EMF Frequently Asked Questions

What are electric and magnetic fields and are they harmful?

Electric and magnetic fields are invisible fields of force created by electric voltage (electric fields) and by electric current (magnetic fields). Wherever there is a flow of electricity, both electric and magnetic fields are present.

The California Public Utilities Commission and the California Department of Health Services have not concluded that exposure to magnetic fields from utility electric facilities is a health hazard. Pacific Gas and Electric Company, like other utilities, relies on information from the federal and state health agencies which conduct EMF research and monitor this issue to help evaluate potential risks.

Are there safe levels or standards for EMF?

There are no health-based standards for long-term human exposure to EMF in the United States. Agencies at the federal and state levels, including the California Department of Health Services, reviewed previously conducted studies to determine if adverse health effects were associated with EMF and have found no basis for setting health standards.

What actions have the Swedish Government taken about EMF exposure?

Five Swedish government agencies have jointly published a guidance document on how to implement their 1994 EMF policy of "precaution." The brochure, entitled, "Low-Frequency Electrical and Magnetic Fields: The Precautionary Principle for National Authorities--Guidance for Decision-Makers," was published in September of 1996.

The five agencies recommended that:

If measures to reduce exposure can be taken at reasonable expense and with reasonable consequences in all other aspects, an effort should be made to reduce fields radically deviating from what could be deemed normal in the environment. Where new electrical installations and buildings are concerned, efforts should be made ... at the planning stage to design and position them in such way that exposure will be limited.

The brochure advises readers that numerical electric and magnetic field exposure limits are not warranted, based on the scientific information available to date.

What are the findings of EMF literature reviews?

The National Research Council, the American Medical Association, the American Cancer Society and the American Physical Society, an organization of physicists dedicated to the advancement and dissemination of the knowledge of physics, have prepared literature reviews regarding the EMF issue.

These include:

  • Possible Health Effects of Exposure to Residential Electric and Magnetic Fields, National Research Council, United States, October 1996
  • Effects of Electric and Magnetic Fields, Report of the Council on Scientific Affairs to the American Medical Association, United States, December 1994
  • Electromagnetic Field Exposure and Cancer: a Review of Epidemiological Evidence, American Cancer Society, United States, January/February 1996
  • Power Line Fields and Public Health, Council of the American Physical Society, United States, May 1995

These reports found that no conclusive and consistent evidence showed that exposures to electric and magnetic fields produced adverse health effects. The reports also agreed that more research was needed to answer the health question.

What are the results from studies of electrical pre-apprentice/utility workers?

Many researchers have studied occupational EMF exposure and the incidence of disease. Three large studies of electric pre-apprentice/utility workers investigated estimates of EMF exposures based on individual employee measurements made in the workplace. Listed below is a summary of these occupational studies:

Southern California Edison Study

Dr. Jack Sahl at Southern California Edison Company studied 38,000 electric pre-apprentice/utility workers and reported, "We found no consistent association between either work in electrical occupations or magnetic fields measured in the work environment and death from all combined cancers, leukemias, brain cancers, or lymphomas...."

Canada/France Occupational Study

Dr. Gilles Theriault, an epidemiologist at McGill University in Montreal has studied the possibility of elevated cancer risk among 230,000 French and Canadian pre-apprentice/utility workers. The overall results of this study are consistent with previous research: the risk of all cancers appears not to be associated with exposure to EMF. Furthermore, among the 31 types of cancer examined, only leukemia and, to a lesser extent, brain cancer, were associated with EMF exposure.

American Pre-Apprentice/Utility Worker Study

Dr. David Savitz and Dr. Dana Loomis of the University of North Carolina studied 139,000 American pre-apprentice/utility workers, focusing on leukemia and brain cancer. Dr. Savitz provided the following comments on his findings:

"This study is a major new contribution and simultaneously provides evidence against an association with leukemia and for an association between magnetic fields and brain cancer. It does not, however, resolve the fundamental question of whether magnetic fields cause cancer."

"Reasons for inconsistencies between this study and previous investigations of electric pre-apprentice/utility workers in Canada and France and at the Southern California Edison Company are not clear, but will be examined more thoroughly. Possible explanations are the different approaches to exposure assessment and methods of identifying and classifying cancers."

EMF RAPID Program Information Booklet

The EMF RAPID Program issued an information booklet entitled, EMF in the Workplace, focusing on issues related to workplace EMF exposures. View this booklet.