What the San Francisco 49ers and Data Centers Have in Common: An EMF Transparency Problem (Part 1)
Outside the football and youth soccer playing fields, I found EMF levels higher than the 3-4 mG linked to childhood leukemia. The team's professional EMF report should be released.
When measurements of the EMF from an electric power substation and power lines near a workplace and children’s sports fields are used to dismiss public concerns, but the EMF report remains secret, and no federal EMF health standard exists, what exactly does “safe” mean?
Let’s start with the San Francisco 49ers.
It all started in January 2026, when Peter Cowan’s Substack post questioned whether the 49ers high injury rate could be due to the EMF exposure from the electric substation adjacent to the team’s practice facility. Cowan’s X post got 22 million views. The viral controversy appeared settled last month when the team stated they hired an expert to take professional measurements which concluded levels were “400x lower than the safe zone.” The 49ers general manager, John Lynch, called the “injury conspiracy a ‘big nothing burger.”
However, the consultant’s report and the EMF measurements used to support those safety claims were not publicly released.
How does this relate to data centers?
The 49ers substation EMF transparency issue mirrors a growing national issue as communities are facing an onslaught of new substations and power lines to serve energy-guzzling AI data centers without full public disclosure of the science on increased EMF exposure levels.
Back to the 49ers.
Because the team’s EMF report was never made public, I became curious. I traveled to Levi’s Stadium and measured magnetic field EMF levels outside the team’s practice facility and Santa Clara Youth Soccer fields.
Watch my Youtube video here with measurements.
The levels I recorded are well above EMF levels of 3-4 mG linked to childhood leukemia and other health effects in published scientific research. The measurements exceeded 10 mG near the substation and practice field and were as high as 17 mG near the youth soccer fields. I found 20–45 mG at ground level in some areas.
See below this post for links and references to the full peer-reviewed studies.
Children are playing for hours on youth soccer fields next to this electric substation, workers are spending their careers around it. If the professional measurements truly support claims of safety, then why not release the report. Parents, workers, and the public deserve facts, not secrecy.
Cowan remarked on the 49ers “nothing burger” EMF report:
“The report was quietly announced at a small press conference during a busy sports weekend, with no name, no methodology, and no published data, and the reporters there accepted its conclusions at face value. I followed the few clues that were reported and identified the scientist as almost certainly working for a firm that specializes in defending corporations against liability claims, and which previously produced the discredited science behind the NFL’s Deflategate investigation. What’s striking is that the ‘400 times below unsafe’ — maps directly to the field estimates I published in January. We apparently agree on what the levels are. The only difference is our interpretation of them. So why is the report still not public?”
Who is being protected by withholding the report from the public?
This is not just about football: Data centers are driving up EMF exposure in several communities.
AI data-center-driven substations and high voltage transmission lines are being built near homes, schools, parks, and athletic fields without communities being fully informed of the fact that scientific evidence has reported increased risks. Utilities are also increasing the capacity of existing power lines to carry substantially more electricity and these “upgrades” can also increase EMF exposures along the transmission corridors, which can be far away from the data centers they are running power to.
A Bloomberg report with over 770,000 sensors found degraded power quality, meaning harmonics, another kind of EMF pollution referred to as dirty electricity, up to 50 miles away from data center clusters. More on that here.
I have first-hand witnessed communities misleadingly being told that the EMF levels are safe. But without a federal EMF safety standard in the United States, what does ‘safe’ actually mean?”
There are no federal U.S. health-based human exposure limits for EMF exposure.
In the U.S. the EPA was defunded on developing safety limits for non-ionizing electromagnetic fields decades ago. There is simply no official benchmark for policymakers or the public to use. As a result, consultants often claim EMF exposures are “so low” and thousands of times below “harmful” levels, but those comparisons are based on industry IEEE limits, which have remained largely unchanged for decades and are focused on preventing short-term nerve stimulation effects (from very high levels). ICNIRP limits are also often put forward, which, like the IEEE limits, are not designed to protect against the risk of cancer or disease from long-term exposures.
Industry studies find “no effect” more often.
David Carpenter, MD, who recently retired as 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 significantly affects study findings when it comes to powerline EMF. He concluded there is “strong evidence linking EMF exposure to cancers beyond leukemia, particularly brain and breast cancer.”
Dr. Henry Lai just related his latest analysis showing the majority of peer-reviewed studies published since 1990 on non-ionizing EMF have reported effects.
Oxidative Effects: 90% (n=319) of 353 ELF/static EMF papers oxidative effects (or free radical) published since 1990 reported significant effects.
