EMF Cancer Evidence "Weak"

From ACGIH Today!, June 1999, Vol. 7, No. 4, p. 10

After six years of accelerated and Congressionally mandated research, a report of the National Institue of Environmental Health Science (NIEHS) has concluded that the evidence for a risk of cancer and other human disease from the electric and magnetic fields (EMF) around power lines is "weak." The report applies to the extremely low frequency electric and magnetic fields (EMF) surrounding both the big power lines that distribute power and the smaller but closer electric lines in homes and appliances.

NIEHS said that the "strongest evidence" for health effects comes from statistical associations observed in human populations with childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults such as electric utility workers, machinists, and welders. According to the report, this evidence is weak, but "these epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia than for childhood leukemia."

However, lab studies and investigations of basic biological function do not support these epidemiological associations according to the report. "Virtually all of the laboratory evidence in animals and humans and most of the mechanistic studies in cells fail to support a causal relationship."

Several panels of scientists reviewed the data in open, public hearings to assist NIEHS in reaching its conclusions. The panel rejected EMF as a "known" or proven, or even "probable" carcinogen but a majority of the panel said a role in cancer could not be ruled out and so it should be regarded as a "possible" carcinogen. The NIEHS reports say the evidence does not seem to meet the standard for listing a a known or even "anticipated" human carcinogen in the National Toxicology Program's "Report on Carcinogens."

Another recent study of EMF by the U.S. National Research Council yielded a report entitled "Research on Power-Frequency Fields Completed under the Energy Policy Act of 1992," that was published in May by the National Academy Press. This study also concluded that there was no convincing evidence that power-frequency fields contribute to the risk of cancer or other human diseases. This report can be accessed at http://books.nap.edu/catalog/9587.html. ACGIH TLV-Physical Agents Committee member Thomas Tenforde, Ph.D., was involved in creation of both reports.