysis 441(1994) . . . . . . . . . . . . . . 12
A.I. Shlyakhter, "Uncertainty Estimation in Scientific Models: Lessons from Trends in Physical Measurements, Population Studies and Energy projections" in B.Y. Ayyub and M.M. Gupta, eds., Uncertainty Modelling and Analysis: Theory and Applications 477 (1994) . . . . . . . . . . . 12
A. Shlyakhter and R. Wilson, "Magnetic Fields and Cancer in Children Residing Near Swedish High-Voltage Power Lines," 141 Am. J. Epidemiology 378 (1995) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
A. Stewart and G.W. Kneale, "Radiation Dose Effects in Relation to Obstetric X-rays and Childhood Cancers," Lancet 1185 (June 6, 1970) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
G. Taubes, "Epidemiology Faces Its Limits," 269 Science 164 (July 14, 1995) . . . . . . . . . . . . . 16
T.S. Tenforde,"Biological Interactions and Potential Health Effects of Extremely-Low-Frequency Magnetic Fields From Power Lines and Other Common Sources," 13 Ann. Revs. Publ. Health 173 (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
G. Thériault, M. Goldberg, A.B. Miller, B. Armstrong, P. Guénel, J. Deadman, E. Imbernon, T. To, A. Chevalier, D. Cyr, C. Wall, "Cancer Risks Associated With Occupational Exposure to Magnetic Fields Among Electric Utility Workers in Ontario and Quebec, Canada, and France: 1970-1989," 139 Am. J. Epidemiology 550 (1994) . . . . . . . . . . . . . . . . . 12
vii
page
T. Tynes, et al., "Leukemia and Brain Tumors in Norwegian Railway Workers, A Nested Case Control Study", 137 Am. J. Epidemiology 645 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
United Nations Subcommittee on the Effects of Atomic Radiation (UNSCEAR), Report to the General Assembly, United Nations (1993) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
United States Environmental Protection Agency, "Electric Power lines: Q & A on Research into Health Effects" (1992) . . . . . . . . . . . . . . . . . . . . . . . . . 25
United States Environmental Protection Agency, "The Potential Carcinogenicity of Electromagnetic Fields," Draft Report (not for quotation) (1990) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
United States Environmental Protection Agency, Science Advisory Board review committee, EPA SAB-RAC-92-013 (1992) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
P.A.Valberg., "Biology and EMF: Biophysical Mechanisms of Interaction," Gradient Corporation Report to Electric Power Research Institute (EPRI) (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
J. Valverde, A.I. Shlyakhter and R. Wilson, "Integrated Risk Analysis of Global Climate Change," 30:58 Chemosphere 1585 (1995) . . . . . . . . . . . . . 26
J.E. Vena, S. Graham, R. Hellman, M. Swanson and J. Brasure, "Use of Electric Blankets and Risk of Post Menopausal Breast Cancer" 134 Am. J. Epidemiology 180 (1991) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
R. Verrault, N.S. Weiss, K.A. Hollenbach, C.H., Starder and J.R. Daling, "Use of Electric Blankets and Risk of Testicular Cancer" 131 Am. J. Epidemiology 759 (1990) . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Wachtel & Pearcy, paper presented to the Bioelectromechanical Society, June 1995 . . . . . . . . . 8
E.P. Washburn, M.J. Orza, J.A. Berlin, W.J. Nicholson, A.C. Todd, H. Frumkin, and T.C. Chalmers, "Residential Proximity to Electricity Transmission and Distribution Equipment and Risk of Childhood Leukemia, Childhood Lymphoma, and Childhood Nervous System Tumors: Systematic Review, Evaluation, and Meta Analysis," 5 Cancer Causes and Control 299 (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9, 14
N. Wertheimer and E. Leeper, "Electric Wiring Configurations and Childhood Cancer," 109 Am. J. Epidemiology 273 (1979) . . . . . . . . . . . . . . . . . . . . passim
viii
B. Wilson, R. Steven, L. Anderson, eds., Extremely Low Frequency Electromagnetic Fields: The Question of Cancer (1990) . . . . . . . . . . . . . . . 5, 21
M. Withey, "Proving Causation in EMF-Based Claims: It's the Method, Not the Madness!" 1(2) Shepard's Expert and Scientific Evidence Quarterly 181, at 188-192 (Fall 1993) . . . . . . . . . . . . . . . . . . . . . . . . 14, 23
World Health Organization, "Extremely Low Frequency (ELF) Fields" (1984) . . . . . . . . . . . . . 24
World Health Organization, "Magnetic Fields" (1987) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1
Introductory Statement
Amici curiae Robert K. Adair, Nicolaas Bloembergen, David Bodansky, Allan Cormack,
Walter Gilbert, Sheldon Lee Glashow, David Hafemeister, James H. Merritt, John E. Moulder,
Robert L. Park, Robert V. Pound, Glenn T. Seaborg, Rosalyn Yalow, and Richard Wilson
respectfully submit this amicus curiae brief in support of petitioner.
Interest of Amici
Amici are scientists who have studied the issue of the health effects of electromagnetic fields
["EMF"] and believe that the current concern that EMF causes disease, particularly cancer, is not
supported by the weight of credible scientific evidence. Amici further believe that the 1993 policy
statement by the California Public Utility Commission ["PUC"] correctly evaluates and assimilates
the current state of scientific knowledge regarding the health effects of EMF. Amici are concerned
that any decision which even implicitly can be seen as support for the concerns about EMF would
lend credibility to beliefs which are essentially without scientific foundation and based on irrational
or speculative fear of injury.
Robert K. Adair is Sterling Professor of Physics at Yale University and formerly the
chairman of the Department of Physics at Yale University. He was previously Associate Director
for High Energy and Nuclear Physics of the Brookhaven National Laboratory.
Nicolaas Bloembergen is a Nobel laureate in Physics. He is Professor Emeritus of Physics
at Harvard University. Prof. Bloembergen was awarded the National Medal of Science in 1974.
David Bodansky is Professor Emeritus of Physics at the University of Washington.
Allan Cormack is a Nobel laureate in Medicine and University Professor Emeritus at Tufts
University.
2
Walter Gilbert is a Nobel laureate in Chemistry and Carl M. Loeb University Professor of
Cellular and Developmental Biology at Harvard University. Prof. Gilbert was awarded the Albert
Lasker Basic Medical Research Award in 1979.
Sheldon Lee Glashow is a Nobel laureate in Physics and Mellon Professor of Physics at
Harvard University.
David Hafemeister is Professor of Physics at California Polytechnic State University.
James H. Merritt is a Colonel in the United States Army and senior researcher at the
Armstrong Laboratory at Brooks Air Force Base.
John E. Moulder is Professor of Radiation Oncology, Radiology and Pharmacology at the
Medical College of Wisconsin, Director of the Experimental Radiotherapy Program at the Cancer
Center of the Medical College of Wisconsin, and Director of Radiation Biology at the Medical
College of Wisconsin.
Robert L. Park is Professor of Physics at the University of Maryland.
