Magnetic Field Levels Around Your Home

Over the years the issue of electric and magnetic fields (EMF) near power lines and, in many cases, around common home and work appliances, has caused concern on the part of consumers. LIPA is pleased to provide this information as a public service and without further opinion. We encourage customers who are concerned to seek additional information about the issue.

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What is EMF?
The transmission, distribution and use of electric power result in weak electric and magnetic fields (EMF - the term “EMF” as used here refers to electric and magnetic fields at a frequency of 60 cycles per second or Hertz). EMF is an invisible force field that occurs naturally (e.g., lightning, the Earth’s magnetic field) and also is a byproduct of technology. EMF surrounds any electrical device including power lines, house wiring and appliances. At electric power frequency (60 Hertz in the U.S. and 50 Hertz abroad), EMF levels fall off very rapidly with distance from the source and have very low energy. Radio, television and cellular and microwave communication are electromagnetic in nature as are visible light, x-rays and cosmic rays. All these forms of electromagnetic energy are part of the ‘electromagnetic spectrum’ that describes the frequency and energy of both visible and invisible fields. Cellular communications, for example, operate at frequencies almost a billion times higher than EMF resulting from electric power, which means they are much more powerful and can transmit signals over long distances. The frequency of visible light is a trillion times higher than power frequency EMF while X-rays and cosmic rays are millions of times higher still. These forms of electromagnetic energy are ubiquitous in our modern day environment.

While electric and magnetic fields associated with power line frequencies are part of the electromagnetic spectrum, they are classified as being in the Extremely Low Frequency (ELF) range and have vastly different and distinguishable characteristics than other electromagnetic energy. At 60 cycles per seconds, these fields have very little energy and decrease rapidly with distance. Electric and magnetic fields at power line frequency can be measured and predicted as independent entities. back to top

Are there health effects associated with EMF from power lines?
Many studies have been conducted about health effects from EMF. These studies have focused primarily on magnetic rather than electric fields. Early epidemiological studies (statistical analyses of exposed human populations) did not actually measure magnetic field exposures but rather relied on proximity to power lines as an assumption of exposure. Some of these studies appear to show a weak association between exposure to power-frequency magnetic fields and the incidence of certain cancers particularly childhood leukemia. This statistical association, however, is not strong enough to say whether it reflects any real effect or not. Laboratory studies have shown little evidence of a link between power-frequency fields and cancer. Still other studies have shown that life-time exposure of animals to power-frequency magnetic fields does not cause cancer. Overall, many scientists consider that the evidence that power line fields cause or contribute to cancer is weak to nonexistent. However, acute effects, such as induced currents in the body, are known to occur at very high magnetic field levels, well above levels associated with power-line and home exposures.

Since 1977, over 130 reviews of EMF science have been conducted by scientific panels, public health organizations, or governmental bodies. Based on the weight of evidence from statistical and laboratory studies, the following conclusions have been published by recognized scientific organizations.

  • In 1999 the U.S. National Institute of Health concluded that: "The scientific evidence suggesting that [power-frequency electromagnetic field] exposures pose any health risk is weak."
     
  • In 2001, the International Agency for Research on Cancer (IARC), an agency of the World Health Organization classified power-frequency magnetic fields as “possibly carcinogenic” on the basis of “limited” evidence from humans concerning childhood leukemia. Others of the over 250 agents in this category include coffee, Aflotoxin (found in peanut butter), caffeic acid (naturally occurring in fruits, vegetables, seasonings and beverages), pickled vegetables, gasoline, gasoline engine exhaust and fuel oils.
     
  • A 2001 review by the International Commission on Non-Ionizing Radiation Protection concluded that: "In the absence of evidence from cellular or animal studies, and given the methodological uncertainties and in many cases inconsistencies of the existing epidemiological literature, there is no chronic disease for which an etiological [causal] relation to [power-frequency fields] can be regarded as established".
     
  • In 2004, a U.K. National Radiation Protection Board (NRPB) review stated: “… the epidemiological evidence that …exposure to power frequency magnetic fields above 0.4 µT (ed. Note = 4 mG) is associated with a small absolute raised risk of leukemia in children is, at present, an observation for which there is no sound scientific explanation. There is no clear evidence of a carcinogenic effect of ELF EMFs in adults and no plausible biological explanation of the association that can be obtained from experiments with animals or from cellular and molecular studies....Thus any judgments developed on the assumption that the association is causal would be subject to a very high level of uncertainty.” Also from the review: “NRPB concludes that the results of epidemiological studies, taken individually or as collectively reviewed by expert groups, cannot currently be used as a basis for restrictions on exposure to EMFs.”
     
  • In March 2007, the Scientific Committee on Emerging and Newly Identified Health Risks of the European Union stated: “The previous conclusion that ELF fields are possibly carcinogenic, chiefly based on childhood leukemia results, is still valid.” (See IARC above.) And “There is no known mechanism to explain how electromagnetic field exposure may induce leukemia. The effects have not been replicated in animal studies.”
     
