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Electromagnetic fields
The information below relates to the electromagnetic fields (EMF) that are linked to electricity and electrical appliances and are considered to be in the extremely low frequency (ELF) range. Visit our other pages for more information on different types of ionizing and non-ionizing radiation or on EMF in the radio frequency range associated with cell phones and cell phone towers.
Canadian children and adults are exposed to electric and magnetic fields (EMF) from a variety of sources every day. For example, coffee makers, hair dryers, computers, household wires and high voltage power lines produce both electric and magnetic fields. More information about products that create EMF.
Researchers have long been concerned about the potential relationship between exposure to EMF and an increased risk of cancer. After more than 25 years of research, scientific evidence does not show a consistent relationship between exposure to EMF and cancer risk in adults. However, some research studies have found a relationship between EMF exposure and childhood leukemia.
More information about EMF
What are electric and magnetic fields?
Electric and magnetic fields are invisible lines of force around electrical equipment, power cords and wires that carry electricity, including outdoor power lines.
Electric fields
Electric fields are produced by voltage, such as when a hair dryer, coffee maker, fan or light plug is plugged into an electrical outlet. Increasing your distance from the source of the electric field will weaken the strength of the field. Electrical fields are also usually blocked or weakened by things that conduct (transmit) electricity, including trees, buildings and even human skin.
Magnetic fields
Magnetic fields are produced when current travels through wires or other electrical devices. For example, turning on a coffee maker creates a magnetic field. Like electric fields, increasing your distance from the source of the magnetic field weakens the strength of the field. Unlike electrical fields, magnetic fields pass through most materials, including trees, buildings and human skin.
Exposure to electric and magnetic fields from household appliances
Since most appliances are turned on briefly and then turned off, exposure to EMF is usually only for short periods of time. That is why – even though the magnetic field may be stronger around some appliances – most scientific research has looked at magnetic exposure from power lines. Power lines always produce magnetic fields.
Exposure to magnetic fields and cancer risk
Over the past 25 years, there have been more than 100 studies published on the relationship between exposure to electric and magnetic fields (EMF) and cancer risk. Many of the studies have looked specifically at magnetic fields because they are more likely to enter the human body than electric fields. Studies have looked at EMF exposure at work, at home and in the community.
Researchers have not found a consistent relationship between exposure to EMF, at levels normally found at home or in the community, and an increased risk of cancer in adults or children – with the exception of childhood leukemia. However, the risk of childhood leukemia appears to be greater when EMF exposure is higher than levels normally found at home or in the community. Although experts agree that exposure to such high levels is uncommon, they have not been able to rule out a potential relationship from exposure to EMF at such levels.
Due to the lack of consistent scientific evidence, the link between EMF and childhood leukemia is unclear. In 2002, the World Health Organization’s cancer research agency concluded that magnetic fields possibly cause cancer. Experts agree that there may be other explanations for the potential link between exposure to EMF and childhood leukemia.
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Limitations to current research
There are limitations to some of the studies that have been done. For example:
- Researchers have not consistently measured exposure to electric and magnetic fields the same way.
- Scientists have not been able to effectively rule out other reasons for the increase in childhood leukemia. As a result, scientists are not sure if the potential increase in risk is related to exposure to EMF or something else.
All of these factors make it difficult to compare studies or to know if there is a consistent relationship between EMF exposure and cancer risk.
Reducing your exposure to electric and magnetic fields
Because there is no conclusive evidence of any harm caused by exposure to electric and magnetic fields normally found in typical Canadian living environments, Health Canada suggests that taking special precautions is not necessary.
If you are concerned about your exposure to EMF, you can increase the distance between yourself and the source of the electric and magnetic field. Here are some other things to consider:
- The strength of a magnetic field does not depend on how large, complex, powerful or noisy the appliance is (in fact, the magnetic fields near large appliances are often weaker than those near smaller appliances).
- Stand back from an appliance when it is in use. The strength of both electric and magnetic fields from appliances weakens the farther away you are from the source.
- Until scientific evidence can clarify the link between exposure to magnetic fields from high voltage power lines and cancer risk, you may not want your children to play directly beneath them for long periods of time.
- Fix any household wiring problems or update household wiring in an older home.
Suggested links
Canada
Health Canada
United States
National Institute of Environmental Health Sciences
United States National Cancer Institute
International
World Health Organization
Last modified on:
04 November 2009
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