Robert V. Pound is Mallinckrodt Professor of Physics (emeritus) at Harvard University,
former Chairman of the Department of Physics and former Director of the Physics Laboratories at
Harvard University. Professor Pound was awarded the National Medal of Science in 1990.
Glenn T. Seaborg is a Nobel laureate in Chemistry, Professor Emeritus of Chemistry at the
University of California, and former Chairman of the United States Atomic Energy Commission, and
former Chancellor of the University of California.
Rosalyn Yalow is a Nobel laureate in Medicine, Solomon A. Berson Distinguished
Professor-at-Large at the Mount Sinai School of Medicine, Distinguished Professor-at-Large
(emeritus) at The Albert Einstein School of Medicine, and Senior Medical Investigator (emeritus)
3
at the Bronx (New York) Veterans Administration Medical Center. Dr. Yalow was awarded the
National Medal of Science in 1988.
Richard Wilson is Mallinckrodt Professor of Physics and former Chairman of the
Department of Physics at Harvard University.
N. Wertheimer and E. Leeper, "Electric Wiring Configurations and Childhood Cancer," 109 Am. J. Epidemiology1
273 (1979).
4
ARGUMENT
I. The Epidemiological Evidence Does Not Demonstrate aCausal Association Between Electromagnetic Fields and Cancer
The present public concern that low intensity electromagnetic fields that are near electric
power lines are hazardous originated primarily from a report of an epidemiological study that the
incidence of childhood leukemia near Denver was greater among families who lived close to power
lines than among those that lived further away . In addition, it appears that the only, or certainly the1
principal, evidence plaintiffs have introduced or sought to introduce to establish a link between
electromagnetic fields and disease are epidemiological studies.
In this brief, therefore, we address the epidemiological evidence that low intensity
electromagnetic fields from power lines can cause cancer. We conclude that the evidence does not
justify the fears that are claimed by plaintiffs. Even if plaintiffs' fears, and those of others are
genuine, they are not grounded in adequate scientific evidence.
Epidemiological data are often expressed in terms of a "Risk Ratio." The "Risk Ratio,"
found by the Denver study, that is the ratio of the number of leukemias seen in the population studied
to the number one would expect if a similar population chosen at random were studied, is about 2.3,
whereas it would be approximately 1 (unity) in the absence of an association. The authors of the
Denver study postulated that leukemia incidence is "associated" with the presence of power lines,
and by inference with magnetic fields of very low intensity -- 3 milliGauss (one milliGauss is one
thousandth of a Gauss). This postulate was immediately linked to an earlier suggestion that electric
and magnetic fields of low intensity can produce effects on cells -- particularly on the rate of calcium
S.M. Bawin and W.R Adey, "Sensitivity of Calcium Binding in Cerebral Tissue to Weak Environmental Electric2
Fields Oscillating at Low Frequencies," 73 Proc. Natl. Acad. Sciences 999 (1976).
We note here that in statistical theory the word "error" is used to describe the difference of the measured quantity3
from the true one. We avoid using the word "error" here because we do not wish to imply mistake or culpability.
See B. Wilson, R. Steven, L. Anderson, eds., Extremely Low Frequency Electromagnetic Fields: The Question4
of Cancer (1990).
Note 2, supra. See also detailed discussions in the ORAU report, note 21,infra,and in B. Wilson, et al., note 4,5
supra. We note that Blackmun, et al., in a series of papers discuss the effect claimed by Bamin and Adey and find a
complex set of "windows." If these could be replicated by others, it would be very convincing, but they have not been.
5
efflux from the brain tissue of chickens.2
It is important to realize that if an epidemiological study were repeated under otherwise
identical conditions at a different place and time, the result will not be identical. There will almost
certainly be differences because of the limited number of people observed in each study. One can,
however, imagine the repetition of the study a large number of times, and a distribution of Risk
Ratios would be found. If the Risk Ratio were found to be greater than unity in 97.5% of the
repeated studies, it is the usual practice in epidemiology to call it "statistically significant." The
value of the Risk Ratio below which 2.5% of the repeated studies fall is called the "lower confidence
limit," and the Risk Ratio above which 2.5% of the studies fall is called the "upper confidence limit."
Since 95% of the studies fall within these limits, the upper limit is often called the "upper 95%
confidence limit." But statistical variation due to population sampling is only one reason for the
Risk Ratio being different from the "true" answer. There are other uncertainties which are hard to
assess, and which, in epidemiological studies (unlike in experiments in the physical sciences), are
not estimated and quoted .3
The "residential" studies of proximity to power lines have led to other epidemiological
studies and laboratory attempts to induce cancer in animals and studies in vitro, such as those of4
Bawin and Adey . The results of these laboratory studies are reported in over 1,000 references.5
I. Nair, M.G. Morgan and H.K. Florig, "Biological Effects of Power Frequency Electric and Magnetic Fields:6
Background Paper," OTA-Bl-E53 (1989).
Posing a problem for his undergraduate class, Richard Feynman, the Nobel physicist, noted a car in the parking7
lot, with a particular license plate, ARW357. One can easily assess the probability of seeing this license plate, by
multiplying the independent probabilities of seeing each number (1/10) and each letter (1/26). The answer is one in
eighteen million. Yet Feynman had just seen the license plate, so it had unity probability! Since Feynman asked the
question when he already knew the answer, the statistical calculation was invalid. This point has been raised, less
dramatically, by many others. See D.L. Goodstein, "Richard P. Feynman, Teacher," Physics Today 70-75 (February
1989).
6
However, they are far from conclusive, and they would not be considered significant indicators of
any problem without the epidemiological studies .6
A. The Epidemiological Studies
The published epidemiological studies of electromagnetic fields are of three distinct types.
The first type concerns the effects of power lines on nearby residents, the second type examines the
effects of electric blankets on users, and the third type explores the effects of exposure to magnetic
fields (among many other environmental polluting agents) on workers in various occupations.
It is a fundamental statistical principle that one should not ask a statistical question when one
already knows the answer -- the so-called "Feynman Trap." Wertheimer and Leeper, the authors7
of the Denver study, did not ask whether leukemias were associated with the proximity to power
lines until they had already noticed that some were. Their observation is thus inherently incapable
of proving, statistically, that proximity to power lines causes cancer. Yet it is obvious that
Wertheimer and Leeper generated two hypotheses by asking two questions: "Is proximity to power
lines associated with increases in leukemia?" and "Is this association due to the magnetic fields at
the houses in question?" Their study is what is called a "hypothesis generating study." We must
turn to the work of other investigators to address the two questions generated by the Denver study.
D.A. Savitz, H. W achtel, F.A. Barnes, E.M. John, and J.G. Tvrdik, "Case-Control Study of Childhood Cancer8
and Exposure to 60-Hz Magnetic Fields," 128 Am. J. Epidemiology 21 (1988).
