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What are Electromagnetic Fields - EMFs?

This article and others in this series discuss common sources of exposure to electromagnetic fields and methods to reduce exposure, as well as mentioning some exposure standards.

We explain which electrical fields may be hazardous and which are not and we explain how to insepect & measure for and where possible remedy EMF hazards.

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- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

EMF EXPOSURE - What do we know about workplace exposures to Electromagnetic Fields - EMFs?

EMFs are invisible lines of force created whenever electricity is generated or used. EMFs are producedby power lines, electric wiring, and electric equipment and appliances. Thefrequency of EMFs is measured in hertz (Hz, or cycles per second).

People are exposed to both electric and magnetic fields, but scientists are most concerned about magnetic fields. This fact sheet deals only with magnetic fields that have frequencies near 60 Hz the frequency of electric power in North America.

Static magnetic field around a bar magnet.

Article Contents:

While this NIOSH document is focused on the workplace it is of interest to home owners as well. Everyone in our modern society is exposed to the electric and magnetic fields (EMFs) that surround all electric devices.

Recently, scientific studies have raised questions about the possible health effects of EMFs. This fact sheet answers frequently asked questions about EMFs in the workplace.

You can use this information to help identify EMF sources at work and to take simple steps for reducing exposures. However, you cannot use this information to judge the safety of your exposures, since the scientific evidence does not yet show whether EMF exposures are hazardous. [This is a NIOSH document. ]

Also see EMF RF FIELD & FREQUENCY DEFINITIONS for a simple explanation of different types of radio frequency (RF) and electromagnetic frequency (EMF) types and where they are found.

Workers may be exposed to high magnetic fields if they work near electrical systems that use large amounts of electric power (for example, large electric motors, generators, or the power supply or electric cables of a building).

High magnetic fields are also found near power saws, drills, copy machines, electric pencil sharpeners, and other small electric appliances.

The strength of the magnetic field depends on equipment design and current flow not on equipment size, complexity, or voltage. Though some electric equipment produces EMFs of other frequencies, most health research has considered only frequencies near 60 Hz.

[Click to enlarge any image]

These electric heaters for metal parts expose workers to magnetic fields that are 10,000 times greater than the average magnetic fields found outside the workplace.

ICNIRP Secretariat Issues Updated EMF Exposure Guidelines - March 2020

23 March 2020

New Radiofrequency EMF Guidelines Released by the ICNIRP

ICNIRP Secretariat

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has released new guidelines for the protection of humans exposed to radiofrequency electromagnetic fields (RF EMFs). These cover exposures from a range of technologies, including existing 3G/4G and the upcoming 5G mobile telecommunications technologies, as well as DAB radio, WiFi, Bluetooth, radar, and wireless power transfer devices.

This is the first revision of the guidelines since 1998. Since then there has been an extensive scientific research effort to identify and better quantify potential adverse health effects resulting from exposure to radiofrequency EMFs. This has enabled a thorough update of the guidelines, with the result a protection system that can deal effectively with both contemporary and future technologies.

There are important changes to both the structure and restrictions of the new ICNIRP (2020) guidelines. Regarding structure, greater transparency should make the logic and scientific basis of the guidelines easier for the health protection community to engage with, additional means of assessing compliance with the guidelines have been provided, and there is now greater specification of how to assess complicated exposure scenarios.

Under the topic of restrictions, a number of additions and changes were made to ensure that the guidelines are not only protective for current radiofrequency EMF exposure scenarios but will continue to be protective for future technological developments.

These include the addition of a restriction for exposure to the whole body for EMFs >6 GHz, to restrict body core temperature rise; the addition of a restriction for brief (less than six-minute) exposures to small regions of the body for EMFs >400 MHz, to restrict localised temperature rise; and the reduction of the maximum exposure permitted over a small region of the body for EMFs >6 GHz, again to restrict localised temperature rise.

The full guidelines are published in Health Physics ("Guidelines for Limiting Exposure to Electromagnetic Fields [100 kHz to 300 GHz]") and can be accessed at ICNIRP.org at

https://journals.lww.com/health-physics/Abstract/publishahead/Guidelines_for_Limiting_Exposure_to.99797.aspx

Additional detail concerning the differences between the ICNIRP (2020) and ICNIRP (1998) guidelines is available on the ICNIRP website.

- source: Health Physics Society, Health Physics Society 950 Herndon Parkway, Suite 450 Herndon, VA 20170 Phone: 703-790-1745 Email: hps@BurkInc.com Website: Health Physics Society 950 Herndon Parkway, Suite 450 Herndon, VA 20170 Phone: 703-790-1745 Email: hps@BurkInc.com Website: http://hps.org/ - HPS Specialists in Radiation Protection, Current News, retrieved 2020-04-03 original source: http://hps.org/newsandevents/societynews.html#1614

TYPICAL EMF EXPOSURES - What are some typical Electromagnetic Fields - EMF exposures on the job?

