Electric & Magnetic Fields | National Institute of Environmental Health Sciences
Source: https://www.niehs.nih.gov/health/topics/agents/emf
Archived: 2026-04-23 17:32
Electric & Magnetic Fields | National Institute of Environmental Health Sciences
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Electric & Magnetic Fields
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Electric and magnetic fields (EMFs) are invisible areas of energy, often called radiation, that are associated with the use of electrical power and various forms of natural and man-made lighting. Learn the difference between ionizing and non-ionizing radiation, the electromagnetic spectrum, and how EMFs may affect your health.
Table of Contents
What is NIEHS Doing?
Further Reading
Introduction
Electric and magnetic fields (EMFs) are invisible areas of energy, often referred to as
Radiation
, that are associated with the use of electrical power and various forms of natural and man-made lighting. EMFs are typically grouped into one of two categories by their frequency:
Non-ionizing
: low-level radiation which is generally perceived as harmless to humans
Ionizing
: high-level radiation which has the potential for cellular and DNA damage
← Back to Page
Radiation Type
Definition
Forms of Radiation
Source Examples
Non-Ionizing
Low to mid-frequency radiation which is generally perceived as harmless due to its lack of potency.
Extremely Low Frequency (ELF)
Radio Frequency (RF)
Microwaves
Visual Light
Microwave ovens
Computers
House energy smart meters
Wireless (wifi) networks
Cell Phones
Bluetooth devices
Power lines
MRIs
Ionizing
Mid to high-frequency radiation which can, under certain circumstances, lead to cellular and or DNA damage with prolonged exposure.
Ultraviolet (UV)
X-Rays
Gamma
Sunlight
X-Rays
Some
Gamma Rays
Can EMFs be harmful to my health?
During the 1990s, most EMF research focused on extremely low frequency exposures stemming from conventional power sources, such as power lines, electrical substations, or home appliances. While some of these studies showed a possible link between EMF field strength and an increased risk for childhood
Leukemia
, their findings indicated that such an association was weak. The few studies that have been conducted on adults show no evidence of a link between EMF exposure and adult cancers, such as leukemia, brain cancer, and breast cancer.
Now, in the age of cellular telephones, wireless routers, and the Internet of things, all of which use EMF, additional research is needed on practical ways to reduce exposures to EMFs.
Does my cell phone emit EMF radiation?
Cell phones emit a form of radio frequency radiation at the lower end of the non-ionizing radiation spectrum. Currently, scientific evidence has not conclusively linked cell phone use with any adverse human health problems.
The National Toxicology Program (NTP), headquartered at NIEHS, conducted toxicology studies in rats and mice to help clarify potential health hazards, including cancer risk, from exposure to radio frequency radiation like that used in 2G and 3G cell phones. Please visit the
Cell Phone Radio Frequency Radiation webpage
to learn more.
What if I live near a power line?
EMF: Electric and Magnetic Fields Associated with the Use of Electric Power Booklet
NIEHS educational booklet, "EMF: Electric and Magnetic Fields Associated with the Use of Electric Power"
It is important to remember that the strength of a magnetic field decreases dramatically with increasing distance from the source. This means that the strength of the field reaching a house or structure will be significantly weaker than it was at its point of origin.
For example, a magnetic field measuring 57.5 milligauss immediately beside a 230 kilovolt transmission line measures just 7.1 milligauss at a distance of 100 feet, and 1.8 milligauss at a distance of 200 feet, according to the World Health Organization in 2010.
For more information, see the NIEHS educational booklet, “
EMF: Electric and Magnetic Fields Associated with the Use of Electric Power
”.
What is NIEHS Doing?
NIEHS Research Efforts
NIEHS Report on Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields: Prepared in Response to the 1992 Energy Policy Act (PL 102-486, Section 2118)
(751KB)
- Prepared in Response to the 1992 Energy Policy Act (PL 102-486, Section 2118)
Further Reading
Additional Resources
Electromagnetic Fields and Cancer
- National Cancer Institute
IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans
- The WHO/International Agency for Research on Cancer (IARC) has classified radio frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer1, associated with wireless phone use.