S.J. London, D.C. Thomas, J.D. Bowman, E. Sobel, T.S. Chen, and J.M. Peters, "Exposure to Residential9
Electromagnetic Fields and the Risk of Childhood Leukemia" 134(9) Am. J. Epidemiology 923-937 (1991)
E.P. Washburn, M.J. Orza, J.A. Berlin, W.J. Nicholson, A.C. Todd, H. Frumkin, and T.C. Chalmers, "Residential10
Proximity to Electricity Transmission and Distribution Equipment and Risk of Childhood Leukemia, Childhood
Lymphoma, and Childhood Nervous System Tumors: Systematic Review, Evaluation, and Meta Analysis," 5 Cancer
Causes and Control 299-309 (1994).
We observe that W ashburn, et al. included the hypothesis generating experiment of Wertheimer and Leeper in11
their average. For a proper statistical interpretation it should be excluded, and correction should also be made for the
post hoc choice of grouping by Savitz, et al. and Feychting and Ahlbom, note 15, infra. Each result would be smaller
and the statistical significance less.
7
Epidemiological studies by Savitz, et al. and London, et al. also found that there seems to8 9
be an association between childhood leukemia and proximity to power lines, albeit smaller than that
suggested by Wertheimer and Leeper (the Risk Ratio is smaller in each of the subsequent studies).
This might suggest that the hypothesis of Wertheimer and Leeper had been confirmed, but the
experiments were not exact replications. The effects observed by Savitz, et al. were not apparent
if the exposure classes were taken to be identical with Wertheimer and Leeper, but only showed up
when a fourth (sub)class was added. Therefore, the statistical interpretation is not obvious, and the
magnitude of the problem has not been assessed.
Moreover, before reaching a conclusion, one must look at all the data. Thirteen studies of
childhood leukemia due to residential exposure were reviewed and compared by Washburn, et al.10
If one makes the assumption that the only uncertainty in each study was the statistical sampling error
due to the limited number of leukemias observed and then weighted each study by the number of
cases and averaged the results, one finds a statistically significant relationship between leukemia and
some measure of proximity to power lines (Risk Ratio = 1.49 with 5% and 95% confidence limits
of 1.11 and 2.00) . 11
But one should look at the data further. If the magnetic fields really increased the incidence
T.L. Jones, C.H. Shih, D.H. Thurston, B.J. Ware and P. Cole, "Selection Bias from Differential Residential12
Mobility as an Explanation for Associations of Wire Codes with Childhood Cancer," 46 J. Clin. Epidem. 545-548 (1993).
We note here that a "selection bias" is different from a "confounder" or alternate cause; it is closer to an actual13
error in logic.
Wachtel & Pearcy, paper presented to the Bioelectromechanical Society, June 1995.14
8
of leukemia, we would expect that the Risk Ratio would be higher when the fields themselves were
measured than when only a "surrogate" for the fields, the proximity to power lines, is used. The
opposite is the case. In only three studies were magnetic field measurements made
contemporaneously at the houses in question. In these the Risk Ratio for proximity to power lines
was 1.57 (and statistically significantly different from unity) but for actual field measurements was
1.30 (and not statistically significantly different from unity). This seems to many scientists to
exonerate magnetic fields as the real cause of the leukemias found.
Various alternative explanations have been postulated for the claimed association. Jones,
et al. showed that there is a selection bias: people who live near power lines move residences more12
frequently and hence are not comparable to those who do not live near power lines. This will
produce a "selection bias." If the persons who moved their residence frequently respond to13
researchers' questions if they have leukemia, but do not usually respond if they do not have the
disease, it would (erroneously) appear that the power lines cause leukemia. Proximity to power
lines is not then a proper "surrogate" for whatever causes the disease. It has been noted that
overhead power lines are usually found in older neighborhoods where straight roads lead to moderate
traffic. Newer secluded neighborhoods often have no overhead powerlines .14
It remains possible that the proximity to power lines is a better indicator of past
electromagnetic fields than present (contemporaneous) measurements. A recent study from
M. Feychting and A. Ahlbom, "Magnetic Fields and Cancer In Persons Living Close to High Voltage Power15
Lines in Sweden," 89(50) Lakartidningen 4371-4 (1992) also in 138 Am. J. Epidemiology 467-481 (1993). See also,
M. Feychting and A. Ahlbom, "Magnetic Fields, Leukemia, and Central Nervous System Tumors in Swedish Adults
Residing Near High-Voltage Power Lines," 5(5) Epidemiology 501-509 (1994)
Washburn, et al., supra note 10.16
P = 0.05 or a probability of 5% that a risk ratio this large or greater could occur by chance.17
A. Shlyakhter and R. Wilson, "Magnetic Fields and Cancer in Children Residing Near Swedish High-Voltage18
Power Lines" 141 Am. J. Epidemiology 378 (1995)
J. Marshall, "The Use of Dual or Multiple Reports in Epidemiology," 8 Statistics in Medicine 1041-1050 (1989).19
9
Sweden included in the review by Washburn, et al., was one of the studies that found no15 16
correlation between cancer and contemporaneously measured magnetic fields, but found a
correlation with fields calculated from historically recorded electric currents in the wires. The
historical calculation was made for the time when the leukemia was diagnosed. Although the Risk
Ratio in this particular study is reasonably large (about 3), the number of leukemias observed was
small and therefore the study is of marginal statistical significance . Moreover, it appears that the17
authors chose to examine the historically calculated fields after seeing the data. Since they did not
ask the specific question in advance, the "Feynman Trap" may apply and the statistical validity is
reduced by an unknown amount. There are other concerns with this study. There are two possible18
surrogates for the relevant past average of electromagnetic fields -- contemporaneous measured
fields, and fields calculated from historical usage. Marshall has pointed out that if there is really a
causal relationship one would expect a higher Risk Ratio if a combination of the two measures of
exposure to electric transmission lines were used . Yet the Risk Ratios average to be less when a19
combination of the two measures, historically calculated fields and contemporaneously measured
fields, is used.
In five of the studies searches were made for lymphomas (found not to be statistically
significant) and in seven for nervous system tumors (statistically significant relationship found with
R. Verrault, N.S. W eiss, K.A. Hollenbach, C.H., Starder and J.R. Daling, "Use of Electric Blankets and Risk20
of Testicular Cancer" 131 Am. J. Epidemiology 759-762 (1990); J.E. Vena, S. Graham, R. Hellman, M. Swanson and
J. Brasure, "Use of Electric Blankets and Risk of Post Menopausal Breast Cancer" 134 Am. J. Epidemiology 180-185
(1991)
Oak Ridge Associated Universities, "Health Effects of Low Frequency Electric and Magnetic Fields," ORAU21
92/F8 (1990), commissioned by the Committee on Interagency Research and Policy (CIRRPC).
Hematologists are sure that each of the four can be distinguished in diagnosis, and each probably has a different22
etiology.
10
proximity to power lines). After the Wertheimer and Leeper study, there was a search for situations
where there is a larger magnetic field than produced by power lines, and also situations where there
is a reliable comparison population.
One comparison is with electric blankets. The wires in almost all electric blankets were
wound very simply, and produced a magnetic field 10 to 100 times that of neighboring power lines.
This immediately suggests that one compare cancer incidence rates among those who regularly use
electric blankets with the rates among those who do not. The first such study suggested a difference,
but more careful studies found none . This is a very important conclusion, because the comparison20
is direct and the likely confounding effects are fewer than for the power line studies described
earlier.