Genetic Effects: 84% (n=363) of 424 ELF/static EMF genetic effects papers published since 1990 reported significant effects including 92% (n=232) of 252 studies of gene expression.
Neurological Effects: 92% (n=364) of 397 ELF/static EMF neurological papers published since 2007 reported significant effects.
Reproduction and Development Impacts: 78% (n=82) of 105 ELF/static EMF reproduction and development published since 1990 reported significant effects.
If I had a substation or high voltage power line going up in my back yard, the relevant question for me would not be how the EMF measurements compare to industry’s IEEE exposure limit, but how the EMF levels compare to levels associated with health effects in published scientific research.
It is essential that communities are informed of the actual EMF level increases the project will create. The data should be publicly available.
Independent scientists caution that IEEE limits do not ensure safety.
I reached out to several expert scientists regarding EMF levels above 3 mG. Here is what they said.
Joel Moskowitz PHD, Director of the Center for Family and Community Health at the University of California, Berkeley BIO
“IEEE’s current safety limits for power line magnetic fields do not protect us from adverse health effects because they were designed only to protect us from acute exposures which cause nerve or muscle stimulation and not from the chronic, low-level exposures that people experience every day.”
David O. Carpenter, MD, Vincent O’Leary Professor of Environmental Health Sciences, University at Albany BIO
“There is overwhelming evidence that exposure to magnetic fields at intensities greater than 4 mG cause cancer. It is outrageous to allow exposure of children to levels so much higher than levels known to cause cancer.”
Dr. Carpenter previously served as Director of the Institute for Health and the Environment, a World Health Organization Collaborating Center focused on the health impacts of environmental pollutants. Dr. Carpenter has worked on power line EMF research for over 40 years, including leading the New York Power Line Project, testifying before the President’s Cancer Panel, and publishing extensively on the health effects of EMF and other toxic agents.
Paul Héroux, PhD, Professor of Toxicology and Health Effects of Electromagnetism, Department of Epidemiology, Biostatistics and Occupational Health, McGill University
“As my own research has shown, there are significant biological and health effects of power frequency fields at levels well below IEEE limits. When children are regularly exposed on athletic fields next to major electrical infrastructure, the prudent response is to measure, disclose the data, and ensure a safe environment.”
EMF Levels Associated with Cancer and Other Health Effects in Scientific Research
The World Health Organization 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 of 3-4 mG to childhood leukemia. See 2001 Press release here. Since then, additional scientific studies have reported associations between power-line EMF exposure and cancer, as well as other health effects.
How do the Santa Clara EMF measurements compare to science?
1-3 mG: Increased risk of dementia and Alzheimer’s death in Swiss study of over 3.5 M people. LINK
1.6 mG: Kaiser Permanente research reported an increased risk of poor sperm quality, and those exposed for more than six hours per day were three to four times more likely to experience reduced fertility. LINK, KP Press Release
2.5 mG: Kaiser Permanente research found an increased risk for miscarriage. LINK
3-4 mG: The level that several European countries set for homes and schools due to the science on childhood cancer. LINK
4 mG: Increased childhood leukemia cancer risk in scientific reviews. 2022 systematic review, 2021 meta-analysis, 2019 review that also analyzed funding source and found industry-funded studies more often did not report effects.
4 mG: A 2025 study of children in Mexico City found a significantly increased risk of central nervous system tumors. LINK
6 mG: Canadian health agencies found men occupationally exposed to 6 mG or greater had an elevated risk of breast cancer, and those exposed for 30 years or more had nearly a threefold increased risk compared with men exposed to less than 3 mG. LINK
9,200 mG: 9,200 mG: IEEE limit (industry group) based on effects of short-term exposure only. The IEEE states the effects of long-term exposure are “not established” and thus are not considered in the limits. LINK
If you go to the IEEE standard for magnetic fields, you will see they have a disclaimer right at the beginning that “IEEE Standards do not guarantee or ensure safety, security, health, or environmental protection…” and then they say in all caps, “in no event shall IEEE be liable for any direct, indirect, incidental, ….damage arising in any way out of the publication, use of, or reliance upon any standard.”
So who is liable? Who is responsible here?
High voltage power lines are not allowed near schools in California.
California code states regarding schools, “The property line of the site, even if it is a joint use agreement as described in subsection (o) of this section, shall be at least the following distance from the edge of respective power line easements:
100 feet for 50-133 kV line.
150 feet for 220-230 kV line.
350 feet for 500-550 kV line.”
