High-Voltage Transmission Lines, Electric Substations, Public Health and Environment 

Scientific Evidence, Regulatory Gaps, and Policy Recommendations for Protecting People, Agriculture and Wildlife 

This report reviews the scientific evidence on the health and environmental effects associated with extremely low-frequency electromagnetic fields (ELF-EMFs) generated by high-voltage transmission lines, substations, and other electrical grid infrastructure. It examines research on cancer, childhood leukemia, neurodegenerative disease, reproductive health, biological mechanisms, occupational exposure, wildlife, agriculture, and ecosystems. 

The report also reviews the evolution of scientific assessments by national and international health agencies, compares U.S. policies with those adopted in other countries, identifies deficiencies in the current U.S. regulatory framework, and presents recommendations for federal, state, and local policymakers to better protect public health and the environment while improving transparency, monitoring, and decision-making for future electric transmission projects.

Report Contents

Executive Summary

The Scientific Basis for Concern: Why the United States Still Lacks Comprehensive Health-Based EMF Standards

• Notable scientific reviews and reports on EMF over the years
• The U.S. EPA’s abandoned effort to develop health-based EMF safety standards

Scientific Research on EMF and Human Health

• The majority of studies link EMF exposure to a broad range of health effects
• Studies linking EMF to childhood leukemia and cancer
• Industry funding has been found to influence study results
• Children are more vulnerable to EMF exposure
• Studies linking EMF to Alzheimer’s disease and other types of dementia
• Studies linking EMF to reproductive impacts
• Studies linking EMF to breast cancer
• Studies on occupational exposure
• Studies reporting a range of biological effects from EMF exposure
• EMF can act systemically with other toxic exposures

Ecological Impacts of Transmission Lines

• EMF has been found to affect animals and their habitat
• Studies on EMF, flora, and fauna
• Studies on high-voltage power lines, EMFs, and bees
• EMFs may increase the effects of pesticides and other stressors on bees
• EMF can affect fish development and reproduction
• EMF and the endocrine system: implications for agriculture, especially dairy cows
• Studies finding stray voltage and electrical disturbances can affect dairy cattle
• Studies finding power line EMFs can affect dogs, deer, and other large mammals
• Biological effects of high-voltage transmission line EMFs on plants

Stray Voltage, Electrical Disturbances, and Infrastructure

• Studies finding stray voltage and electrical disturbances can affect dairy cattle
• Transmission lines can cause AC interference with buried pipelines

Transmission Lines and Biodiversity

• Transmission lines can impact biodiversity through their construction and operation
• High-voltage power lines and birds: EMFs, collisions, and electrocution
• The United States lacks a comprehensive federal framework to protect birds from power lines
• Many countries require bird-safe power line designs—the U.S. does not
• Publications on bird electrocutions and effective mitigation strategies

Other Environmental and Safety Impacts

• High-voltage transmission lines emit corona discharge, audible noise, and ozone
• High-voltage transmission lines and substations pose a fire risk

The United States Lacks a Comprehensive Regulatory Framework to Protect Public Health

• Key deficiencies in the U.S. regulatory framework
• Countries that have implemented measures to protect public health
• U.S. state power-frequency EMF policies and permitting requirements
• Comparison of health-based magnetic field guidelines and regulatory limits
• Local U.S. government policies that are more protective than state requirements

Policy Recommendations

• Federal regulatory reform recommendations
• Policy recommendations for protecting wildlife and ecosystems
• State and local public health and siting policy recommendations
• Questions policymakers and the public can ask when a power line or substation is proposed

Executive Summary

The United States is undergoing its largest expansion of high-voltage electric transmission infrastructure in decades to support growing electricity demand of artificial intelligence and data centers. However there is no comprehensive federal framework to assess or manage health and environmental effects of long-term exposure to the electric and magnetic fields (EMFs) generated by high-voltage power lines. 