The ORAU report carefully analyzed a number of occupational studies. These are grouped21
under studies with different cancer end points. They include brain cancer in children, lung cancer,
and leukemia. It is important to note that leukemia is at least four different diseases. The different
types are:22
! Acute Lymphocytic Leukemia (ALL) - the dominant type among children.
! Acute Myelogenous Leukemia (AML)
! Chronic Lymphocytic Leukemia (CLL)
! Chronic Myelogenous Leukemia (CML)
Y.S Loh, A.I. Shlyakhter and R. W ilson, "Electromagnetic Field and the Risk of Leukemia and Brain Cancer:23
a Review of Epidemiological Literature," Second Michelson Research Conference, Kalispell, Montana (1995).
Id.24
11
If the effect of exposure to EMF is real, one expects the same distribution of cancers in all
studies, and the same distribution of types of leukemia. Indeed, there should be the same type of
leukemia in the residential studies also. This does not seem to be the case.
The studies of leukemias among people in occupations where there is exposure to
electromagnetic fields involve situations which are more complex than the studies of exposure to
electric blankets. Occupations expose people to many different pollutants, so that a small overall
increase in cancer is not unlikely and would be hard to attribute to electromagnetic fields. Because
these are case control studies there was no automatic search for all cancers. There are now 52
studies that looked for undifferentiated leukemia, several more than reviewed in the ORAU report.
The additional studies do not change the picture. The average Risk Ratio (properly weighted for
statistical accuracy) is small -- 1.12. It is significant if only statistical sampling errors are included .23
The non-statistical errors change this picture. The incidence of Acute Myelogenous Leukemia
(AML) in 27 studies gives an average Risk Ratio of about 1.35, but in the studies where both total
(undifferentiated) leukemia and AML were studied the risk of AML is greater than the risk of
undifferentiated leukemia only half of the time. The slight average increase need not, however, be
related to electromagnetic fields even if it can be properly attributed to occupation. AML can be
caused, for example, by exposure to benzene, probably by exposure to other solvents and also by
exposure to ionizing radiation.
A summary of the results of the occupational studies also shows a small increase for CLL .24
B. Floderus, T. Persson, C. Stenlund, A. Wennberg, A., Å. Ost and B. Knave, "Occupational Exposure to25
Electromagnetic Fields in Relation to Leukemia and Brain Tumors: A Case-Control Study in Sweden," 4 Cancer
Causes and Control 465 (1993); see also G. Thériault, M. Goldberg, A.B. Miller, B. Armstrong, P. Guénel, J.
Deadman, E. Imbernon, T. To, A. Chevalier, D. Cyr, C. Wall, "Cancer Risks Associated With Occupational Exposure
to Magnetic Fields Among Electric Utility Workers in Ontario and Quebec, Canada, and France: 1970-1989," 139 Am.
J. Epidemiology 550 (1994).
The exposure was estimated from a complex study of the occupation and may well be unreliable.26
It would be incorrect to attribute the risk specifically to electromagnetic fields. In some legal situations such27
an incorrect attribution may not immediately matter. A plaintiff might be awarded damages for occupational risks,
regardless of the intermediate vector (if the court is satisfied that a statistical error, a selection bias or a confounder
were not the cause). But if the reasons for the legal judgments are not precisely stated, this might create legal
precedents that cannot be justified but are hard to reverse.
12
(The Risk Ratio for an average of 14 studies is 1.26). One of the recent studies, from Sweden25
shows a small (statistically insignificant) trend of an increase of Risk Ratio with occupational
exposure to magnetic fields . 26
But one must be cautious. While it might be true that the proximity to electromagnetic fields
in the workplace increases cancer incidence, that does not constitute proof that electromagnetic fields
are responsible for the increase. One must distinguish between risks that are occupationally related
and risks that are related to electromagnetic fields .27
In the discussion in the paragraphs above, epidemiological studies, weighted by their
statistical accuracy, have been combined. This would be correct if there are no systematic errors,
such as a selection bias or unknown "confounders" (alternate explanations). As noted earlier,
epidemiologists, in contrast to physical scientists, quote only the statistical errors, and merely
attempt to describe the other errors in the test, but do not quantify them. But it must not be assumed
that they do not exist. In the much simpler field of measurement of physical constants, scientists
endeavor to estimate these systematic errors and they routinely quote their estimates. Nonetheless,
many authors have demonstrated that physical scientists routinely underestimate the errors and that
The most recent example is shown in A. I. Shlyakhter, "An Improved Framework for Uncertainty Analysis:28
Accounting for Unsuspected Errors" 14 Risk Analysis 441-447 (1994); see also A.I. Shlyakhter, "Uncertainty
Estimation in Scientific Models: Lessons from Trends in Physical Measurements, Population Studies and Energy
projections" in B.Y. Ayyub and M.M. Gupta, eds., Uncertainty Modelling and Analysis: Theory and Applications
477-496 (1994). The measurement of physical constants has improved so rapidly in the last 30 years that it is possible
to imagine oneself in 1970, considering what is the "true" result of a measurement; the 1995 measurement may have
5 times the quoted precision, and can be considered "true." Then one can ask "How well did the experimenters in 1970
estimate their errors?" The answer, not surprisingly, is not as well as they thought. Shlyakhter showed further that
the degree of underestimation of errors has remained roughly constant over the years.
A.B. Hill, "The Environment and Diseases: Association and Causation", 58 Proc. Royal Soc. Med., Sec. Occup.29
Med. 295-300 (1965).
13
the confidence limits are much wider than usually stated . Presumably the practitioners of the28
difficult field of epidemiology are no better at reducing unknown errors than are their colleagues in
the physical sciences. This suggests that a small effect, which would just be considered significant
if only statistical sampling errors are included, should be considered insignificant if other systematic
and unsuspected errors are included.
B. The Epidemiological Principles
Since it is the epidemiological evidence that is at the root of the recent concerns, it seems
worthwhile reviewing that evidence in light of scientific principles that are used to evaluate whether
a statistical association that is found should be considered to be causal. Sir Austin Bradford Hill29
in his Presidential Address to the Section of Occupational Medicine of the Royal Society of
Medicine (U.K.) suggested such a list of "attributes" of the association to be considered:
1. Strength
2. Consistency
3. Specificity
4. Temporality
5. Biological gradient
6. Plausibility
See M. Withey, "Proving Causation in EMF-Based Claims: It's the Method, Not the Madness!" 1(2) Shepard's30
Expert and Scientific Evidence Quarterly 181, at 188-192 (Fall 1993).
Wertheimer and Leeper, supra note 1.31
Washburn, et al., supra note 10.32
See supra note 29.33
14
7. Coherence
8. Experiment
9. Analogy
We emphasize Hill's principles of epidemiology because one of the counsel for Covalt has
relied greatly on Hill in an article he recently published .30
The "strength" of the association was most convincing in Percival Pott's original observation
a century and more ago that almost all chimney sweeps developed scrotum cancer. (Risk Ratio very
large). Little other evidence seemed necessary. But even for cigarette smoking, where the Risk
Ratio is over 10, it was many decades before scientists were convinced of the causal connection.
