Understanding EMF, ELF and Magnetic Fields from Powerlines and Electricity

The Science on Health Effects, Policy, and Expert Recommendations to Reduce Health Risk

Electromagnetic fields (EMFs) are invisible energized waves present wherever electricity flows. They span a broad spectrum—from extremely low-frequency (ELF) fields produced by power lines and household wiring to high-energy radiation such as X-rays. ELF fields and their associated magnetic fields are generated by common electrical sources. This type of exposure is often referred to as ELF-EMF, magnetic fields, or simply EMF.

Health Risks Linked to EMF Exposure:

  • Childhood leukemia
  • Brain and breast cancers
  • Miscarriage  
  • ADHD, asthma, and obesity in prenatally-exposed children
  • Cognitive decline and neurological impacts

Jumplinks:

  • Sources of Exposure
  • Science on Health Risks Linked to EMF Exposure
  • The Science on ELF and Magnetic Fields
  • Exposure at School
  • How to Protect Your Health
  • Policy Issues and Expert Recommendations 
  • Global Policies to Minimize ELF-EMF Exposure in Sensitive Areas
  • Scientific Research Studies 

Sources of Exposure

ELF magnetic fields are emitted by a wide range of everyday sources, both inside and outside the home.

  • Power lines and electrical infrastructure: High-voltage transmission lines, transformers, and electrical substations generate continuous exposure. 
  • Household electrical wiring: Utility meters, wiring in walls, and circuit breakers can produce fields that affect nearby living spaces, particularly when circuits carry heavy loads.
  • Everyday appliances: Many common household devices emit ELF magnetic fields during use, including refrigerators, microwaves, electric ovens, and space heaters.
  • Electronics, particularly when charging: Laptops, cell phones, and tablets can create localized magnetic field exposure near the charging cords and device.

Chronic exposure—such as living, attending school, or working near high voltage power lines, or working in industries with high exposures—is considered the greatest concern by many researchers, because it exposes the body continuously, and exposure accumulates over time.

The Science on ELF and Magnetic Fields

The International Agency for Research on Cancer classified ELF-EMF magnetic fields as a “possible” human carcinogen in 2001, based largely on evidence linking power line exposure to childhood leukemia. In addition, some studies report associations with adult cancers, miscarriage, sleep disruption, and other health effects. Research is ongoing and many countries have protective policies to reduce power line exposures.

Childhood Leukemia:

  • A 2022 systematic review by Brabant et al. in Reviews on Environmental Health found that long-term exposure to magnetic fields above 0.4 µT (4 milligauss) was associated with increased risk of childhood leukemia, particularly acute lymphoblastic leukemia.
  • A 2021 meta-analysis of 33 studies concluded a significant association between powerline ELF exposure and childhood leukemia, with possible dose-response effects.

“This study presents the epidemiological evidence of childhood cancer risk on exposure to ELF-MFs, which implies that we can confirm the risk of childhood leukemia among pediatric cancers followed exposure to ELF-MFs, which is associated with a higher risk than what was previously known.”

-Seomun, Lee and Park in PLOS One ‘Exposure to extremely low-frequency magnetic fields and childhood cancer: A systematic review and meta-analysis”

Industry funding can significantly impact study results, as power companies have substantial financial interests

David Carpenter, MD, Director of the Institute for Health and the Environment at the University at Albany, published a review of the research showing that the source of funding affects study findings.

“The evidence that magnetic fields increase the risk of cancer is neither inconsistent nor inconclusive. Furthermore, adults are also at risk, not just children, and there is strong evidence for cancers in addition to leukemia, particularly brain and breast cancer.”

-David Carpenter in Environmental Research “Extremely low frequency electromagnetic fields and cancer: How source of funding affects results”

Brain Tumors and Other Cancers:

  • A 2020 study in Environmental Research linked residential proximity to power lines with an increased risk of brain tumors.
  • A 2022 study published in Occupational and Environmental Medicine linked childhood ELF-EMF exposure to adult melanoma.  
  • Animal studies such as those conducted by the Ramazzini Institute, found that long-term ELF-EMF exposure combined with other carcinogens increased tumor incidence in rats.

Pregnancy and Developmental Effects:

Cognitive Effects:

“The results of this study indicate that working in an occupation with high or M/H MF exposure may increase the risk of severe cognitive dysfunction. Smoking and older age may increase the deleterious effect of MF exposure.”

-Davanipour et al in Journal of Advances in Medicine and Medical Research “Severe Cognitive Dysfunction and Occupational Extremely Low Frequency Magnetic Field Exposure among Elderly Mexican Americans”

Household Appliances Create EMF Exposures

Studies on induction cookers, computers, and microwaves show mixed effects. Some case-control studies suggest higher risks for congenital heart defects with early pregnancy exposure, while others, like the 2021 Kyushu Okinawa study, found reduced risk of preterm birth with induction heat cooker use.

Exposure at School

While many countries have safeguards in place for schools, the United States has no special federal protections to reduce exposures on school grounds. In California, new schools must maintain minimum distances from transmission line right-of-ways, as nearby power lines can increase ELF‑EMF exposure. 

Even if a school is not near a powerline, the EMF exposure can be significant. A 2020 study found that exposure in classrooms was mainly from electrical appliances, wiring, and electrical equipment, and the scientists concluded that, “it is important to design safe and appropriate environments for digital learning in schools, such as proper seating arrangements, to avoid ELF-MFs exposure to students as much as possible.” 

The Importance of Knowing Your Exposure

Measuring ELF-EMF levels is especially important for homes near power lines, substations, or heavy electrical equipment. A simple magnetic field meter can help identify high-exposure areas in your home so you can move beds, cribs, or workspaces farther from wiring, unplug unused devices, and use battery-powered electronics when possible. Testing is particularly valuable for households with children or pregnant women, as even modest reductions in exposure may help lower health risks.