Radiofrequency Background
- U.S. Food and Drug Administration
RadTown
- Learn about radiation in your town: where it is and how it's used. Explore the Burbs, Countryside, Downtown or Waterfront. Just pick and click! From the U.S. Environmental Protection Agency
Workplace Safety and Health Topics: EMF (ELECTRIC AND MAGNETIC FIELDS)
- The National Institute for Occupational Safety and Health (NIOSH)
Related Health Topics
Cell Phone Radio Frequency Radiation
Back
to Top
Last Reviewed: March 06, 2026
Skip Navigation
Electric & Magnetic Fields
Close the left navigation
Add
Electric and magnetic fields (EMFs) are invisible areas of energy, often called radiation, that are associated with the use of electrical power and various forms of natural and man-made lighting. Learn the difference between ionizing and non-ionizing radiation, the electromagnetic spectrum, and how EMFs may affect your health.
Table of Contents
What is NIEHS Doing?
Further Reading
Introduction
Electric and magnetic fields (EMFs) are invisible areas of energy, often referred to as
Radiation
, that are associated with the use of electrical power and various forms of natural and man-made lighting. EMFs are typically grouped into one of two categories by their frequency:
Non-ionizing
: low-level radiation which is generally perceived as harmless to humans
Ionizing
: high-level radiation which has the potential for cellular and DNA damage
← Back to Page
Radiation Type
Definition
Forms of Radiation
Source Examples
Non-Ionizing
Low to mid-frequency radiation which is generally perceived as harmless due to its lack of potency.
Extremely Low Frequency (ELF)
Radio Frequency (RF)
Microwaves
Visual Light
Microwave ovens
Computers
House energy smart meters
Wireless (wifi) networks
Cell Phones
Bluetooth devices
Power lines
MRIs
Ionizing
Mid to high-frequency radiation which can, under certain circumstances, lead to cellular and or DNA damage with prolonged exposure.
Ultraviolet (UV)
X-Rays
Gamma
Sunlight
X-Rays
Some
Gamma Rays
Can EMFs be harmful to my health?
During the 1990s, most EMF research focused on extremely low frequency exposures stemming from conventional power sources, such as power lines, electrical substations, or home appliances. While some of these studies showed a possible link between EMF field strength and an increased risk for childhood
Leukemia
, their findings indicated that such an association was weak. The few studies that have been conducted on adults show no evidence of a link between EMF exposure and adult cancers, such as leukemia, brain cancer, and breast cancer.
Now, in the age of cellular telephones, wireless routers, and the Internet of things, all of which use EMF, additional research is needed on practical ways to reduce exposures to EMFs.
Does my cell phone emit EMF radiation?
Cell phones emit a form of radio frequency radiation at the lower end of the non-ionizing radiation spectrum. Currently, scientific evidence has not conclusively linked cell phone use with any adverse human health problems.
The National Toxicology Program (NTP), headquartered at NIEHS, conducted toxicology studies in rats and mice to help clarify potential health hazards, including cancer risk, from exposure to radio frequency radiation like that used in 2G and 3G cell phones. Please visit the
Cell Phone Radio Frequency Radiation webpage
to learn more.
What if I live near a power line?
EMF: Electric and Magnetic Fields Associated with the Use of Electric Power Booklet
NIEHS educational booklet, "EMF: Electric and Magnetic Fields Associated with the Use of Electric Power"
It is important to remember that the strength of a magnetic field decreases dramatically with increasing distance from the source. This means that the strength of the field reaching a house or structure will be significantly weaker than it was at its point of origin.
For example, a magnetic field measuring 57.5 milligauss immediately beside a 230 kilovolt transmission line measures just 7.1 milligauss at a distance of 100 feet, and 1.8 milligauss at a distance of 200 feet, according to the World Health Organization in 2010.
For more information, see the NIEHS educational booklet, “
EMF: Electric and Magnetic Fields Associated with the Use of Electric Power
”.
What is NIEHS Doing?
NIEHS Research Efforts
NIEHS Report on Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields: Prepared in Response to the 1992 Energy Policy Act (PL 102-486, Section 2118)
(751KB)
- Prepared in Response to the 1992 Energy Policy Act (PL 102-486, Section 2118)
Further Reading
Additional Resources
Electromagnetic Fields and Cancer
- National Cancer Institute
IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans
- The WHO/International Agency for Research on Cancer (IARC) has classified radio frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer1, associated with wireless phone use.
Radiofrequency Background
- U.S. Food and Drug Administration
RadTown
- Learn about radiation in your town: where it is and how it's used. Explore the Burbs, Countryside, Downtown or Waterfront. Just pick and click! From the U.S. Environmental Protection Agency
Workplace Safety and Health Topics: EMF (ELECTRIC AND MAGNETIC FIELDS)
- The National Institute for Occupational Safety and Health (NIOSH)
Related Health Topics
Cell Phone Radio Frequency Radiation
Back
to Top
Last Reviewed: March 06, 2026