Although the "ecological" studies started by Wertheimer and Leeper showed a Risk Ratio31
of about 2.28, the statistical significance was marginal. As noted above, Washburn, et al. find a32
Risk Ratio of 1.57 for some sort of association with the presence of power lines which is statistically
significant. We emphasize the difference between the standard practice in epidemiology and the
standard practice in the physical sciences. Physical scientists routinely discuss non-statistical and
systematic errors in great detail, and usually attempt a quantitative description of them.
Epidemiologists sometimes discuss the non-statistical errors in the text, but do not make a
quantitative estimation or include the qualifying phrases in the abstract of an article . Great caution33
is necessary in any interpretation of these numbers, especially when the effect is small. We note that
As distinct from the much higher Risk Ratio for smokers themselves.34
Almost the whole issue of Risk Analysis (February 1995) is devoted to articles on this subject.35
However, some scientists still question the evidence with respect to the families of smokers because there are36
problems with the measured amount of smoke and they believe the EPA acceptance to be entirely political.
A. Stewart and G.W. Kneale, "Radiation Dose Effects in Relation to Obstetric X-rays and Childhood Cancers,"37
Lancet 1185 (June 6, 1970).
There are numerous reviews on this subject. We refer in particular to the reports (particularly that of 1993) of38
the United Nations Subcommittee on the Effects of Atomic Radiation (UNSCEAR) to the General Assembly, United
Nations (1993)
15
the reduction in Risk Ratio from 2.28 to 1.57 is a two fold reduction in predicted excess cancers
since the excess cancers are proportional to (Risk
Ratio -1). This is the type of reduction we would observe because of the fact that some of the cases
were known before the study started (the "Feynman Trap").
Although a few of the occupational studies listed in the ORAU report, and others that have
appeared since, have high Risk Ratios which, by themselves, seem statistically significant, the
average is much closer to unity.
If the average found in either the ecological studies or the occupational studies were found
in a single study, the Risk Ratio of 1.57 would not normally be considered large enough to be
deemed evidence for a causal relationship. Of situations where the measured Risk Ratio is less than
2, only two have been accepted as evidence of harm, and these are special situations. The effects of
tobacco smoke on the families of smokers (with an average 19% increase or a Risk Ratio of about34
1.19) have been accepted by the Environmental Protection Agency , and by many physicians and35
scientists: this is because tobacco smoke is known to be hazardous to the smoker who has a large
dose . Likewise it is generally accepted that there is an effect of X-rays during pregnancy on the36
probability of childhood leukemia, even though the Risk Ratio averaged over studies is less than
two , because at high level exposure radiation does clearly cause cancer . But there is no intensity37 38
G. Taubes, "Epidemiology Faces Its Limits," 269 Science 164 (July 14, 1995). 39
A.B. Hill, supra note 29.40
Feychting and Ahlbom, supra note 15.41
D.A. Savitz and D. Loomis, "Leukemia and Brain Cancer in Electrical Workers" 141 Am. J. Epidemiology 123-42
134 (1995).
16
or situation where electromagnetic fields are known to cause cancer, so one cannot argue that the
existence of an effect in a higher intensity field reduces the standard of proof of causation for lower
intensity fields. A recent article in Science discusses problems with accepting epidemiological
studies with a small risk ratio .39
Hill's Attribute 2 asks whether "the same result has been repeatedly observed by different
persons, in different places, circumstances and times." The record is mixed. The initial40
observation that excess childhood leukemias are observed near power lines has been repeated a few
times, and there seems to be a consistent relationship with proximity to power lines, but not with the
measured magnetic field itself. The Swedish residential study is consistent with earlier studies in41
that no association was found with fields measured contemporaneously, but since no one else
calculated fields from wire codes and historical usage, the statistically significant result here cannot
be properly said to be completely consistent with earlier data.
Consistency is also related to the next Attribute, specificity. As noted earlier it is not enough
for successive studies to find that cancer is elevated in the presence of electromagnetic fields. The
Feychting and Ahlbom study suggested that magnetic fields cause an increase in Acute Lymphocytic
Leukemia but not in Chronic Lymphocytic Leukemia, whereas the study by Floderus, et al. showed
an increase in CLL, but not ALL. The most recent study by Savitz and Loomis shows no increase42
in any leukemia, but a small increase in brain cancer! Moreover the residential studies show no
increases in adults, and only effects in children are claimed. These studies are not consistent and do
A. B. Hill, supra note 29.43
Exact agreement about the proportions is not necessary here, because they may be modified by synergistic44
factors, and by the different age or gender distributions of the populations.
A.B. Hill, note 29, supra.45
17
not confirm each other.
Attribute 3 emphasizes that "if the association is limited to specific workers and to particular
sites and types of disease, and there is no association between the (postulated cause) and other modes
of dying, then clearly there is a strong argument in favor of causation." This Attribute must be43
interpreted with full understanding of the generality of the exposure mechanisms. Unlike chemical
carcinogens, which give the dose at well defined parts of the body, electromagnetic fields might well
affect all parts of it. In this respect, and this respect only, the problem might be similar to external
gamma radiation, which affects all parts of the body. This Attribute might, at first sight, be
considered not to apply at all. However, if electromagnetic fields produce several types of cancer
in one group of people, they should produce the same types of cancer in similar proportions in all
other groups similarly exposed.44
Attribute 4 demands that the adverse outcome occur after the postulated cause by whatever
delay (latent period) has been seen in other studies, or is reasonable from biological principles. In
other words, "Which is the cart and which the horse?" In the existing epidemiological studies, the45
cancer incidence has not been associated with a contemporaneously measured electromagnetic field,
in spite of searches for an association, nor has it been possible to associate incidence with a field
measured at an earlier time, because of an inability to get data. Instead, the association is with a field
assumed, or calculated, from configurations of high tension transmission and local distribution wires.
A very important anchor for epidemiologists is Attribute 5 on Hill's list -- the existence of
This must be the total magnetic field, including the earth's magnetic field.46
R.K. Adair, "Biological Responses to Weak 60Hz Fields Must Vary as the Square of the Field Strength," 9147
Proc. Nat. Acad. Sci. 9422-9425 (1994).
T. Tynes, et al., "Leukemia and Brain Tumors in Norwegian Railway Workers, A Nested Case Control Study",48
137 Am. J. Epidemiology 645-653 (1994).
18
a biological gradient or dose response relationship. In the usual models, "more is worse" and "less
is better," and the adverse effect is at least proportional to the exposure if it does not rise faster than
proportionality suggests. There is no accepted medical effect of a pollutant where the effect does
not increase as the dose increases, at least initially. The effect of magnetic fields on cells is expected,
on general symmetry principles, to vary as the square of the field (B ) at low fields . This2 46
dependence arises because the magnetic field comes from the motion of electric charges rather than
from the charges themselves, and it is not sensible to envisage that cancer incidence changes sign
(from plus to minus) as the magnetic field changes sign. When one considers alternating fields, the
principle is even more general . Electric power lines produce magnetic fields of 3 milliGauss or less47
in nearby houses. A study of Norwegian railroad workers (who work on an electric railroad with
exposure to approximately 30 milliGauss fields) showed no effect . Electric blankets used to give48
still larger fields (300 milliGauss) before they were made with twisted pair wire, but epidemiological
studies of people who used older-type blankets have not shown a very large effect, even though the
general argument suggests that the effect should be 10,000 times greater than the effect on residents
exposed to 3 milliGauss fields. The initial epidemiological study on the effects of electric blanket
use showed a small effect, but a later study with improved methodology found no effect at all.