How to Protect Your Health

Extremely low frequency electromagnetic fields (ELF-EMF) from household electronics and electrical appliances weaken quickly as you move away from the source. At about one foot, the field strength is typically much lower, and by two to three feet, it drops sharply. Experts are most concerned about long-term or nightly exposure while sleeping.

Easy First Steps:

  • Charge devices away from where you sleep. Keep phones, tablets, and laptops off the nightstand. Charge them during the day and in another room.
  • Unplug after charging. EMFs are strongest when devices are plugged in and charging. Use battery power whenever possible.
  • Keep the bedroom clear. Reduce electronic clutter — no routers, TVs, or charging stations near the bed. Swap out corded alarm clocks and radios for battery-powered models.
  • Avoid sleeping against walls with wiring or large appliances. Keep beds and cribs away from walls with electrical panels, meters, or major appliances on the other side.

Reducing Long-Term and Nightly Exposure

  • Unplug unused devices. Use power strips with switches to easily turn off multiple items when not in use.
  • Skip plugged-in heating products. Unplug electric blankets, heating pads, and water beds before sleeping — turning them off isn’t enough to stop EMFs.
  • Install a master “kill switch.” A kill switch can safely turn off power to bedroom circuits at night, reducing wiring-related EMFs without daily breaker use.

Check your home’s magnetic fields. Use a simple magnetic field meter to spot high-EMF areas. Unusually high readings may indicate wiring or grounding issues a licensed electrician can fix.

What If I Live Near a Power Line

Homes close to high-voltage power lines or substations can experience elevated ELF magnetic field levels indoors. The strength of these fields depends on how much electricity the lines carry, their height, their distance from your home, and local wiring conditions.  

If you live near a high voltage power line:

  • Measure field levels indoors and outdoors. A simple magnetic field meter can show whether EMF levels in your home are higher than typical background readings.
  • Rearrange living spaces. Place beds, play areas, and home offices in rooms farther from the side of the home facing the power line, if possible.

If measurements show persistently high levels, contact your local utility or an EMF specialist for further testing and mitigation advice. Most utility companies will come out for free to measure levels. Even small adjustments—such as relocating sleeping or sitting areas—can meaningfully reduce long-term exposure.

Policy Issues and Expert Recommendations 

Policy experts continue to urge reduced exposure to EMF due to the science on leukemia and biological effects.

In 2019, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) published its Report on the Health Effects of Exposure to Low-Frequency Electromagnetic Fields, reaffirming scientific evidence linking childhood leukemia to exposure and calling for minimizing exposure in sensitive areas such as schools, hospitals, and for pregnant women. ANSES updated its 2010 recommendations, emphasizing that new schools and hospitals should avoid proximity to power lines, occupational exposure should be better controlled (especially for pregnant women), manufacturers should measure and disclose ELF-EMF emissions, and regulations should extend beyond transmission lines to cover all significant sources of exposure.

Failed U.S. Policy

The U.S. once had a strong EPA research program, but it was defunded. Thus, the U.S. does not have a federal limit for exposure to ELF or magnetic fields.  A major 2002 California report stated that EMFs may increase risks of childhood leukemia, brain cancer, ALS, and miscarriage. There have been out-of-court settlements for EMF exposure, such as one in Massachusetts where high magnetic fields in a child’s bedroom were linked to leukemia. However, the U.S. has no ongoing activities to ensure public health protection. 

Global Policies to Minimize ELF-EMF Exposure in Sensitive Areas

  • The Netherlands: Since 2005, policies reduce ELF-EMF near homes, schools, and kindergartens. In 2013, houses under 380–220 kV lines were bought out because of the ELF exposure. A 2018 Health Council report reaffirmed links to cancer and recommended reducing ELF-EMF.
  • Germany: A 2013 Ordinance requires all feasible measures to minimize ELF-EMF exposure. 220 kV lines cannot be erected over buildings intended for long-term human occupancy.
  • France: Ministerial guidance discourages new hospitals, maternity wards, and childcare facilities near power lines, cables, and transformers where fields exceed 1 µT. The grid operator must monitor EMF emissions near power lines, and citizens can request measurements via local authorities.
  • Slovenia: ELF limits are set at 10% of the EU reference value for new or modified installations near residences, schools, kindergartens, hospitals, playgrounds, parks, and public buildings.
  • Denmark: Utilities must measure magnetic fields at new installations; annual averages should not exceed 4 mG, and no kindergartens or new buildings may be built near high-voltage lines.
  • Croatia: Reduced ELF-EMF limits apply to sensitive areas, including homes, offices, schools, playgrounds, kindergartens, maternity wards, hospitals, and care facilities.
  • Luxembourg: Ministerial recommendation prohibits new living spaces within 20 meters of 65 kV lines and 30 meters of 100–220 kV lines.
  • Finland: The radiation authority STUK advises avoiding permanent residences where magnetic flux density continuously exceeds ~0.4 µT.
  • Norway: A 0.4 µT “investigation level” applies to new homes, schools, kindergartens, and power lines; if exceeded, exposure-reduction measures are evaluated and implemented if reasonable.
  • Italy: The 2017 Environment Ministry Decree recommends minimizing indoor ELF-EMF exposure; a precautionary “attention value” applies to 24-hour median exposure in homes, schools, playgrounds, and other spaces where people spend over 4 hours.
  • Belgium: In Flanders, new power lines should be avoided near schools and childcare centers, and exposure over homes should be minimized. Year-averaged exposure near new schools and childcare centers should not exceed 4 mG. In Brussels, transformers near areas where children under 15 may be present must maintain a 24-hour average below 4 mG.