The San Francisco 49ers have consistently been one of the most injured teams in the NFL.
In a league where franchises are worth billions of dollars and players invest millions into training, recovery, and medical care, it is jarring how often San Francisco finds itself broken down.
Every season begins with championship expectations and ends with an injury report that looks like a roster obituary.
Bad luck explains a year.
It does not explain a decade.
Since Levi’s Stadium opened in 2014, the 49ers have quietly become the most injured organization in professional football.
Different rosters.
Different coordinators.
Different medical staffs.
The same outcome.
On January 5, Peter Cowan published an article titled “Could Chronic EMF Exposure from a Nearby Substation Be Causing the 49ers’ Epidemic of Tendon Ruptures?” The idea sounded absurd at first.
Electricity hurting elite athletes felt closer to conspiracy than science.
But the details refused to disappear.
The question spread fast.
Other reporters covering the team added their opinions.
Former players began speaking publicly.
The theory reached press conferences, where both the general manager and head coach were forced to respond.
What emerged was not a smoking gun, but something more uncomfortable.
The realization that this had been discussed quietly for years.
In early 2025, retired 49ers guard Jon Feliciano let slip a long-running locker room theory.
“Players have joked around about there being an electrical substation that’s right next to the practice field and how that has led to the Niners’ injury problems,” said Feliciano.
Jokes, however, tend to be rooted in reality.
The injury data supports the concern.
Since Levi’s Stadium opened in 2014:
- The 49ers have lost more games to injury than any team in the NFL. This is calculated by Sports Info Solutions who counts how many games are missed by players due to injury, and then estimates how many points the team has lost based on the player who was out. For example, future Hall of Fame Left Tackle Trent Williams would have more of an impact on this than rookie running back Jordan James, who Kyle Shanahan refuses to play.
- They have suffered seven to eight Achilles or patellar tendon ruptures per year. The league average is two to three total per year.
- More than 40 hamstring and calf strains have sidelined players.
Since Kyle Shanahan became head coach in 2017:
- The 49ers have ranked top ten in injury rate every season except one.
- More than 2,000 total games have been lost to injury, the most in the NFL over that span.
No other franchise lives in this range for this long.
Measuring the exposure adds another layer.
Peter Cowan continued his research, reporting “At 11:00 a.m. on a quiet Monday (far from peak load), it read 8.5+ milligauss (to put that in perspective, the average background level in a typical American home or office is usually between 0.5 and 3.0 mG). One hundred yards closer, in the facilities where players lift, watch film, and recover, the fields could be several times higher: potentially 13–21 mG on a normal day, spiking even higher during peak grid demand—like evening practices or hot/cold weather when more electricity flows through the substation.”
Closer to the facilities where players lift, watch film, and recover, estimates suggest levels could reach 13 to 21 milligauss on a normal day. During peak demand, evening practices, or extreme weather, those numbers could spike higher.
This is chronic exposure to extremely low-frequency electromagnetic fields in a biologically active range. Players cannot avoid it. It is built into their workday.
And it is the only environmental variable unique to the 49ers.
The official explanation has always been the same.
If anyone inside the organization ever asked PG&E, the county, or an engineering firm about the substation, the response would have been uniform.
“Perfectly safe. Federal and international guidelines only recognize harm from non-ionizing radiation when it causes measurable heating.”
Under Federal Communications Commission (FCC), International Commission on Non-Ionizing Radiation Protection (ICNIRP), and Institute of Electrical and Electronics Engineers (IEEE) standards, there is no recognized danger unless tissue temperature rises. The fields measured near the facility fall well below those thermal thresholds.
That answer is technically correct. It is also deeply limited.
Those guidelines rely on a thermal-only model written decades ago and ignore non-thermal biological effects entirely. Research examining mitochondrial disruption, cellular dehydration, and collagen fragility is excluded because it does not involve heat.
The rulebook says heat or nothing. So the substation is never flagged.