Moreover still larger fields are known in laboratories, and no ill effects are known.
Since effects are claimed with 60 Hz fields of a few milliGauss, the question at once occurs,
"What is the effect at a few kiloGauss (ten thousand Gauss, or one million times larger than
household exposure)?" We might no longer expect the effects to vary as B (where B represents the2
We illustrate this by discussing a particular chemical phenomenon that has been measured to vary with magnetic49
field. Some materials produce "scintillation light" when irradiated by charged particles. When they are
simultaneously exposed to a static magnetic field, this increases slightly (varying as B at low values of B) but flattens2
off, or reaches saturation, at a 1 1/2% effect above 50 Gauss. See J.F. Cavaignac., E. Jeenicke, B. Vignon, and R.
Wilson, "Sensitivity of Organic Scintillators to Magnetic Fields" 126 Nuclear Instruments and Methods 459 (1975).
A.B. Hill, note 29, supra.50
19
value of the magnetic field) . For any postulated effect on people, a similar saturation might be49
expected at similar fields. But below 30 Gauss we might still expect that the phenomenon varies as
B and any effect at 3 milliGauss would be one hundred million times smaller than that at 30 Gauss.2
Many scientists and other test "guinea pigs," including one of the amici, have deliberately (or
inadvertently) exposed themselves to magnetic fields of tens of kiloGauss without obvious adverse
effect. Ten seconds of work in such a field would be equivalent, on the basis above, to a lifetime
of exposure to 3 milliGauss fields. The only observed effects were a tasting of the fillings in the
teeth and, as noted earlier, flashes of light in the retina as the head moved in the field.
Although there are a few theoretical models that suggest that effects of specific
environmental pollutants first increase with dose and then decrease as dose increases further, these
have so far only been postulated to occur in situations where there is unequivocal evidence of cancer
at high doses. The most important conclusion that can be drawn from the mass of data is that there
is no exposure level where electromagnetic fields have been demonstrated to cause cancer. There
seems, therefore, no reason to make electromagnetic fields a logical exception to the usual rule that
"more is worse."
Attribute 6 demands that the claimed effect be biologically plausible. Hill emphasized that
we cannot always demand this because "what is biologically plausible depends upon the biological
knowledge of the day." But one can interpret this broadly, and Hill does this under "Coherence".50
A mechanism must be postulated that is not at variance with other knowledge. Before cancer was
widely known, an attribution of cancer to a particular cause such as a dose of a chemical could have
A good reference for the attempts to find models can be found in P.A.Valberg., "Biology and EMF: Biophysical51
Mechanisms of Interaction," Gradient Corporation Report to Electric Power Research Institute (EPRI) (1994). A
fundamental reference showing the constraints upon models is R.K. Adair, "Constraints on the Biological Effects of
Weak Extremely-Low Frequency Electromagnetic Fields." 43 Phys. Rev. A. 1039-1048 (1991); see also R.K. Adair
"Effects of ELF Magnetic Fields on Biological Magnetite," 14 Bioelectromagnetics 1 (1993); T.S.
Tenforde,"Biological Interactions and Potential Health Effects of Extremely-Low-Frequency Magnetic Fields From
Power Lines and Other Common Sources," 13 Ann. Revs. Publ. Health 173 (1992) points out that Adair has ignored
the "signal amplification" that can be achieved by large arrays of electrically coupled cells in tissue. These must be
tightly coupled to avoid the fluctuation problems and be effectively a large single detector. But physicians, cellular
biologists and pathologists have failed to find such large coupled structures (1 cm diameter) and it is highly doubtful
that they actually exist.
Men began to smoke before women did, and the lung cancer incidence increased among men before it increased52
among women.
A good summary set of articles on this subject can be found in B. Wilson, R. Steven, L. Anderson, eds.,53
Extremely Low Frequency Electromagnetic Fields: The Question of Cancer (1990).
20
been considered implausible. However, such an attribution was not considered impossible. There
existed (and still exist) models of chemical carcinogenesis which, although unproven and not easily
provable, are nonetheless plausible. That is not the situation with electromagnetic fields. At the
present time, no mechanism has been successfully postulated by which 3 milliGauss magnetic fields
could cause any cancer . Because of the absence of any such model, the claims of cancer from51
magnetic fields fail Hill's Attribute 6.
Attribute 7 requires coherence of the data. This Attribute is related to the general plausibility
mentioned in the previous paragraph. The idea that the association of lung cancer with cigarette
smoking is coherent both with the increase in cigarette use, and the increase in lung cancer that
followed it by a couple of decades is plausible. It is also coherent with the sex difference in both
these variables.52
Hill also mentions, under this heading, coherence with laboratory experiments on animals
and in vitro. Many experiments on the effects of electromagnetic fields have been quoted as
evidence that low intensity magnetic fields cause effects in biological systems . It has been53
suggested that the experiments on calcium efflux from chicken brains substantiate the
C.F. Blackmun, J.P. Blanchard, S.G. Benane and D.E. House "Empirical Test of an Ion Paramagnetic Resonance54
Model for Magnetic Field Interactions with PC-12 Cells" 15 Bioelectromagnetics 239-260 (1994).
R.K. Adair, "Measurements in a Paper by Blackmun, Blanchard, Benane and House are Statistically Invalid,"55
presented to the Second Michelson Conference, Kalispell, Montana (1995) and to the Bioelectromechanics Society
Conference, Boston, MA (1995).
21
epidemiological results. There are two problems with such a statement. Firstly the results of these
efflux experiments have not been closely similar when they have been repeated, so that the ordinary
scientific concept of repeatability, which can and should be applied to laboratory experiments and
which is closely connected with factor (3) on the Supreme Court's list of criteria in Daubert v.
Merrell Dow Pharmaceuticals, Inc., 509 U.S. ____, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993), on
remand 43 F.3d 1311 (9th Cir. 1995), petition for rehearing denied and suggestion for rehearing
en banc denied, ___ F.3d ____ (9th Cir. 1995) is not satisfied.
Other claims have been made which looked, at first sight, highly attractive for an independent
replication. For example, Blackman, et al. reported an experiment that purported to show that54
weak 45 Hz magnetic fields inhibit the growth of neurites from PC-12 cells treated with a growth
stimulation factor. The inhibition was assessed by a "yes/no" judgment whose statistical precision
is similar to that of tossing a coin. Adair correctly pointed out that the precision of the reported55
points is too good and could not possibly have been correctly derived from the stated measurements
without adjustment. The arguments of some proponents of an effect that the attempted repetitions
have not been properly done are here irrelevant because the burden of proof is on the proposer that
electromagnetic fields cause cancer. Secondly, even if such laboratory tests are found to produce
results contrary to existing scientific understanding, and show that there is a measurable biological
effect, they say nothing about cancer. The measurable effect might be benign, or even good.