The EMF exposures for many jobs have not been measured, but the following table shows average exposures to magnetic fields for typical workers who use electric equipment. Exposures during a work shift vary with the strength of the magnetic field, the worker s distance from the EMF source, and the time the worker spends in the field. For comparison, the table also lists worker exposures off the job.

Average magnetic field exposures for various types of workers (in milligauss*

                                    Average daily exposures
        Type of worker                 Median**     Range
Workers on the job:
    Clerical workers without
       computers                       0.5      0.2 - 2.0
    Clerical workers with
       computers                       1.2       0.5 - 4.5
    Machinists                         1.9       0.6 - 27.6
    Electric line workers              2.5       0.5 - 34.8
    Electricians                      5.4       0.8 - 34.0
    Welders                            8.2       1.7 - 96.0
 
 Workers off the job
    (home, travel, etc.)               0.9       0.3 - 3.7
*Magnetic fields are often measured in gauss or milligauss (one thousandth of a gauss = 1 milligauss).
**The median is the middle measurement: half the workers have average daily exposures above this point and half below.

EMF and CANCER? - Do Electromagnetic Fields - EMFs cause cancer or other health effects?

Studies have shown that some workers exposed to high magnetic fields have increased cancer rates. But such associations do not necessarily show that EMF exposures cause cancer (any more than the springtime association of robins and daffodils shows that one causes the other). Scientists have looked carefully at all the EMF evidence, but they disagree about the health effects of EMFs except to say that better information is needed.

EMF EFFECTS - What DO studies show about the health effects of Electromagnetic Fields - EMFs in workers?

Many studies report small increases in the rate of leukemia or brain cancer in groups of people living or working in high magnetic fields. Other studies have found no such increases.

The most important data come from six recent studies of workers wearing EMF monitors to measure magnetic fields. All but one study found significantly higher cancer rates for men with average workday exposures above 4 milligauss.

However, the results of these studies disagree in important ways such as the type of cancer associated with EMF exposures. So scientists cannot be sure whether the increased risks are caused by EMFs or by other factors.

A few preliminary studies have also associated workplace EMFs with breast cancer, and one study has reported a possible link between occupational EMF exposure and Alzheimer s disease.

The data from all of these studies are too limited for scientists to draw conclusions. However, a national research effort is under way, and more study results are expected in a few years.

No increased leukemia has been reported overall in studies of welders, yet they are among the occupations with the highest EMF exposures.

EMF EXPOSURE LIMITS - Have limits been set for worker exposures to Electromagnetic Fields - EMFs ?

Because of the scientific uncertainty, no Federal limits for worker exposures to EMFs have been recommended or established in the United States.

Two private organizations have developed guidelines to protect workers from the known effects of extremely high exposures (that is, those more than 1,000 times the exposures typically found in occupational environments). However, these guidelines do not address the possible health effects of the low EMF exposures usually found on the job.

Current EMF Electromagnetic Field Exposure Limit Recommendations

Should workers and employers try to reduce exposures to Electromagnetic Fields - EMFs?

The National Institute for Occupational Safety and Health (NIOSH) and other government agencies do not consider EMFs a proven health hazard.

Because some studies have associated high magnetic field exposures with increased cancer risks, the government will continue studying EMFs.

While research continues, concerned workers and employers might consider the following simple, inexpensive measures for reducing EMF exposures:

EMF exposures depend on the worker's distance from the source.

What is NIOSH doing about Electromagnetic Fields - EMF exposures?

NIOSH has been evaluating the possible health effects of EMFs since 1991. NIOSH scientists have measured the fields in workplaces where employees are concerned about their EMF exposures; they are also studying the biological effects of EMFs. In addition, NIOSH scientists work cooperatively with researchers in universities and other Federal agencies to share their study results.

These cooperative efforts have increased recently under the National EMF Research and Public Information Dissemination (RAPID) program.

How to obtain printed copies of the NIOSH Electromagnetic Fields Fact Sheet.

"NIOSH Fact Sheet: EMFs in the Workplace," DHHS (NIOSH) Publication No. 96-129, is available from:

NIOSH Publications Dissemination, [CDC Website http://www.cdc.gov/niosh/pubs.html ] 4676 Columbia Parkway Cincinnati, Ohio 45226-1998 USA Tel: 1-800-35-NIOSH (1-800-356-4674) Fax: (513) 533-8573


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