During recent years, questions have been raised about the possible health effects of 60-hertz (power frequency) EMF, which are found wherever you have electricity. The following information is provided to help you understand the EMF issue, plus practical tips you can use if you want to reduce your exposure at home and at work.
Can EMF Harm Your Health?
EMF are present wherever electricity flows - around appliances, power lines, in offices, schools, and homes. Many researchers believe that if there is a risk of adverse health effects from EMF, it is probably low but warrants further investigation. Most, but not all, childhood studies have reported a weak association between estimates, but not direct measures, of residential magnetic field exposure and certain types of childhood cancer. Worker studies have shown mixed results. Laboratory experiments have shown that magnetic fields can cause changes in living cells. It is not clear whether these changes suggest any risk to human health.
Given the uncertainty of the issue, the medical and scientific communities have been unable to determine that EMF causes health effects or to establish any standard or level of exposure that is known to be either safe or harmful.
Types of Fields
The Two Types of Fields
|60-hertz Magnetic Fields
|60-hertz Electronic Fields
|Can pass through most objects
|Can be blocked or partially shielded
|Get weaker with distance
|Get weaker with distance
|Are created by the current - or flow of electricity - through a wire, such as when an appliance is turned on
|Are produced by the voltage - or electrical "pressure" - in a wire, such as when an appliance is plugged in (but not turned on)
Typical Magnetic Field Levels
Magnetic Fields in the Home
Measurements are in milligauss (mG)
|At 1.2 inches away
|At 12 inches away
|At 39 inches away
| 750 to 4,000 mG
|40 to 80 mG
| 3 to 8 mG
|8 to 400 mG
|2 to 30 mG
|0.1 to 2 mG
|60 to 2,000 mG
|4 to 40 mG
|0.1 to 1 mG
|400 to 4,000 mG
|5 to 20 mG
|0.1 to 0.3 mG
|60 to 20,000 mG
|1 to 70 mG
|0.1 to 3 mG
|25 to 500 mG
|0.4 to 20 mG
|0.1 to 2 mG
Magnetic Fields Outside
(Maximum range in California utilities will vary)
|1 to 80 mG under the line
|1 to 300 mG edge of right-of-way
Research Is Ongoing
A number of research studies are under way to determine if magnetic fields do pose any health risk and, if so, what aspect of the fields might be harmful. For example, at this time, no one knows whether the length of time in a field, the field strength, going "in and out" of a field, or combinations of these with other factors might be relevant.
Action in CA
What Is Being Done About EMF in California
As a result of a 1993 decision by the California Public Utilities Commission, an EMF research and information program has been established. The purpose of the program is to perform research and policy analysis, and provide education and technical assistance to benefit Californians.
More information on the CPUC and EMF
What You Can Do
Studies of EMF have not shown that people need to change the way they use electric appliances or equipment. However, if you feel reducing your exposure would be beneficial, you can increase your distance from electric appliances and/or limit the amount of time you use appliances at home or at work. Following are some examples of things you can do to reduce your exposure:
- Place telephone answering machines and electric clocks away from the head of your bed
- Increase your distance from appliances such as televisions, computer monitors and microwave ovens
- Limit the time you spend using personal appliances such as hair dryers, electric razors, heating pads and electric blankets
- Limit the time you spend using electric cooking appliances
- Locate sources of EMF in your work environment and spend break time in lower-field areas
It is not known whether such actions will have any impact on your health.
EMF exists wherever there is electricity: in homes, in workplaces, and near power lines. Electric fields exist whenever equipment is plugged in, but magnetic fields exist only when equipment is turned on. Both types of fields get weaker with distance from their source. Until more is known, your best strategy is to stay informed and, if you think it's necessary, to limit your exposure. You may be able to reduce your exposure by identifying EMF sources, changing the way you use electric appliances, and increasing your distance from EMF sources.