Join Our Petition to the NFL and Santa Clara City Officials For Full Transparency
We respectfully call on the NFL, the San Francisco 49ers, and Santa Clara City officials to publicly release the full report of EMF measurements in the practice facility and playing fields located near the electrical substation adjacent to the 49ers training facility and Youth Soccer fields located at the Levi’s Stadium.
Whats Next?
In Part 2 of this investigation, I’ll take a closer look at a data center powerline case in Loudoun County, Virginia, where homeowners and the School Board are challenging a proposed 500-kV transmission line.
One of the electric utility’s expert witnesses is an Exponent scientist who has testified not only in power-line EMF cases, but also in legal proceedings for asbestos, talc and hexavalent chromium, the carcinogen made famous by Erin Brockovich.) He argues that the projected EMF levels remain below the IEEE and ICNIRP exposure limits. Most people, unaware of the full body of EMF research, the absence of a federal EMF health standard, and the fact that no U.S. health agency, nor the World Health Organization, has comprehensively reviewed magnetic field EMF and health for decades, would likely interpret his testimony as meaning the exposures are safe.
More on that soon.
Science Resources on Health Impacts of Data Centers:
Scientific References From the Graph
Below are just the research studies that were referenced on the graph. Read more here.
Sperm Quality
Exposure to magnetic fields and the risk of poor sperm quality Reproductive Toxicology
Dementia and Alzheimer’s
Long-term residential magnetic field exposure and neurodegenerative disease mortality: An 18-year nationwide cohort study in Switzerland, Environment International
Residence near power lines and mortality from neurodegenerative diseases: longitudinal study of the Swiss population. American Journal of Epidemiology
Occupational exposure to extremely low frequency magnetic fields and risk of Alzheimer disease: A systematic review and meta-analysis. Neurotoxicology.
Long-term exposure to magnetic fields and the risks of Alzheimer’s disease and breast cancer: Further biological research. Pathophysiology
Childhood Leukemia
Exposure to magnetic fields and childhood leukemia: a systematic review and meta-analysis of case-control and cohort studies, Reviews on Environmental Health.
Magnetic fields exposure and childhood leukemia risk: A meta-analysis based on 11,699 cases and 13,194 controls Leukemia Research
Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia. Environmental Research
Acute childhood leukemias and exposure to magnetic fields generated by high voltage overhead power lines - a risk factor in Iran. Asian Pac J Cancer Prev.
Childhood leukemia and magnetic fields in Japan: A case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan International Journal of Cancer
Residential exposure to magnetic fields from high-voltage power lines and risk of childhood leukemia in an Italian population, Population Medicine
Exposure to residential electric and magnetic fields and risk of childhood leukemia, American Journal of Epidemiology
Miscarriage (Prenatal Exposure)
Exposure to Magnetic Field Non-Ionizing Radiation and the Risk of Miscarriage: A Prospective Cohort Study, Scientific Reports
Asthma (Prenatal Exposure)
Maternal Exposure to Magnetic Fields During Pregnancy in Relation to the Risk of Asthma in Offspring. Archives of Pediatrics & Adolescent Medicine
Obesity (Prenatal Exposure)
A Prospective Study of In-utero Exposure to Magnetic Fields and the Risk of Childhood Obesity. Scientific Reports
Brain Tumors
Residential proximity to power lines and risk of brain tumor in the general population. Environmental Research
Power-Frequency Magnetic Fields and Childhood Brain Tumors: A Case-Control Study in Japan, Journal of Epidemiology
Industry Funding Impacts Results
Extremely low frequency electromagnetic fields and cancer: How source of funding affects results Environmental Research
Skin Cancer
Residential extremely low frequency magnetic fields and skin cancer. Occupational and Environmental Medicine
Human‑made electromagnetic fields: Ion forced‑oscillation and voltage‑gated ion channel dysfunction, oxidative stress and DNA damage (Review). International Journal of Oncology
Peter Cowan’s Substack Posts
The Electrical Substation, Deflategate, and an ‘Independent Scientist’
Harvard-Trained Inflammation Researcher Confirms Plausibility of 49ers EMF Injury Hypothesis
Disclaimer: The EMF measurements reported here are provided for informational purposes and transparency. I am not offering an opinion as to whether the measured levels are safe or unsafe, nor am I making a health risk assessment. My purpose is simply to document the magnetic field EMF measurements I recorded and to compare them with levels discussed in published scientific research. The professional EMF report supposedly conducted robust measurements all over the facility. Readers should draw their own conclusions regarding the significance of these measurements and how they want to consider the issue.