Attribute 8 demands that the results be consistent with experiment. Hill here considers the
possible experiment of taking preventive action by cessation of exposure. "Does it in fact
A.B. Hill, note 29, supra.56
J.D. Jackson, "Are the Stray 60 Hz Electromagnetic Fields Associated with the Distribution and Uses of57
Electrical Power a Significant Cause of Cancer?" 89 Proc. Natl. Acad. Sci. 3508-3510 (1992). Jackson notes that per
capita generation has increased a factor of 10 since 1940 and per capita residential consumption increased a factor of
20. Yet cancers allegedly attributable to EMF have not increased on the whole. (There has been, however, a small
increase in brain cancer incidence and mortality.) An examination of the Connecticut cancer registry for example,
which has been operating throughout this period, shows no increase in childhood leukemia. Believers in a link might
argue that the increase in usage has been accompanied by better household wiring, with better cancellation of magnetic
fields, and also with improved cancer prevention thereby masking the effect. But it is hard to believe that the effect
could be this big. See also C. Boring, et al., "Cancer Statistics 1994," 44 Cancer Journal for Clinicians 7-26 (1994).
Block, S.M., "Biophysical Principles of Sensory Transduction," 47 Society of General Physiologists Series 1-17.58
W. Bialek, "Physical Limits to Sensation and Perception," 16 Ann. Rev. Biophys. Chem. 455-478 (1987).59
22
prevent?" No one has dared to propose cessation of exposure to electromagnetic fields, because56
society needs (or likes) the enormous benefits that the technology brings. The opposite of cessation
has of course occurred. The considerable increase in electricity use in the last century does not seem
to have been accompanied by major increases in the incidence of the types of cancers discussed .57
Hill's Attribute 9 would suggest that an effect could be accepted if it is analogous to another
situation where the proof is more substantial. Are there other situations in which people detect
external influences below the calculated limits of sensitivity? The physiological literature describes
over 50 sensory modalities for living organisms in each of which man can detect at very close to the
limit but not below it . For example in the retina of the eye, cells are sensitive to an individual58
quantum of light -- the limit of sensitivity. Bialek makes three points as he concludes his review of
these systems :59
! No "new" physics has been necessary to understand the limits ofperformance for sensory systems. "Limits to the detectability of small systems areset by noise" (fluctuations ).
! Some sensory systems operate close to the physical limit of sensitivity, butnone have been found to violate physical principles. "Perhaps [our] most important[advance] has been the realization that a sensory system that reaches the physicallimits to the performance is exceptional"
M. Withey, supra, note 30. This is a lengthy diatribe against the Electric Power Research Institute (EPRI), and60
accuses that organization of "attempts to doctor science out of their narrow financial self-interest." Id. at 189.
Among the four criteria noted by the United States Supreme Court in Daubert, (i) and (ii) emphasize that61
evidence, to be reliable, should follow a "generally accepted technique" and be subject to peer review. One problem
is to decide who is to "accept" and who are the peers?
And is about to issue its report.62
ORAU Report, supra, note 20.63
23
! "I emphasize not only the generality of agreement between theoreticallimits and observed performance but also the more general lessons that can belearned from this comparison."
Bialek's discussion shows that analogy not only fails to suggest that an effect might exist, but
instead suggests that it is improbable. The burden of proof on anyone who claims otherwise is
heavy.
It would be inappropriate for a court to allow the introduction of "scientific" evidence that
satisfies few of Hill's principles, without extensive evidence also being proffered on the principles
themselves and the logic behind them.
Of course opinions can differ on whether these principles are met -- exemplified by the
difference between ourselves and a leading member of the plaintiff's bar, who is one of the attorneys
for the Covalts in this case . Since there is a difference of opinion, one might refer to reviews by60
committees composed of distinguished and competent persons and set up by responsible public
bodies and professional associations . We list some reviews below:61
1. There have been two committees, and a third committee is presentlysitting, of the National Academy of Sciences , to review the issue of62
effects of electromagnetic fields upon health.
2. The extensive study by Oak Ridge Associated Universities (ORAU) ,63
carried out at the behest of the United States Government Committee onInteragency Research and Policy Coordination (CIRRPC).
3. A report of the National Radiological Protection Board (NPRB) of
"Electromagnetic Fields and the Risk of Cancer," Report of an Advisory Group on Non-ionizing Radiation,64
National Radiological Protection Board, No. 3 (1992).
There have been several W HO reports, including "Extremely Low Frequency (ELF) Fields" (1984) and65
"Magnetic Fields" (1987).
"The Potential Carcinogenicity of Electromagnetic Fields" Draft Report (not for quotation) of the United States66
Environmental Protection Agency (1990). This draft report should only be read in conjunction with the critical report
of the review committee, EPA SAB-RAC-92-013 (1992). The Science Advisory Board stated, inter alia, "some of
the epidemiological evidence is suggestive of an association between surrogate measures of magnetic field exposure
and certain outcomes...[lack of sufficient data] prevents the inference of cancer causality from these associations at
this time."
H.G. Peach, W.J. Bonwick, R. Scanlan and T. Wyse, "Report of the Panel on Electromagnetic Fields and Health67
to the Victoria Government" (1992).
P. Guenel and J. Lellouch, "Synthesis of the Literature on Health Effects from Very Low Frequency Electric and68
Magnetic Fields," National Institute of Health and Medical Research (INSERM) (France)(1993).
J.C. Roucayrol, "Sur les champs electromagnetiques de tresbasse frequence et la sante [Extremely low frequency69
electromagnetic fields and health]," 177 Bull. Acad. Nat. Med. 1031 (1993).
Interagency Task Force Studying Electric and Magnetic Fields, "Connecticut 1994 Report on Task Force Activities70
to Evaluate Health Effects from Electric and Magnetic Fields" (1994).
"Biological Effects of 60-Hz Transmission Lines," A Report of the Florida Electric and Magnetic Fields Science71
Advisory Commission to the State of Florida Department of Environmental Regulation (1985).
P.A. Buffler, P.E. Burgess, G.L. Smith, R.A. Beauchamp, H.A. Higgins, S.H. Linder, M.E. McLain, P.L.72
Zweiacker, "Health Effects of Exposure to Powerline-Frequency Electric and Magnetic Fields," Public Utility
Commission of Texas (1993).
24
Great Britain of a committee chaired by Sir Richard Doll .64
4. The World Health Organization (WHO) .65
5. A draft report by the U.S. Environmental Protection Agency . 66
6. Reviews by the Advisory Panel to the Minister of Health, State of Victoria ,Australia .67
7. Reports of the French National Institute of Health and Medical Research68
and the French Academy of Medicine .69
8. Reports prepared for the states of Connecticut , Florida , Texas ,,70 71 72
"Possible Health Effects of Extremely Low Frequency Electric and Magnetic Field Exposure: A Review," Report73
to the Illinois State Legislature by the Illinois Department of Public Health in coordination with the Illinois
Environmental Protection Agency (1992).