  • In June 2007, the World Health Organization (WHO) issued an Environmental Health Criteria for EMF. The WHO established an International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF. The Criteria concludes there is no new evidence to change the IARC classification, the ICNIRP guidelines (see below) are adequate to protect people from known acute effects of magnetic fields, no proposed biophysical mechanism whereby magnetic fields could cause cancer seem plausible, evidence not strong enough for childhood leukemia to be considered causal, and it recommended against lowering numerical limits in exposure guidelines to some arbitrary level (i.e. less than the ICNIRP limit) in the name of precaution. In its recommendations to member states and other policy makers, the Criteria states that precaution should be applied to EMF based on the “limited evidence” for a link between magnetic fields and childhood leukemia. It also states that based on the weakness of the evidence and the limited impact on public health if there is a link, the benefits of exposure reduction on health are unclear. Thus the costs of precautionary measures should be very low and should not compromise the benefits of a public electricity supply. Other recommendations include implementing an effective and open communication strategy to enable informed decision-making, implementation of very low-cost measures when constructing new facilities and designing new equipment including appliances, enforcing wiring regulations to reduce fields in the home, improving planning of ELF EMF-emitting facilities, and including better consultation between industry, local government, and citizens when siting major ELF EMF-emitting sources. back to top

Is there a link between EMF exposure and breast cancer?
A link between EMF exposure and alterations in the hormone melatonin was motivation to conduct research addressing a possible link between EMF exposure and breast cancer. While a number of smaller studies showed no association between EMF and breast cancer, the results of two large multiyear epidemiological studies were announced in 2003. The first, a study of over 1,100 women on Long Island was conducted by researchers at SUNY Stony Brook as part of the Long Island Breast Cancer Study Project, was the largest and most thorough to-date. The study found no association between breast cancer and residential EMF exposures. The second study, led by the U.S. National Institute of Environmental Health, involved over 1,400 women in Los Angeles and Hawaii. The study was careful to use a multiethnic population to control bias and also resulted in what the authors termed “a pertinent negative finding.” The results of this study were in concurrence with previous studies and in the words of the authors “provide some reasonable reassurance to the public regarding this ubiquitous low-level exposure.” The 2007 World Health Organization Environmental Health Criteria for EMF states that evidence is sufficient to say that breast cancer is not caused by magnetic fields. back to top

Are there any health-based standards for EMF level at power line frequencies?
All mainstream regulatory bodies have consistently recommended setting limits on acute effects and not on the epidemiological evidence. The International Commission on Non-Ionizing Radiation Protection, an organization of 15,000 scientists from 40 nations that specialize in radiation protection, has published a guideline value for magnetic field level exposure to the general public based on known acute effects. This value for 60 cycles per second power frequency is 833 milligauss. The ICNIRP guideline has been supported in the U.K. and is recognized by the World Health Organization, whose website states “The main conclusion from the WHO reviews is that EMF exposures below the limits recommended in the ICNIRP international guidelines do not appear to have any known consequence on health.”

In New York State, the Public Service Commission limits the magnetic field levels of transmission lines to 200 milligauss measured at the edge of the right-of-way. This is an engineering-based exposure standard intended to make the field levels from new power lines similar to the field levels from existing lines. back to top

What are typical EMF levels encountered in the home?
In a 1993 study, measurements of EMF were collected at nearly a thousand homes throughout the U.S. The reported levels were the average of all measurements collected in all rooms of the home, away from any electric appliance, and reflected levels from house wiring. An average magnetic field measurement of 0.6 milligauss was reported in half the homes studied. A quarter of the homes had average levels of 1.1 milligauss and 15% had levels of 2.1 milligauss. A smaller percentage had levels between 2.9 and 6.6 milligauss.

Electric appliances and electronic equipment give off EMF that can be measured. The table below indicates measured fields typically associated with common household items. Please note that appliances and electronics such as microwave ovens, TV and computer monitors also have electromagnetic energy associated with them at different frequencies (for example, microwaves produce fields in the 2.5 billion cycle per second frequency inside the oven to heat food (these are shielded by the oven) while TV and computer monitors have fields in the 10,000 – 30,000 cycles per second range associated with the monitor).

Magnetic Fields from Household Appliances
Appliance Distance of 12 Inches Distance of 24 Inches
Hair Dryer Bg – 70 Bg – 10
Window A/C Bg – 20 Bg – 6
Color TV Bg - 20 Bg - 8
Dishwasher 6 – 30 2 – 7
Refrigerator Bg – 20 Bg -10
Can Opener 40 – 300 3 – 30
Microwave Oven 1 – 200 1 - 30
Washing Machine 1 – 30 Bg - 6
Power Drill 20 - 40 3 – 6
Computer Monitor 2 – 6 1 - 3

Measurements in milligauss; Source EMFRAPID Program June 2002
Bg = Measurement indistinguishable from background levels

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Can EMF levels be measured in the home?
LIPA offers a free EMF demonstration of EMF levels in the home. To schedule an appointment, please call 631-844-3711. back to top

What are typical EMF levels from power lines and substations?
Magnetic fields levels associated with transmission and distribution power lines vary greatly depending on the voltage of the line, the amount of current in the line, the way the lines are spaced and distance from the line (since EMF is a byproduct of the use of electric power it is very localized and falls off rapidly with distance). Typically, magnetic field levels will decrease to background levels within a few to 200 feet of the line.

Generally, EMF around the outside of a substation results from the electric lines entering and exiting the facility. The strength of the EMF from the equipment within the substation, such as transformers, capacitors and circuit breakers, decreases rapidly with increasing distance. Beyond the substation fence, the EMF from the substation equipment is typically slightly higher to indistinguishable from background levels. back to top

Are there other sources of EMF information available on the Web?

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Last Updated: 10/02/2009