What those guidelines ignore is how low-level electromagnetic fields interact with biology over time.
In a follow-up investigation, Cowan outlined the non-thermal mechanisms that could plausibly connect a humming electrical substation to chronic soft-tissue failure. The theory does not rely on heat, radiation burns, or acute exposure. It focuses instead on cellular energy production and collagen integrity.
Collagen, the primary structural protein in tendons and ligaments, is not inert. It is electrically sensitive. Research dating back to the 1970s showed that collagen exhibits piezoelectric properties, meaning mechanical stress creates electrical signals that guide repair. Cowan argued that chronic external fields can interfere with those signals, disrupting collagen synthesis and maintenance.
At the cellular level, the proposed damage begins inside the mitochondria. These organelles generate energy through the electron transport chain, a process that also produces structured metabolic water essential for keeping collagen hydrated and elastic. According to Cowan, low-frequency magnetic fields in the 8 to 50 milligauss range can interfere with electron transfer timing, increasing oxidative stress while reducing ATP and metabolic water production. Over time, collagen fibers lose hydration, stiffen, and become brittle.
Cowan summarized the outcome simply: tendons that should behave like steel cables begin to resemble old rope.
A second pathway compounds the issue. Biophysicist Martin Pall’s research suggests that low-level electromagnetic fields can activate voltage-gated calcium channels on cell membranes. Excess calcium floods cells, triggering oxidative damage and suppressing collagen production in fibroblasts. A landmark study published in Science showed that 60 Hz fields, the same frequency emitted by electrical substations, can reduce collagen synthesis by up to 30 percent.
None of this guarantees causation. But it does establish biological plausibility. It explains how athletes could train, recover, and eat at elite levels while their connective tissue quietly degrades underneath them. It also explains why injuries would cluster in tendons and soft tissue rather than bones or joints.
The substation does not have to be the sole cause. It only has to be a constant stressor layered on top of an already violent sport.
Football explanations fall short.
Early Levi’s Stadium turf was uneven and slippery, contributing to injuries in its first seasons. That problem was addressed by 2017 with hybrid grass. Teams playing on far worse surfaces do not experience the same volume of tendon ruptures.
Kyle Shanahan’s outside-zone offense demands violent cuts and sustained blocking effort. But the Rams under Sean McVay and Dolphins under Mike McDaniel run nearly identical schemes without the same injury outcomes.
Training, turf, and scheme cannot fully explain this.
Ownership knew about the substation.
Documents from Santa Clara Plays Fair reveal that the original Levi’s Stadium proposal included $20 million to relocate the Tasman electrical substation.
“All that is necessary is for the City of Santa Clara to submit the bill for the Tasman substation move, in the amount of $20,000,000, directly to Dr. John York, owner of the San Francisco 49ers.”
The substation was not a surprise. It was discussed. It was priced.
If the substation matters, the fallout is massive.
Former Tight End Delanie Walker confirmed concerns during his tenure.
“That’s been an issue since I’ve been there.”
Walker described feeling physical effects, witnessing explosions, and hearing fears about cancer and ligament damage.
“You can even feel it sometimes. I don’t know what it is. You can feel the energy,” said Walker.
If chronic exposure contributed to injury or long-term health consequences, generations of players could have legal standing. The financial loss would be staggering. The reputational damage would be permanent.
No other teams practice next to an electrical substation in the National Football League. This year, Super Bowl 60 takes place in Santa Clara in the 49ers stadium, and neither of the competing teams are choosing to practice there. This may be due to preference to other fields or stadiums, or it’s possible that the players, coaches, and owners are afraid of the substation and want to take no risks in the biggest game of the season.
Whether the substation is the cause or not, the fact that it was never fully addressed is the true failure.
Because when the same franchise leads the league in injuries year after year, the problem is no longer luck.
It is environment.
It is leadership.
And eventually, it demands change.