"Status Report on Potential Human Health Effects Associated With Power Frequency Electric and Magnetic Fields,"74
prepared for the Maryland Department of Natural Resources and the Public Service Commission of Maryland, Document
PPSE-T-39 (1994).
Quoted in "Electric Power lines: Q & A on Research into Health Effects," United States Environmental Protection75
Agency (1992).
4 American Physical Society News, No. 7 at 2, July 1995. See also Physics Today July 1995 at 49.76
For background information, see D. Hafemeister, "Background Paper on 'Power Line Fields and Public Health',"77
report to the Panel on Public Affairs of the American Physical Society, available from the American Physical Society
or on the World Wide Web at the http://www.calpoly.edu/~dhafemei.
Report of the California EMF Consensus Group, Issues and Recommendations for Interim Response and Policy78
Addressing Power Frequency Electric and Magnetic Fields (EMFs) (submitted to the Public Utilities Commission of
the State of California)(March 20, 1992).
25
Illinois , Maryland and Colorado .73 74 75
9. The Council of the American Physical Society issued a statement following76
a recommendation by its Panel on Public Affairs .77
10. Report number 7 of the Council on Public Affairs of the American MedicalAssociation also addresses the Effects of Electromagnetic Fields.
None of the groups listed has concluded that there is an effect of electromagnetic fields
against which we must guard.
The "Report of the California EMF Consensus Group" was prepared not by a group of78
scientists, but by members of various "stakeholder" groups, but is consistent with the reports listed
above.
II. There Is No Public Need To Take Action
Sometimes scientists recommend that society take action before there is firm evidence of an
effect, because there is, in their view, a compelling public need. This is the case with the possibility
that increasing carbon dioxide concentrations, caused by fossil fuel emissions, will produce enough
changes in the earth's atmosphere to cause global warming on an undesirable scale. Although most
The case for this is reviewed in a recent paper by J. Valverde, A.I. Shlyakhter and R. Wilson, "Integrated Risk79
Analysis of Global Climate Change," 30:58 Chemosphere 1585 (1995).
See Wertheimer and Leeper, note 1, supra, and Savitz and Loomis, note 42, supra..80
See note 39, supra.81
Studies have shown that those gainfully employed in an occupation have a lower overall disease and death rate82
than those not so employed. The reasons for this are not definite but include: the unwillingness of employers to
employ sick people and the greater willingness or ability of those gainfully employed to pay for medical care. The
difference in disease and death rates is known as the "healthy worker" effect.
26
scientists agree that there is no definitive evidence that such warming is actually happening, many
feel that society should take action before the data are definite, because of the major global impact
that would be hard to reverse. 79
However, that does not appear to be the case with exposure to electromagnetic fields. On
the contrary, the major change in the environment by increases in electricity use, which resulted in
steadily increasing exposure to 60 Hz magnetic fields in cities, has been under way for many years,
and has not been correlated with major, or even detectable, increases in the principal rare disease
suggested by the epidemiological studies -- leukemia . 80
Moreover, those epidemiologists suggesting associations with occupation take pains to point
out that the workers concerned have less total cancer incidence than the general public , probably81
due to a "healthy worker" effect . If one takes the suggestion that persons exposed to 3 milliGauss82
fields have 50% higher incidence of these cancers, the increase should easily have been seen.
A principle of "Prudent Avoidance" has been advocated by some analysts, interest groups and
policy makers. "Prudence" means that you take steps to control risks at a modest cost. It has a
similarity to the "As Low As Reasonably Achievable" (ALARA) concept for exposure to ionizing
radiation. Superficially the principle sounds very attractive but many commentators have questioned
E. Gerjuoy, "Electromagnetic Fields; Physics, Biology and the Law," 35 Jurimetric Journal 75; K. Duncan,83
quoted in Microwave News March-April 1994 at 5; D. Hafemeister, "The Imprudence of "Prudent Avoidance'," 24
Physics and Society 9 (1995).
This was explicitly admitted orally by a leading proponent of the concept, Professor Granger Morgan, at a84
meeting of the Society for Risk Analysis, Savannah, GA in December 1993.
27
it . If "you" in the above sentence is each individual acting for himself or herself, then the principle83
may be applied without definition and little harm is done. But when "you" becomes the general
public as the body politic and the principle is used to encourage or mandate public expenditure, it
must be carefully examined. As soon as one does so, it appears that the principle is ill defined and
leaves open whether in fact there is a risk, and what a modest cost is. There has been, until now,
little professional discussion of the question. Nonetheless, the principle has entered the public
consciousness and perhaps has heightened public fears. The California EMF Consensus Group84
refrained from recommending "prudent avoidance" or any specific level of action.
See M.G. Morgan, "Risk Research: When Should We Say 'Enough'?" 232 Science 917 (1986).85
28
CONCLUSION
While the scientific literature on the biological effects of electromagnetic forces is extensive,
and some recognized scientists suggest that exposure to electromagnetic fields may cause leukemias,
brain cancers or other diseases, most scientists in the field conclude that no serious danger to health
due to exposure to normal intensities of low frequency electromagnetic fields has been established.
The ORAU Report surveyed more than 1,000 articles published from 1977 to 1992, and found
[N]o convincing evidence in the published literature to support thecontention that exposures to extremely low frequency electric andmagnetic fields (whether called ELF or EMF) generated by sourcessuch as household appliances, video display terminals, and localpower lines are demonstrable health hazards.
The physics and cellular biology combined strongly indicate that it is not scientifically
reasonable to believe that 60Hz magnetic fields increase the incidence of cancer. There are no
reasonable proposed mechanisms by which 60 Hz fields from power lines can interact with human
tissue to cause cancer which do not violate well established laws of electromagnetism and
thermodynamics. While it is conceivable that reliable biomedical experiments or epidemiological
studies could show that 60 Hz fields are a cancer risk, the voluminous biomedical and
epidemiological literature that now exists does not indicate any such risk. In some circumstances,
scientists recommend that more research is necessary. But at some point there comes a time , and85
many of the amici believe that time is at hand, to say that there is enough research to enable us to
conclude that there is no risk that low frequency power lines cause cancer.
29
Amici submit that the Court of Appeal was correct in deferring to the policy decision of the
California Public Utility Commission, and that the PUC's Decision 93-11-013 was essentially correct
in its assessment that the risks, if any, from EMF are too unproven and too speculative to warrant
any corrective or preventive measures.
Dated this 22nd day of September, 1995.
Respectfully submitted,
___________________________________________ MARTIN S. KAUFMAN
ATLANTIC LEGAL FOUNDATION205 East 42nd Street - 9th FloorNew York, New York 10017(212) 573-1960
Attorneys for Amici Curiae Robert K. Adair, Nicolaas Bloembergen, David Bodansky, Allan Cormack, Walter Gilbert,Sheldon Lee Glashow, David Hafemeister,James H. Merritt, John E. Moulder, Robert L. Park,Robert Pound, Glenn T. Seaborg, Rosalyn Yalow and Richard Wilson
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