This report reviews key scientific evidence related to EMF, current U.S. policies, and international approaches to identify gaps and recommendations for public health protections. Additional issues associated with wildfire risk, bird electrocutions, habitat, pipeline interference, stray voltage, and noise are reviewed. 

Key Findings

• Scientific evidence supports a risk mitigation approach. The majority of research has reported effects from exposure. Studies have found increased risks of childhood leukemia, adult cancers, Alzheimer’s, oxidative stress, endocrine disruption, and other biological effects. The evidence on childhood leukemia was sufficient for the International Agency for Research on Cancer (IARC) to classify extremely low-frequency EMF magnetic fields as a Group 2B Possible Human Carcinogen in 2002 and the link continues to be found in more recent studies. 
• The United States has never completed a federal health-based review of power-frequency EMFs to develop safety standards. Although the U.S. EPA was developing health-based safety recommendations during the 1990s, its EMF health effects program was defunded before the assessment was finalized. Since then, no federal agency has assumed responsibility for developing health-based exposure standards, nor has any agency reviewed the scientific evidence, or established a comprehensive framework to protect the public from long-term EMF exposure.
• Industry guidelines do not address long-term health risks. IEEE and ICNIRP exposure limits were developed primarily to prevent acute effects such as nerve stimulation and electric shock. They were not designed to protect against long-term outcomes including cancer or neurological disease.
• The United States has no comprehensive federal EMF health policy. There are no federal health-based safety standards for exposure to power-frequency EMFs, no national EMF measuring and monitoring program, no federal requirements for industry to report measurements around transmission lines or substations, no setbacks for schools or homes, and no post-construction verification program to ensure predicted EMF exposure levels are accurate.
• Current federal and state regulations lack transparency. In most states, utilities are generally not required to publicly disclose electric and magnetic field levels, prepare publicly accessible EMF maps, nor to conduct ongoing EMF monitoring for their lines.  
• Wildlife impacts extend beyond collisions and habitat loss. Transmission infrastructure can affect wildlife through collisions, electrocution, habitat fragmentation, and also exposure to electric and magnetic fields. Research has reported effects on bird behavior and breeding density, honey bees and other pollinators, fish, amphibians, livestock, and other wildlife. Despite these findings, there is no comprehensive federal framework that evaluates or mitigates EMF-related impacts on wildlife or ecosystem health.
• Pollinators deserve greater consideration. Studies suggest EMF may alter honey bee navigation, behavior, reproduction, and colony health, particularly when combined with other environmental stressors such as pesticides.  
• Many countries have adopted precautionary policies that exceed current U.S. practice. Numerous governments, including the Netherlands, Switzerland, France, Italy, Belgium, Germany, Israel, Denmark, Norway and Finland, and the United Kingdom have implemented policies or measures to reduce public exposure including protecting schools and homes with setbacks, optimizing transmission line design to reduce EMF, conducting EMF calculations before construction and publishing public guidance or EMF maps. 

Policy Recommendations

This review supports modernizing U.S. policy for high voltage transmission lines, substations and other electric grid equipment by addressing EMF impacts to health and environment. Key steps include: 

• Establishing a comprehensive federal regulatory framework that takes a risk mitigation approach. 
• Developing health-based human and wildlife exposure limits that consider long-term exposure and vulnerable populations.
• Requiring EMF modeling and public disclosure at the beginning of project proposals. 
• Conducting post-construction measurements to verify predicted exposures.
• Establishing protective siting policies for schools, homes, childcare centers, hospitals, and parks. 
• Expanding research and national surveillance on EMF exposure, health and environmental outcomes.
• Incorporating wildlife and pollinator protection into transmission planning and environmental review.
• Evaluating international best practices that have successfully reduced public exposure while maintaining reliable electric infrastructure.

As the United States invests billions of dollars in expanding its electric grid, there are opportunities to improve safety and transparency to align infrastructure planning with the best available scientific evidence and international practices.